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Mechanical behaviour of standardized, endoskeleton-including hip spacers implanted into composite femurs
Thielen, T.; Maas, S.; Zuerbes, A.; Waldmann, D.; Anagnostakos, K.; Kelm, J.
Two-stage reconstruction using an antibiotic loaded cement spacer is the preferred treatment method of late hip joint infections. Hip spacers maintain stability of the joint and length of the limb during treatment period. However, as the material strength of bone cement (PMMA) is limited, spacer fractures led to serious complications in the past. This study investigated the load capacity of custom made hip spacers, developed at the 'Klinik für Orthopädie und Orthopädische Chirurgie' (Universitätsklinikum des Saarlandes, Homburg / Saar, Germany), and implanted into composite femurs. In a quasi-static test, non-reinforced spacers tolerated hip joint loads of about 3000 N, whereas reinforced spacers with titanium-grade-two endoskeletons doubled this load up to 6000 N. Even for cyclic loading, endoskeleton-including hip spacers tolerated loads of >4500 N with 500,000 load cycles. Thus, an endoskeleton-including spacer should provide a mobile and functional joint through the treatment course. A generated FE-model was used to determine the fracture stresses and allows for further sensitivity analysis. PMID:19834594
Preventing mechanical complications of hip spacer implantation: technical tips and pearls.
Barreira, Pedro; Leite, Pedro; Neves, Pedro; Soares, Daniel; Sousa, Ricardo
Periprosthetic joint infection is a frequent complication after total hip replacement. Two-stage exchange with the use of a temporary cement spacer is commonplace. Several complications are possible with its use. In addition to infection persistence, mechanical complications such as dislocation or fractures are among the most common. Several risk factors can and should be addressed during first stage or spacer implantation surgery in order to minimize complications. Technical aspects as well as practical tips and pearls to overcome common nuisances such as spacer instability or femoral and acetabular bone loss will be discussed. PMID:26280978
Mechanical evaluation of unipolar hip spacer constructs.
Kummer, Frederick J; Strauss, Eric; Wright, Kevin; Kubiak, Erik N; Di Cesare, Paul E
The strengths of 3 hip spacer constructs--Steinmann pins, a short intramedullary nail (both cement-incorporated), and a Charnley prosthesis--were determined and compared with the strength of a commercially available hip spacer. The hip prosthesis construct was more than twice as strong as the other 2 constructs and was equivalent in strength to the commercial spacer. For spacer applications in which limited weight-bearing is anticipated, the hip prosthesis construct appears more efficacious, but its pros and cons should be compared with those of the commercial product. PMID:19081880
Titanium-copper-nitride coated spacers for two-stage revision of infected total hip endoprostheses
Ellenrieder, Martin; Haenle, Maximilian; Lenz, Robert; Bader, Rainer; Mittelmeier, Wolfram
Within the first two years after total hip arthroplasty implant-associated infection has become the second most common reason for a revision surgery. Two-stage implant exchange is frequently conducted using temporary spacers made of antibiotic-loaded cement in order to prevent a bacterial colonization on the spacer. Avoiding several disadvantages of cement spacers, a conventional hemi-endoprosthesis was equipped with a copper-containing implant coating for inhibition of bacterial biofilms. In the present paper details of this novel treatment concept are presented including a case report. PMID:22242097
Cadossi, Matteo; Tedesco, Giuseppe; Sambri, Andrea; Mazzotti, Antonio; Giannini, Sandro
EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Describe the advantages of hip resurfacing. 2. Describe the disadvantages of hip resurfacing. 3. Identify the population in which hip resurfacing is most often indicated. 4. Demonstrate how to properly postoperatively manage patients with metal-on-metal prostheses. Hip resurfacing offers a suitable solution for young patients affected by hip disease who have high function demands and good bone quality. Bone stock preservation, restoration of the normal proximal femur anatomy, the lack of stress shielding, and the possibility of resuming sporting activity are proven advantages of hip resurfacing. However, there are some disadvantages, such as fracture of the femoral neck, onset of neck narrowing, and possible complications due to the metal-on-metal bearings, including pseudotumors, peri-implant osteolysis, and chronic elevation of metal ions in serum levels. Recent data suggest that the ideal candidate for hip resurfacing is an active male, younger than 65 years, with primary or posttraumatic osteoarthritis, and with a femoral head diameter larger than 50 to 54 mm. Based on these selection criteria, the literature reports implant survival to be similar to that of total hip arthroplasty. The current authors' experience confirms a low failure rate and excellent functional outcomes, with metal ion serum levels becoming stable over time in well-functioning implants. Proper surgical technique, correct patient selection, and the right choice of a well-established prosthetic model are essential elements for the long-term success of these implants. PMID:26270748
... hip replacement surgery, the damaged portions of the hip joint are removed. The ball (femoral head) is removed ... hip or leg Swelling at or near the hip joint A limp or change in walking ability Noise ( ...
Burnishing Techniques Strengthen Hip Implants
NASA Technical Reports Server (NTRS)
In the late 1990s, Lambda Research Inc., of Cincinnati, Ohio, received Small Business Innovation Research (SBIR) awards from Glenn Research Center to demonstrate low plasticity burnishing (LPB) on metal engine components. By producing a thermally stable deep layer of compressive residual stress, LPB significantly strengthened turbine alloys. After Lambda patented the process, the Federal Aviation Administration accepted LPB for repair and alteration of commercial aircraft components, the U.S. Department of Energy found LPB suitable for treating nuclear waste containers at Yucca Mountain. Data from the U.S. Food and Drug Administration confirmed LPB to completely eliminate the occurrence of fretting fatigue failures in modular hip implants.
Implant Design in Cementless Hip Arthroplasty
Kim, Jung Taek
When performing cementless hip arthroplasty, it is critical to achieve firm primary mechanical stability followed by biological fixation. In order to achieve this, it is essential to fully understand characteristics of implant design. In this review, the authors review fixation principles for a variety of implants used for cementless hip replacement and considerations for making an optimal selection. PMID:27536647
A Hip Implant Energy Harvester
NASA Astrophysics Data System (ADS)
Pancharoen, K.; Zhu, D.; Beeby, S. P.
This paper presents a kinetic energy harvester designed to be embedded in a hip implant which aims to operate at a low frequency associated with body motion of patients. The prototype is designed based on the constrained volume available in a hip prosthesis and the challenge is to harvest energy from low frequency movements (< 1 Hz) which is an average frequency during free walking of a patient. The concept of magnetic-force-driven energy harvesting is applied to this prototype considering the hip movements during routine activities of patients. The magnetic field within the harvester was simulated using COMSOL. The simulated resonant frequency was around 30 Hz and the voltage induced in a coil was predicted to be 47.8 mV. A prototype of the energy harvester was fabricated and tested. A maximum open circuit voltage of 39.43 mV was obtained and the resonant frequency of 28 Hz was observed. Moreover, the power output of 0.96 μW was achieved with an optimum resistive load of 250Ω.
Sliding screw implants for extracapsular hip fractures.
Mavrogenis, Andreas F; Kouvidis, George; Stavropoulos, Nikolaos A; Stavrakakis, Loannis; Katonis, Pavlos; Papagelopoulos, Panayiotis J
Hip fractures are associated with significant mortality and morbidity for the patients, more dependent residual status, and increased socio-economic cost. Many hip-fracture patients experience severe functional impairment, and most never recover their pre-fracture level of function. Current research has sought to identify the most effective treatments to reduce the incidence of hip fractures, improve survival and quality of life, and minimize complications and disability. The treatment of these fractures in the elderly aims to return these people to their pre-fracture mobility and functional level. This article reviews the surgical treatment options for extracapsular hip fractures and discusses their associated advantages, disadvantages, and complications. Two types of implants are currently available: the dynamic hip screw (DHS), and the intramedullary hip nail with one or two sliding screws. In this review, no clear advantage of one implant over another for the treatment of extracapsular hip fractures was evident. Both the DHS and hip nails can be used successfully for the treatment of stable hip fractures; for unstable fractures and low subtrochanteric fractures, hip nails are preferred. Although hip nails are associated with limited exposure, lower blood loss and transfusion requirements, and shorter operative time, complications are more common with hip nails. Long-term survival and function are similar in the two approaches. Hip nails with two sliding screws do not seem to make the difference in clinical practice that is reported in biomechanical studies. PMID:23016784
Release of gentamicin and vancomycin from preformed spacers in infected total hip arthroplasties: measurement of concentrations and inhibitory activity in patients' drainage fluids and serum.
Regis, Dario; Sandri, Andrea; Samaila, Elena; Benini, Anna; Bondi, Manuel; Magnan, Bruno
Gentamicin (G) and vancomycin (V) concentrations in drainage fluids obtained from patients during the first 24 hours after implantation of antibiotic-loaded polymethylmethacrylate (PMMA) spacers in two-stage revision of infected total hip arthroplasty were studied. The inhibitory activity of drainage fluids against different multiresistant clinical isolates was investigated as well. Seven hips were treated by implantation of industrial G-loaded spacers. Vancomycin was added by manually mixing with PMMA bone cement. Serum and drainage fluid samples were collected 1, 4, and 24 hours after spacer implantation. Antibiotics concentrations and drains bactericidal titer of combination were determined against multiresistant staphylococcal strains. The release of G and V from PMMA cement at the site of infection was prompt and effective. Serum levels were below the limit of detection. The local release kinetics of G and V from PMMA cement was similar, exerting a pronounced, combined inhibitory effect in the implant site. The inhibitory activity of drainage fluids showed substantial intersubject variability related to antibiotic concentrations and differed according to the pathogens tested. Gentamicin and vancomycin were released from temporary hip spacers at bactericidal concentrations, and their use in combination exerted strong inhibition against methicillin-resistant S. aureus and Coagulase Negative Staphylococci strains. PMID:24174916
Standardized Loads Acting in Hip Implants.
Bergmann, Georg; Bender, Alwina; Dymke, Jörn; Duda, Georg; Damm, Philipp
With the increasing success of hip joint replacements, the average age of patients has decreased, patients have become more active and their expectations of the implant durability have risen. Thus, pre-clinical endurance tests on hip implants require defining realistic in vivo loads from younger and more active patients. These loads require simplifications to be applicable for simulator tests and numerical analyses. Here, the contact forces in the joint were measured with instrumented hip implants in ten subjects during nine of the most physically demanding and frequent activities of daily living. Typical levels and directions of average and high joint loads were extracted from the intra- and inter-individually widely varying individual data. These data can also be used to analyse bone remodelling at the implant-bone interface, evaluate tissue straining in finite element studies or validate analytical loading predictions, among other uses. The current ISO standards for endurance tests of implant stems and necks are based on historic analytical data from the 1970s. Comparisons of these test forces with in vivo loads unveiled that their unidirectional orientations deviate from the time-dependent in vivo directions during walking and most other activities. The ISO force for testing the stem is substantially too low while the ISO force for the neck better matches typical in vivo magnitudes. Because the magnitudes and orientations of peak forces substantially vary among the activities, load scenarios that reflect a collection of time-dependent high forces should be applied rather than using unidirectional forces. Based on data from ten patients, proposals for the most demanding activities, the time courses of the contact forces and the required cycle numbers for testing are given here. Friction moments in the joint were measured in addition to the contact forces. The moment data were also standardized and can be applied to wear tests of the implant. It was shown that
Standardized Loads Acting in Hip Implants
Bergmann, Georg; Bender, Alwina; Dymke, Jörn; Duda, Georg; Damm, Philipp
With the increasing success of hip joint replacements, the average age of patients has decreased, patients have become more active and their expectations of the implant durability have risen. Thus, pre-clinical endurance tests on hip implants require defining realistic in vivo loads from younger and more active patients. These loads require simplifications to be applicable for simulator tests and numerical analyses. Here, the contact forces in the joint were measured with instrumented hip implants in ten subjects during nine of the most physically demanding and frequent activities of daily living. Typical levels and directions of average and high joint loads were extracted from the intra- and inter-individually widely varying individual data. These data can also be used to analyse bone remodelling at the implant-bone interface, evaluate tissue straining in finite element studies or validate analytical loading predictions, among other uses. The current ISO standards for endurance tests of implant stems and necks are based on historic analytical data from the 1970s. Comparisons of these test forces with in vivo loads unveiled that their unidirectional orientations deviate from the time-dependent in vivo directions during walking and most other activities. The ISO force for testing the stem is substantially too low while the ISO force for the neck better matches typical in vivo magnitudes. Because the magnitudes and orientations of peak forces substantially vary among the activities, load scenarios that reflect a collection of time-dependent high forces should be applied rather than using unidirectional forces. Based on data from ten patients, proposals for the most demanding activities, the time courses of the contact forces and the required cycle numbers for testing are given here. Friction moments in the joint were measured in addition to the contact forces. The moment data were also standardized and can be applied to wear tests of the implant. It was shown that
Hip Implant Modified To Increase Probability Of Retention
NASA Technical Reports Server (NTRS)
Canabal, Francisco, III
Modification in design of hip implant proposed to increase likelihood of retention of implant in femur after hip-repair surgery. Decreases likelihood of patient distress and expense associated with repetition of surgery after failed implant procedure. Intended to provide more favorable flow of cement used to bind implant in proximal extreme end of femur, reducing structural flaws causing early failure of implant/femur joint.
Hip and knee arthroplasty implants contraindicated in obesity.
Craik, J D; Bircher, M D; Rickman, M
Introduction High patient weight is a risk factor for mechanical implant failure and some manufacturers list obesity as a contraindication for implant use. We reviewed data from the 2012-2013 UK National Joint Registry to determine whether surgical practice reflects these manufacturer recommendations. Methods The product literature for the most commonly used hip and knee implants was reviewed for recommendations against use in obese patients (body mass index [BMI] ≥ 30kg/m(2)). The total number of obese patients undergoing hip and knee arthroplasty was calculated, as was the proportion receiving implants against manufacturer recommendations. Results Out of 200,054 patient records, 147,691 (74%) had a recorded BMI. The mean BMI for patients undergoing primary total hip arthroplasty was 29kg/m(2), compared with 31kg/m(2) for total knee arthroplasty. Of the 25 components reviewed, 5 listed obesity as a contraindication or recommended against implant use in obese patients. A total of 10,745 patients (16% of all obese patients) received implants against manufacturer recommendations. Conclusions A high proportion of patients are receiving implants against manufacturer recommendations. However, there are limitations to using BMI for stratifying risk of implant fatigue failure and manufacturers should therefore provide more detailed guidelines on size specific implant load limits to facilitate surgical decisions. PMID:27023636
Metallographic evaluation of hip joint implants wear and electrochemical implants potential.
Kmieć, Krzysztof; Sibinski, Marcin; Synder, Marek; Drobniewski, Marek; Kozłowski, Piotr
We performed metallographic evaluations of implants, removed during revision hip arthroplasty. The implants were evaluated for electrochemical potentials and the presence of wear products on the implants surface. A total of 50 patients (50 hips) underwent revision hip arthroplasty during the years 2007-2009 for aseptic loosening. The mean follow-up from primary hip replacement to revision was 10.1 years (from six months to 17 years). All hip joint implants removed during the revision arthroplasty were submitted to metallographic analysis and all heads were submitted to analysis under a scanning microscope. All polyethylene (PE) cups and inserts showed numerous features of wear (friction wear, plastic deformation and creeping, fatigue wear and degradation), six PE cups were broken. In six ceramic cups, only friction wear features were found; one of them was mechanically broken. In all heads articulating on PE not one had any mechanical damage. Heads of ceramic implants in ceramic-ceramic articulation undergo abrasive wear. None of the studied stems (cemented or uncemented) revealed any features of wear. Areas of titanium crystals (formed by electrolytic sedimentation of metals) were macroscopically identified on the sliding surface of six heads that was confirmed by chemical composition and scanning microscope.In the course of prosthesis use, wear products are produced and transferred onto the sliding surfaces of implant heads and cups via ways other than purely mechanical contact. It has been confirmed that metals used for implant construction, make galvanic cells with different electrochemical potentials. PMID:25362874
Optimal design of composite hip implants using NASA technology
NASA Technical Reports Server (NTRS)
Blake, T. A.; Saravanos, D. A.; Davy, D. T.; Waters, S. A.; Hopkins, D. A.
Using an adaptation of NASA software, we have investigated the use of numerical optimization techniques for the shape and material optimization of fiber composite hip implants. The original NASA inhouse codes, were originally developed for the optimization of aerospace structures. The adapted code, which was called OPORIM, couples numerical optimization algorithms with finite element analysis and composite laminate theory to perform design optimization using both shape and material design variables. The external and internal geometry of the implant and the surrounding bone is described with quintic spline curves. This geometric representation is then used to create an equivalent 2-D finite element model of the structure. Using laminate theory and the 3-D geometric information, equivalent stiffnesses are generated for each element of the 2-D finite element model, so that the 3-D stiffness of the structure can be approximated. The geometric information to construct the model of the femur was obtained from a CT scan. A variety of test cases were examined, incorporating several implant constructions and design variable sets. Typically the code was able to produce optimized shape and/or material parameters which substantially reduced stress concentrations in the bone adjacent of the implant. The results indicate that this technology can provide meaningful insight into the design of fiber composite hip implants.
Successful hip arthroplasty using cementless titanium implants in rheumatoid arthritis.
Effenberger, Harald; Ramsauer, Thomas; Böhm, Gerhard; Hilzensauer, Gerhard; Dorn, Ulrich; Lintner, Felix
Over a period of eight years, we implanted a total of 76 cementless hip prostheses in patients with rheumatoid arthritis. The clinical results of 47 patients (70 hips) increased from a mean Harris Hip Score of 33 to 85 after an average of 49 months (range 1-11 years). One threaded cup has had to be revised because of loosening, and one stem because of femoral fracture. At the latest follow-up, 88% of Hofer-Imhof threaded cups had complete bone ingrowth (Type 0); 10% had near-complete bone ingrowth with minimal radiolucency in one third of the bone contact area (Type 1), and 2% had radiolucency in two thirds of the bone contact area (Type 2). Hemispherical push-in cups showed significantly more radiolucency around the cup. For the stems (Uni, Zweymüller SL), 83% showed no radiolucency (Type 0); 17% had radiolucency only very proximally (Type 1). Minor remodelling (Type 1) occurred in 60% of the femoral shafts; 30% had moderate femoral density loss (Type 2), and 10% had severe bone loss and cortical thinning (Type 3). There was no correlation between marked shaft atrophy and clinical symptoms. With regard to radiolucency and remodelling, there was no significant difference between the two types of stem used. Cementless hip arthroplasty using titanium implants has an excellent outcome in the medium term. PMID:11880907
Management of periprosthetic joint infection after total hip arthroplasty using a custom made articulating spacer (CUMARS); the Exeter experience.
Tsung, Jason D; Rohrsheim, James A L; Whitehouse, Sarah L; Wilson, Matthew J; Howell, Jonathan R
Periprosthetic joint infection (PJI) after THA is a major complication with an incidence of 1%-3%. We report our experiences with a technique using a custom-made articulating spacer (CUMARS) at the first of two-stage treatment for PJI. This technique uses widely available all-polyethylene acetabular components and the Exeter Universal stem, fixed using antibiotic loaded acrylic cement. Seventy-six hips were treated for PJI using this technique. Performed as the first of a two-stage procedure, good functional results were commonly seen, leading to postponing second stage indefinitely with retention of the CUMARS prosthesis in 34 patients. The CUMARS technique presents an alternative to conventional spacers, using readily available components that are well tolerated, allowing weight bearing and mobility, and achieving comparable eradication rates. PMID:24851790
Saving Implants BMP-2 Application in Revision Total Hip Surgery
Jäger, M.; Emami, R.; Thorey, F.; Krauspe, R.
Objective: Besides others, there are two major problems in total hip replacement surgery which result in implant failure. First there is aseptic loosening due to a lack of implant biocompatibility or micromovements and second periimplant wear debris induced osteolysis which limits the survival rate of an implant. Regarding to recent data there are only limited therapeutic strategies to heal these bony defects without arthroplasty revision surgery. Since the investigation and characterization of adult mesenchymal stem cells (MSCs) from bone marrow, a cell and tissue engineering based therapy might be a promising solution to heal endoprosthesis associated bony defects. Moreover the application of growth factors in bone reconstructive surgery is another treatment concept to promote local bone regeneration. Patient and Methods: We report about a 73-year old patient with a painful weight bearing and a large, wear debris induced pelvic osteolysis after total hip arthroplasty. To prevent from salvage surgical procedures and preserve bone, a healing attempted was performed by filling the critical bony defect zone with a BMP-2/MSC composit. Results: Clinical and radiological follow-ups showed a progressive bony healing of the critical size defect area without any complications. Fifteen months after application the patient is still pain free, has no limitations in daily life or sport activities. Conclusion: The case embarks on a strategy of non-embryonic stem cell and growth factor application to heal bony defects at patients with total hip endoprosthesis. PMID:23674982
Iodine-Supported Hip Implants: Short Term Clinical Results
Kabata, Tamon; Maeda, Toru; Kajino, Yoshitomo; Hasegawa, Kazuhiro; Inoue, Daisuke; Yamamoto, Takashi; Takagi, Tomoharu; Ohmori, Takaaki; Tsuchiya, Hiroyuki
We developed a new povidone iodine coating technology for titanium hip implants and performed a clinical trial to assess its usefulness in suppressing postoperative infection. Results indicate that iodine-supported titanium has favorable antibacterial activity, biocompatibility, and no cytotoxicity. Thirty joints in 28 patients were treated using iodine-supported implants. Fourteen joints were revision total hip arthroplasty (THA) after periprosthetic infection, 13 were primary THA for immunosuppressive conditions or pyogenic arthritis, and 3 were conversions from hemiarthroplasty to THA for immunosuppressive conditions. Two examinations were conducted sequentially until final follow-up: white blood cell (WBC) and C-reactive protein (CRP) were measured pre- and postoperatively and thyroid hormone levels in the blood were examined. The mean follow-up period was 33 months (14–78). There were no signs of infection in any patient at the last follow-up. WBC and CRP levels returned to normal within several weeks. No abnormalities of thyroid gland function were detected. Loosening of the implants did not occur in any patient. Excellent bone ingrowth and ongrowth were found around prostheses. No cytotoxicity or adverse effects were detected. These results suggest that iodine-supported THA implants can be highly effective in preventing and treating postoperative infections. PMID:26583103
Sensitivity to implant materials in patients undergoing total hip replacement.
Granchi, Donatella; Cenni, Elisabetta; Trisolino, Giovanni; Giunti, Armando; Baldini, Nicola
Sensitivity to implant materials is an unpredictable event, which may contribute to the process leading to the failure of the total hip replacement (THR). The aim of the current study was to investigate the informative power of skin testing in detecting the sensitization to the implant components in patients undergoing THR. A consecutive series of 223 patients was enrolled in the study, including 66 candidates to THR, 53 with stable implant, and 104 with THR loosening. The patch testing was performed by using the most relevant components of cobalt-based alloys (CoCrMo), Ti-based alloys (TiAlV), and bone cements. The frequency of positive patch testing in preimplant patients did not differ from that observed after THR. Patients with CoCrMo-failed implant showed a significant low frequency of nickel-positive skin reaction, while patients with TiAlV-THR had a high incidence of vanadium-positive patch testing. The panel of haptens showed a good performance in the identification of patients known to have a contact dermatitis. With regard to the THR outcome, patch testing was not able to discriminate between stable and failed implant. Sensitivity to at least one hapten, namely bone cement, as well as the positive medical history of hypersensitivity, influenced negatively the THR survival. Our results show the reliability of patch testing for investigating the sensitivity to implant components. The cause-effect relationship between sensitization and negative outcome cannot be established, but the shorter lifespan of THR in patients who have a positive patch testing supports the significant role of this event in contributing to the implant failure. PMID:16265661
Antibiotic Spacer Arthroplasty for Revision MTP Arthrodesis: A Novel Means to Build the Implant: A Case Report
Bitterman, Adam; Patel, Milap; Gurtowski, James P
Metatarsophalangeal (MTP) joint osteoarthritis (OA), also known as hallux rigidus (HR), is the most common degenerative arthropathy of the foot and is often the result of trauma. There are multiple methods of addressing the patient's pain and limited function. Arthrodesis is the gold standard to manage severe MTP arthritis with a highly significant union rate. With various techniques of arthrodesis available, ranging from cannulated screw fixation, Kirschner wires, as well as plate and screw fixation, the orthopedic surgeon has multiple modalities to address this ailment; however, when these fail due to infection, the armament is limited. Through the idea of articulating antibiotic spacers in other regions of the body such as the knee and hip, we present a novel technique to the creation of an antibiotic spacer in the setting of a failed infected MTP arthrodesis. PMID:27114892
Antibiotic Spacer Arthroplasty for Revision MTP Arthrodesis: A Novel Means to Build the Implant: A Case Report.
Bitterman, Adam; Mathew, Cristin; Patel, Milap; Gurtowski, James P
Metatarsophalangeal (MTP) joint osteoarthritis (OA), also known as hallux rigidus (HR), is the most common degenerative arthropathy of the foot and is often the result of trauma. There are multiple methods of addressing the patient's pain and limited function. Arthrodesis is the gold standard to manage severe MTP arthritis with a highly significant union rate. With various techniques of arthrodesis available, ranging from cannulated screw fixation, Kirschner wires, as well as plate and screw fixation, the orthopedic surgeon has multiple modalities to address this ailment; however, when these fail due to infection, the armament is limited. Through the idea of articulating antibiotic spacers in other regions of the body such as the knee and hip, we present a novel technique to the creation of an antibiotic spacer in the setting of a failed infected MTP arthrodesis. PMID:27114892
The lubrication performance of the ceramic-on-ceramic hip implant under starved conditions
Meng, Qingen; Wang, Jing; Yang, Peiran; Jin, Zhongmin; Fisher, John
Lubrication plays an important role in the clinical performance of the ceramic-on-ceramic (CoC) hip implant in terms of reducing wear and avoiding squeaking. All the previous lubrication analyses of CoC hip implants assumed that synovial fluid was sufficiently supplied to the contact area. The aim of this study was to investigate the lubrication performance of the CoC hip implant under starved conditions. A starved lubrication model was presented for the CoC hip implant. The model was solved using multi-grid techniques. Results showed that the fluid film thickness of the CoC hip implant was affected by fluid supply conditions: with the increase in the supplied fluid layer, the lubrication film thickness approached to that of the fully blooded solution; when the available fluid layer reduced to some level, the fluid film thickness considerably decreased with the supplying condition. The above finding provides new insights into the lubrication performance of hip implants. PMID:26114217
Finding the right hip implant for patient and surgeon: the Dutch strategy--empowering patients.
Poolman, Rudolf W; Verhaar, Jan A N; Schreurs, B Willem; Bom, L Paul A; Nelissen, Rob G H H; Koot, Henk W J; Goosen, Jon H M; Verheyen, Cees C P M
We describe the implementation process of hip prostheses selection in the Netherlands. The recent problems with large head metal-on-metal hip prostheses resulted in substantial damage to the surgeons' credibility and reputation in the media. This led to a true sense of urgency among orthopaedic surgeons to increase their activities to secure patient safety. The board of the Dutch Orthopaedic Association (NOV) in the Netherlands established a Dutch Hip Task Force (DHTF) with the explicit assignment of formulating criteria to classify the quality of total hip implants on the Dutch market based on survivorship. The aim was to offer unequivocal information enabling a balanced choice of total hip prosthesis. The ultimate goal of the NOV is that all implanted total hip prostheses implanted in the Netherlands are based on reliable clinical evidence. The DHTF decided to adapt the principles of the National Institute for Health and Care Excellence (NICE, UK) (www.nice.org.uk). The taskforce uses data from the registries as well as the Orthopaedic Data Evaluation Panel (ODEP). If the ODEP guidelines had been chosen as standard alone, one quarter of our listed hip components would not have been included. In our view this underlines the strength in the Dutch approach where high quality registry data and ODEP ratings are complementary and result in a list of reliable hip prostheses. Most importantly we offer patients insights into the known quality of the implants by sharing the results of our implant review. This will facilitate shared decision making by empowering patients in their knowledge on available hip arthroplasties. PMID:25633758
Mortality and implant revision rates of hip arthroplasty in patients with osteoarthritis: registry based cohort study
McMinn, D J W; Snell, K I E; Daniel, J; Treacy, R B C; Pynsent, P B
Objectives To examine mortality and revision rates among patients with osteoarthritis undergoing hip arthroplasty and to compare these rates between patients undergoing cemented or uncemented procedures and to compare outcomes between men undergoing stemmed total hip replacements and Birmingham hip resurfacing. Design Cohort study. Setting National Joint Registry. Population About 275 000 patient records. Main outcome measures Hip arthroplasty procedures were linked to the time to any subsequent mortality or revision (implant failure). Flexible parametric survival analysis methods were used to analyse time to mortality and also time to revision. Comparisons between procedure groups were adjusted for age, sex, American Society of Anesthesiologists (ASA) grade, and complexity. Results As there were large baseline differences in the characteristics of patients receiving cemented, uncemented, or resurfacing procedures, unadjusted comparisons are inappropriate. Multivariable survival analyses identified a higher mortality rate for patients undergoing cemented compared with uncemented total hip replacement (adjusted hazard ratio 1.11, 95% confidence interval 1.07 to 1.16); conversely, there was a lower revision rate with cemented procedures (0.53, 0.50 to 0.57). These translate to small predicted differences in population averaged absolute survival probability at all time points. For example, compared with the uncemented group, at eight years after surgery the predicted probability of death in the cemented group was 0.013 higher (0.007 to 0.019) and the predicted probability of revision was 0.015 lower (0.012 to 0.017). In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group. In terms of revision, the Birmingham hip resurfacings had a similar revision rate to uncemented total hip replacements. Both uncemented total hip replacements and Birmingham hip
High-tech hip implant for wireless temperature measurements in vivo.
Bergmann, Georg; Graichen, Friedmar; Dymke, Jörn; Rohlmann, Antonius; Duda, Georg N; Damm, Philipp
When walking long distances, hip prostheses heat up due to friction. The influence of articulating materials and lubricating properties of synovia on the final temperatures, as well as any potential biological consequences, are unknown. Such knowledge is essential for optimizing implant materials, identifying patients who are possibly at risk of implant loosening, and proving the concepts of current joint simulators. An instrumented hip implant with telemetric data transfer was developed to measure the implant temperatures in vivo. A clinical study with 100 patients is planned to measure the implant temperatures for different combinations of head and cup materials during walking. This study will answer the question of whether patients with synovia with poor lubricating properties may be at risk for thermally induced bone necrosis and subsequent implant failure. The study will also deliver the different friction properties of various implant materials and prove the significance of wear simulator tests. A clinically successful titanium hip endoprosthesis was modified to house the electronics inside its hollow neck. The electronics are powered by an external induction coil fixed around the joint. A temperature sensor inside the implant triggers a timer circuit, which produces an inductive pulse train with temperature-dependent intervals. This signal is detected by a giant magnetoresistive sensor fixed near the external energy coil. The implant temperature is measured with an accuracy of 0.1°C in a range between 20°C and 58°C and at a sampling rate of 2-10 Hz. This rate could be considerably increased for measuring other data, such as implant strain or vibration. The employed technique of transmitting data from inside of a closed titanium implant by low frequency magnetic pulses eliminates the need to use an electrical feedthrough and an antenna outside of the implant. It enables the design of mechanically safe and simple instrumented implants. PMID:22927973
High-Tech Hip Implant for Wireless Temperature Measurements In Vivo
Bergmann, Georg; Graichen, Friedmar; Dymke, Jörn; Rohlmann, Antonius; Duda, Georg N.; Damm, Philipp
When walking long distances, hip prostheses heat up due to friction. The influence of articulating materials and lubricating properties of synovia on the final temperatures, as well as any potential biological consequences, are unknown. Such knowledge is essential for optimizing implant materials, identifying patients who are possibly at risk of implant loosening, and proving the concepts of current joint simulators. An instrumented hip implant with telemetric data transfer was developed to measure the implant temperatures in vivo. A clinical study with 100 patients is planned to measure the implant temperatures for different combinations of head and cup materials during walking. This study will answer the question of whether patients with synovia with poor lubricating properties may be at risk for thermally induced bone necrosis and subsequent implant failure. The study will also deliver the different friction properties of various implant materials and prove the significance of wear simulator tests. A clinically successful titanium hip endoprosthesis was modified to house the electronics inside its hollow neck. The electronics are powered by an external induction coil fixed around the joint. A temperature sensor inside the implant triggers a timer circuit, which produces an inductive pulse train with temperature-dependent intervals. This signal is detected by a giant magnetoresistive sensor fixed near the external energy coil. The implant temperature is measured with an accuracy of 0.1°C in a range between 20°C and 58°C and at a sampling rate of 2–10 Hz. This rate could be considerably increased for measuring other data, such as implant strain or vibration. The employed technique of transmitting data from inside of a closed titanium implant by low frequency magnetic pulses eliminates the need to use an electrical feedthrough and an antenna outside of the implant. It enables the design of mechanically safe and simple instrumented implants. PMID:22927973
Influence of PEEK Coating on Hip Implant Stress Shielding: A Finite Element Analysis.
Anguiano-Sanchez, Jesica; Martinez-Romero, Oscar; Siller, Hector R; Diaz-Elizondo, Jose A; Flores-Villalba, Eduardo; Rodriguez, Ciro A
Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan. PMID:27051460
Influence of PEEK Coating on Hip Implant Stress Shielding: A Finite Element Analysis
Anguiano-Sanchez, Jesica; Martinez-Romero, Oscar; Siller, Hector R.; Diaz-Elizondo, Jose A.; Flores-Villalba, Eduardo
Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan. PMID:27051460
Unconstrained tripolar implants for primary total hip arthroplasty in patients at risk for dislocation.
Guyen, Olivier; Pibarot, Vincent; Vaz, Gualter; Chevillotte, Christophe; Carret, Jean-Paul; Bejui-Hugues, Jacques
We performed a retrospective study on 167 primary total hip arthroplasty (THA) procedures in 163 patients at high risk for instability to assess the reliability of unconstrained tripolar implants (press-fit outer metal shell articulating a bipolar polyethylene component) in preventing dislocations. Eighty-four percent of the patients had at least 2 risk factors for dislocation. The mean follow-up length was 40.2 months. No dislocation was observed. Harris hip scores improved significantly. Six hips were revised, and no aseptic loosening of the cup was observed. The tripolar implant was extremely successful in achieving stability. However, because of the current lack of data documenting polyethylene wear at additional bearing, the routine use of tripolar implants in primary THA is discouraged and should be considered at the present time only for selected patients at high risk for dislocation and with limited activities. PMID:17826276
Surface evaluation of orthopedic hip implants marketed in Brazil
NASA Astrophysics Data System (ADS)
Souza, M. M.; Trommer, R. M.; Maru, M. M.; Roesler, C. R. M.; Barros, W. S.; Dutra, M. S.
One of the factors that contribute to the quality of total hip prostheses is the degree of accuracy in the manufacturing of the joint surfaces. The dimensional control of joint components is important because of its direct influence on the durability and, consequently, in the patients' life quality. This work presents studies on the form and roughness of orthopedic hip prostheses marketed in Brazil. The results provide data for quality control of the surfaces of the femoral heads and acetabular components of hip prostheses and indicate the need of improvement in the procedures used to this control.
Investigation of Wear and Corrosion of a High-Carbon Stellite Alloy for Hip Implants
NASA Astrophysics Data System (ADS)
Hu, P. S.; Liu, R.; Liu, J.; McRae, G.
Low-carbon Stellite 21 has been used as hip implant material for a number of decades; however, its limited metal-on-metal bearing has resulted in loosening between the femoral head and the acetabular cup of hip implants. In order to improve the metal-on-metal bearing, it is proposed that a high-carbon alloy, Stellite 720, surface coating be applied on Stellite 21 hip implants to improve mechanical and tribological performance. For this coating to be practical, it must also meet the requirements of corrosion resistance for orthopedic implant materials. In this research, Stellite 720 is investigated with pin-on-disk wear tests, and electrochemical and immersion corrosion tests in simulated human body fluid (Hank's solution; pH 7.4 at temperature of 37°C). The experimental results demonstrate that Stellite 720 exhibits much better wear resistance than Stellite 21, and has the potential for better corrosion resistance as well. The applicability of coating Stellite 21 hip implants with Stellite 720 is discussed.
Sheep Hip Arthroplasty Model of Failed Implant Osseointegration
Jakobsen, Thomas; Kold, Søren; Baas, Jørgen; Søballe, Kjeld; Rahbek, Ole
Early secure stability of an implant is important for long-term survival. We examined whether micromotion of implants consistently would induce bone resorption and formation of a fibrous membrane and thereby prevent osseointegration. One micromotion implant was inserted into one of the medial femoral condyles in ten sheep. The micromotion device consists of an anchor bearing a PMMA implant and a PE plug. During each gait cycle the PE plug will make the PMMA implant axially piston 0.5 mm. After 12 weeks of observation the bone specimens were harvested and a post-mortem control implant was inserted into the contra-lateral medial femoral condyle. Histomorphometrical evaluation showed that the surface on the implant observed for 12 weeks was covered by fibrous tissue. The control implants were covered by lamellar bone. No difference was found with respect to the volume fraction of lamellar bone in a 1 mm zone around the implants. This study indicates that implant micromotion is sufficient to induce bone resorption and formation of a fibrous membrane. PMID:26664497
Management of metal-on-metal hip implant patients: Who, when and how to revise?
Berber, Reshid; Skinner, John A; Hart, Alister J
The debate on how best to manage patients with metal-on-metal (MOM) hip implants continues. With over 1 million patients affected worldwide, the impact is far reaching. The majority of the aggressive failures of MOM hip implants have been dealt with by revision hip surgery, leaving patients with a much more indolent pattern of failure of devices that have been in situ for more than 10 years. The longer-term outcome for such patients remains unknown, and much debate exists on how best to manage these patients. Regulatory guidance is available but remains open to interpretation due to the lack of current evidence and long-term studies. Metal ion thresholds for concern have been suggested at 7 ppb for hip resurfacing arthroplasty and below this level for large diameter total hip arthroplasties. Soft tissue changes including pseudotumours and muscle atrophy have been shown to progress, but this is not consistent. New advanced imaging techniques are helping to diagnose complications with metal hips and the reasons for failure, however these are not widely available. This has led to some centres to tackle difficult cases through multidisciplinary collaboration, for both surgical management decisions and also follow-up decisions. We summarise current evidence and consider who is at risk, when revision should be undertaken and how patients should be managed. PMID:27190754
Management of metal-on-metal hip implant patients: Who, when and how to revise?
Berber, Reshid; Skinner, John A; Hart, Alister J
The debate on how best to manage patients with metal-on-metal (MOM) hip implants continues. With over 1 million patients affected worldwide, the impact is far reaching. The majority of the aggressive failures of MOM hip implants have been dealt with by revision hip surgery, leaving patients with a much more indolent pattern of failure of devices that have been in situ for more than 10 years. The longer-term outcome for such patients remains unknown, and much debate exists on how best to manage these patients. Regulatory guidance is available but remains open to interpretation due to the lack of current evidence and long-term studies. Metal ion thresholds for concern have been suggested at 7 ppb for hip resurfacing arthroplasty and below this level for large diameter total hip arthroplasties. Soft tissue changes including pseudotumours and muscle atrophy have been shown to progress, but this is not consistent. New advanced imaging techniques are helping to diagnose complications with metal hips and the reasons for failure, however these are not widely available. This has led to some centres to tackle difficult cases through multidisciplinary collaboration, for both surgical management decisions and also follow-up decisions. We summarise current evidence and consider who is at risk, when revision should be undertaken and how patients should be managed. PMID:27190754
Is a Sliding Hip Screw or IM Nail the Preferred Implant for Intertrochanteric Fracture Fixation?
Aros, Brian; Tosteson, Anna N. A.; Gottlieb, Daniel J.
This study was performed to determine whether patients who sustain an intertrochanteric fracture have better outcomes when stabilized using a sliding hip screw or an intramedullary nail. A 20% sample of Part A and B entitled Medicare beneficiaries 65 years or older was used to generate a cohort of patients who sustained intertrochanteric femur fractures between 1999 and 2001. Two fracture implant groups, intramedullary nail and sliding hip screw, were identified using Current Procedural Terminology and International Classification of Diseases, 9th Revision codes. The cohort consisted of 43,659 patients. Patients treated with an intramedullary nail had higher rates of revision surgery during the first year than those treated with a sliding hip screw (7.2% intramedullary nail versus 5.5% sliding hip screw). Mortality rates at 30 days (14.2% intramedullary nail versus 15.8% sliding hip screw) and 1 year (30.7% intramedullary nail versus 32.5% sliding hip screw) were similar. Adjusted secondary outcome measures showed significant increases in the intramedullary nail group relative to the sliding hip screw group for index hospital length of stay, days of rehabilitation services in the first 6 months after discharge, and total expenditures for doctor and hospital services. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18465180
Magnetic resonance imaging on disc degeneration changes after implantation of an interspinous spacer and fusion of the adjacent segment
Liu, Xiaokang; Liu, Yingjie; Lian, Xiaofeng; Xu, Jianguang
The aim of the study was to investigate the changes of the lumbar intervertebral disc degeneration by magnetic resonance imaging (MRI) after the implantation of interspinous device and the fusion of the adjacent segment. A total of 62 consecutive patients suffering L5/S1 lumbar disc herniation (LDH) with concomitant disc space narrowing or low-grade instability up to 5 mm translational slip in L5/S1 level were treated with lumbar interbody fusion (LIF) via posterior approach. Thirty-four of these patients (Coflex group) received an additional implantation of the interspinous spacer device (Coflex™) in the level L4/L5, while the rest of 28 patients (fusion group) underwent the fusion surgery alone. Clinical and radiographic examinations were performed at pre- and postoperative visits to compare the clinical outcomes and the changes of the L4/L5 vertebral disc degeneration on MRI in both Coflex and fusion group. Although both Coflex and fusion group showed improvements of the clinical outcomes assessed by the Oswestry Disability Index (ODI) after surgery, patients in Coflex group had more significant amelioration (P < 0.05) compared to fusion group. During follow up, the postoperative disc degeneration changes in Coflex group assessed by the relative signal intensity (RSI) differed from those in fusion group (P < 0.05). The supplemental implantation of Coflex™ after the fusion surgery could delay the disc degeneration of the adjacent segment. PMID:26131210
Implant failure in a proximal femoral fracture treated with dynamic hip screw fixation
Dabis, John; Abdul-Jabar, Hani B.; Dabis, Hosam
Dynamic hip screw fixation is a common orthopaedic procedure and to date, still can cause difficulties to the senior trauma surgeon. We present a case where an extra-capsular fracture of the proximal femur was managed with a dynamic hip screw (DHS) fixation. She proceeded to the operating theatre, where the fracture was stabilized with a 75-mm DHS and short-barrelled plate. The implant position was checked with intraoperative screening and the position accepted. Following attempted mobilization at 11 days post-operatively, the patient developed a recurrence of her preoperative pain. X-ray showed that the implant screw had separated from the barrel. Later scrutiny of the intraoperative screening films revealed that the barrel and screw were not engaged at the time of surgery. Intraoperative screening films should be carefully checked to ensure congruity of implant components. PMID:26136561
Implant failure in a proximal femoral fracture treated with dynamic hip screw fixation.
Dabis, John; Abdul-Jabar, Hani B; Dabis, Hosam
Dynamic hip screw fixation is a common orthopaedic procedure and to date, still can cause difficulties to the senior trauma surgeon. We present a case where an extra-capsular fracture of the proximal femur was managed with a dynamic hip screw (DHS) fixation. She proceeded to the operating theatre, where the fracture was stabilized with a 75-mm DHS and short-barrelled plate. The implant position was checked with intraoperative screening and the position accepted. Following attempted mobilization at 11 days post-operatively, the patient developed a recurrence of her preoperative pain. X-ray showed that the implant screw had separated from the barrel. Later scrutiny of the intraoperative screening films revealed that the barrel and screw were not engaged at the time of surgery. Intraoperative screening films should be carefully checked to ensure congruity of implant components. PMID:26136561
Precaution, governance and the failure of medical implants: the ASR((TM)) hip in the UK.
Wienroth, Matthias; McCormack, Pauline; Joyce, Thomas J
Hip implants have provided life-changing treatment, reducing pain and improving the mobility and independence of patients. Success has encouraged manufacturers to innovate and amend designs, engendering patient hopes in these devices. However, failures of medical implants do occur. The failure rate of the Articular Surface Replacement metal-on-metal hip system, implanted almost 100,000 times world-wide, has re-opened debate about appropriate and timely implant governance. As commercial interests, patient hopes, and devices' governance converge in a socio-technical crisis, we analyse the responses of relevant governance stakeholders in the United Kingdom between 2007 and 2014. We argue that there has been a systemic failure of the governance system entrusted with the safety of patients fitted with medical implants. Commercial considerations of medical implants and the status quo of medical implant governance have been given priority over patient safety despite the availability of significant failure data in an example of uncertainty about what constitutes appropriate precautionary action. PMID:26573983
A biomechanical assessment of modular and monoblock revision hip implants using FE analysis and strain gage measurements
Background The bone loss associated with revision surgery or pathology has been the impetus for developing modular revision total hip prostheses. Few studies have assessed these modular implants quantitatively from a mechanical standpoint. Methods Three-dimensional finite element (FE) models were developed to mimic a hip implant alone (Construct A) and a hip implant-femur configuration (Construct B). Bonded contact was assumed for all interfaces to simulate long-term bony ongrowth and stability. The hip implants modeled were a Modular stem having two interlocking parts (Zimmer Modular Revision Hip System, Zimmer, Warsaw, IN, USA) and a Monoblock stem made from a single piece of material (Stryker Restoration HA Hip System, Stryker, Mahwah, NJ, USA). Axial loads of 700 and 2000 N were applied to Construct A and 2000 N to Construct B models. Stiffness, strain, and stress were computed. Mechanical tests using axial loads were used for Construct A to validate the FE model. Strain gages were placed along the medial and lateral side of the hip implants at 8 locations to measure axial strain distribution. Results There was approximately a 3% average difference between FE and experimental strains for Construct A at all locations for the Modular implant and in the proximal region for the Monoblock implant. FE results for Construct B showed that both implants carried the majority (Modular, 76%; Monoblock, 66%) of the 2000 N load relative to the femur. FE analysis and experiments demonstrated that the Modular implant was 3 to 4.5 times mechanically stiffer than the Monoblock due primarily to geometric differences. Conclusions This study provides mechanical characteristics of revision hip implants at sub-clinical axial loads as an initial predictor of potential failure. PMID:20462448
Lubrication and friction prediction in metal-on-metal hip implants
NASA Astrophysics Data System (ADS)
Wang, F. C.; Brockett, C.; Williams, S.; Udofia, I.; Fisher, J.; Jin, Z. M.
A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.
Hip and buttock implants to enhance the feminine contour for patients with HIV.
Benito-Ruiz, J; Fontdevila, J; Manzano, M; Serra-Renom, J M
The antiretroviral therapy for patients with human immunodeficiency virus (HIV) causes lipodystrophy, or a change in the distribution of body. Treatment for the facial changes is well addressed and covered in the recent literature, but female patients also report changes in their buttocks and lower limbs. There is no treatment for the lower limb deformity, but plastic surgeons can do something for the buttock. The authors propose a classification for the deformities of these patients and a new solution to improve the contour of this area and to reduce the social impact of deformity on women with HIV. This consists of placing two silicone implants, in the buttock and on the hip, to give a rounder appearance. The authors think that hip implants may be indicated also for gender reassignment surgery and for women with masculine features. PMID:16402157
Removal of trabecular metal osteonecrosis intervention implant and conversion to primary total hip arthroplasty.
Owens, Joshua B; Ely, Erin E; Guilliani, Nathania M Figueroa; Suarez, Juan C; Patel, Preetesh D
Core decompression and placement of the Trabecular Metal Osteonecrosis Intervention Implant have shown to be initially successful in treating early osteonecrosis. When treatment fails, however, patients often undergo primary total hip arthroplasty (THA) requiring removal of a previously inserted trabecular metal implant. We describe a technical tip for removal of a well-ingrown trabecular metal screw. A metal-cutting trephine placed over the screw allows for removal in an efficient manner while minimizing additional dissection and bone loss during conversion to THA. PMID:22425306
Optical measurement system for preparation and after-OP-check of a hip joint endoprothetic implantation
NASA Astrophysics Data System (ADS)
Maschke, R.; Lempe, B.; Taudt, Ch.; Rudek, F.; Baselt, T.; Basan, F.; Grunert, R.; Hartmann, P.
With 332,000 operations carried out every year, the implantation of an artificial hip joint is one of the most common surgical operations performed in the US. According to prognosis which takes the demographical change into account, the number of these operations will increase in the coming years. One of the essential requirements is the perfect reconstruction of the biomechanical functions, especially the knowledge about the center of the hip rotation and the length of the leg. Based on this information it is possible to ensure the right position of the newly set leg during surgery. The aim of this work is to present and evaluate an optical measurement method in order to gather information about the center of the hip joint and the leg length. An appropriate laboratory setup has been designed and implemented in order to evaluate two different approaches: a structured light-method consisting of a DLP-Beamer or a laser source which projects defined patterns onto the patient and a marker-based system. Together with this both methods are combined with custom software to determine the hip joint center and the leg length with an accuracy of around +/- 0.2 inches. The clinical use of the tested approaches would give the surgeon the opportunity to reset the implant-parameters in the course of the surgery. In this way subsequent illnesses such as scoliotic pelvis can be prevented.
Inflammatory response to therapeutic gold bead implantation in canine hip joint osteoarthritis.
Lie, K-I; Jæger, G; Nordstoga, K; Moe, L
Inflammatory changes associated with periarticular pure gold bead implants were studied in dogs involved in a clinical trial investigating motor dysfunction and chronic pain owing to hip joint dysplasia and osteoarthritis. Gold beads were percutaneously implanted via a needle into different locations surrounding the greater trochanter of the femur. Nine dogs with implants were necropsied. In all examined animals, characteristic histologic lesions were observed in the tissue surrounding the gold implants--namely, a fibrous capsule composed of concentric fibroblasts intermixed with a variable number of inflammatory cells and a paucicellular innermost layer of collagen with a few fibrocyte-like cells in empty lacunae. Lymphocytes dominated the inflammatory infiltrate, with rarely observed macrophages present in close proximity to the implant site. No giant cells were observed. Immunohistochemistry showed mixed populations of lymphocytes, both CD3 positive (T cells) and CD79a positive (B cells), which in some cases formed lymphoid follicles. Diffuse inflammatory changes were present to a minor extent in the perimysium and surrounding fascia. The inflammation observed in dogs is similar to that observed with gold implants in humans. It is possible that the clinically beneficial effect of gold beads for chronic osteoarthritis depends on sustained localized inflammation with localized release of soluble mediators. The encapsulation of the implant by a paucicellular and poorly vascularized fibrous capsule may help prevent an exaggerated inflammatory reaction by sequestering the gold bead from the surrounding tissue. PMID:20861497
Good short-term outcome of primary total hip arthroplasty with cementless bioactive glass ceramic bottom-coated implants
Background and purpose Cementless total hip arthroplasty is currently favored by many orthopedic surgeons. The design of the porous surface is critically important for long-term fixation. We examined the clinical and radiographic outcome of the cementless titanium hip implant with a bottom coating of apatite-wollastonite containing bioactive glass ceramic. Methods We retrospectively reviewed 109 hips (92 patients) that had undergone primary cementless total hip arthroplasty with bioactive glass ceramic bottom-coated implants. The mean follow-up period was 7 (3–9) years. Hip joint function was evaluated with the Merle d'Aubigné and Postel hip score, and radiographic changes were determined from anteroposterior radiographs. Results The mean hip score improved from 9.7 preoperatively to 17 at the final follow-up. The overall survival rate was 100% at 9 years, when radiographic loosening or revision for any reason was used as the endpoint. 3 stems in 2 patients subsided more than 3 mm vertically within 1 year after implantation. Radiographs of the interface of the stem and femur were all classified as bone ingrowth fixation. Conclusions The short-term results of this study show good outcome for cementless implants with a bottom coating of apatite-wollastonite containing bioactive glass ceramic. PMID:23043270
Influence of ingrowth regions on bone remodelling around a cementless hip resurfacing femoral implant.
Haider, Ifaz T; Speirs, Andrew D; Beaulé, Paul E; Frei, Hanspeter
Hip resurfacing arthroplasty is an alternative to traditional hip replacement that can conserve proximal bone stock and has gained popularity but bone resorption may limit implant survival and remains a clinical concern. The goal of this study was to analyze bone remodelling patterns around an uncemented resurfacing implant and the influence of ingrowth regions on resorption. A computed tomography-derived finite element model of a proximal femur with a virtually implanted resurfacing component was simulated under peak walking loads. Bone ingrowth was simulated by six interface conditions: fully bonded; fully friction; bonded cap with friction stem; a small bonded region at the stem-cup intersection with the remaining surface friction; fully frictional, except for a bonded band along the distal end of the cap and superior half of the cap bonded with the rest frictional. Interface condition had a large influence on remodelling patterns. Bone resorption was minimized when no ingrowth occurred at the bone-implant interface. Bonding only the superior half of the cap increased bone resorption slightly but allowed for a large ingrowth region to improve secondary stability. PMID:24697332
Two-stage revision of implant-associated infections after total hip and knee arthroplasty
Ellenrieder, Martin; Lenz, Robert; Haenle, Maximilian; Bader, Rainer; Mittelmeier, Wolfram
Septic loosening of total hip and knee endoprostheses gains an increasing proportion of revision arthroplasties. Operative revisions of infected endoprostheses are mentally and physically wearing for the patient, challenging for the surgeon and a significant economic burden for healthcare systems. In cases of early infection within the first three weeks after implantation a one-stage revision with leaving the implant in place is widely accepted. The recommendations for the management of late infections vary by far. One-stage revisions as well as two-stage or multiple revision schedules have been reported to be successful in over 90% of all cases for certain patient collectives. But implant associated infection still remains a severe complication. Moreover, the management of late endoprosthetic infection requires specific logistics, sufficient and standardized treatment protocol, qualified manpower as well as an efficient quality management. With regard to the literature and experience of specialized orthopaedic surgeons from several university and regional hospitals we modified a commonly used treatment protocol for two-stage revision of infected total hip and knee endoprostheses. In addition to the achievement of maximum survival rate of the revision implants an optimisation of the functional outcome of the affected artificial joint is aimed for. PMID:22242098
Life expectancy of modular Ti6Al4V hip implants: influence of stress and environment.
Chandra, A; Ryu, J J; Karra, P; Shrotriya, P; Tvergaard, V; Gaisser, M; Weik, T
Stress dependent electrochemical dissolution is identified as one of the key mechanisms governing surface degradation in fretting and crevice corrosion of biomedical implants. The present study focuses on delineating the roles of mechanical stress and chemical conditions on the life expectancy of modular hip implants. First, material removal on a stressed surface of Ti6Al4V subjected to single asperity contact is investigated experimentally to identify the influence of contact load, in-plane stress and chemical environment on mean wear rates. A range of known stress levels are applied to the specimen while its surface is mechanically stimulated in different non-reactive to oxidizing aqueous environments. Evolution of surface degradation is monitored, and its mechanism is elucidated. This phase allows estimation of Preston Constant which is later used in the analysis. Second phase of the work is semi-analytical and computational, where, based on the estimated Preston constant and other material and process parameters, the scratch propensity (consisting of magnitude of scratch depth and their frequency per unit area) due to micro-motion in modular hip implants is estimated. The third phase views these scratches as initial notches and utilizes a mixed-mode fatigue crack propagation model to estimate the critical crack length for onset of instability. The number of loading cycles needed to reach this critical crack length is then labeled as the expected life of the implant under given mechanical and chemical conditions. Implications of different material and process conditions to life expectancy of orthopedic implants are discussed. It is observed that transverse micro-motion, compared to longitudinal micro-motion, plays a far more critical role in determining the implant life. Patient body weight, as well as proximity of the joint fluid to its iso-electric point play key roles in determining wear rates and associated life expectancies of modular hip implants
Anterior Cervical Discectomy and Fusion (ACDF): Comparison Between Zero Profile Implants and Anterior Cervical Plate and Spacer
Alimi, Marjan; Njoku, Innocent; Hofstetter, Christoph P; Tsiouris, Apostolos J; Kesavabhotla, Kartik; Boockvar, John; Härtl, Roger
Introduction: Interposition grafts combined with anterior plating currently remain the gold standard for anterior cervical discectomy and fusion. The use of anterior plates increases fusion rates but may be associated with higher rates of postoperative dysphagia. The aim of the current study was to determine the clinical and radiological outcomes following anterior cervical discectomy and fusion (ACDF) using zero-profile anchored spacers versus standard interposition grafts with anterior plating. Methods: This was a retrospective case series. A total of 53 male and 51 female consecutive patients (164 total operated levels) who underwent ACDF between 2007 and 2011 were included. The mean clinical follow-up was 15.7 ± 1.2 (SEM) months for patients with zero-profile implants and 14.8 ± 2.1 months for patients with conventional ACDF with anterior plating. Patient demographics, operative details, clinical outcomes, complications, and radiographic imaging were reviewed. Dysphagia was determined using the Bazaz criteria. Results: Clinical outcome scores improved in both groups as measured by the modified Japanese Orthopedic Association and Nurick scores. Zero-profile constructs gave rise to significantly less prevertebral soft tissue swelling compared to constructs with anterior plates postoperatively (15.74 ± 0.52 as compared to 20.48 ± 0.85 mm, p < 0.001) and at the latest follow-up (10.88 ± 0.39 mm vs. 13.72 ± 0.67 mm, p < 0.001). There was a significant difference in the incidence of dysphagia at the latest follow-up (1.5% vs. 20%, p=0.001, zero-profile vs. anterior plate, respectively). Conclusion: Zero-profile implants lead to functional outcomes similar to standard anterior plate constructs. Avoiding the use of an anterior locking plate may decrease the risk of persistent postoperative dysphagia. PMID:27200226
Revision total hip and knee arthroplasty implant identification: implications for use of Unique Device Identification 2012 AAHKS member survey results.
Wilson, Natalia A; Jehn, Megan; York, Sally; Davis, Charles M
FDA's Unique Device Identification (UDI) Rule will mandate manufacturers to assign unique identifiers to their marketed devices. UDI use is expected to improve implant documentation and identification. A 2012 American Association of Hip and Knee Surgeons membership survey explored revision total hip and knee arthroplasty implant identification processes. 87% of surgeons reported regularly using at least 3 methods to identify failed implants pre-operatively. Median surgeon identification time was 20 min; median staff time was 30 min. 10% of implants could not be identified pre-operatively. 2% could not be identified intra-operatively. UDI in TJA registry and UDI in EMR were indicated practices to best support implant identification and save time. FDA's UDI rule sets the foundation for UDI use in patient care settings as standard practice for implant documentation. PMID:23890830
[15-year results following implantation of a stem type AML hip prosthesis].
Schwerter, K; Meyenberg, A; Sander, K; Layher, F; Roth, A
The trend in arthroplasty of the hip joint to implement new models is partly based on theoretical considerations. In order to verify to which extent the philosophy of individual models is ultimately successful, the presentation of long-term results is required. In the years 1991 and 1992, 433 patients with primary implantation of an uncemented total hip replacement in primary coxarthrosis with a stem type AML (anatomic medullary locking) were treated surgically. 283 of them got a cementless cup type Duraloc. In 311 (71.8 %) patients the mean survival rate of the prosthesis could be determined at a mean follow-up of 15.5 years. 145 (33.5 %) patients were followed up completely both clinically and radiologically. Radiographically, the stem position, changes of the periprosthetic bone of the stem and the cup, as well as the wear of the cups were examined. The cumulative survival rate of the AML stem after 15.5 years was 97.5 %, of the Duraloc cup 88.2 %. The clinical results of the hip scores according to Harris and Merle d'Aubigné were good and excellent and patient satisfaction was very high. There was no relationship between stem position, stress shielding and surrounding lyses at the femur and the acetabulum and survival of stem or cup. There was no correlation between inlay wear and survival of the Duraloc cup. A subsiding of the stem in 2 cases had no effect on the clinical symptoms and quality of life. The press-fit implanted AML stem and the Duraloc cup revealed very good results during the investigation period. Like other implants, the survival rate is limited at the presented implant mainly by the cup. PMID:23696163
Simulation of the mechanical behavior of a HIP implant. Implant fixed to bone by cementation under arbitrary load
NASA Astrophysics Data System (ADS)
Oldani, C. R.; Dominguez, A. A.
In a previous work a finite elements model was constructed to simulate a fatigue assay according to the norm IRAM 9422-3. Three materials were studied, two of them are the most used in this type of implant (Stainless steel 3161 and alloy T16A14V) and the third was a new developed titanium alloy (Ti35Nb7Zr5Ta). Static loads were applied to the model according to the highest requirements of the norm and the stress - strain distribution were determined. In this study a simplified analysis of the material's fatigue was done according to the previous work. The best behavior of the titanium alloys vs. the stainless steel was evident. With the objective of studying the behavior of both: the implant and the femur bone, new finite elements models were realized, in which the presence of the bone was considered. Inside the bone, the femoral component of the implant was placed in a similar way of a cemented prosthesis in a total hip arthroplasty. The advantage of the titanium implant related to the stainless steel one, was very clear.
Implant Optimisation for Primary Hip Replacement in Patients over 60 Years with Osteoarthritis: A Cohort Study of Clinical Outcomes and Implant Costs Using Data from England and Wales
Jameson, Simon S.; Mason, James; Baker, Paul N.; Gregg, Paul J.; Deehan, David J.; Reed, Mike R.
Background Hip replacement is one of the most commonly performed surgical procedures worldwide; hundreds of implant configurations provide options for femoral head size, joint surface material and fixation method with dramatically varying costs. Robust comparative evidence to inform the choice of implant is needed. This retrospective cohort study uses linked national databases from England and Wales to determine the optimal type of replacement for patients over 60 years undergoing hip replacement for osteoarthritis. Methods and Findings Implants included were the commonest brand from each of the four types of replacement (cemented, cementless, hybrid and resurfacing); the reference prosthesis was the cemented hip procedure. Patient reported outcome scores (PROMs), costs and risk of repeat (revision) surgery were examined. Multivariable analyses included analysis of covariance to assess improvement in PROMs (Oxford hip score, OHS, and EQ5D index) (9159 linked episodes) and competing risks modelling of implant survival (79,775 procedures). Cost of implants and ancillary equipment were obtained from National Health Service procurement data. Results EQ5D score improvements (at 6 months) were similar for all hip replacement types. In females, revision risk was significantly higher in cementless hip prostheses (hazard ratio, HR = 2.22, p<0.001), when compared to the reference hip. Although improvement in OHS was statistically higher (22.1 versus 20.5, p<0.001) for cementless implants, this small difference is unlikely to be clinically important. In males, revision risk was significantly higher in cementless (HR = 1.95, p = 0.003) and resurfacing implants, HR = 3.46, p<0.001), with no differences in OHS. Material costs were lowest with the reference implant (cemented, range £1103 to £1524) and highest with cementless implants (£1928 to £4285). Limitations include the design of the study, which is intrinsically vulnerable to omitted variables, a paucity of long
Ultrastructural characterization of soft tissues surrounding implanted hip prosthesis by complementary PIXE and TEM methods
NASA Astrophysics Data System (ADS)
Jallot, E.; Benhayoune, H.; Kilian, L.; Balossier, G.; Bonhomme, P.; Oudadesse, H.; Irigaray, J. L.
We study soft tissues surrounding hip prostheses from three different patients. We evaluate the elemental composition of different fragments. The tissues are examined by means of two complementary methods in such analysis: Particle Induced X-ray Emission (PIXE) and Scanning Transmission Electron Microscopy (STEM) coupled with X-ray microanalysis (Energy Dispersive X-ray, EDX). These methods allow to determine locally at `macro' and `micro' level the chemistry of soft tissues. The findings confirmed the presence of metal in soft tissue near the three different hips. The tissues' composition undergoes important modifications with a systematic elevation of trace metal in patients with failed implants. We observe a corrosion which causes the continual release of particles into the tissues. Corrosion alters the shape size and chemical composition of wear particles embedded in soft tissue around the failed hip. EDX analysis showed that the wear particles contained varying quantities of titanium and aluminium. This phenomenon may be related with the variation of time of contact with soft tissues for each particle and Ti solubility.
Nuclear microbeam analysis of wear particles in tissue surrounding failed hip joint implants
NASA Astrophysics Data System (ADS)
Grime, G. W.; Triffitt, J. T.; Williamson, M. C.; Athanasou, N. A.
Particulate wear debris from hip joint replacements is an important factor in determining the response of the surrounding tissue to the implants. Failed replacement joints are surrounded by a layer of fibrous tissue showing an inflammatory response to the wear debris. This reaction leads to bone resorption and the eventual failure of the prosthesis. In preliminary experiments the Oxford scanning proton microprobe has been used to study the composition of wear particles in the membranes surrounding failed implants constructed from Ti/V/Al alloy. The membranes were observed to contain 1-10 μm particles with major constituents from the alloy and also from the cement and polyethylene used in the fitting and construction of the implant. Histological staining shows that these particles are associated with areas of high macrophage activity. Individual PIXE analysis of the metal particles indicates that two populations (high Ti/low Al and low Ti/high Al) may be present. These observations will provide further information on the mechanisms of implant degradation.
Proposed frequencies of a vibrator used for implant retrieval at the time of hip joint revision surgery.
Roychowdhury, Amit; Hayes, Westley; Rasquinha, Vijay J; Saha, Subrata
The number and the rate of success of hip implantation surgeries have increased significantly during last thirty years, not only in the USA, but also throughout the world. It has been reported that the failure rates of implanted hip joints are less than 8% after 10 years, and less than 20% after twenty years. Failures occur directly or indirectly due to wear, stress shielding and infection. Revision surgery is needed for those failed implant replacements. In the future, as the elderly population increases, the frequency of this type of revision surgery will also increase. At the time of revision surgery, removal of the existing cemented femoral implant can be a problem for the surgeon. Use of a vibrator for loosening of the existing cement layer between the bone and the implant may be a helpful solution. In this study, we investigated the optimum resonance frequencies of such a vibrator that might be used to loosen the cement layer easily and efficiently. Natural frequencies of different-sized implants and of different materials were determined. For harmonic analysis, CT scan data of a femur was processed in the image processing software MIMICS. Then the outline of the total hip was modeled and was analyzed by the finite element software ANSYS. The required portion of the femoral part was edited, implant and cement layer were introduced in that model, and elements were generated in that FEA software. Then elements of the femoral part, except the cement layer and the implant, were sent to MIMICS software again for assignment of different Youngs modulus of each element, which are proportionate to their densities. Then the elements were brought back to the FEA software. The harmonic analysis was performed for the total model in the FEA software ANSYS. For that particular boundary condition, the first three natural frequencies of the three types of implant sizes and materials varied by a maximum of 7-8%. Results of the numerical harmonic analysis showed that at the
Probabilistic finite element analysis of the uncemented hip replacement--effect of femur characteristics and implant design geometry.
Dopico-González, Carolina; New, Andrew M; Browne, Martin
In the present study, a probabilistic finite element tool was assessed using an uncemented total hip replacement model. Fully bonded and frictional interfaces were investigated for combinations of three proximal femurs and two implant designs, the Proxima short stem and the IPS hip stem prostheses. The Monte Carlo method was used with two performance indicators: the percentage of bone volume that exceeded specified strain limits and the maximum nodal micromotion. The six degrees of freedom of bone-implant relative position, magnitude of the hip contact force (L), and spatial direction of L were the random variables. The distal portion of the proximal femurs was completely constrained and some of the main muscle forces acting in the hip were applied. The coefficients of the linear approximation between the random variables and the output were used as the sensitivity values. In all cases, bone-implant position related parameters were the most sensitive parameters. The results varied depending on the femur, the implant design and the interface conditions. Values of maximum nodal micromotion agreed with results from previous studies, confirming the robustness of the implemented computational tool. It was demonstrated that results from a single model study should not be generalised to the entire population of femurs and that bone variability is an important factor that should be investigated in such analyses. PMID:19896129
Microfocus study of metal distribution and speciation in tissue extracted from revised metal on metal hip implants
NASA Astrophysics Data System (ADS)
Hart, Alister J.; Sandison, Ann; Quinn, Paul; Sampson, Barry; Atkinson, Kirk D.; Skinner, John A.; Goode, Angela; Powell, Jonathan J.; Mosselmans, J. Frederick W.
Unexplained tissue inflammation in metal-on-metal hip replacements is suspected to be caused by implant-derived nanoparticles. The aim of this study was to investigate the nature of the metal particles in tissue surrounding metal-on-metal (MOM) hips that has been extracted during revision. Mapping of tissue surrounding the failed MOM hips was performed using microfocus X-ray Fluorescence (XRF). This revealed mainly Cr which was localized to the cellular regions. There was co-localisation of Co, were present, to areas of high Cr abundance. XANES of the tissue and appropriate standards revealed that the most common species were Cr(III) and Co(II). EXAFS analysis of the tissue and various metal standards revealed that the most abundant implant-related species was Cr(III) phosphate. Different tissue preparation methods, including frozen sectioning, were examined but were found not to affect the distribution or speciation of the metals in the tissue.
Do we need hip-ankle radiographs to assess the coronal alignment and implant position after total knee replacement?
Dargel, Jens; Oppermann, Johannes; Eysel, Peer; Penning, Lenhard
Aims and Objectives: Restoration of the coronal alignment of the knee is known to be one of the major criteria of a successful total knee arthroplasty (TKA). It therefore appears to be mandatory to routinely assess the postoperative limb alignment using hip-ankle radiographs and to identify implants that may be at risk of premature failure. However, there is no clear consensus whether weight-bearing hip-ankle radiographs or rather standardized a-p knee-radiographs should be used to assess implant position and coronal alignment after TKA. It is the aim of the present study to investigate if implant position and the mechanical alignment after TKA can reproducibly be assessed using standardized a-p knee-radiographs or rather if weight-bearing hip-ankle radiographs are needed. Materials and Methods: This study was performed on 100 postoperative weight-bearing hip-ankle radiographs after conventional primary TKA. The true mechanical and anatomical femorotibial angle as well as coronal implant position (MPTA, LDFA) was assessed using the MediCAD software, which served as a control. The hip-ankle radiographs were then digitally cropped to 80%, 60% and 40% of the leg-length. In each cropped radiograph, tibial coronal implant position was assessed by referencing against the visible mid-shaft, whereas femoral implant position was referenced against the visible mid-shaft (anatomical axis) or against a surrogate mechanical axis, which was drawn perpendicular to the distal tangent of the femoral component. Each measurement was performed by three independent observers. The difference between the alignment parameters in the hip-ankle radiographs were statistically compared with the cropped radiographs and the inter-observer correlation coefficient (ICC) was calculated for each parameter. Results: The ICC for inter-observer agreement of measurement of the mechanical femorotibial angle was significantly higher in hip-ankle radiographs (.95) when compared with a radiograph cropped
Comparative Effectiveness of Ceramic-on-Ceramic Implants in Stemmed Hip Replacement
Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Pons, Miquel; Havelin, Leif; Mehle, Susan; Paxton, Elizabeth; Barber, Thomas; Cafri, Guy
Background: The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). Methods: A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. Results: A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head
Comparison and Combination of Dual-Energy- and Iterative-Based Metal Artefact Reduction on Hip Prosthesis and Dental Implants
Bongers, Malte N.; Schabel, Christoph; Thomas, Christoph; Raupach, Rainer; Notohamiprodjo, Mike; Nikolaou, Konstantin; Bamberg, Fabian
Purpose To compare and combine dual-energy based and iterative metal artefact reduction on hip prosthesis and dental implants in CT. Material and Methods A total of 46 patients (women:50%,mean age:63±15years) with dental implants or hip prostheses (n = 30/20) were included and examined with a second-generation Dual Source Scanner. 120kV equivalent mixed-images were derived from reconstructions of the 100/Sn140kV source images using no metal artefact reduction (NOMAR) and iterative metal artefact reduction (IMAR). We then generated monoenergetic extrapolations at 130keV from source images without IMAR (DEMAR) or from source images with IMAR, (IMAR+DEMAR). The degree of metal artefact was quantified for NOMAR, IMAR, DEMAR and IMAR+DEMAR using a Fourier-based method and subjectively rated on a five point Likert scale by two independent readers. Results In subjects with hip prosthesis, DEMAR and IMAR resulted in significantly reduced artefacts compared to standard reconstructions (33% vs. 56%; for DEMAR and IMAR; respectively, p<0.005), but the degree of artefact reduction was significantly higher for IMAR (all p<0.005). In contrast, in subjects with dental implants only IMAR showed a significant reduction of artefacts whereas DEMAR did not (71%, vs. 8% p<0.01 and p = 0.1; respectively). Furthermore, the combination of IMAR with DEMAR resulted in additionally reduced artefacts (Hip prosthesis: 47%, dental implants 18%; both p<0.0001). Conclusion IMAR allows for significantly higher reduction of metal artefacts caused by hip prostheses and dental implants, compared to a dual energy based method. The combination of DE-source images with IMAR and subsequent monoenergetic extrapolation provides an incremental benefit compared to both single methods. PMID:26600188
Subsurface changes of a MoM hip implant below different contact zones.
Pourzal, Robin; Theissmann, Ralf; Williams, Sophie; Gleising, Birgit; Fisher, John; Fischer, Alfons
Metal-on-metal hip arthroplasties undergo distinct release of toxic metal particles and ions. Thus, it is necessary to minimize this. In order to evaluate the wear behaviour of metal-on-metal hip replacements it is essential to understand the micro-structural changes in the sub-surface region. Previous studies revealed that cobalt chromium metal-on-metal implants are able to alter their mechanical behaviour by adjusting the microstructure to load. The reason for this is the so-called mechanical mixing. This means that a nano-crystal layer is formed by rotating clusters of atoms that incorporate denatured proteins from the interfacial medium. This is followed by a layer of rhombic shaped nano-crystals in between sheared epsilon-martensite lathes, twins, and stacking faults. Although the primary wear zone has been well characterized, the sub-surface structure of the stripe wear and the non-contact zone of the hip ball have yet to be analysed. For this study a 28-mm cobalt base alloy femoral head and acetabular cup were analysed. The implant was simulator tested for 5 million cycles with the application of micro-separation resulting in a clearly visible stripe wear appearance. The TEM micrograph of the primary wear zone of the ball confirmed the presence of a sub-surface layer of nano-crystals. The thickness of this layer was approximately 200 nm and the average grain diameter ranged from 35 to 40 nm. Within the stripe wear zone the micrographs also revealed a nano-crystal layer but with a thickness of only 50 nm and an average grain diameter from 15 to 20 nm. The carbon and oxygen content was highest closest to the surface which proves the occurrence of mechanical mixing. The non-contact zone of the ball was analysed as well. When compared to the primary wear zone a nano-crystal layer with similar thickness but with an average grain diameter smaller than 15 nm was observed. PMID:19627822
Implant based differences in adverse local tissue reaction in failed total hip arthroplasties: a morphological and immunohistochemical study
Background Adverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes. Methods Consecutive patients presenting with ALTR from two major hip implant classes (N = 54 patients with Dual-Modular Neck implant; N = 14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry. Results Length of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p < 0.005) suggesting differences in implant performance. Morphologic examination revealed a common spectrum of neo-synovial proliferation and necrosis in both groups. Macrophages were more commonly present in diffuse sheets (Grade 3) in the MoM relative to DMN group (p = 0.016). Perivascular lymphocytes with germinal centers (Grade 4) were more common in the DMN group, which trended towards significance (p = 0.066). Qualitative differences in corrosion product morphology were seen between the two groups. Immunohistochemistry showed features of a CD4 and GATA-3 rich lymphocyte reaction in both implants, with increased ratios of perivascular T
The manufacture of generic replicas of implants for arthroplasty of the hip and knee: is it regulated and will it save money?
Atrey, A; Heylen, S; Gosling, O; Porteous, M J L; Haddad, F S
Joint replacement of the hip and knee remain very satisfactory operations. They are, however, expensive. The actual manufacturing of the implant represents only 30% of the final cost, while sales and marketing represent 40%. Recently, the patents on many well established and successful implants have expired. Companies have started producing and distributing implants that purport to replicate existing implants with good long-term results. The aims of this paper are to assess the legality, the monitoring and cost saving implications of such generic implants. We also assess how this might affect the traditional orthopaedic implant companies. Cite this article: Bone Joint J 2016;98-B:892-900. PMID:27365466
Measurement of transient and residual stresses during polymerization of bone cement for cemented hip implants.
Nuño, N; Madrala, A; Plamondon, D
The initial fixation of a cemented hip implant relies on the strength of the interface between the stem, bone cement and adjacent bone. Bone cement is used as grouting material to fix the prosthesis to the bone. The curing process of bone cement is an exothermic reaction where bone cement undergoes volumetric changes that will generate transient stresses resulting in residual stresses once polymerization is completed. However, the precise magnitude of these stresses is still not well documented in the literature. The objective of this study is to develop an experiment for the direct measurement of the transient and residual radial stresses at the stem-cement interface generated during cement polymerization. The idealized femoral-cemented implant consists of a stem placed inside a hollow cylindrical bone filled with bone cement. A sub-miniature load cell is inserted inside the stem to make a direct measurement of the radial compressive forces at the stem-cement interface, which are then converted to radial stresses. A thermocouple measures the temperature evolution during the polymerization process. The results show the evolution of stress generation corresponding to volumetric changes in the cement. The effect of initial temperature of the stem and bone as well as the cement-bone interface condition (adhesion or no adhesion) on residual radial stresses is investigated. A maximum peak temperature of 70 degrees C corresponds to a peak in transient stress during cement curing. Maximum radial residual stresses of 0.6 MPa in compression are measured for the preheated stem. PMID:18692188
Surface composition analysis of failed cementless CoCr- and Ti-base-alloy total hip implants.
Decking, R; Reuter, P; Hüttner, M; Puhl, W; Claes, L E; Scharf, H P
The surfaces of retrieved failed cementless total hip implants made of cobalt-chromium-molybdenum casting alloy and of wrought titanium 6-aluminum 4-vanadium alloy were studied with the use of scanning-electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). New implants of the same make served as controls. The XPS scans revealed a dense carbon layer on the entire analyzed specimen. The relative composition of the titanium alloy implants showed an overall agreement with the international standards for implants for surgery, and the overall surface composition did not change over the period of the implantation. However, an inhomogeneous distribution of the constituents could be demonstrated in the retrieved as well as in the new MEC-screw rings made of TiAl6V4 alloy, an implant that has been linked to a high early failure rate. In the CoCr-alloy components (Lord-screw rings) a high percentage of aluminum, mainly organized in aluminum inclusions, was found in the retrieved as well as in the new implants. PMID:12516084
In vivo severe corrosion and hydrogen embrittlement of retrieved modular body titanium alloy hip-implants.
Rodrigues, Danieli C; Urban, Robert M; Jacobs, Joshua J; Gilbert, Jeremy L
Titanium alloys are widely used in total-joint replacements due to a combination of outstanding mechanical properties, biocompatibility, passivity, and corrosion resistance. Nevertheless, retrieval studies have pointed out that these materials can be subjected to localized or general corrosion in modular interfaces when mechanical abrasion of the oxide film (fretting) occurs. Modularity adds large crevice environments, which are subject to micromotion between contacting interfaces and differential aeration of the surface. Titanium alloys are also known to be susceptible to hydrogen absorption, which can induce precipitation of hydrides and subsequent brittle failure. In this work, the surface of three designs of retrieved hip-implants with Ti-6Al-4V/Ti-6Al-4V modular taper interfaces in the stem were investigated for evidence of severe corrosion and precipitation of brittle hydrides during fretting-crevice corrosion in the modular connections. The devices were retrieved from patients and studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and chemical analysis. The surface qualitative investigation revealed severe corrosion attack in the mating interfaces with evidence of etching, pitting, delamination, and surface cracking. In vivo hydrogen embrittlement was shown to be a mechanism of degradation in modular connections resulting from electrochemical reactions induced in the crevice environment of the tapers during fretting-crevice corrosion. PMID:18683224
Rodrigues, Danieli C.; Urban, Robert M.; Jacobs, Joshua J.; Gilbert, Jeremy L.
Titanium alloys are widely used in total-joint replacements due to a combination of outstanding mechanical properties, biocompatibility, passivity and corrosion resistance. Nevertheless, retrieval studies have pointed out that these materials can be subjected to localized or general corrosion in modular interfaces when mechanical abrasion of the oxide film (fretting) occurs. Modularity adds large crevice environments, which are subject to micromotion between contacting interfaces and differential aeration of the surface. Titanium alloys are also known to be susceptible to hydrogen absorption, which can induce precipitation of hydrides and subsequent brittle failure. In this work, the surface of three designs of retrieved hip-implants with Ti-6Al-4V/Ti-6Al-4V modular taper interfaces in the stem were investigated for evidence of severe corrosion and precipitation of brittle hydrides during fretting-crevice corrosion in the modular connections. The devices were retrieved from patients and studied by means of scanning electron microscopy (SEM), x-ray diffraction (XRD) and chemical analysis. The surface qualitative investigation revealed severe corrosion attack in the mating interfaces with evidence of etching, pitting, delamination and surface cracking. In vivo hydrogen embrittlement was shown to be a mechanism of degradation in modular connections resulting from electrochemical reactions induced in the crevice environment of the tapers during fretting-crevice corrosion. PMID:18683224
Effect of implant material properties on the performance of a hip joint replacement.
Rotem, A
A composite material implant prosthesis for hip replacement has been developed. The design of the prosthesis substructure was based on investigation of the stress and strain fields that were developed in the human femur at the proximal end when a prosthesis stem had been inserted into it. The prosthesis stem structure was of unidirectional fibrous composite material core (graphite fibres in polysulfone matrix), wrapped with four layers of the same material but orientated at different angles. The orthotropic moduli of the outer layer are very close to the moduli of a human cortical bone in the vertical and circumferential directions. The moduli increased gradually from the outer layer to the inner core. A three-dimensional finite element model of the prosthesis and the bone has been constructed and loaded with the range of forces that might appear upon operation. The behaviour of the composite prosthesis and the femur was then compared with the intact femur and three other types of prosthesis materials, namely stainless steel, titanium, an isoelastic material and a hypothetical one with moduli identical to the cortical bone. The titanium has modulus of elasticity that is only half of the stainless steel. It was found that the composite prosthesis gave the best performance for most of the categories that were examined. PMID:7595934
Wilson, W.N.; Bradshaw, R.D.; Wilton, B.S.; Carpenter, R.B.
This patent describes a method for cementing a wellbore penetrating an earth formation into which a conduit extends, the wellbore having a space occupied by a drilling fluid. It comprises displacing the drilling fluid from the space with a spacer fluid comprising: sulfonated styrene-maleic anhydride copolymer, bentonite, welan gum, surfactant and a weighting agent; and displacing the spacer composition and filling the wellbore space with a settable cement composition.
Tribo-biological deposits on the articulating surfaces of metal-on-polyethylene total hip implants retrieved from patients
Cui, Zhiwei; Tian, Yi-Xing; Yue, Wen; Yang, Lei; Li, Qunyang
Artificial total hip arthroplasty (THA) is one of the most effective orthopaedic surgeries that has been used for decades. However, wear of the articulating surfaces is one of the key failure causes limiting the lifetime of total hip implant. In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed to explore the composition and formation mechanism of the tribo-layer on the articulating surfaces of metal-on-polyethylene (MoPE) implants retrieved from patients. Results showed that, in contrast to conventional understanding, the attached tribo-layer contained not only denatured proteins but also a fraction of polymer particles. The formation of the tribo-layer was believed to relate to lubrication regime, which was supposed to be largely affected by the nature of the ultra-high-molecule-weight-polyethylene (UHMWPE). Wear and formation of tribo-layer could be minimized in elasto-hydrodynamic lubrication (EHL) regime when the UHMWPE was less stiff and have a morphology containing micro-pits; whereas the wear was more severe and tribo-layer formed in boundary lubrication. Our results and analyses suggest that enhancing interface lubrication may be more effective on reducing wear than increasing the hardness of material. This finding may shed light on the design strategy of artificial hip joints. PMID:27345704
Tribo-biological deposits on the articulating surfaces of metal-on-polyethylene total hip implants retrieved from patients
NASA Astrophysics Data System (ADS)
Cui, Zhiwei; Tian, Yi-Xing; Yue, Wen; Yang, Lei; Li, Qunyang
Artificial total hip arthroplasty (THA) is one of the most effective orthopaedic surgeries that has been used for decades. However, wear of the articulating surfaces is one of the key failure causes limiting the lifetime of total hip implant. In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed to explore the composition and formation mechanism of the tribo-layer on the articulating surfaces of metal-on-polyethylene (MoPE) implants retrieved from patients. Results showed that, in contrast to conventional understanding, the attached tribo-layer contained not only denatured proteins but also a fraction of polymer particles. The formation of the tribo-layer was believed to relate to lubrication regime, which was supposed to be largely affected by the nature of the ultra-high-molecule-weight-polyethylene (UHMWPE). Wear and formation of tribo-layer could be minimized in elasto-hydrodynamic lubrication (EHL) regime when the UHMWPE was less stiff and have a morphology containing micro-pits; whereas the wear was more severe and tribo-layer formed in boundary lubrication. Our results and analyses suggest that enhancing interface lubrication may be more effective on reducing wear than increasing the hardness of material. This finding may shed light on the design strategy of artificial hip joints.
Tribo-biological deposits on the articulating surfaces of metal-on-polyethylene total hip implants retrieved from patients.
Cui, Zhiwei; Tian, Yi-Xing; Yue, Wen; Yang, Lei; Li, Qunyang
Artificial total hip arthroplasty (THA) is one of the most effective orthopaedic surgeries that has been used for decades. However, wear of the articulating surfaces is one of the key failure causes limiting the lifetime of total hip implant. In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed to explore the composition and formation mechanism of the tribo-layer on the articulating surfaces of metal-on-polyethylene (MoPE) implants retrieved from patients. Results showed that, in contrast to conventional understanding, the attached tribo-layer contained not only denatured proteins but also a fraction of polymer particles. The formation of the tribo-layer was believed to relate to lubrication regime, which was supposed to be largely affected by the nature of the ultra-high-molecule-weight-polyethylene (UHMWPE). Wear and formation of tribo-layer could be minimized in elasto-hydrodynamic lubrication (EHL) regime when the UHMWPE was less stiff and have a morphology containing micro-pits; whereas the wear was more severe and tribo-layer formed in boundary lubrication. Our results and analyses suggest that enhancing interface lubrication may be more effective on reducing wear than increasing the hardness of material. This finding may shed light on the design strategy of artificial hip joints. PMID:27345704
Superelastic Orthopedic Implant Coatings
NASA Astrophysics Data System (ADS)
Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew
The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.
N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases
Lonati, Davide; Ragghianti, Benedetta; Ronchi, Anna; Vecchio, Sarah; Locatelli, Carlo Alessandro
Systemic toxicity associated with cobalt (Co) and chromium (Cr) containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014). After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL) are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable. PMID:27148463
Successful staged hip replacement in septic hip osteoarthritis in osteopetrosis: a case report
Background Osteopetrosis is a rare, inherited, bone disorder, characterized by osteosclerosis, obliteration of the medullary cavity and calcified cartilage. The autosomal dominant form is compatible with a normal life span, although fractures often result from minimal trauma, due to the pathologic nature of bone. Osteomyelitis is common in patients with osteopetrosis because of a reduced resistance to infection, attributed to the lack of marrow vascularity and impairment of white cell function. Only one case of osteomyelitis of the proximal third of the femur has been previously reported, treated with several repeated debridements and finally with femoral head resection. Here we present for the first time a case of a staged implant of a cementless total hip prosthesis for the treatment of a septic hip in femoral neck nonunion in osteopetrosis. Case presentation A 36-years-old woman, affected by autosomal dominant osteopetrosis was referred to our department because of a septic hip arthritis associated with femoral neck septic non-union, with draining fistulas. The infection occurred early after a plate osteosynthesis for a closed perthrocanteric fracture of the femur and persisted in spite of osteosynthesis removal, surgical debridement and external fixation. In our hospital the patient underwent accurate debridement, femoral head and greater trochanter resection, preparation of the diaphyseal intramedullary canal and implant of an antibiotic-loaded cement spacer. The spacer was exchanged after one month, due to infection recurrence and four months later, a cementless total hip arthroplasty was implanted, with no clinical and laboratory signs of infection recurrence at two years follow-up. Conclusions In case of hip septic arthritis and proximal femur septic non-union, femoral head resection may not be the only option available and staged total hip arthroplasty can be considered. PMID:22472060
No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty
Søballe, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken
Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the
Toxicology-based cancer causation analysis of CoCr-containing hip implants: a quantitative assessment of genotoxicity and tumorigenicity studies.
Christian, Whitney V; Oliver, Lindsay D; Paustenbach, Dennis J; Kreider, Marisa L; Finley, Brent L
In this paper, quantitative methods were used to evaluate the weight of evidence regarding a causative relationship between cobalt-chromium (CoCr)-containing hip implants and increased cancer risk. We reviewed approximately 80 published papers and identified no-observed-adverse-effect level (NOAEL) and/or lowest-observed-adverse-effect level (LOAEL) values for specific endpoints of interest: genotoxic effects from in vitro studies with human cell lines as well as genotoxicity and tumor formation in animal bioassays. Test articles included Co particles and ions, Cr particles and ions, and CoCr alloy particles as well as CoCr alloy implants. The NOAEL/LOAEL values were compared with body burdens of Co/Cr particles and ions we calculated to exist in systemic tissues of hip implant patients under normal and excessive wear conditions. We found that approximately 40 tumor bioassays have been conducted with CoCr alloy implants or Co/Cr particles and ions at levels hundreds to thousands of times higher than those present in hip implant patients, and none reported a statistically significant increased incidence of systemic tumors. Results from in vitro and in vivo genotoxicity assays, which are relatively less informative owing to false positives and other factors, also indicated that DNA effects would be highly unlikely to occur as a result of wear debris from a CoCr implant. Hence, the toxicological weight of evidence suggests that CoCr-containing hip implants are unlikely to be associated with an increased risk of systemic cancers, which is consistent with published and ongoing cancer epidemiology studies involving patients with CoCr hip implants. PMID:25080401
Analysis of contact mechanics in McKee-farrar metal-on-metal hip implants.
Yew, A; Jagatia, M; Ensaff, H; Jin, Z M
Contact mechanics analysis for a typical McKee-Farrar metal-on-metal hip implant was carried out in this study. The finite element method was used to predict the contact area and the contact pressure distribution at the bearing surfaces. The study investigated the effects of the cement and underlying bone, the geometrical parameters such as the radial clearance between the acetabular cup and the femoral head, and the acetabular cup thickness, as well as other geometrical features on the acetabular cup such as lip and studs. For all the cases considered, the predicted contact pressure distribution was found to be significantly different from that based upon the classical Hertz contact theory, with the maximum value being away from the centre of the contact region. The lip on the cup was found to have a negligible effect on the predicted contact pressure distribution. The presence of the studs on the outside of the cup caused a significant increase in the local contact pressure distribution, and a slight decrease in the contact region. Reasonably good agreement of the predicted contact pressure distribution was found between a three-dimensional anatomical model and a simple two-dimensional axisymmetric model. The interfacial boundary condition between the acetabular cup and the underlying cement, modelled as perfectly fixed or perfectly unbonded, had a negligible effect on the predicted contact parameters. For a given radial clearance of 0.079 mm, the decrease in the thickness of the acetabular cup from 4.5 to 1.5 mm resulted in an increase in the contact half angle from 15 degrees to 26 degrees, and a decrease in the maximum contact pressure from 55 to 20 MPa. For a given acetabular cup thickness of 1.5 mm, a decrease in the radial clearance from 0.158 to 0.0395 mm led to an increase in the contact half-angle from 20 degrees to 30 degrees, and a decrease in the maximum contact pressure from 30 to 10 MPa. For zero clearance, although the contact pressure was
Are all metal-on-metal hip revision operations contributing to the National Joint Registry implant survival curves?
Sabah, S. A.; Henckel, J.; Koutsouris, S.; Rajani, R.; Hothi, H.; Skinner, J. A.; Hart, A. J.
Aims The National Joint Registry for England, Wales and Northern Ireland (NJR) has extended its scope to report on hospital, surgeon and implant performance. Data linkage of the NJR to the London Implant Retrieval Centre (LIRC) has previously evaluated data quality for hip primary procedures, but did not assess revision records. Methods We analysed metal-on-metal hip revision procedures performed between 2003 and 2013. A total of 69 929 revision procedures from the NJR and 929 revised pairs of components from the LIRC were included. Results We were able to link 716 (77.1%) revision procedures on the NJR to the LIRC. This meant that 213 (22.9%) revision procedures at the LIRC could not be identified on the NJR. We found that 349 (37.6%) explants at the LIRC completed the full linkage process to both NJR primary and revision databases. Data completion was excellent (> 99.9%) for revision procedures reported to the NJR. Discussion This study has shown that only approximately one third of retrieved components at the LIRC, contributed to survival curves on the NJR. We recommend prospective registry-retrieval linkage as a tool to feedback missing and erroneous data to the NJR and improve data quality. Take home message: Prospective Registry – retrieval linkage is a simple tool to evaluate and improve data quality on the NJR. Cite this article: Bone Joint J 2016;98-B:33–9. PMID:26733513
Role of ceramic implants. Design and clinical success with total hip prosthetic ceramic-to-ceramic bearings.
Clarke, I C
Ceramic implants have become of great interest because of the increased awareness that wear debris from metal-polyethylene components of total hip prostheses can cause osteolysis around implants. Polyethylene wear rates with the Charnley total hip prosthesis were found to be from 0.1 to 0.2 mm/year in the elderly, which corresponded to 30 to 80 mm3 of polyethylene debris being released to the joint tissues. This in turn can be related to 40 million to 40 billion particles being released into the joint every year. This polyethylene particulate is heavily implicated in the osteolytic destruction of periarticular tissues. The ceramic ball, ceramic cup combination of total hip prostheses may have promise of wear rates that could be thousands of times smaller than polyethylene alone. Such alumina ceramic prosthetic concepts were introduced in Europe from 1970 to 1973. Under Food and Drug Administration regulations at that time, the only U.S. introductions allowed circa 1980 were the Autophor and Xenophor types of ceramic prostheses. However, this particular prosthetic design was not successful in the United States because of pain, neck-socket impingement, ceramic fracture, and component loosening. This did not therefore appear to be a successful compromise in the hands of U.S. surgeons. Ceramic innovations from Europe now include cemented ceramic cups of "matching" tolerances with the femoral ball, and press-fit Ti-alloy acetabular shells with modular ceramic inserts. In addition, alumina and zirconia ceramic balls are now in routine clinical use in Europe. The objectives of this Symposium are to highlight these ceramic ball, ceramic cup innovations with their long-term clinical results from Europe. Then one can evaluate which of these innovations in material and design selections offers the best possible alternatives in the 1990s. PMID:1516312
Information for Patients Who Have Metal-on-Metal Hip Implants
... their implants. These problems included: General hypersensitivity reaction (skin rash) Cardiomyopathy Neurological changes including sensory changes (auditory, or visual impairments) Psychological status change ( ...
Bisphosphonate Use and Risk of Implant Revision after Total Hip/Knee Arthroplasty: A Meta-Analysis of Observational Studies
Teng, Songsong; Yi, Chengqing; Krettek, Christian; Jagodzinski, Michael
Objective Several studies investigated the association between bisphosphonate use and the risk of implant revision after total hip or knee arthroplasty (THA or TKA); However, the findings were inconsistent. We performed this meta-analysis to evaluate the overall relative risk of such an event. Methods We searched the PubMed, EMBASE and Cochrane library databases to identify relevant publications on April 22, 2015. To calculate the pooled risk ratios (RRs) with 95% confidential intervals (CIs), a fixed- or random-effects model was applied based on the heterogeneity across studies. Results Three cohort studies and one case-control study were included in this meta-analysis. Compared with the bisphosphonate nonusers, the patients who used bisphosphonates for a long period of time had a significantly decreased risk of implant revision after THA/TKA (summary adjusted RR = 0.48, 95% CI: 0.38–0.61), and the summary adjusted RRs for the users who underwent THA and those who underwent TKA were 0.47 (95% CI: 0.36–0.61) and 0.45 (95% CI: 0.21–0.95), respectively. Conclusions Long-term use of bisphosphonates is correlated with a significantly decreased risk of implant revision after THA/TKA. However, due to limited number of the included studies, the findings of the present study should be treated with caution. More well-designed studies are required to further confirm our findings. PMID:26444555
Expertise modeling for automated planning of acetabular cup in total hip arthroplasty using combined bone and implant statistical atlases.
Otomaru, Itaru; Kobayashi, Kazuto; Okada, Toshiyuki; Nakamoto, Masahiko; Kagiyama, Yoshiyuki; Takao, Masaki; Sugano, Nobuhiko; Tada, Yukio; Sato, Yoshinobu
Intraoperative robotic and computer-guided assistances are now commonly used in total hip arthroplasty (THA) for accurate execution of the preoperative plan. Although the preoperative plan to be accurately executed is critical, it is still interactively prepared in a time-consuming and subjective manner. In this paper, atlas-based approach to automated surgical planning of the acetabular cup in THA is described to stabilize its quality as well as reduce its time-consuming nature. Surgeon's expertise is embedded in two types of statistical atlases, which are constructed from training datasets of CT-based 3D plans prepared by experienced surgeons. One is a statistical shape model which encodes global spatial relationships between the patient anatomy and implant. The other is the statistical map of residual bone thickness on the implant surface, which encodes local spatial constraints of the anatomy and implant. Given the 3D pelvis shape of the patient, we formulate a procedure to determine the best size and position of the acetabular cup which satisfy the constraints derived from the two statistical atlases. We validated the proposed planning method by retrospective study using the datasets which were actually used in the THA surgery. PMID:20426029
The biomechanical effect of anteversion and modular neck offset on stress shielding for short-stem versus conventional long-stem hip implants.
Goshulak, Peter; Samiezadeh, Saeid; Aziz, Mina S R; Bougherara, Habiba; Zdero, Radovan; Schemitsch, Emil H
Short-stem hip implants are increasingly common since they preserve host bone stock and presumably reduce stress shielding by improving load distribution in the proximal femur. Stress shielding may lead to decreased bone density, implant loosening, and fracture. However, few biomechanical studies have examined short-stem hip implants. The purpose of this study was to compare short-stem vs. standard length stemmed implants for stress shielding effects due to anteversion-retroversion, anterior-posterior position, and modular neck offset. Twelve artificial femurs were implanted with either a short-stem modular-neck implant or a conventional length monolithic implant in 0° or 15° of anteversion. Three modular neck options were tested in the short-stem implants. Three control femurs remained intact. Femurs were mounted in adduction and subjected to axial loading. Strain gauge values were collected to validate a Finite Element (FE) model, which was used to simulate the full range of physiologically possible anteversion and anterior-posterior combinations (n = 25 combinations per implant). Calcar stress was compared between implants and across each implant's range of anteversion using one and two-way ANOVA. Stress shielding was defined as the overall change in stress compared to an intact femur. The FE model compared well with experimental strains (intact: slope = 0.898, R = 0.943; short-stem: slope = 0.731, R = 0.948; standard-stem: slope = 0.743, R = 0.859); correction factors were used to adjust slopes to unity. No implant anteversion showed significant reduction in stress shielding (α = 0.05, p > 0.05). Stress shielding was significantly higher in the standard-stem implant (63% change from intact femur, p < 0.001) than in short-stem implants (29-39% change, p < 0.001). Short-stem implants reduce stress shielding compared to standard length stemmed implants, while implant anteversion and anterior-posterior position had no effect. Therefore, short-stem implants have
Microseparation and stripe wear in alumina-on-alumina hip implants.
Affatato, Saverio; Traina, Francesco; Toni, Aldo
The combination of materials that still has highest wear resistance for total hip replacement is ceramic-on-ceramic. However, brittleness is a major concern for ceramics: in vivo and in vitro studies on ceramic hip prostheses correlate microseparation with hip noise, ceramic wear, or ceramic liner damage. Ceramic microseparation can lead to edge load, ceramic head wear, and squeaking. The aim of this in vitro study was to investigate whether different angles of inclination influence the wear pattern of alumina-on-alumina hip joints with micro-separation during the swing phase. We also evaluated the wear rate obtained from this in vitro investigation with retrieval specimens obtained at 13 years' mean follow-up. The study was performed using a 12-station hip joint wear simulator (Shore Western, Monrovia, CA, USA) under bovine calf serum used as lubricant. Wear was evaluated by the gravimetric method and the test length was set at two million cycles. After two million cycles, a volumetric loss of 0.11 ±0.03 mm3 and 0.12 ±0.06 mm3 was observed, respectively, for 23° and 63° angles of inclination. In particular, the results obtained in this work revealed an increase of about 12-fold compared to previous results without microseparation conditions. No significant differences were observed between the two different inclinations on the wear patterns of the acetabular cups with a level of significance of a = 0.5. The location and general shape of the stripes wear were similar for the retrieved and simulator balls. PMID:21725932
Clinical usefulness of blood metal measurements to assess the failure of metal-on-metal hip implants
Sampson, Barry; Hart, Alister
In April 2010, a Medicines and Healthcare Products Regulatory Agency safety alert concerning all metal-on-metal (MOM) hip replacements recommended measuring chromium and cobalt concentrations when managing patients with painful prostheses. The need for this review is illustrated by the recent surge in requests for these blood tests from orthopaedic surgeons following this alert. The aim is to provide guidance to laboratories in assessing these requests and advising clinicians on interpretation. First, we summarize the basic terminology regarding the types of hip replacements, with emphasis on the MOM type. Second, we describe the clinical concerns over implant-derived wear debris in the local tissues and distant sites. Analytical aspects of the measurement of the relevant metal ions and what factors affect the levels measured are discussed. The application of inductively coupled plasma mass spectrometry techniques to the measurement of these metals is considered in detail. The biological effects of metal wear products are summarized with local toxicity and systemic biological effects considered, including carcinogenicity, genotoxicity and systemic toxicity. Clinical cases are used to illustrate pertinent points. PMID:22155921
Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft
Winkler, Heinz
Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage exchange, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeons´ decisions and in the majority of cases directs them to multiple stage protocols. However, there is no scientifically based argument for that practice. Successful eradication of infection with two stage procedures is reported to average 80% to 98%. On the other hand a literature review of Jackson and Schmalzried (CORR 2000) summarizing the results of 1,299 infected hip replacements treated with direct exchange (almost exclusively using antibiotic loaded cement), reports of 1,077 (83%) having been successful. The comparable results suggest, that the major factor for a successful outcome with traditional approaches may be found in the quality of surgical debridement and dead space management. Failures in all protocols seem to be caused by small fragments of bacterial colonies remaining after debridement, whereas neither systemic antibiotics nor antibiotic loaded bone cement (PMMA) have been able to improve the situation significantly. Reasons for failure may be found in the limited sensitivity of traditional bacterial culturing and reduced antibiotic susceptibility of involved pathogens, especially considering biofilm formation. Whenever a new prosthesis is implanted into a previously infected site the surgeon must be aware of increased risk of failure, both in single or two stage revisions. Eventual removal therefore should be easy with low risk of additional damage to the bony substance. On the other hand it should also have potential of a good long term result in case of success. Cemented revisions generally show inferior long term results compared to uncemented techniques; the addition of antibiotics to cement reduces its
Modular titanium alloy neck adapter failures in hip replacement - failure mode analysis and influence of implant material
Background Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery. The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68) of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years) postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years) and the average weight 102.3 kg (75 to 130 kg). The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. Methods A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Results Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck connection. A continuous
Factors influencing patients' willingness to pay for new technologies in hip and knee implants.
Schwarzkopf, Ran; Sagebin, Fabio M; Karia, Raj; Koenig, Karl M; Bosco, Joseph A; Slover, James D
Rising implant prices and evolving technologies are important factors contributing to the increased cost of arthroplasty. Assessing how patients value arthroplasty, new technologies, and their perceived outcomes is critical in planning cost-effective care, as well as evaluating new-technologies. One hundred one patients undergoing arthroplasty took part in the survey. We captured demographics, spending practices, knowledge of implants, patient willingness to pay for implants, and preferences related to implant attributes. When patients were asked if they would be satisfied with "standard of care" prosthesis, 80% replied "no". When asked if they would pay for a higher than "standard of care" prosthesis, 86% replied "yes". The study demonstrated that patients, regardless of their socio-economic status, are not satisfied with standard of care implants when newer technologies are available, and they may be willing to share in the cost of their prosthesis. Patients also prefer the option to choose what they perceive to be a higher quality or innovative implant even if the "out of pocket" cost is higher. PMID:23142436
Sensitivity analysis of a cemented hip stem to implant position and cement mantle thickness.
Shi, J; Browne, M; Strickland, M; Flivik, G; Taylor, M
Patient-specific finite element models of the implanted proximal femur can be built from pre-operative computed tomography scans and post-operative X-rays. However, estimating three-dimensional positioning from two-dimensional radiographs introduces uncertainty in the implant position. Further, accurately measuring the thin cement mantle and the degree of cement-bone interdigitation from imaging data is challenging. To quantify the effect of these uncertainties in stem position and cement thickness, a sensitivity study was performed. A design-of-experiment study was implemented, simulating both gait and stair ascent. Cement mantle stresses and bone-implant interface strains were monitored. The results show that small variations in alignment affect the implant biomechanics, especially around the most proximal and most distal ends of the stem. The results suggest that implant position is more influential than cement thickness. Rotation around the medial-lateral axis is the dominant factor in the proximal zones and stem translations are the dominant factors around the distal tip. PMID:23405986
A Randomised Multi-centre Study to Compare the Long-term Performance of the Future Hip to 3 Other Implants in Primary Total Hip Replacement
Osteoarthritis; Post-traumatic Arthritis; Collagen Disorders; Avascular Necrosis; Traumatic Femoral Fractures; Nonunion of Femoral Fractures; Congenital Hip Dysplasia; Slipped Capital Femoral Epiphysis; Perthes Disease
[Technical principles for removal of femoral bone cements in hip prosthesis implant revision].
Lauer, W; Neuss, M; Wirtz, D C; Radermacher, K
As the removal of femoral bone cement is one of the most challenging tasks in cemented total Hip Revision, a lot of different technical devices have been developed to aid the surgeon. All of their pros and cons are partly consequences of the specific system-design but mainly arise from the basic physical principles used. The known methods and devices as well as their data-handling have therefore been analysed, reduced to their principles according to the criteria of systematic engineering design and systematized in order to provide a better comparability and starting point for the development of new devices. PMID:12451769
Radiological evaluation of acetabular erosion after antibiotic-impregnated polymethylmethacrylate spacer (Spacer-G).
García-Oltra, Ester; Bori, Guillem; Tomas, Xavier; Gallart, Xavier; Garcia, Sebastian; Soriano, Alex
Different types of hip spacers have been described (hand-made, custom-molded or prefabricated) for treatment of a chronic hip infection. A potential disadvantage of monoblock prefabricated spacer is that it may cause acetabular bone loss. This study assesses the radiological acetabular erosion using an antibiotic-impregnated pre-fabricated polymethylmethacrylate Spacer-G. We retrospectively reviewed the radiographs of thirty five patients who were managed with Spacer-G to treat chronic hip infection. No acetabular erosion were observed in thirty two patients with a mean time from the first to second stage and from the first to the last radiograph of 5.09 and 3.77 months respectively. In three patients the time between the radiographs was more than one year and the second stage was not performed; two developed a protrusion acetabuli whereas the other one a destruction of the acetabular roof. Using a Spacer-G in chronic hip infection treatment for less than one year is not associated with radiological acetabular erosion if the patient is maintained at partial weight bearing. PMID:23142448
Full-field in vitro measurements and in silico predictions of strain shielding in the implanted femur after total hip arthroplasty.
Chanda, Souptick; Dickinson, Alexander; Gupta, Sanjay; Browne, Martin
Alterations in bone strain as a result of implantation may contribute towards periprosthetic bone density changes after total hip arthroplasty. Computational models provide full-field strain predictions in implant-bone constructs; however, these predictions should be verified using experimental models wherever it is possible. In this work, finite element predictions of surface strains in intact and implanted composite femurs were verified using digital image correlation. Relationships were sought between post-implantation strain states across seven defined Gruen zones and clinically observed longer-term bone density changes. Computational predictions of strain distributions in intact and implanted femurs were compared to digital image correlation measurements in two regions of interest. Regression analyses indicated a strong linear correlation between measurements and predictions (R = 0.927 intact, 0.926 implanted) with low standard error (standard error = 38 µε intact, 26 µε implanted). Pre- to post-operative changes in measured and predicted surface strains were found to relate qualitatively to clinically observed volumetric bone density changes across seven Gruen zones: marked proximal bone density loss corresponded with a 50%-64% drop in surface strain, and slight distal density changes corresponded with 4%-14% strain increase. These results support the use of digital image correlation as a pre-clinical tool for predicting post-implantation strain shielding, indicative of long-term bone adaptations. PMID:26112349
Biophysical stimulation and the periprosthetic bone: is there a rationale in the use of Pulsed Electromagnetic Fields after a hip or knee implant?
Massari, L; Osti, R; Lorusso, V; Setti, S; Caruso, G
The biophysical stimulation of bone and cartilage, using Pulsed ElectroMagnetic Fields (PEMF), covers many different aspects of bone formation and/or cartilage repair, such as healing of delayed or non-union of fracture, bone necrosis, osteocartilagineous defects. To date there are no specific data on the effects of PEMFs in osteointegration of prosthetic implants but there are some papers that denote clinical advantages, in terms of early recovery, in patients treated with these procedures. Considering these clinical applications, PEMF stimulation around hip or knee joint implants could be useful to reduce the bone oedema, pain and to reduce excessive bone reabsorption around the femoral stems. PMID:26753669
[Use of gold implants as a treatment of pain related to canine hip dysplasia--a review. Part 2: Clinical trials and case reports].
Deisenroth, A; Nolte, I; Wefstaedt, P
Gold bead implantation/gold acupuncture is becoming increasingly used in veterinary medicine as a method of pain treatment in cases of osteoarthritic diseases. Part one of the overview dealing with the use of gold implants as a treatment of canine hip joint dysplasia (cHD) introduced the method of implanting gold in tissue and publications which investigated the subsequent effects of implantation. This article focuses on publications concerning the clinical effectiveness of gold implantation within the scope of pain therapy in cHD. Due to the study design, a classification using evidence-based levels (EbL) was carried out. Three double-blind, placebo-controlled randomised studies (EbL II) were considered together with three retrospective studies on own patients (EbL IV) and five case studies (EbL IV). While the case and retrospective studies reported impressive therapeutic success in treating cHD-incurred pain with gold implantation, a pain-reducing effect through gold implantation was only demonstrated in one of the three double-blind studies. The two remaining EbL II studies found no differences between the placebo-group and the group of dogs treated with gold implantation. In one of these two studies, kinematic and kinetic gait analyses were used for objective evaluation of the effects of the treatment. Thus, the only study that carried out an objective evaluation of the therapeutic result of gold implantation came to the conclusion that the method is ineffective. For a concluding assessment of gold implantation in the case of cHD, gait analysis studies investigating the effects of gold implantation in comparison to a standard treatment with nonsteroidal anti-inflammatory drugs are currently lacking. PMID:23958708
Pore Geometry Optimization of Titanium (Ti6Al4V) Alloy, for Its Application in the Fabrication of Customized Hip Implants
Roy, Sandipan; Panda, Debojyoti; Khutia, Niloy; Chowdhury, Amit Roy
The present study investigates the mechanical response of representative volume elements of porous Ti-6Al-4V alloy, to arrive at a desired range of pore geometries that would optimize the reduction in stiffness necessary for biocompatibility with the stress concentration arising around the pore periphery, under physiological loading conditions with respect to orthopedic hip implants. A comparative study of the two is performed with the aid of a newly defined optimizing parameter called pore efficiency that takes into consideration both the stiffness quantity and the stress localization around pores. To perform a detailed analysis of the response of the porous structure over the entire spectrum of loading conditions that a hip implant is subjected to in vivo, the mechanical responses of 3D finite element models of cubic and rectangular parallelepiped geometries, with porosities varying over a range of 10% to 60%, are simulated under representative compressive, flexural as well as combined loading conditions. The results that are obtained are used to suggest a range of pore diameters that lower the effective stiffness and modulus of the implant to around 60% of the stiffness and modulus of dense solid implants while keeping the stress levels within permissible limits. PMID:25400663
Management of Periprosthetic Hip Joint Infection
Lee, Hee Dong; Prashant, Kumar
Total hip joint replacement offers dramatic improvement in the quality of life but periprosthetic joint infection (PJI) is the most devastating complication of this procedure. The infection threatens the function of the joint, the preservation of the limb, and occasionally even the life of the patient due to long term hospitalization and high cost. For the surgeon it is a disastrous burden, which requires repeated, complicated procedures to eradicate infection and to provide a mobile joint without pain. Yet in the absence of a true gold standard, the diagnosis of PJI can be elusive. Synovial fluid aspiration, diagnostic imaging, traditional culture, peripheral serum inflammatory markers, and intraoperative frozen sections each have their limitations but continue to be the mainstay for diagnosis of PJI. Treatment options mainly include thorough irrigation and debridement with prosthesis retention, or a two-stage prosthesis exchange with intervening placement of an antibiotic-loaded spacer. Success in treating PJI depends on extensive surgical debridement and adequate and effective antibiotic therapy. Treatment in two stages using a spacer is recommended for most chronic PJI. Debridement, antibiotics and implant retention is the obvious choice for treatment of acute PJI, with good success rates in selected patients. This article presents an overview of recent management concepts for PJI of the hip emphasizing diagnosis and the clinical approach, and also share own experience at our institution.
Radiographic identification of loose bodies in the traumatized hip joint
Baird, R.A.; Schobert, W.E.; Pais, M.J.; Ahmed, M.; Wilson, W.J.; Farjalla, G.L.; Imray, T.J.
Acrylic spacers and cubes of cortical bone of known dimensions were placed in predetermined locations in cadaver hip joints, which were then studied with plain radiography and linear, hypocycloidal, and computed tomography (CT). Joint space widening was not measurable on plain radiographs of the pelvis when 2-mm spacers were placed anywhere within the hip joint. When 4-mm spacers were used, widening measured 2 mm in the axis of measurement corresponding to the location of the spacer. Linear tomography did not permit identification of the 2-mm cubes; however, hypocycloidal tomography and CT consistently showed them anywhere within the hip joint. Radiation dose and clinical recommendations are discussed.
First insight on the impact of an osteoblastic layer on the bio-tribocorrosion performance of Ti6Al4V hip implants.
Runa, M J; Mathew, M T; Fernandes, M H; Rocha, L A
In uncemented Ti6Al4V hip implants, the bone-stem interface is subjected to cyclic loading motion driven by the daily activities of the patients, which may lead to the complete failure of the implant in the long term. It may also compromise the proliferation and differentiation processes of osteoblastic cells (bone-forming cells). The main objective of this work is to approach for the first time the role of these organic materials on the bio-tribocorrosion mechanisms of cultured Ti6Al4V alloys. The colonized materials with MG63 osteoblastic-like cells were characterized through cell viability/proliferation and enzymatic activity. Tribocorrosion tests were performed under a reciprocating sliding configuration and low contact pressure. Electrochemical techniques were used to measure the corrosion kinetics of the system, under free potential conditions. All tests were performed at a controlled atmosphere. The morphology and topography of the wear scar were evaluated. The results showed that the presence of an osteoblastic cell layer on the implant surface significantly influences the tribocorrosion behavior of Ti6Al4V alloy. It was concluded that the cellular material was able to form an extra protective layer that inhibits further wear degradation of the alloy and decreases its corrosion tendency. PMID:25448346
Mechanical implications of interfacial defects between femoral hip implants and cement: a finite element analysis of interfacial gaps and interfacial porosity.
Scheerlinck, T; Broos, J; Janssen, D; Verdonschot, N
Two types of defect between femoral hip implants and cement have been identified. Interfacial porosity arises from cement shrinkage during curing and presents as pores randomly located along the stem. Interfacial gaps are much larger stem-cement separations caused by air introduced during stem insertion. To investigate the mechanical consequences of both types of defect, a finite element analysis model was created on the basis of a computed tomography image of a Charnley-Kerboul stem, and alternating torsional and transverse loads were applied. The propagation of fatigue cracks within the cement and the rotational stability of the stem were assessed in models simulating increasing amounts of interfacial gaps and pores. Anterior gaps covering at least 30 per cent of the implant surface promoted cement cracks and destabilized the stem. Anterolateral gaps were less destabilizing, but had more potential to promote cracks. In both cases, cracks occurred mainly outside gap regions, in areas where the stem contacted the cement during cyclic loading. Although random interfacial pores did not destabilize the implant, they acted as crack initiators even at low fractions (10 per cent). In conclusion, random interfacial pores were more harmful for the cement mantle integrity than were larger regions of interfacial gaps, although gaps were more detrimental for the rotational stability of the stem. PMID:19024152
A Two Phase Treatment of an Infected Hip Endoprosthesis.
Ciriviri, Jasmin; Talevski, Darko; Nestorovski, Zoran; Vraniskoski, Tode; Mishevska-Perchinkova, Snežana
The revision of the two phase treatment represents a golden standard in the treatment of infected endoprosthesis. Throughout this study, the results of 21 patients with an infected hip endoprosthesis treated in two phases have been processed, with the use of an antibiotic spacer, within the period of 2009 and 2012. Thereby, a unique protocol for diagnosis and treatment of infections has been applied to all the patients, which entails a preoperational x-ray image, laboratory findings (Se, CRP), as well as a puncture aspiration with a microbiological and biochemical examination of the aspirated fragments. The operational treatment consists of: taking a sample for microbiological and histopathological diagnosis, removal of the implanted endoprosthesis, excision of the avascular and necrotic tissue and installing an antibiotic spacer. Postoperatively, the patients are treated with a parenteral application of an antibiotics based on an antibiogram, throughout a period of two weeks, and later on an oral treatment, a combination of two antibiotics, depending on the antibiogram, within the following four to six weeks. After the appeasement of the local findings and the laboratory results, a revision with a removal of the antibiotic spacer and reimplantation of an endoprosthesis - revisional or primary has been conducted on the patients, depending on the bone deficit. The functionality of the joint is graded based on the Haris Hip Score. The patients are being observed postoperatively for a period of 12 to 36 months. A definite reimplantation has been applied to 20 patients, while one patient has been treated with a resection method. The Haris Hip Score was 45 preoperatively, and 80 postoperatively. The applied protocol of the treatment of infected endoprosthesis is effective in the eradication of the infection and the final reimplantation. PMID:27442385
Metal-on-Metal Hip Prostheses and Systemic Health: A Cross-Sectional Association Study 8 Years after Implantation
Prentice, Jennifer R.; Clark, Matthew J.; Hoggard, Nigel; Morton, Allison C.; Tooth, Claire; Paley, Martyn N.; Stockley, Ian; Hadjivassiliou, Marios; Wilkinson, J. Mark
There is public concern over the long term systemic health effects of metal released from hip replacement prostheses that use large-diameter metal-on-metal bearings. However, to date there has been no systematic study to determine which organs may be at risk, or the magnitude of any effect. We undertook a detailed cross-sectional health screen at a mean of 8 years after surgery in 35 asymptomatic patients who had previously received a metal-on-metal hip resurfacing (MoMHR) versus 35 individually age and sex matched asymptomatic patients who had received a conventional hip replacement. Total body bone mineral density was 5% higher (mean difference 0.05 g/cm2, P = 0.02) and bone turnover was 14% lower (TRAP 5b, mean difference −0.56IU/L, P = 0.006; osteocalcin, mean difference −3.08 ng/mL, P = 0.03) in the hip resurfacing versus conventional hip replacement group. Cardiac ejection fraction was 7% lower (mean absolute difference −5%, P = 0.04) and left ventricular end-diastolic diameter was 6% larger (mean difference 2.7 mm, P = 0.007) in the hip resurfacing group versus those patients who received a conventional hip replacement. The urinary fractional excretion of metal was low (cobalt 5%, chromium 1.5%) in patients with MoMHR, but creatinine clearance was normal. Diuretic prescription was associated with a 40% increase in the fractional excretion of chromium (mean difference 0.5%, P = 0.03). There was no evidence of difference in neuropsychological, renal tubular, hepatic or endocrine function between groups (P>0.05). Our findings of differences in bone and cardiac function between patient groups suggest that chronic exposure to low elevated metal concentrations in patients with well-functioning MoMHR prostheses may have systemic effects. Long-term epidemiological studies in patients with well-functioning metal on metal hip prostheses should include musculoskeletal and cardiac endpoints to quantitate the risk of clinical disease. PMID
Autoclaved metal-on-cement spacer versus static spacer in two-stage revision in periprosthetic knee infection
Chen, Yu-Pin; Wu, Cheng-Chun; Ho, Wei-Pin
Background: Periprosthetic knee infection is troublesome for Orthopedic surgeons and a catastrophy for patients. Reported rates of periprosthetic joint infection following primary total knee arthroplasty (TKA) are 0.39–2%. Two stage revision arthroplasty, which has success rates exceeding 90%, has been the gold standard for treating subacute and chronic periprosthetic infection following TKA. Antibiotic spacers, a well established means of delivering local antibiotic therapy, maintain soft tissue tension during two stage revision arthroplasty. However, controversy remains around whether static or mobile antibiotic impregnated spacers are superior for treating infection following TKA. Various mobile spacers are available, including cement-on-cement, cement-on-polyethylene and metal-on-polyethylene. In this study, the efficacy of the modified metal-on-cement spacer, consisting of reinsertion of the autoclaved femoral component and implantation of antibiotic-loaded cement in the proximal tibia, is assessed. Materials and Methods: Records of 19 patients diagnosed as periprosthetic knee infection were reviewed in this retrospective study. Among these patients, 10 patients received first stage debridement with the autoclaved metal-on-cement spacer and 8 patients with the static spacer, who eventually underwent two-stage re-implantation, were listed in the final comparison. Patient demographics, infection eradication rates, average range of motion (ROM), surgical time and blood loss during the second-stage of the surgery, and Knee Society (KS) knee scores at last followup after revision total knee replacement were clinically evaluated. Results: At a minimum of 2-year followup after re-implantation, infection eradication rates, surgical times, blood loss during the second-stage of the surgery, and KS knee score after re-implantation were similar for the two groups. Patients receiving autoclaved metal-on-cement spacers had superior ROM after re-implantation compared to
Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre
Sabah, S. A.; Henckel, J.; Cook, E.; Whittaker, R.; Hothi, H.; Pappas, Y.; Blunn, G.; Skinner, J. A.; Hart, A. J.
Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67 045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. Cite this article: Bone Joint J 2015;97-B:10–18. PMID:25568407
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Preliminary Results of Implantation in Animal Model and Osteoblast Culture Evaluation of Prototypes of Biomimetic Multispiked Connecting Scaffold for Noncemented Stemless Resurfacing Hip Arthroplasty Endoprostheses
Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; Kędzia, Andrzej; Ruszkowski, Piotr
We present the new fixation method for RHA (resurfacing hip arthroplasty) endoprostheses by means of the biomimetic multispiked connecting scaffold (MSC-Scaffold). Such connecting scaffold can generate new type of RHA endoprostheses, that is stemless and fixed entirely without cement. The preprototypes of this MSC-Scaffold were manufactured with modern additive laser additive technology (SLM). The pilot surgical implantations in animal model (two laboratory swine) of MSC-Scaffold preprototypes have showed after two months neither implant loosening, migration, and nor other early complications. From the results of performed histopathological evaluation of the periscaffold spikes bone tissue and 10-day culture of human osteoblasts (NHOst) we can conclude that (1) the scaffolding effect was obtained and (2) to improve the osseointegration of the scaffold spikes, their material surface should be physicochemically modified (e.g., with hydroxyapatite). Some histopathological findings in the periscaffold domain near the MSC-Scaffold spikes bases (fibrous connective tissue and metallic particles near the MSC-Scaffold spikes bases edges) prompt considering the necessity to optimize the design of the MSC-Scaffold in the regions of its interspike space near the spikes bases edges, to provide more room for new bone formation in this region and for indispensable post-processing (glass pearl blasting) after the SLM manufacturing. PMID:23984397
Impaction grafting in the femur in cementless modular revision total hip arthroplasty: a descriptive outcome analysis of 243 cases with the MRP-TITAN revision implant
Background We present a descriptive and retrospective analysis of revision total hip arthroplasties (THA) using the MRP-TITAN stem (Peter Brehm, Weisendorf, GER) with distal diaphyseal fixation and metaphyseal defect augmentation. Our hypothesis was that the metaphyseal defect augmentation (Impaction Bone Grafting) improves the stem survival. Methods We retrospectively analyzed the aggregated and anonymized data of 243 femoral stem revisions. 68 patients with 70 implants (28.8%) received an allograft augmentation for metaphyseal defects; 165 patients with 173 implants (71.2%) did not, and served as controls. The mean follow-up was 4.4 ± 1.8 years (range, 2.1–9.6 years). There were no significant differences (p > 0.05) between the study and control group regarding age, body mass index (BMI), femoral defects (types I-III as described by Paprosky), and preoperative Harris Hip Score (HHS). Postoperative clinical function was evaluated using the HHS. Postoperative radiologic examination evaluated implant stability, axial implant migration, signs of implant loosening, periprosthetic radiolucencies, as well as bone regeneration and resorption. Results There were comparable rates of intraoperative and postoperative complications in the study and control groups (p > 0.05). Clinical function, expressed as the increase in the postoperative HHS over the preoperative score, showed significantly greater improvement in the group with Impaction Bone Grafting (35.6 ± 14.3 vs. 30.8 ± 15.8; p ≤ 0.05). The study group showed better outcome especially for larger defects (types II C and III as described by Paprosky) and stem diameters ≥ 17 mm. The two groups did not show significant differences in the rate of aseptic loosening (1.4% vs. 2.9%) and the rate of revisions (8.6% vs. 11%). The Kaplan-Meier survival for the MRP-TITAN stem in both groups together was 93.8% after 8.8 years. [Study group 95.7% after 8.54 years ; control group 93.1% after 8
Multi-Disciplinary Antimicrobial Strategies for Improving Orthopaedic Implants to Prevent Prosthetic Joint Infections in Hip and Knee
Getzlaf, Matthew A.; Lewallen, Eric A.; Kremers, Hilal M.; Jones, Dakota L.; Bonin, Carolina A.; Dudakovic, Amel; Thaler, Roman; Cohen, Robert C.; Lewallen, David G.; van Wijnen, Andre J.
Like any foreign object, orthopaedic implants are susceptible to infection when introduced into the human body. Without additional preventative measures, the absolute number of annual prosthetic joint infections will continue to rise, and may exceed the capacity of health care systems in the near future. Bacteria are difficult to eradicate from synovial joints due to their exceptionally diverse taxonomy, complex mechanistic attachment capabilities, and tendency to evolve antibiotic resistance. When a primary orthopaedic implant fails from prosthetic joint infection, surgeons are generally challenged by limited options for intervention. In this review, we highlight the etiology and taxonomic groupings of bacteria known to cause prosthetic joint infections, and examine their key mechanisms of attachment. We propose that antimicrobial strategies should focus on the most harmful bacteria taxa within the context of occurrence, taxonomic diversity, adhesion mechanisms, and implant design. Patient-specific identification of organisms that cause prosthetic joint infections will permit assessment of their biological vulnerabilities. The latter can be targeted using a range of antimicrobial techniques that exploit different colonization mechanisms including implant surface attachment, biofilm formation, and/or hematogenous recruitment. We anticipate that customized strategies for each patient, joint, and prosthetic component will be most effective at reducing prosthetic joint infections, including those caused by antibiotic-resistant and polymicrobial bacteria. PMID:26449208
Multi-disciplinary antimicrobial strategies for improving orthopaedic implants to prevent prosthetic joint infections in hip and knee.
Getzlaf, Matthew A; Lewallen, Eric A; Kremers, Hilal M; Jones, Dakota L; Bonin, Carolina A; Dudakovic, Amel; Thaler, Roman; Cohen, Robert C; Lewallen, David G; van Wijnen, Andre J
Like any foreign object, orthopaedic implants are susceptible to infection when introduced into the human body. Without additional preventative measures, the absolute number of annual prosthetic joint infections will continue to rise, and may exceed the capacity of health care systems in the near future. Bacteria are difficult to eradicate from synovial joints due to their exceptionally diverse taxonomy, complex mechanistic attachment capabilities, and tendency to evolve antibiotic resistance. When a primary orthopaedic implant fails from prosthetic joint infection, surgeons are generally challenged by limited options for intervention. In this review, we highlight the etiology and taxonomic groupings of bacteria known to cause prosthetic joint infections, and examine their key mechanisms of attachment. We propose that antimicrobial strategies should focus on the most harmful bacteria taxa within the context of occurrence, taxonomic diversity, adhesion mechanisms, and implant design. Patient-specific identification of organisms that cause prosthetic joint infections will permit assessment of their biological vulnerabilities. The latter can be targeted using a range of antimicrobial techniques that exploit different colonization mechanisms including implant surface attachment, biofilm formation, and/or hematogenous recruitment. We anticipate that customized strategies for each patient, joint, and prosthetic component will be most effective at reducing prosthetic joint infections, including those caused by antibiotic-resistant and polymicrobial bacteria. PMID:26449208
Wear particles derived from metal hip implants induce the generation of multinucleated giant cells in a 3-dimensional peripheral tissue-equivalent model.
Dutta, Debargh K; Potnis, Pushya A; Rhodes, Kelly; Wood, Steven C
Multinucleate giant cells (MGCs) are formed by the fusion of 5 to 15 monocytes or macrophages. MGCs can be generated by hip implants at the site where the metal surface of the device is in close contact with tissue. MGCs play a critical role in the inflammatory processes associated with adverse events such as aseptic loosening of the prosthetic joints and bone degeneration process called osteolysis. Upon interaction with metal wear particles, endothelial cells upregulate pro-inflammatory cytokines and other factors that enhance a localized immune response. However, the role of endothelial cells in the generation of MGCs has not been completely investigated. We developed a three-dimensional peripheral tissue-equivalent model (PTE) consisting of collagen gel, supporting a monolayer of endothelial cells and human peripheral blood mononuclear cells (PBMCs) on top, which mimics peripheral tissue under normal physiological conditions. The cultures were incubated for 14 days with Cobalt chromium alloy (CoCr ASTM F75, 1-5 micron) wear particles. PBMC were allowed to transit the endothelium and harvested cells were analyzed for MGC generation via flow cytometry. An increase in forward scatter (cell size) and in the propidium iodide (PI) uptake (DNA intercalating dye) was used to identify MGCs. Our results show that endothelial cells induce the generation of MGCs to a level 4 fold higher in 3-dimentional PTE system as compared to traditional 2-dimensional culture plates. Further characterization of MGCs showed upregulated expression of tartrate resistant alkaline phosphatase (TRAP) and dendritic cell specific transmembrane protein, (DC-STAMP), which are markers of bone degrading cells called osteoclasts. In sum, we have established a robust and relevant model to examine MGC and osteoclast formation in a tissue like environment using flow cytometry and RT-PCR. With endothelial cells help, we observed a consistent generation of metal wear particle- induced MGCs, which heralds
Cementless Hydroxyapatite Coated Hip Prostheses
Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda
More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848
... surgeon removes damaged cartilage and bone from your hip joint and replaces them with new, man-made parts. A hip replacement can Relieve pain Help your hip joint work better Improve walking and other movements The ...
Accuracy of methods for calculating volumetric wear from coordinate measuring machine data of retrieved metal-on-metal hip joint implants.
Lu, Zhen; McKellop, Harry A
This study compared the accuracy and sensitivity of several numerical methods employing spherical or plane triangles for calculating the volumetric wear of retrieved metal-on-metal hip joint implants from coordinate measuring machine measurements. Five methods, one using spherical triangles and four using plane triangles to represent the bearing and the best-fit surfaces, were assessed and compared on a perfect hemisphere model and a hemi-ellipsoid model (i.e. unworn models), computer-generated wear models and wear-tested femoral balls, with point spacings of 0.5, 1, 2 and 3 mm. The results showed that the algorithm (Method 1) employing spherical triangles to represent the bearing surface and to scale the mesh to the best-fit surfaces produced adequate accuracy for the wear volume with point spacings of 0.5, 1, 2 and 3 mm. The algorithms (Methods 2-4) using plane triangles to represent the bearing surface and to scale the mesh to the best-fit surface also produced accuracies that were comparable to that with spherical triangles. In contrast, if the bearing surface was represented with a mesh of plane triangles and the best-fit surface was taken as a smooth surface without discretization (Method 5), the algorithm produced much lower accuracy with a point spacing of 0.5 mm than Methods 1-4 with a point spacing of 3 mm. PMID:24531891
The 3-6-year results of a modular noncemented low-bending stiffness hip implant. A preliminary study.
Cameron, H U
A review of the 3-6-year clinical and radiographic results of a modular noncemented stem has been carried out. This is a three-part stem consisting of a head, stem, and proximal sleeve. The stems are split distally like a clothespin in the coronal plane to reduce bending stiffness. No mechanical failures have occurred, including no bead separation from the single-layer porous-coated taper lock sleeves. Of the 48 cases, 13 had smooth stems distally while the rest were fluted. Five of the fluted stems were solid, that is, nonsplit. Clinical results are 93.7% excellent, 4.2% good, and 2.1% poor with the Harris hip rating. There have been no revisions. Thigh pain incidence with the distal split stem was 4.4%. Radiographic follow-up evaluations revealed nonprogressive radiolucency around one of the ingrowth sleeves. When inserted in varus the smooth stems developed some radiolucency around the distal end. Fluting of the stem appeared to prevent this. PMID:8326303
Total Hip Arthroplasty Dislocations Are More Complex Than They Appear: A Case Report of Intraprosthetic Dislocation of an Anatomic Dual-Mobility Implant After Closed Reduction
Waddell, Bradford S.; De Martino, Ivan; Sculco, Thomas; Sculco, Peter
Background: Total hip arthroplasty is a successful operation for the treatment of hip pain. One of the common complications of hip arthroplasty is dislocation. While reduction of standard prosthetic dislocations is highly successful, new prostheses add the potential for new complications. Case Report: We present the case of a patient who experienced intraprosthetic dislocation of an anatomic dual-mobility total hip prosthesis after a closed hip reduction and include the prereduction and postreduction radiographic findings. Conclusion: Emergency department physicians should be aware of intraprosthetic dislocation. This complication can be easily missed because the metal/ceramic femoral head appears to be reduced in the acetabulum. PMID:27303232
Comparison of Whole-Blood Metal Ion Levels Among Four Types of Large-Head, Metal-on-Metal Total Hip Arthroplasty Implants: A Concise Follow-up, at Five Years, of a Previous Report.
Hutt, Jonathan; Lavigne, Martin; Lungu, Eugen; Belzile, Etienne; Morin, François; Vendittoli, Pascal-André
Few studies of total hip arthroplasty (THA) implants with a large-diameter femoral head and metal-on-metal design have directly compared the progression of metal ion levels over time and the relationship to complications. As we previously reported, 144 patients received one of four types of large-diameter-head, metal-on-metal THA designs (Durom, Birmingham, ASR XL, or Magnum implants). Cobalt, chromium, and titanium ion levels were measured over five years. We compared ion levels and clinical results over time. The Durom group showed the highest levels of cobalt (p ≤ 0.002) and titanium ions (p ≤ 0.03). Both the Durom and Birmingham groups demonstrated significant ongoing cobalt increases up to five years. Eight patients (seven with a Durom implant and one with a Birmingham implant) developed adverse local tissue reaction. Six Durom implants and one Birmingham implant required revision, with one pseudotumor under surveillance at the time of the most recent follow-up. We found that ion generation and related complications varied among designs. More concerning was that, for some designs, ion levels continued to increase. Coupling a cobalt-chromium adapter sleeve to an unmodified titanium femoral trunnion along with a large metal-on-metal bearing may explain the poor performances of two of the designs in the current study. PMID:26888673
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Gollwitzer, H; Banke, I J; Schauwecker, J
Hip arthroscopy represents an important component in the treatment of diseases of the hip joint and is nowadays an indispensible tool in modern hip-preserving surgery. This article provides a review of the basic technical principles, typical indications and complications of hip arthroscopy. Furthermore, current developments as well as possibilities and limitations of the arthroscopic technique are reviewed. PMID:26781702
Cementless total hip arthroplasty.
Morscher, E W
The differences between prostheses fixed with and without cement are mainly in the design and nature of the surface implant. The shapes of the sockets to be implanted without cement show a wide variety: cylinder, square, conus, and ellipsoid with and without threads. The hemispheric shape, however, which was chosen for the acetabular component of the isoelastic hip joint, does not disturb the natural form and function of the hip joint since the outer surface is closely adapted to the original subchondral bone layer. The noncemented cup is secured by threads, pegs, screws, etc., and by ingrowth of bony tissue in the grooves of the surfaces. Most femoral stems are based on the self-locking principle. All prosthetic models incorporate attempts to increase the surface of the stem (ribs, wings, corrugations, rims, etc.). There is a tendency to use less rigid elastic implants instead of the well known rigid metallic prostheses. The aim is to overcome the problems of stress protection and stress concentration observed with rigid implants. For the biomechanical integration of an implant, the properties of the surface, especially macroporosity and microporosity, are important. Most European models of noncemented endoprostheses are based on macroporosity (porometal, madreporic, etc.). The increase in implant surface area achieved with macroscopic perforations and recesses is relatively minor compared with the possibilities offered by microporosity ("alumine fritée," Proplast, fiber-metal, etc.). The best indication for use of a cementless hip endoprosthesis is in revision arthroplasty. The lost bone stock is replaced by bone grafts, thereby creating a situation comparable with that of a primary arthroplasty. Clinical experience with noncemented hip endoprostheses is, to date, promising, although the observation time for most models is short. PMID:6357588
Smith, Matthew V; Sekiya, Jon K
Hip instability is becoming a more commonly recognized source of pain and disability in patients. Traumatic causes of hip instability are often clear. Appropriate treatment includes immediate reduction, early surgery for acetabular rim fractures greater than 25% or incarcerated fragments in the joint, and close follow-up to monitor for avascular necrosis. Late surgical intervention may be necessary for residual symptomatic hip instability. Atraumatic causes of hip instability include repetitive external rotation with axial loading, generalized ligamentous laxity, and collagen disorders like Ehlers-Danlos. Symptoms caused by atraumatic hip instability often have an insidious onset. Patients may have a wide array of hip symptoms while demonstrating only subtle findings suggestive of capsular laxity. Traction views of the affected hip can be helpful in diagnosing hip instability. Open and arthroscopic techniques can be used to treat capsular laxity. We describe an arthroscopic anterior hip capsular plication using a suture technique. PMID:20473129
What is the risk of death or severe harm due to bone cement implantation syndrome among patients undergoing hip hemiarthroplasty for fractured neck of femur? A patient safety surveillance study
Rutter, Paul D; Panesar, Sukhmeet S; Darzi, Ara; Donaldson, Liam J
Objective To estimate the risk of death or severe harm due to bone cement implantation syndrome (BCIS) among patients undergoing hip hemiarthroplasty for fractured neck of femur. Setting Hospitals providing secondary and tertiary care throughout the National Health Service (NHS) in England and Wales. Participants Cases reported to the National Reporting and Learning System (NRLS) in which the reporter clearly describes severe acute patient deterioration associated with cement use in hip hemiarthroplasty for fractured neck of femur (assessed independently by two reviewers). Outcome measures Primary—number of reported deaths, cardiac arrests and periarrests per year. Secondary—timing of deterioration and outcome in relation to cement insertion. Results Between 2005 and 2012, the NRLS received 62 reports that clearly describe death or severe harm associated with the use of cement in hip hemiarthroplasty for fractured neck of femur. There was one such incident for every 2900 hemiarthroplasties for fractured neck of femur during the period. Of the 62 reports, 41 patients died, 14 were resuscitated from cardiac arrest and 7 from periarrest. Most reports (55/62, 89%) describe acute deterioration occurring during or within a few minutes of cement insertion. The vast majority of deaths (33/41, 80%) occurred on the operating table. Conclusions These reports provide narrative evidence from England and Wales that cement use in hip hemiarthroplasty for fractured neck of femur is associated with instances of perioperative death or severe harm consistent with BCIS. In 2009, the National Patient Safety Agency publicised this issue and encouraged the use of mitigation measures. Three-quarters of the deaths in this study have occurred since that alert, suggesting incomplete implementation or effectiveness of those mitigation measures. There is a need for stronger evidence that weighs the risks and benefits of cement in hip hemiarthroplasty for fractured neck of femur. PMID
... HIPS. See your doctor. Use ice and an anti-inflammatory medicine to relieve the pain. *3. Do you ... hip pain may be from ARTHRITIS. Try an anti-inflammatory medicine. If you don't feel better, see ...
... replacement is an operation in which a damaged hip joint is removed and replaced with an artificial joint. ... are many medical conditions that can damage the hip joint. (Watch the video to learn about what goes ...
Ertapenem Articulating Spacer for the Treatment of Polymicrobial Total Knee Arthroplasty Infection
Marinkovic, Jugoslav
Introduction. Periprosthetic joint infections (PJIs) are the primary cause of early failure of the total knee arthroplasty (TKA). Polymicrobial TKA infections are often associated with a higher risk of treatment failure. The aim of the study was to assess the efficacy of ertapenem loaded spacers in the treatment of polymicrobial PJI. Methods. There were 18 patients enrolled; nine patients with polymicrobial PJI treated with ertapenem loaded articulating spacers were compared to the group of 9 patients treated with vancomycin or ceftazidime loaded spacers. Results. Successful reimplantation with revision implants was possible in 66.67%. Ertapenem spacers were used in 6 cases in primary two-stage procedure and in 3 cases in secondary spacer exchange. Successful infection eradication was achieved in all cases; final reimplantation with revision knee arthroplasty implants was possible in 6 cases. Conclusion. Ertapenem can be successfully used as antimicrobial addition to the cement spacers in two-stage revision treatment of polymicrobial PJIs. However, this type of spacer may also be useful in the treatment of infections caused by monomicrobial extended spectrum beta-lactamases producing gram-negative bacilli. Further clinical studies are required to evaluate the efficacy and safety of ertapenem spacers in the treatment of polymicrobial and monomicrobial PJIs. PMID:27366173
Nanoparticles based brachytherapy spacers for delivery of localized combined chemo-radiation therapy
Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G; Sridhar, Srinivas
Purpose In radiation therapy (RT), brachytherapy inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Materials and Methods Here we have fabricated Implantable Nanoplatforms or Chemo-Radiation Therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow release drug depot for simultaneous localized chemo-radiation therapy. The spacers are made of poly(lactic-coglycolic) acid (PLGA) as matrix, were physically identical (size) to the commercially available brachytherapy spacers (5mm×0.8mm). The silica nanoparticles with diameter 250nm conjugated with near infrared fluorophore Cy7.5 as a model drug and the INCeRT spacers were characterized in terms of size, morphology and composition using different instrumentation techniques. The spacers were further doped with anticancer drug, docetaxel. We have evaluated the in vivo stability, biocompatibility and biodegradation of these spacers in live mouse tissues. Results The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked using optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue as opposed to the control Cy7.5-PLGA spacer which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth as opposed to control mice over 16 days. Conclusions The imaging with the Cy7.5-spacer and therapeutic efficacy with docetaxel-spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in slow, sustained manner in conjunction with brachytherapy, as opposed to rapid clearance of the drugs when administered systemically. The results demonstrate
Nanoparticle-Based Brachytherapy Spacers for Delivery of Localized Combined Chemoradiation Therapy
Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G.; Sridhar, Srinivas
Purpose: In radiation therapy (RT), brachytherapy-inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Methods and Materials: Here we have fabricated implantable nanoplatforms or chemoradiation therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow-release drug depot for simultaneous localized chemoradiation therapy. The spacers are made of poly(lactic-co-glycolic) acid (PLGA) as matrix and are physically identical in size to the commercially available brachytherapy spacers (5 mm × 0.8 mm). The silica nanoparticles, 250 nm in diameter, were conjugated with near infrared fluorophore Cy7.5 as a model drug, and the INCeRT spacers were characterized in terms of size, morphology, and composition using different instrumentation techniques. The spacers were further doped with an anticancer drug, docetaxel. We evaluated the in vivo stability, biocompatibility, and biodegradation of these spacers in live mouse tissues. Results: The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked by the use of optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue in contrast to the control Cy7.5-PLGA spacer, which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth in contrast to control mice over 16 days. Conclusions: The imaging with the Cy7.5 spacer and therapeutic efficacy with docetaxel spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in a slow, sustained manner in conjunction with brachytherapy, in contrast to the rapid clearance of the drugs when
Active Robotics for Total Hip Arthroplasty.
Dungy, Danton S; Netravali, Nathan A
Robotics and computer-assisted navigation have been developed to increase the accuracy of hip implant placement and improve long-term outcomes of total hip arthroplasty (THA). These technologies have shown significant improvements in implant positioning when compared to conventional techniques. Currently, 3 robotic systems are cleared for use for THA in the US. The lead author (DSD) describes his preferred technique for using one of these systems, the TSolution One® (Think Surgical, Inc.). PMID:27327918
Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre: a study using the NJR dataset.
Sabah, S A; Henckel, J; Cook, E; Whittaker, R; Hothi, H; Pappas, Y; Blunn, G; Skinner, J A; Hart, A J
Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67,045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. PMID:25568407
Relative importance of gait vs. joint positioning on hip contact forces after total hip replacement.
Foucher, Kharma C; Hurwitz, Debra E; Wimmer, Markus A
Implant loosening is a common indication for total hip replacement (THR) revision. High contact forces and implant twisting moments are thought to be associated with implant loosening. Relationships between joint positioning and hip forces, or outcomes, have been investigated through in vivo and in vitro modalities. Relationships between hip forces and gait are less understood, despite repeated findings that gait following a THR does not fully return to normal. We tested the hypothesis that gait parameters would be better predictors of implant force (peak contact forces and peak twisting moment during walking) than joint positioning parameters. Subjects underwent gait analysis, hip force modeling, and measurement of clinical radiographs 1 year after successful THR surgery. Gait parameters were consistently more influential in determining hip forces. Alone, gait explained as much as 67% of the variation in force, compared to a maximum of 33% by joint geometry. Combinations of gait and joint positioning parameters together explained up to 86% of the variation in hip force parameters. Results suggest that gait may provide a valuable postoperatively modifiable target to improve hip loads and potentially reduce the risk for implant loosening. PMID:19514072
Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay
Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4(th) generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063
Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay
Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4th generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063
Recent Patents and Designs on Hip Replacement Prostheses
Derar, H; Shahinpoor, M
Hip replacement surgery has gone through tremendous evolution since the first procedure in 1840. In the past five decades the advances that have been made in technology, advanced and smart materials innovations, surgical techniques, robotic surgery and methods of fixations and sterilization, facilitated hip implants that undergo multiple design revolutions seeking the least problematic implants and a longer survivorship. Hip surgery has become a solution for many in need of hip joint remedy and replacement across the globe. Nevertheless, there are still long-term problems that are essential to search and resolve to find the optimum implant. This paper reviews several recent patents on hip replacement surgery. The patents present various designs of prostheses, different materials as well as methods of fixation. Each of the patents presents a new design as a solution to different issues ranging from the longevity of the hip prostheses to discomfort and inconvenience experienced by patients in the long-term. PMID:25893020
Recent patents and designs on hip replacement prostheses.
Derar, H; Shahinpoor, M
Hip replacement surgery has gone through tremendous evolution since the first procedure in 1840. In the past five decades the advances that have been made in technology, advanced and smart materials innovations, surgical techniques, robotic surgery and methods of fixations and sterilization, facilitated hip implants that undergo multiple design revolutions seeking the least problematic implants and a longer survivorship. Hip surgery has become a solution for many in need of hip joint remedy and replacement across the globe. Nevertheless, there are still long-term problems that are essential to search and resolve to find the optimum implant. This paper reviews several recent patents on hip replacement surgery. The patents present various designs of prostheses, different materials as well as methods of fixation. Each of the patents presents a new design as a solution to different issues ranging from the longevity of the hip prostheses to discomfort and inconvenience experienced by patients in the long-term. PMID:25893020
NASA Astrophysics Data System (ADS)
Hyatt, Michael; Huang, Karen; DeVilliers, Anton; Slezak, Mark; Liu, Zhi
With extreme UV not ready for HVM for the 20nm and 14nm nodes, double patterning options that extend the use of 193nm immersion lithography beyond the optical resolution limits, such as LELE (Litho-Etch-Litho-Etch) and SADP (Self Aligned Double Patterning), are being used for critical layers for these nodes. LELE requires very stringent overlay capability of the optical exposure tool. The spacer scheme of SADP starts with a conformal film of material around the mandrels and etched along the mandrel sidewalls to form patterns with doubled frequency. SADP, while having the advantage of being a self-aligned process, adds a number of process steps and strict control of the mandrel profile is required. In this paper, we will demonstrate a novel technique - ASDP (Anti-Spacer Double Patterning), which uses only spin-on materials to achieve self-aligned double patterning. After initial resist patterning, an Anti-Spacer Generator (ASG) material is coated on the resist pattern to create the developable spacer region. Another layer of material is then coated and processed to generate the second pattern in between the first resist pattern. We were able to define 37.5nm half pitch pattern features using this technique as well as sub-resolution features for an asymmetric pattern. In this paper we will review the capability of the process in terms of CD control and LWR (line width roughness) and discuss the limitations of the process.
Unilateral total hip replacement patients with symptomatic leg length inequality have abnormal hip biomechanics during walking
Li, Junyan; McWilliams, Anthony B.; Jin, Zhongmin; Fisher, John; Stone, Martin H.; Redmond, Anthony C.; Stewart, Todd D.
Background Symptomatic leg length inequality accounts for 8.7% of total hip replacement related claims made against the UK National Health Service Litigation authority. It has not been established whether symptomatic leg length inequality patients following total hip replacement have abnormal hip kinetics during gait. Methods Hip kinetics in 15 unilateral total hip replacement patients with symptomatic leg length inequality during gait was determined through multibody dynamics and compared to 15 native hip healthy controls and 15 'successful' asymptomatic unilateral total hip replacement patients. Finding More significant differences from normal were found in symptomatic leg length inequality patients than in asymptomatic total hip replacement patients. The leg length inequality patients had altered functions defined by lower gait velocity, reduced stride length, reduced ground reaction force, decreased hip range of motion, reduced hip moment and less dynamic hip force with a 24% lower heel-strike peak, 66% higher mid-stance trough and 37% lower toe-off peak. Greater asymmetry in hip contact force was also observed in leg length inequality patients. Interpretation These gait adaptions may affect the function of the implant and other healthy joints in symptomatic leg length inequality patients. This study provides important information for the musculoskeletal function and rehabilitation of symptomatic leg length inequality patients. PMID:25900447
Johnson D, Weiss WM. Basic arthroscopic principles. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ... 11. Sanchez VMI, Meza AO. Hip arthroscopy. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ...
de Amorim Cabrita, Henrique Antônio Berwanger; de Castro Trindade, Christiano Augusto; de Campos Gurgel, Henrique Melo; Leal, Rafael Demura; de Souza Marques, Ricardo da Fonseca
Hip arthroscopy is a safe method for treating a variety of pathological conditions that were unknown until a decade ago. Femoroacetabular impingement is the commonest of these pathological conditions and the one with the best results when treated early on. The instruments and surgical technique for hip arthroscopy continue to evolve. New indications for hip arthroscopy has been studied as the ligamentum teres injuries, capsular repair in instabilities, dissection of the sciatic nerve and repair of gluteal muscles tears (injuries to the hip rotator cuff), although still with debatable reproducibility. The complication rate is low, and ever-better results with fewer complications should be expected with the progression of the learning curve. PMID:26229924
Martinoli, Carlo; Garello, Isabella; Marchetti, Alessandra; Palmieri, Federigo; Altafini, Luisa; Valle, Maura; Tagliafico, Alberto
In newborns, US has an established role in the detection and management of developmental dysplasia of the hip. Later in childhood, when the limping child is a major diagnostic dilemma, US is extremely helpful in the identification of the varied disease processes underlying this condition, as transient synovitis, septic arthritis, Perthes disease and slipped femoral capital epiphysis. In adolescent practicing sporting activities, US is an excellent means to identify apophyseal injures about the pelvic ring, especially when avulsions are undisplaced and difficult-to-see radiographically. Later on, in the adulthood, US is an effective modality to diagnose tendon and muscle injuries about the hip and pelvis, identify effusion or synovitis within the hip joint or its adjacent bursae and guide the treatment of these findings. The aim of this article is to provide a comprehensive review of the most common pathologic conditions about the hip, in which the contribution of US is relevant for the diagnostic work-up. PMID:21571471
[Use of gold implants as a treatment of pain related to canine hip dysplasia--a review. Part 1: Background and current state of research regarding the effects of implanting gold in tissue].
Deisenroth, A; Nolte, I; Wefstaedt, P
Gold-bead implantation as a method of pain treatment in dogs suffering from osteoarthritic disease is receiving increasing attention in veterinary medicine. For the present article, publications from veterinary books and journals were collected and evaluated, together with related articles in human medicine. After providing an overview of the historical use of gold and gold compounds, the technique of implanting this noble metal is introduced. The reasons for establishing the terms gold acupuncture and gold (bead) implantation are described, considering the question whether and what kind of methodological differences exist behind these terms. Next, previous publications concerning the effects of gold implantation in tissue are summarised. In 2002 it was proven that gold ions are released from the surface of gold implants by a process termed dissolucytosis. Subsequent publications further investigated details about the interaction between gold ions and tissue as well as the distribution pattern of bio-released ions. Gold compounds were previously used for chrysotherapy in human medicine until medication with fewer side effects became established. The anti-inflammatory and immuno-modulatory properties of gold compounds were used to treat rheumatoid arthritis. Current research aims to ascertain whether the anti-inflammatory and immuno-modulating effects of gold compounds are imitated by gold ions released from gold implants at a local level. In conclusion, the present review summarises important findings about the effects of gold implanted in tissue. However, further research is necessary to estimate the limitations and benefits of this auromedication. PMID:23608966
Pulled hip flexor - aftercare; Hip flexor injury - aftercare; Hip flexor tear - aftercare; Iliopsoas strain - aftercare; Strained iliopsoas muscle - aftercare; Torn iliopsoas muscle - aftercare; Psoas strain - aftercare
Biotribology of artificial hip joints
Di Puccio, Francesca; Mattei, Lorenza
Hip arthroplasty can be considered one of the major successes of orthopedic surgery, with more than 350000 replacements performed every year in the United States with a constantly increasing rate. The main limitations to the lifespan of these devices are due to tribological aspects, in particular the wear of mating surfaces, which implies a loss of matter and modification of surface geometry. However, wear is a complex phenomenon, also involving lubrication and friction. The present paper deals with the tribological performance of hip implants and is organized in to three main sections. Firstly, the basic elements of tribology are presented, from contact mechanics of ball-in-socket joints to ultra high molecular weight polyethylene wear laws. Some fundamental equations are also reported, with the aim of providing the reader with some simple tools for tribological investigations. In the second section, the focus moves to artificial hip joints, defining materials and geometrical properties and discussing their friction, lubrication and wear characteristics. In particular, the features of different couplings, from metal-on-plastic to metal-on-metal and ceramic-on-ceramic, are discussed as well as the role of the head radius and clearance. How friction, lubrication and wear are interconnected and most of all how they are specific for each loading and kinematic condition is highlighted. Thus, the significant differences in patients and their lifestyles account for the high dispersion of clinical data. Furthermore, such consideration has raised a new discussion on the most suitable in vitro tests for hip implants as simplified gait cycles can be too far from effective implant working conditions. In the third section, the trends of hip implants in the years from 2003 to 2012 provided by the National Joint Registry of England, Wales and Northern Ireland are summarized and commented on in a discussion. PMID:25621213
Photoelastic and thermoelastic measurement of stress on the proximal femur before and after implantation of a hip prosthesis with retention of the femoral neck.
Refior, Jans Jürgen; Schidlo, Christoph; Plitz, Wolfgang; Heining, Sandro
This study demonstrated the improved medial support and the transfer of load onto the retained neck of the femur using seven fresh frozen femurs. Results confirm the reliability of the thermoelastic stress analysis method, which is comparable to the photoelastic surface coating method, but with greater sensitivity. The loading pattern after stem implantation shows a homogeneous transfer of force onto the preserved femoral neck. After femoral neck removal, an inhomogeneous increase of the intertrochanteric compression loading was observed. Therefore, improved biomechanical conditions are created for a permanently stable implantation of stem prostheses with retention of the femoral neck. PMID:12046909
[Is a physician liable for an unsafe implant?].
Wijne, Rolinka P
In recent years, various incidents involving unsafe implants have drawn a lot of attention. Examples include problems with breast prostheses (PIP implants), artificial hips (metal-on-metal hip prostheses) and synthetic mesh implants, and possible dysfunctional leads of implantable cardioverter defibrillators. This article highlights the regulations concerning physicians' liability if it transpires that the implants they used for the treatment of patients prove to be unsafe. PMID:27007937
Total hip replacement for high dislocated hips without femoral shortening osteotomy.
Zhao, X; Zhu, Z-A; Xie, Y-Z; Yu, B; Yu, D-G
When performing total hip replacement (THR) in high dislocated hips, the presence of soft-tissue contractures means that most surgeons prefer to use a femoral shortening osteotomy in order to avoid the risk of neurovascular damage. However, this technique will sacrifice femoral length and reduce the extent of any leg-length equalisation. We report our experience of 74 THRs performed between 2000 and 2008 in 65 patients with a high dislocated hip without a femoral shortening osteotomy. The mean age of the patients was 55 years (46 to 72) and the mean follow-up was 42 months (12 to 78). All implants were cementless except for one resurfacing hip implant. We attempted to place the acetabular component in the anatomical position in each hip. The mean Harris hip score improved from 53 points (34 to 74) pre-operatively to 86 points (78 to 95) at final follow-up. The mean radiologically determined leg lengthening was 42 mm (30 to 66), and the mean leg-length discrepancy decreased from 36 mm (5 to 56) pre-operatively to 8.5 mm (0 to 18) postoperatively. Although there were four (5%) post-operative femoral nerve palsies, three had fully resolved by six months after the operation. No loosening of the implant was observed, and no dislocations or infections were encountered. Total hip replacement without a femoral shortening osteotomy proved to be a safe and effective surgical treatment for high dislocated hips. PMID:21911529
Spacer grid assembly and locking mechanism
Snyder, Jr., Harold J.; Veca, Anthony R.; Donck, Harry A.
A spacer grid assembly is disclosed for retaining a plurality of fuel rods in substantially parallel spaced relation, the spacer grids being formed with rhombic openings defining contact means for engaging from one to four fuel rods arranged in each opening, the spacer grids being of symmetric configuration with their rhombic openings being asymmetrically offset to permit inversion and relative rotation of the similar spacer grids for improved support of the fuel rods. An improved locking mechanism includes tie bars having chordal surfaces to facilitate their installation in slotted circular openings of the spacer grids, the tie rods being rotatable into locking engagement with the slotted openings.
Generator stator core vent duct spacer posts
Griffith, John Wesley; Tong, Wei
Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.
Zacher, Josef; Gursche, Angelika
'Hip' pain is usually located in the groin, upper thigh or buttock and is a common complaint. Slipped capital femoral epiphysis, avascular femoral head necrosis and apophyseal avulsion are the most common diagnoses in childhood and adolescents. Strains and fractures are common in sport-active adults. Osteoarthritis occurs in middle-aged and older adults. Trauma may result in femoral head fracture or typical muscle and tendon sprains and bursitis. Septic or inflammatory arthritis can occur at every age. Septic arthritis, fractures and acute epiphyseal slipping are real emergency cases. Congenital dysplasia of the hip joint may lead to labral tears and early osteoarthritis. The most important hip problems in children, adolescents, adult and older people are discussed; these problems originate from intra-articular disorders and the surrounding extra-articular soft tissues. Medical history, clinical examination and additional tests, including imaging, will be demonstrated. Principles of treatment are given for specific disorders. PMID:12659822
Schwartsmann, Carlos Roberto; Boschin, Leonardo Carbonera; Gonçalves, Ramiro Zilles; Yépez, Anthony Kerbes; de Freitas Spinelli, Leandro
Total hip arthroplasty is being increasingly indicated for younger and more active patients, in addition to a naturally growing demand for the procedure because of increasing life expectancy among patients. The high costs of this surgery and the controversies regarding implant performance have made this topic the subject of constant research, seeking new materials with better resistance to wear and better biocompatibility. The present article provides a review of new surfaces in total hip arthroplasty. PMID:27042614
[An assistant artificial hip joint].
Shi, Zhen-man; Chen, Jian-chang; Shi, Jiang; Chen, Wenhong; Zhang, Chunhao
The assistant artificial hip joint (AAHJ) is a new impermanent hip support implanted in the body. It is used for treatment of ischemic necrosis of the femoral head at the early stage. It reserves the natural femoral head, increases its containment and decreases its load, thus makes the recovery of the necrosed femoral head. The AAHJ's moving axis center is the same as that of the femoral head. Therefore, the moving range of the hip joint is very close to the normal postoperatively. The patient can walk with loading in 3 weeks after the surgical operation, and can regain his (or her) daily work and life in 2 to 3 months of the operation. The AAHJ's structure is simple and the price is cheap. PMID:16104164
Evaluation of the hip center in total hip arthroplasty for old developmental dysplasia.
Flecher, Xavier; Parratte, Sebastien; Brassart, Nicolas; Aubaniac, Jean-Manuel; Argenson, Jean-Noël
We describe the problems with positioning the hip center according to the severity of dislocation in 97 cementless total hip arthroplasty for developmental dysplasia of the hip. The mean location of the hip center from the interteardrop was 30.4 +/- 8.7 mm horizontally and 23.4 +/- 5.4 mm vertically. The presence of a limp correlated with a superior placement of the cup. Four cups were revised, 2 of which with a significant high hip center. The survival rate of the acetabular component was 95% at 12 years. Craniopodal repositioning was easy in class 1. In class 2, the cup was the largest. In class 3, the greatest variations of the hip center were found. In class 4, the smallest implants were necessary for positioning in the true acetabulum. PMID:18534475
The effect of metal artefact reduction on CT-based attenuation correction for PET imaging in the vicinity of metallic hip implants: A phantom study
Harnish, Roy; Prevrhal, Sven; Alavi, Abass; Zaidi, Habib; Lang, Thomas
Background To determine if metal artefact reduction (MAR) combined with a priori knowledge of prosthesis material composition can be applied to obtain CT-based attenuation maps with sufficient accuracy for quantitative assessment of 18F-fluorodeoxyglucose uptake in lesions near metallic prostheses. Methods A custom hip prosthesis phantom with a lesion-sized cavity filled with 0.2 ml 18F-FDG solution having an activity of 3.367 MBq adjacent to a prosthesis bore was imaged twice with a chrome-cobalt steel hip prosthesis and a plastic replica, respectively. Scanning was performed on a clinical hybrid PET/CT system equipped with an additional external 137Cs transmission source. PET emission images were reconstructed from both phantom configurations with CT-based attenuation correction (CTAC) and with CT-based attenuation correction using MAR (MARCTAC). To compare results with the attenuation-correction method extant prior to the advent of PET/CT, we also carried out attenuation correction with 137Cs transmission-based attenuation correction (TXAC). CTAC and MARCTAC images were scaled to attenuation coefficients at 511 keV using a tri-linear function that mapped the highest CT values to the prosthesis alloy attenuation coefficient. Accuracy and spatial distribution of the lesion activity was compared between the three reconstruction schemes. Results Compared to the reference activity of 3.37 MBq, the estimated activity quantified from the PET image corrected by TXAC was 3.41 MBq. The activity estimated from PET images corrected by MARCTAC was similar in accuracy at 3.32 MBq. CTAC corrected PET images resulted in nearly 40% overestimation of lesion activity at 4.70 MBq. Comparison of PET images obtained with the plastic and metal prostheses in place showed that CTAC resulted in a marked distortion of the 18F-FDG distribution within the lesion, whereas application of MARCTAC and TXAC resulted in lesion distributions similar to those observed with the plastic replica
Total Hip Arthroplasty in a Girdlestone Hip following a Failed Hemiarthroplasty
Purushotham, VJ; Ranganath, BT
Introduction: Girdlestone hip arthroplasty, though described as a salvage procedure for infected hip joints, can also be considered for failed Hemiarthroplasty procedures. The functional results of such Girdlestone hip may not be satisfactory. They may require total hip replacement to improve the quality of life, which are technically challenging. Here we are reporting such a case ina 60 year old male patient, with review of literature. Case Report: A 60 year old male patient underwent cemented bipolar hemiarthroplasty for fracture neck of femur which failed, owing to improper implantation. Subsequently he underwent Girdlestone arthroplasty which resulted in persistent painful hip. He presented to us in this situation, where we successfully converted the Girdlestone arthroplasty to a Total Hip arthroplasty. Conclusion: Improper implantation in Hemiarthroplasty fails subsequently. In such cases Girdlestone arthroplasty may be an option to consider, though it may not give requisite relief to patient in some cases. In such situations total hip arthroplasty procedure, though technically challenging will give stable painless hip to the patient. PMID:27299043
21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.
Code of Federal Regulations, 2010 CFR
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...
21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.
Code of Federal Regulations, 2011 CFR
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...
Gate Spacer Width Monitoring Study with Scatterometry Based on Spectroscopic Ellipsometry
NASA Astrophysics Data System (ADS)
Vachellerie, V.; Kremer, S.; Elazami, A.; Morin, P.; Julien, C.; Duca, D.; Guiheux, D.; Bicais, N.; Pokrant, S.
Critical Dimension (CD) control of Gate Spacers is key to achieve in well controlled implantations and a tight distribution of Vt for transistors on semiconductors devices. Presently, historical methods for CD control (top-down low-voltage Scanning Electron Microscopy, Atomic Force Microscopy, Transmission Electron Microscopy or Electrical CD measurement) are facing limitations with regards to precision, matching, throughput or sample damage. So, with the reduction of design rules approaching the 65nm technology node, the need for a fast, precise and versatile "in-line" (at the process step) measurement of the spacer width and profile becomes critical, in order to shorten the spacer process development phase and the response time to production excursions. In this paper, we investigate the metrology performances and limitations (sensitivity, precision and accuracy) of Scatterometry (SCD) based on Spectroscopic Ellipsometry (SE) for this application using a KLA-TENCOR SpectraCD system. We show that it will be suitable for, at least, a simple oxide-nitride spacer configuration. We also explore its capability to measure more complex structures like the double-spacer configuration (LDD offset & S/D spacer). Finally, we show how additional information provided by Scatterometry helps in understanding process variations and how they correlate to end of line parametric test results.
[Total hip arthroplasty in the treatment of arthrosis with coexistent high developmental hip dislocation].
Matewski, Dariusz; Szymkowiak, Edward; Gumański, Ryszard
The question if total hip arthroplasty ought to be advised for patients with high developmental hip dislocation is still actual. The subject of hip arthroplasty, as a method of surgical treatment of high developmental hip dislocation, was analyzed on the base of follow up of seven patients, who underwent this procedure. The mean age of patients was 44.5 (+/- 12.6) years. The mean time of follow up was 64.4 (21.6) months. Initial three patients were treated in two stage regime. In first stage, a surgical hip liberalization and skeletal traction through 3 weeks was performed. In 2nd stage we did total hip replacement with simultaneous shortening of the femoral shaft just below the lesser trochanter. In next four patients we performed total hip arthroplasty with simultaneous shortening of the femoral shaft in one stage. Protection of undesirable rotational instability after osteotomy was done by means of different ways of osteotomy fixation describe in paper. Applied surgical treatment allowed for implanting a cup of prosthesis in original place of acetabulum and reduction of the big anteversion of the femoral neck. The hip congruency was improved in all patients. Score in functional Harris hip scale increased from mean value of 50 points before hip arthroplasty to mean value of 85 points after surgery. The symptoms of late consolidation of osteotomy were observed in one patient with transverse osteotomy without anty-rotational fixation. Total hip replacement with simultaneous "Z" shortening osteotomy of the femoral shaft give good such clinical as radiological results in the treatment of hip osteoarthritis in accordance to high developmental hip dislocation. PMID:18847022
Hip Squeaking after Ceramic-on-ceramic Total Hip Arthroplasty
Wu, Guo-Liang; Zhu, Wei; Zhao, Yan; Ma, Qi; Weng, Xi-Sheng
Objective: The present study aimed to review the characteristics and influencing factors of squeaking after ceramic-on-ceramic (CoC) total hip arthroplasty (THA) and to analyze the possible mechanisms of the audible noise. Data Sources: The data analyzed in this review were based on articles from PubMed and Web of Science. Study Selection: The articles selected for review were original articles and reviews found based on the following search terms: "total hip arthroplasty", "ceramic-on-ceramic", "hip squeaking", and "hip noise." Results: The mechanism of the squeaking remains unknown. The possible explanations included stripe wear, edge loading, a third body, fracture of the ceramic liner, and resonance of the prosthesis components. Squeaking occurrence is influenced by patient, surgical, and implant factors. Conclusions: Most studies indicated that squeaking after CoC THA was the consequence of increasing wear or impingement, caused by prosthesis design, patient characteristics, or surgical factors. However, as conflicts exist among different articles, the major reasons for the squeaking remain to be identified. PMID:27453238
The combined use of simulation and navigation to demonstrate hip kinematics.
Thornberry, Robert L; Hogan, Andrew J
Computer navigation of total hip arthroplasty and computer simulation of hip motions based on collision detection were both introduced more than ten years ago. Neither of these promising technologies has achieved its full potential to improve patient outcomes. Combining these two technologies allows the individual strengths of each to more easily demonstrate hip kinematics in a clinically useful way. All normal and pathologic combined hip motions must be clearly and accurately reported to fully evaluate the kinematics involved in total hip arthroplasty, femoroacetabular impingement syndrome, and other hip disorders. The use of three-dimensional data graphs allows for a rapid and thorough evaluation of the very large data sets that are required for the purpose of making a complete report of all combined hip motions. Data can be obtained from simulations made with use of high-resolution computed tomographic scans and computer-aided implant-design files or from clinically obtained motion analysis on fresh cadavers or normal subjects. The use of these methods and graphics allows for the thorough evaluation of the geometries of current implant designs and will help improve future implant designs. The pathologic structures in hips with femoroacetabular impingement can be modeled in three dimensions, and surgical treatment plans can be developed to provide impingement-free normal hip motion without excessive osseous resection. The combination of these technologies provides hope for the improved surgical placement of total hip implants by providing the basis for a kinematic, impingement-based total hip navigation system. PMID:19182043
LISA telescope spacer design investigations
NASA Astrophysics Data System (ADS)
Sanjuan, Josep; Mueller, Guido; Livas, Jeffrey; Preston, Alix; Arsenovic, Petar; Castellucci, Kevin; Generie, Joseph; Howard, Joseph; Stebbins, Robin
) and materials such as Silicon Carbide (SiC) and Carbon Fiber Reinforced Plastic (CFRP) are considered to be used in the telescope spacer structure. We will describe our experimental efforts to understand and quantify the behavior of different materials and also discuss a first investigation of a specific on-axis SiC telescope spacer for LISA. This work is supported by NASA contract 00069955.
Posterior Arch Augmentation (Spinoplasty) before and after Single and Double Interspinous Spacer Introduction at the Same Level: Preventing and Treating the Failure?
Manfré, Luigi
Summary Lumbar spinal canal stenosis (LSCS) is one of the most common degenerative diseases in elderly patients. Failure of he treatment can occur, generally related to bone remodelling/fracture of spinous processes. PMMA augmentation of the posterior arch (spinoplasty, SP) has recently been proposed in case of neoplastic involvement. This study evaluated the efficacy of SP as a prophylactic treatment before introducing an interspinous spacer (IS). Moreover, we consider the possibility to treat patients who previously underwent IS implants with subsequent failure of the device, by introducing a second spacer at the same level, performing accessory SP. From January 2009 to September 2011, 174 patients with LSCS underwent CT-guided percutaneous IS implant in our department. From January 2011, all patients with osteoporosis underwent prophylactic SP before introducing the spacer. Moreover, in patients with re-stenosis related to bone remodelling and/or fracture, after strengthening the spinous processes with PMMA introduction, a second similar device was introduced to re-open the stenotic spinal canal. In patients with prophylactic treatment before spacer introduction, no restenosis occurred at three to 12 month follow-up. Patients who underwent second spacer implant at the same level after posterior arch augmentation again obtained a resolution of symptoms, and no further bone remodelling had occurred at follow-up controls. In conclusion, prophylactic SP prevents single spacer failure for bone remodelling/fracture, and allows failure repair by introducing a second spacer at the same level. PMID:25363267
New titanium spacer for cervical laminoplasty: initial clinical experience. Technical note.
Tani, Satoshi; Suetsua, Futoshi; Mizuno, Junichi; Uchikado, Hisaaki; Nagashima, Hiroyasu; Akiyama, Masahiko; Isoshima, Akira; Ohashi, Hiroki; Hirano, Yoshitaka; Abe, Toshiaki
Many commercially available hydroxyapatite (HA) spacers for cervical laminoplasty have been introduced but have disadvantages such as lack of plasticity, easy cracking, and occasional difficulty in fixation by sutures. Here we present the short-term results of a newly designed titanium spacer (Laminoplasty Basket) in open-door cervical laminoplasty, and evaluated clinically and radiologically. The titanium box-shaped spacer with two arms for fixation was easily inserted and fixed into the laminoplasty space with 4-mm or 5-mm length screws after the posterior cervical arch was repositioned for the canal expansion. Twenty-one patients with cervical myelopathy due to spondylosis or ossification of the longitudinal ligament or developmental narrow canal observed for more than 6 months postoperatively were enrolled in this study. The neurological condition of these patients improved from 9.4 points on the Japanese Orthopaedic Association scale preoperatively to 13.5 points at 6 months after surgery. Postoperative radiological evaluation showed no laminar closure or implant failure and cervical spine curvature was maintained. These results seemed to have no significant difference compared with those using HA spacers. This titanium spacer is a potential substitute for conventional HA or other similar devices in cervical laminoplasty. PMID:21206196
Cervical interfacet spacers and maintenance of cervical lordosis.
Tan, Lee A; Straus, David C; Traynelis, Vincent C
OBJECT The cervical interfacet spacer (CIS) is a relatively new technology that can increase foraminal height and area by facet distraction. These offer the potential to provide indirect neuroforaminal decompression while simultaneously enhancing fusion potential due to the relatively large osteoconductive surface area and compressive forces exerted on the grafts. These potential benefits, along with the relative ease of implantation during posterior cervical fusion procedures, make the CIS an attractive adjuvant in the management of cervical pathology. One concern with the use of interfacet spacers is the theoretical risk of inducing iatrogenic kyphosis. This work tests the hypothesis that interfacet spacers are associated with loss of cervical lordosis. METHODS Records from patients undergoing posterior cervical fusion at Rush University Medical Center between March 2011 and December 2012 were reviewed. The FacetLift CISs were used in all patients. Preoperative and postoperative radiographic data were reviewed and the Ishihara indices and cervical lordotic angles were measured and recorded. Statistical analyses were performed using STATA software. RESULTS A total of 64 patients were identified in whom 154 cervical levels were implanted with machined allograft interfacet spacers. Of these, 15 patients underwent anterior-posterior fusions, 4 underwent anterior-posterior-anterior fusions, and the remaining 45 patients underwent posterior-only fusions. In the 45 patients with posterior-only fusions, a total of 110 levels were treated with spacers. There were 14 patients (31%) with a single level treated, 16 patients (36%) with two levels treated, 5 patients (11%) with three levels treated, 5 patients (11%) with four levels treated, 1 patient (2%) with five levels treated, and 4 patients (9%) with six levels treated. Complete radiographic data were available in 38 of 45 patients (84%). On average, radiographic follow-up was obtained at 256.9 days (range 48-524 days
Current role of spacers for prostate cancer radiotherapy
Pinkawa, Michael
Radiotherapy is an established curative treatment method for prostate cancer. Optimal tumor control rates can only be achieved with high local doses, associated with a considerable risk of rectal toxicity. Apart from already widely adapted technical advances, as intensity-modulated radiation therapy, the application of spacers placed between the prostate and rectum has been increasingly used in the last years. Biodegradable spacers, including hydrogel, hyaluronic acid, collagen or an implantable balloon, can be injected or inserted in a short procedure under transrectal ultrasound guidance via a transperineal approach. A distance of about 1.0-1.5 cm is usually achieved between the rectum and prostate, excluding the rectal wall from the high isodoses. Several studies have shown well tolerated injection procedures and treatments. Apart from considerable reduction of rectal irradiation, a prospective randomized trial demonstrated a reduction of rectal toxicity after hydrogel injection in men undergoing prostate image-guided intensity-modulated radiation therapy. The results are encouraging for continuing evaluation in dose escalation, hypofractionation, stereotactic radiotherapy or re-irradiation trials in the future. PMID:26677428
Hydrogel Spacer Prospective Multicenter Randomized Controlled Pivotal Trial: Dosimetric and Clinical Effects of Perirectal Spacer Application in Men Undergoing Prostate Image Guided Intensity Modulated Radiation Therapy
Mariados, Neil; Sylvester, John; Shah, Dhiren; Karsh, Lawrence; Hudes, Richard; Beyer, David; Kurtzman, Steven; Bogart, Jeffrey; Hsi, R. Alex; Kos, Michael; Ellis, Rodney; Logsdon, Mark; Zimberg, Shawn; Forsythe, Kevin; Zhang, Hong; Soffen, Edward; Francke, Patrick; Mantz, Constantine; Rossi, Peter; DeWeese, Theodore; and others
Purpose: Perirectal spacing, whereby biomaterials are placed between the prostate and rectum, shows promise in reducing rectal dose during prostate cancer radiation therapy. A prospective multicenter randomized controlled pivotal trial was performed to assess outcomes following absorbable spacer (SpaceOAR system) implantation. Methods and Materials: Overall, 222 patients with clinical stage T1 or T2 prostate cancer underwent computed tomography (CT) and magnetic resonance imaging (MRI) scans for treatment planning, followed with fiducial marker placement, and were randomized to receive spacer injection or no injection (control). Patients received postprocedure CT and MRI planning scans and underwent image guided intensity modulated radiation therapy (79.2 Gy in 1.8-Gy fractions). Spacer safety and impact on rectal irradiation, toxicity, and quality of life were assessed throughout 15 months. Results: Spacer application was rated as "easy" or "very easy" 98.7% of the time, with a 99% hydrogel placement success rate. Perirectal spaces were 12.6 ± 3.9 mm and 1.6 ± 2.0 mm in the spacer and control groups, respectively. There were no device-related adverse events, rectal perforations, serious bleeding, or infections within either group. Pre-to postspacer plans had a significant reduction in mean rectal V70 (12.4% to 3.3%, P<.0001). Overall acute rectal adverse event rates were similar between groups, with fewer spacer patients experiencing rectal pain (P=.02). A significant reduction in late (3-15 months) rectal toxicity severity in the spacer group was observed (P=.04), with a 2.0% and 7.0% late rectal toxicity incidence in the spacer and control groups, respectively. There was no late rectal toxicity greater than grade 1 in the spacer group. At 15 months 11.6% and 21.4% of spacer and control patients, respectively, experienced 10-point declines in bowel quality of life. MRI scans at 12 months verified spacer absorption. Conclusions: Spacer
Outcome of total knee replacement following explantation and cemented spacer therapy
Ghanem, Mohamed; Zajonz, Dirk; Bollmann, Juliane; Geissler, Vanessa; Prietzel, Torsten; Moche, Michael; Roth, Andreas; Heyde, Christoph-E.; Josten, Christoph
Background: Infection after total knee replacement (TKR) is one of the serious complications which must be pursued with a very effective therapeutic concept. In most cases this means revision arthroplasty, in which one-setting and two-setting procedures are distinguished. Healing of infection is the conditio sine qua non for re-implantation. This retrospective work presents an assessment of the success rate after a two-setting revision arthroplasty of the knee following periprosthetic infection. It further considers drawing conclusions concerning the optimal timing of re-implantation. Patients and methods: A total of 34 patients have been enclosed in this study from September 2005 to December 2013. 35 re-implantations were carried out following explantation of total knee and implantation of cemented spacer. The patient's group comprised of 53% (18) males and 47% (16) females. The average age at re-implantation time was 72.2 years (ranging from 54 to 85 years). We particularly evaluated the microbial spectrum, the interval between explantation and re-implantation, the number of surgeries that were necessary prior to re-implantation as well as the postoperative course. Results: We reported 31.4% (11) reinfections following re-implantation surgeries. The number of the reinfections declined with increasing time interval between explantation and re-implantation. Patients who developed reinfections were operated on (re-implantation) after an average of 4.47 months. Those patients with uncomplicated course were operated on (re-implantation) after an average of 6.79 months. Nevertheless, we noticed no essential differences in outcome with regard to the number of surgeries carried out prior to re-implantation. Mobile spacers proved better outcome than temporary arthrodesis with intramedullary fixation. Conclusion: No uniform strategy of treatment exists after peri-prosthetic infections. In particular, no optimal timing can be stated concerning re-implantation. Our data
[Results of cementless hip arthroplasty].
Grübl, A
Hip arthroplasty is performed nowadays according to the needs of the patients irrespective of their age. Tapered rectangular stems for cementless fixation are chosen in most cases in central Europe. They provide primary stability by press-fit implantation into a precisely rasped osseous bed and secondary stability by bone ingrowth into the highly biocompatible titanium alloy with a microrough surface. The 10-year survival of such devices is 92%. Typical radiographic patterns include cortical atrophy and radiolucent lines in Gruen zones 1 and 7. They are due to stress shielding with these distally fixed implants. The number one reason for revision is polyethylene wear and subsequent osteolysis. Metal-on-metal and ceramic-on-ceramic bearings show less wear but osteolysis continues to be a problem. PMID:16552511
Hip resurfacing after iliofemoral distraction for type IV developmental dysplasia of the hip a case report.
Sambri, A; Cadossi, M; Mazzotti, A; Faldini, C; Giannini, S
Osteoarthritis secondary to developmental dysplasia of the hip is a surgical challenge because of the modified anatomy of the acetabulum which is deficient in its shape with poor bone quality, torsional deformities of the femur and the altered morphology of femoral head. Particularly in Crowe type III and IV, additional surgical challenges are present, such as limb-length discrepancy and adductor muscle contractures. This is a bilateral hip dysplasia case where bilateral hip replacement was indicated, on the left side with a resurfacing one and on the other side a two stage procedure using a iliofemoral external fixator to restore equal leg length with a lower risk of complications. This case report shows both the negative clinical outcome of the left and the excellent one of the right hip where the dysplasia was much more severe. Patient selection and implant positioning are crucial in determining long-term results. PMID:27218252
Developmental dysplasia of the hip
... Developmental hip dysplasia; DDH; Congenital dysplasia of the hip; Congenital dislocation of the hip; CDH; Pavlik harness ... dislocation Shorter leg on the side with the hip dislocation Uneven skin folds of thigh or buttocks After ...
Novel Highly Porous Metal Technology in Artificial Hip and Knee Replacement: Processing Methodologies and Clinical Applications
NASA Astrophysics Data System (ADS)
Muth, John; Poggie, Matthew; Kulesha, Gene; Michael Meneghini, R.
Hip and knee replacement can dramatically improve a patient's quality of life through pain relief and restored function. Fixation of hip and knee replacement implants to bone is critical to the success of the procedure. A variety of roughened surfaces and three-dimensional porous surfaces have been used to enhance biological fixation on orthopedic implants. Recently, highly porous metals have emerged as versatile biomaterials that may enhance fixation to bone and are suitable to a number of applications in hip and knee replacement surgery. This article provides an overview of several processes used to create these implant surfaces.
The ribosomal gene spacer region in archaebacteria
NASA Technical Reports Server (NTRS)
Achenbach-Richter, L.; Woese, C. R.
Sequences for the spacer regions that separate the 16S and 23S ribosomal RNA genes have been determined for four more (strategically placed) archaebacteria. These confirm the general rule that methanogens and extreme halophiles have spacers that contain a single tRNAala gene, while tRNA genes are not found in the spacer region of the true extreme thermophiles. The present study also shows that the spacer regions from the sulfate reducing Archaeglobus and the extreme thermophile Thermococcus (both of which cluster phylogenetically with the methanogens and extreme halophiles) contain each a tRNAala gene. Thus, not only all methanogens and extreme halophiles show this characteristic, but all organisms on the "methanogen branch" of the archaebacterial tree appear to do so. The finding of a tRNA gene in the spacer region of the extreme thermophile Thermococcus celer is the first known phenotypic property that links this organism with its phylogenetic counterparts, the methanogens, rather than with its phenotypic counterparts, the sulfur-dependent extreme thermophiles.
Hip joint replacement - slideshow
... this page: //medlineplus.gov/ency/presentations/100006.htm Hip joint replacement - series—Normal anatomy To use the sharing ... to slide 5 out of 5 Overview The hip joint is made up of two major parts: the ...
... this page: //medlineplus.gov/ency/article/007633.htm Hip joint injection To use the sharing features on this ... injection is a shot of medicine into the hip joint. The medicine helps relieve pain and inflammation. It ...
... or falling can all sometimes lead to hip injuries. These include Strains Bursitis Dislocations Fractures Certain diseases also lead to hip injuries or problems. Osteoarthritis can cause pain and limited ...
... neck fracture repair; Trochanteric fracture repair; Hip pinning surgery; Osteoarthritis-hip ... You may receive general anesthesia before this surgery. This means ... spinal anesthesia. With this kind of anesthesia, medicine is ...
... following: Repeated overuse or stress of the hip Rheumatoid arthritis Gout Pseudogout Injury of the hip Infection with bacteria, such as Staphylococcus aureus (or a staph infection) Diabetes Spine problems, such as scoliosis Uneven leg lengths ...
Hip replacement by a minimal anterior approach.
Paillard, P
The mini-incision anterior approach in total hip replacement is not new, but uses a shorter incision than the traditional Hueter approach, typically only 6-8 cm in length. Despite its size, the single anterior incision allows good exposure. It is very atraumatic, preserves muscles and tendons, and allows the patient early mobilisation and fast postoperative recovery. Although, a special table (e.g., a Judet table) and specific tools (e.g., a curved reamer) are needed to perform hip replacement via the mini-anterior approach, any kind of hip prosthesis (cemented or uncemented) can be implanted. As there is a significant learning curve in mastering the mini-incision anterior approach, surgeons are advised to start with a longer incision and then to decrease its length with increasing experience. PMID:17657491
European experience with cementless total hip replacements.
Morscher, E W
The differences between prostheses fixed with and without cement consist mainly of the design and the nature of the surface of the implant. The shapes of the sockets to be implanted without cement show a wide variety--cylinder, square, conus, ellipsoid with and without threads. The hemispherical shape, which was chosen for the acetabular component of the isoelastic hip joint, does not disturb the natural form and function of the hip joint since the outer surface is closely adapted to the original subchondral bone layer. Undesired stress concentrations therefore are eliminated. The fixation of the noncemented cup is secured by threads, pegs, screws, etc. and by ingrowth of bony tissue in the grooves of the surfaces. Except for some special forms, most of the stems are based on the self-locking principle. All prosthesis models show preparations that increase the surface area (ribs, wings, corrugations, or rims). PMID:6368478
Robot-assisted total hip arthroplasty.
Banerjee, Samik; Cherian, Jeffery J; Elmallah, Randa K; Pierce, Todd P; Jauregui, Julio J; Mont, Michael A
Precise and accurate biomechanical reconstruction during total hip arthroplasty (THA) is essential for durable long-term survivorship. Accurate fit of cementless hip implants is also crucial to reduce micromotion between the bone-implant interfaces to allow for stable osseointegration. Robotic technology aims to minimize potential human errors and improve implant alignment and fit, and address persisting concerns with modern-day cementless THA. Although robotic THA dates back to the early 1990s, concerns with increased operating times, costs, and complications led to its withdrawal. However, semi-active systems have renewed interest in robot-assisted joint arthroplasty. We reviewed the current technology, its potential benefits, and the reported clinical and radiographic outcomes. Early evidence suggests that robotic use may lead to more accurate reconstruction of radiographic parameters, such as implant positioning, fit, center-of-rotation, and leg-length discrepancy. Further research is needed to determine if these will translate into better outcomes and improved implant longevity to justify increased costs. PMID:26592900
Two-Stage Progressive Femoral Lowering Followed by Cementless Total Hip Arthroplasty for Treating Crowe IV-Hartofilakidis Type 3 Developmental Dysplasia of the Hip.
Binazzi, Roberto
High developmental dysplasia of the hip is commonly treated with total hip arthroplasty and shortening osteotomy. We present a two stage technique, consisting of progressive femoral lowering followed by total hip arthroplasty. The clinico-radiographic results of eleven patients (twelve hips) who were operated on with the two-stage technique were evaluated at a mean follow-up of 11 ± 5 years. At the final follow-up, ten patients (eleven hips) had a mean Harris hip score of 85 ± 5 points with no implant loosening. One patient (one hip) was revised at 5 years due to infection. No neurovascular complications were observed in any patients. With this technique, we could place the cup in the anatomical position and obtain complete limb symmetry with excellent clinical results at long-term. PMID:25599863
Patient-adapted treatment for prosthetic hip joint infection.
Baker, Richard P; Furustrand Tafin, Ulrika; Borens, Olivier
Hip joint replacement is 1 of the most successful surgical procedures of the last century and the number of replacements implanted is steadily growing. An infected hip arthroplasty is a disaster, it leads to patient suffering, surgeon's frustration and significant costs to the health system. The treatment of an infected hip replacement is challenging, healing rates can be low, functional results poor with decreased patient satisfaction. However, if a patient-adapted treatment of infected hip joints is used a success rate of above 90% can be obtained.Patient-adapted treatment is based on 5 important concepts: teamwork; understanding the biofilm; diagnostic accuracy; correct definition and classification of PJI; and patient-tailored treatment.This review presents a patient-adapted treatment strategy to prosthetic hip infection. It incorporates the best aspects of the single and staged surgical strategies and promotes the short interval philosophy for the 2-stage approach. PMID:26044528
Total Hip Joint Replacement Biotelemetry System
NASA Technical Reports Server (NTRS)
Boreham, J. F.; Postal, R. B.; Luntz, R. A.
The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.
Alshameeri, Zeiad; Rehm, Andreas
There have been a small number of case reports describing late normal-hip dislocations in children who were later diagnosed with developmental dysplasia of the hip. Here, we contest the assumption that normal hips can dislocate. We argue that (as in our case) the ultrasound scans in all published case reports on late dislocated normal hips did not show results that were entirely normal and therefore, so far, there has been no convincing evidence of a dislocation of a normal hip. We also want to highlight the importance of meticulous ultrasound and clinical assessments of high-risk children by an experienced orthopaedic surgeon. PMID:25144883
Uncemented total hip arthroplasty in osteoarthritis of hip secondary to low and high dislocated hips: A mid-term follow-up study
Munigangaiah, Sudarshan; O'Dwyer, Sinead; Masterson, Eric
Background: Performing successful total hip replacement (THR) in dysplastic, subluxed, and dislocated hip is a challenging task. Here, we assessed midterm clinical and radiological outcomes of uncemented total hip arthroplasty in osteoarthritis (OA) of hip secondary to Hartofilakidis low and high-dislocated hips with a mean follow-up of 8.8 years. Materials and Methods: A retrospective study of prospectively collected data was designed involving all consecutive patients who underwent uncemented THR for OA of hip secondary to developmental dysplasia of the hip and Grade II or Grade III Hartofilakidis classification. Results: Thirty-two patients underwent 45 THR, with 23 Grade II (low dislocation) and 22 Grade III (high-dislocation) of Hartofilakidis classification. Thirteen patients had bilateral hip replacements, 19 patients had unilateral THR. There was highly statistically significant difference between preoperative and postoperative HHS and SF-36v2™ at each follow-up. Survivorship of original implant was 98.88% at a mean follow-up of 8.8 years. The mean improvement in leg length in this series was 3.6 cm (1.8-4.5, 95% confidence interval). No sciatic nerve or femoral nerve palsies were observed. Conclusions: Uncemented THR provides better function and quality of life. However, longer follow-up studies are needed to assess survivorship of uncemented THR in Hartofilakidis low and high-dislocations. PMID:27433063
Hip resurfacing in a district general hospital: 6-year clinical results using the ReCap hip resurfacing system
Background The purpose of our study was to prospectively report the clinical results of 280 consecutive hips (240 patients) who received a ReCap Hip Resurfacing System implant (Biomet Inc., Warsaw, USA) in a single district general hospital. Literature reports a large variation in clinical results between different resurfacing designs and published results using this particular design are scarce. Methods Mean follow up was 3.3 years (1.0 to 6.3) and four patients were lost to follow-up. All patients were diagnosed with end-stage hip osteoarthritis, their mean age was 54 years and 76.4% of all patients were male. Results There were 16 revisions and four patients reported a Harris Hip Score <70 points at their latest follow up. There were no pending revisions. Kaplan-Meier implant survival probability, with revision for any reason as endpoint, was 93.5% at six years follow-up (95%-CI: 88.8-95.3). There were no revisions for Adverse Reactions to Metal Debris (ARMD) and no indications of ARMD in symptomatic non-revised patients, although diagnostics were limited to ultrasound scans. Conclusions This independent series confirms that hip resurfacing is a demanding procedure, and that implant survival of the ReCap hip resurfacing system is on a critical level in our series. In non-revised patients, reported outcomes are generally excellent. Trial registration ClinicalTrials.gov Identifier: NCT00603395 PMID:23234268
Metal-on-Metal Hip Resurfacing Arthroplasty
Sehatzadeh, S; Kaulback, K; Levin, L
Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the
Intra-Pelvic Migration of Sliding Hip Screw During Osteosynthesis of Hip Fracture: A Rare Avoidable Intraoperative Complication
Zarattini, G.; Breda, L.; Zacharia, M.; Sibona, F.
Introduction: Hip fractures, which are common among old patients, are classified into two groups: intracapsular and extracapsular fractures. Extracapsular fractures can be treated with extramedullary implants [e.g. dynamic hip screw (DHS)] or intramedullary nails. Dynamic hip screw is the treatment of choice in stable pertrochanteric fractures. Intrapelvic migration of the sliding screw is a very rare complication. Case Report: We report a case of a 90-year old Caucasian woman who had an unusual intraoperative complication during osteosynthesis procedure for extracapsular hip fracture fixation. In fact, the sliding hip screw went deep into the pelvis during surgery. This mishap required an abdominal surgical approach by the general surgeon to remove the screw. Conclusion: Taking into consideration the poor quality of the bone in very old patients, we emphasize the importance of following every single step of the surgical procedure, in order to minimize the risk of this complication. PMID:27299061
Separator-spacer for electrochemical systems
Grimes, Patrick G.; Einstein, Harry; Newby, Kenneth R.; Bellows, Richard J.
An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.
Trajectories of depressive symptoms after hip fracture
Cristancho, P.; Lenze, E. J.; Avidan, M. S.; Rawson, K. S.
Background Hip fracture is often complicated by depressive symptoms in older adults. We sought to characterize trajectories of depressive symptoms arising after hip fracture and examine their relationship with functional outcomes and walking ability. We also investigated clinical and psychosocial predictors of these trajectories. Method We enrolled 482 inpatients, aged ≥60 years, who were admitted for hip fracture repair at eight St Louis, MO area hospitals between 2008 and 2012. Participants with current depression diagnosis and/or notable cognitive impairment were excluded. Depressive symptoms and functional recovery were assessed with the Montgomery–Asberg Depression Rating Scale and Functional Recovery Score, respectively, for 52 weeks after fracture. Health, cognitive, and psychosocial variables were gathered at baseline. We modeled depressive symptoms using group-based trajectory analysis and subsequently identified correlates of trajectory group membership. Results Three trajectories emerged according to the course of depressive symptoms, which we termed 'resilient', 'distressed', and 'depressed'. The depressed trajectory (10% of participants) experienced a persistently high level of depressive symptoms and a slower time to recover mobility than the other trajectory groups. Stressful life events prior to the fracture, current smoking, higher anxiety, less social support, antidepressant use, past depression, and type of implant predicted membership of the depressed trajectory. Conclusions Depressive symptoms arising after hip fracture are associated with poorer functional status. Clinical and psychosocial variables predicted membership of the depression trajectory. Early identification and intervention of patients in a depressive trajectory may improve functional outcomes after hip fracture. PMID:27032698
The World Hip Trauma Evaluation Study 3
Parsons, N.; Achten, J.; Griffin, X. L.; Costa, M. L.; Reed, M. R.
Background Approximately half of all hip fractures are displaced intracapsular fractures. The standard treatment for these fractures is either hemiarthroplasty or total hip arthroplasty. The recent National Institute for Health and Care Excellence (NICE) guidance on hip fracture management recommends the use of 'proven' cemented stem arthroplasty with an Orthopaedic Device Evaluation Panel (ODEP) rating of at least 3B (97% survival at three years). The Thompsons prosthesis is currently lacking an ODEP rating despite over 50 years of clinical use, likely due to the paucity of implant survival data. Nationally, adherence to these guidelines is varied as there is debate as to which prosthesis optimises patient outcomes. Design This study design is a multi-centre, multi-surgeon, parallel, two arm, standard-of-care pragmatic randomised controlled trial. It will be embedded within the WHiTE Comprehensive Cohort Study (ISRCTN63982700). The main analysis is a two-way equivalence comparison between Hemi-Thompson and Hemi-Exeter polished taper with Unitrax head. Secondary outcomes will include radiological leg length discrepancy measured as per Bidwai and Willett, mortality, re-operation rate and indication for re-operation, length of index hospital stay and revision at four months. This study will be supplemented by the NHFD (National Hip Fracture Database) dataset. Discussion Evidence on the optimum choice of prosthesis for hemiarthroplasty of the hip is lacking. National guidance is currently based on expert opinion rather than empirical evidence. The incidence of hip fracture is likely to continue to increase and providing high quality evidence on the optimum Cite this article: A. L. Sims. The World Hip Trauma Evaluation Study 3: Hemiarthroplasty Evaluation by Multicentre Investigation – WHITE 3: HEMI – An Abridged Protocol. Bone Joint Res 2016;5:18–25. DOI: 10.1302/2046-3758.51.2000473 PMID:26825319
Preclinical investigations towards the first spacer gel application in prostate cancer treatment during particle therapy at HIT
Background The application of spacer gel represents a promising approach to reliably spare the rectal frontal wall during particle therapy (IJROBP 76:1251-1258, 2010). In order to qualify the spacer gel for the clinical use in particle therapy, a variety of measurements were performed in order to ensure the biological compatibility of the gel, its physical stability during and after the irradiation, and a proper definition of the gel in terms of the Hounsfield Unit (HU) values for the treatment planning system. The potential for the use of the spacer gel for particle therapy monitoring with off-line Positron Emission Tomography (PET) was also investigated. Results The spacer gel implanted to the prostate patient in direct neighbourhood to the clinical target volume does not interfere with the particle therapy treatment planning procedure applied at Heidelberg Ion Beam Therapy Centre (HIT). The performed measurements show that Bragg-peak position of the particles can be properly predicted on the basis of computed tomography imaging with the treatment planning system used at HIT (measured water equivalent path length of 1.011 ±0.011 (2σ), measured Hounsfield Unit of 28.9 ±6.1 (2σ)). The spacer gel samples remain physically unchanged after irradiation with a dose exceeding the therapeutic dose level. The independently measured Bragg-Peak position does not change within the time interval of 10 weeks. Conclusions As a result of the presented experiments, the first clinical application of spacer gel implant during prostate cancer treatment with carbon ions and protons was possible at HIT in 2012. The reported pre-clinical investigations demonstrate that use of spacer gel is safe in particle therapy in presence of therapy target motion and patient positioning induced particle range variations. The spacer gel injected between prostate and rectum enlarge the distance between both organs, which is expected to clinically significantly decrease the undesirable exposure of
Hip arthroplasty for failed treatment of proximal femoral fractures.
D'Arrigo, Carmelo; Perugia, Dario; Carcangiu, Alessandro; Monaco, Edoardo; Speranza, Attilio; Ferretti, Andrea
Failed treatment of an intertrochanteric fracture typically leads to profound functional disability and pain. Salvage treatment with hip arthroplasty may be considered. The aim of this study was to evaluate the results and complications of hip arthroplasty performed as a salvage procedure after the failed treatment of an intertrochanteric hip fracture. Twenty-one patients were treated in our hospital with hip arthroplasty for failed treatment of intertrochanteric hip fracture. There were sixteen women and five men with a mean age of 75.8 years (range 61-85 years). Fourteen patients had failure of a previous nail fixation procedure, five had failure of a plate fixation, one of hip screws fixation and one of Ender nail fixation. In 19 out of 21 patients we performed a total hip arthroplasty-14 cases used modular implants with long-stems and five cases used a standard straight stem. In 2 of 21 cases we used a bipolar hemiarthroplasty. A statistically significant improvement was found comparing pre and postoperative conditions (p < 0.05). Our experience confirms that total hip arthroplasty is a satisfactory salvage procedure after failed treatment of an intertrochanteric fracture in elderly patients with few serious orthopaedic complications and acceptable clinical outcomes. PMID:19572131
Migration analysis of a metaphyseal anchored short-stem hip prosthesis
Background and purpose Metaphyseal anchored short-stem hip implants were designed to improve load transmission and preserve femoral bone stock. Until now, only few outcome data have been available and migration studies are one of the few ways of obtaining data that are predictive of implant survival. We therefore evaluated a metaphyseal anchored short-stem hip implant by Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA). Patients and methods First, the EBRA-FCA method was validated for the short-stem hip implant. Then 80 of the first 100 consecutive implants were evaluated after at least 2 years. Clinical assessment was performed using the WOMAC and the UCLA score. Results After 2.7 (2.0–4.2), years none of the implants had been revised and by that time the stems had subsided by a mean of 0.7 mm (SD 1.8) (95% CI: 0.3–1.1). Of the 80 implants, 78 were stable after 2 years, with 74 being primary stable and 4 showing secondary stabilization after initial subsidence. Continuous migration was seen in only 2 patients. The clinical outcome showed good results with a mean WOMAC of 11 (SD 13) and a mean UCLA score of 7.3 (SD 2.0). [OK?] Interpretation The metaphyseal anchored short-stem hip implant showed good functional results and a high degree of stability after 2 years. The outcome is comparable to that of clinically proven conventional hip implants and if the results are confirmed by long-term studies, short-stem hip arthroplasty might be an alternative for young patients requiring hip replacement. PMID:22900913
Tube support grid and spacer therefor
Ringsmuth, Richard J.; Kaufman, Jay S.
A tube support grid and spacers therefor provide radially inward preloading of heat exchange tubes to minimize stress upon base welds due to differential thermal expansion. The grid comprises a concentric series of rings and spacers with opposing concave sides for conforming to the tubes and V-shaped ends to provide resilient flexibility. The flexibility aids in assembly and in transmitting seismic vibrations from the tubes to a shroud. The tube support grid may be assembled in place to achieve the desired inwardly radial preloading of the heat exchange tubes. Tab and slot assembly further minimizes stresses in the system. The radii of the grid rings may be preselected to effect the desired radially inward preloading.
Honeycomb spacer crush stength test results
Leader, D.R.
This report discusses aluminum honeycomb spacers, which are used as an energy absorbent material in shipping packages for off site shipment of radioactive materials and which were ordered in two crush strengths, 1,000 psi and 2,000 psi for use in drop tests requested by the Packaging and Transportation group as part of the shipping container rectification process. Both the group as part of the shipping container rectification process. Both the vendor and the SRTC Materials Laboratory performed crush strength measurements on test samples made from the material used to fabricate the actual spacers. The measurements of crush strength made in the SRTC Materials Laboratory are within 100 psi of the measurements made by the manufacturer for all samples tested and all test measurements are within 10% of the specified crush strength, which is acceptable to the P&T group for the planned tests.
Organization of spacer DNA in chromatin.
Lohr, D; Van Holde, K E
Detailed analysis of the DNA fragment patterns produced by DNase I digestion of yeast, HeLa, and chicken erythrocyte nuclei reveals surprising features of nucleosome phasing. First, the spacer regions in phased yeast chromatin must be of lengths (10m + 5) base pairs, where m = 0, 1, 2,....This feature is not seen in parallel studies of chicken erythrocyte chromatin. The 5-base pair increment in the yeast spacer imposes interesting restraints on the higher order structure of yeast chromatin. Second, we have been able to simulate the DNase I cutting patterns and get good agreement with the observed yeast patterns. Third, three different chromatins show a long range periodicity in the DNase I digest pattern, with a period half that of the staphylococcal nuclease repeat. These results suggest that the amount of chromatin observed in discrete extended-ladder bands is a minimum estimate of phasing and in fact phasing may be a more general feature. Images PMID:392519
Heterogeneous diversity of spacers within CRISPR
NASA Astrophysics Data System (ADS)
Deem, Michael; He, Jiankui
Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of anti-viral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face. 1) J. He and M. W. Deem, Phys. Rev. Lett. 105 (2010) 128102
Inter-trochanteric fracture repair - discharge; Subtrochanteric fracture repair - discharge; Femoral neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - discharge
A Useful Anatomical Reference Guide for Stem Anteversion during Total Hip Arthroplasty in the Dysplastic Hip.
Tsukeoka, Tadashi; Tsuneizumi, Yoshikazu; Lee, Tae Hyun
Computed tomography scans of 50 dysplastic hips were obtained and reconstructed using preoperative planning software for total hip arthroplasty. The anteversion of the stem implanted parallel to the line connecting the trochanteric fossa and the middle of the medial cortex of the femoral neck (T line) was measured. The cutting heights of 5mm and 10mm above the lesser trochanter were simulated. The mean difference of the anteversion of the stem using the T line and the native femoral anteversion was 2.7° (95% CI: 1.0°-4.5°) and 3.5° (95% CI: 1.5°-5.5°) at cutting heights of 5mm and 10mm respectively. An anteversion using a T line is compatible with native femoral anteversion even in developmental dysplasia of the hip. PMID:25873282
Influence of cementless cup surface on stability and bone fixation 2 years after total hip arthroplasty.
Urbański, Wiktor; Krawczyk, Artur; Dragan, Szymon Ł; Kulej, Mirosław; Dragan, Szymon F
Loss of fixation between bone and implant surface is one of the main treatment problems in total hip arthroplasty. It might lead to implant instability, bone loss and treatment failure resulting in revision surgery. Surface modification is a method for improving bone response to implant and increasing implant osseointegration. However, the currently applied modifications such as hydroxyapatite coatings do not meet expectation and do not provide good clinical result. The object of the study was to evaluate the influence of acetabular cup surface modification on fixation and bone remodelling in total hip arthroplasty. Clinical and radiological outcomes were evaluated in patients two years after cementless total hip replacement. Two groups were compared: patients with acetabular component with uncoated titanium surface and patients with hydroxyapatite-coated acetabular surface. Hips X-rays were analysed for early signs of losing stability of acetabular cups. Two years after surgery the analysis of X-rays did not reveal any statistical differences in stability, migration of acetabular components of endoprosthesis between both groups. No differences were also observed in bone remodelling around implants. Particularly high percentage of cups, i.e. 17.64%, were classified into the group with high risk of early implant loosening, i.e., the group with HA coatings. Hydroxyapatite coatings on titanium cementless acetabular cups implanted by press-fit technique have no influence on their stability, bone-implant fixation and the remodelling of bone surrounding an implant two years after surgery. PMID:22793261
Improved nuclear fuel assembly grid spacer
Marshall, John; Kaplan, Samuel
An improved fuel assembly grid spacer and method of retaining the basic fuel rod support elements in position within the fuel assembly containment channel. The improvement involves attachment of the grids to the hexagonal channel and of forming the basic fuel rod support element into a grid structure, which provides a design which is insensitive to potential channel distortion (ballooning) at high fluence levels. In addition the improved method eliminates problems associated with component fabrication and assembly.
Transient Synovitis of the Hip
... inflammation and swelling of the tissues around the hip joint. Usually only one hip is affected. This condition ... to reduce the swelling and inflammation around the hip joint. Your child's doctor will probably ask you to ...
Lower limb length and offset in total hip arthroplasty.
Flecher, X; Ollivier, M; Argenson, J N
Restoration of normal hip biomechanics is a key goal of total hip arthroplasty (THA) and favorably affects functional recovery. Furthermore, a major concern for both the surgeon and the patient is preservation or restoration of limb length equality, which must be achieved without compromising the stability of the prosthesis. Here, definitions are given for anatomic and functional limb length discrepancies and for femoral and hip offset, determined taking anteversion into account. Data on the influence of operated-limb length and offset on patient satisfaction, hip function, and prosthesis survival after THA are reviewed. Errors may adversely impact function, quality of life, and prosthetic survival and may also generate conflicts between the surgeon and patient. Surgeons rely on two- or three-dimensional preoperative templating and on intraoperative landmarks to manage offset and length. Accuracy can be improved by using computer-assisted planning or surgery and the more recently introduced EOS imaging system. The prosthetic's armamentarium now includes varus-aligned and lateralized implants, as well as implants with modular or custom-made necks, which allow restoration of the normal hip geometry, most notably in patients with coxa vara or coxa valga. Femoral anteversion must also receive careful attention. The most common errors are limb lengthening and a decrease in hip offset. When symptoms are caused by an error in length and/or offset, revision arthroplasty may deserve consideration. PMID:26797005
Lesion of the hip abductor mechanism
Caviglia, Horacio; Cambiaggi, Guillermo; Vattani, Nosrat; Landro, María Eulalia; Galatro, Gustavo
Introduction: The disruption of the abductor muscles of the hip after hip revision surgery often causes limping, pain, and instability of the implant. The purpose of our paper is to describe a mesh technique to repair hip abductor mechanism injuries after hip revision. Patients and methods: Forty-six patients with hip abductor damage after prosthetic revision were treated. Inclusion criteria were: patients presenting with prosthetic loosening, complaint of pain, and with a positive Trendelenburg sign due to deficient abductor muscle mechanisms. Thirty-one were women (67.39%) with an average age of 64 years (34–82 years). The number of previous revision surgeries was three (two to seven). The Merle d'Aubigné score and variants before and after treatment were also reported. Results: In the postoperative follow-up after hip revision with the mesh technique, the Merle d'Aubigné score improved and the Trendelenburg sign was negative in 78.3% of the patients (p < 0.001). Also, the Trendelenburg test with the knee flexed was negative in 60.9% (p < 0.001) and the stair-climbing test was negative in 60.9% of cases (p < 0.001). The gluteus medius test in the lateral position was negative in 52.2% of patients, and in the lateral position with the knee flexed it was negative in 47.8% of patients (p < 0.001). Discussion: Repair of the abductor mechanism with the mesh technique has proven effective for both partial and total lesions. PMID:27382925
Total hip arthroplasty revision in elderly patients.
Gasbarra, Elena; Perrone, Fabio Luigi; Celi, Monica; Rao, Cecilia; Feola, Maurizio; Cuozzo, Nicola; Tarantino, Umberto
In the last years, the number of total hip arthroplasty is increased both in young patients and elderly with a poor bone quality due to extension of surgical indications. According to this trend, also revision surgery showed a growth of its number, especially in elderly patients, because of implant loosening, failed osseointegration of prosthetic components, errors in biomechanical restoration and infections. The aim of this study is to analyze life quality improvement through evaluation of articular functionality and postoperative pain, and to examine osseointegration of implant components with periprosthetic bone. During total hip arthroplasty revision, the orthopedic surgeon often has to face complex cases, especially in elderly patients with a preexisting status of poor bone quality and sarcopenia. In these cases, a correct planning and a surgical procedure well-executed are able to ensure a good outcome that led to pain relief and functional recovery. Furthermore anti-osteoporotic therapy surely represents a useful resource both in primary total hip arthroplasty and in revisions, mainly for elderly patients with a poor bone quality. PMID:24046034
... problems that can lead to dislocation of the hip bones. This is also called dysplasia (say: "diss-play-see-uh"). This means that ... problems later in life? Source Screening for Developmental Dysplasia of the Hip by LM French, M.D., and FR Dietz, ...
... because the ball-like top of your thigh bone moves within a cup-like space in your pelvis. Your hips are very stable. When they are healthy, it takes great force to hurt them. However, playing sports, running, ... of the hip causes weak bones that break easily. Both of these are common ...
ERIC Educational Resources Information Center
Clark, Catherine; Scott, Larry
This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…
Total Hip Arthroplasty for Hip Fractures
Monzón, Daniel Godoy; Iserson, Kenneth V.; Jauregui, José; Musso, Carlos; Piccaluga, Francisco; Buttaro, Martin
Introduction: This study aimed to determine the dislocation and reoperation rate, functional outcomes, and the survival rate of the unique subset of very old but lucid and independent patients with hip fractures following a total hip arthroplasty (THA) and geriatric team-coordinated perioperative care. Method: Between 2000 and 2006, previously independent ambulatory patients ≥80 years old presenting with an intracapsular hip fracture were given THAs under the care of an integrated orthopedic surgery–geriatric service. Their fracture-related complications, ambulation, mental status, and survival were followed for 5 to 11 years postinjury. Results: Five years postinjury, 57 (61.3%) patients of the original study group were living. In all, 3 (3.2%) patients had postoperative hip dislocations (and 2 patients had dislocation twice) and 2 reoperations were needed within the first postoperative month. There were no hip dislocations or reoperations after the first year. Radiographs obtained on 88% of the surviving patients at 5 years postoperatively showed that all remained unchanged from their immediate postoperative images. Nearly half of the patients were still able to ambulate as they did preoperatively and their mixed-model equation was statistically unchanged. Conclusion: This study of patients >80 years old with previously good functional status demonstrates that with appropriate surgical (best prosthesis, good operating technique, and regional anesthesia) and geriatric (pre- and postoperative assessments, close follow-up, medication adjustments, and fall-prevention instruction) care, they have few hip dislocations and reoperations, survive postfracture at least as long as their noninjured contemporaries, and continue to function and ambulate as they did prior to their injury. PMID:24660092
Clarke, Kester Diederik
The intent of this report is to document a procedure used at LANL for HIP bonding aluminum cladding to U-10Mo fuel foils using a formed HIP can for the Domestic Reactor Conversion program in the NNSA Office of Material, Management and Minimization, and provide some details that may not have been published elsewhere. The HIP process is based on the procedures that have been used to develop the formed HIP can process, including the baseline process developed at Idaho National Laboratory (INL). The HIP bonding cladding process development is summarized in the listed references. Further iterations with Babcock & Wilcox (B&W) to refine the process to meet production and facility requirements is expected.
Total Hip Arthroplasty in Patient with Aplastic Anemia
Lim, Young Wook; Kim, Seung Chan; Kwon, Soon Yong; Park, Do Joon
Purpose Patients with aplastic anemia (AA) are now living longer and therefore are at increased risk for the development of osteonecrosis of the hip. However, studies on the results of total hip arthroplasty (THA) are lacking. The purpose of this study is to present the result of THA in patients with AA. Materials and Methods We retrospectively reviewed the data for a group of 29 patients (45 hips) with AA who presented to our institution for THA between May 2008 and May 2012. All hips were replaced because of osteonecrosis of the femoral head. A specific prospective protocol was followed for the perioperative transfusion of platelets and blood. The clinical and radiographic evaluations were done, and the minimum follow-up period was 3 years (mean, 49.2 months; range, 36 to 84 months). Results Three hips had excessive perioperative bleeding and hematoma formation, and then hematoma evacuations were done; one hip was finally revised because of infection of acetabular component. One patient with poorly controlled AA died due to delayed infection on the hip joint. All hips showed stable fixation, and the mean Harris hip score was improved from 54.2 points (range, 42 to 69 points) preoperatively to 90.8 points (range, 73 to 97 points) at the time of the latest follow-up. Conclusion In the present study, the durability of implant fixation was maintained and the clinical results demonstrated a sustained increase in function of the hip. Postoperatively, paying attention to bleeding and infection should be needed. PMID:27536640
Medical implants and methods of making medical implants
Shaw, Wendy J; Yonker, Clement R; Fulton, John L; Tarasevich, Barbara J; McClain, James B; Taylor, Doug
A medical implant device having a substrate with an oxidized surface and a silane derivative coating covalently bonded to the oxidized surface. A bioactive agent is covalently bonded to the silane derivative coating. An implantable stent device including a stent core having an oxidized surface with a layer of silane derivative covalently bonded thereto. A spacer layer comprising polyethylene glycol (PEG) is covalently bonded to the layer of silane derivative and a protein is covalently bonded to the PEG. A method of making a medical implant device including providing a substrate having a surface, oxidizing the surface and reacting with derivitized silane to form a silane coating covalently bonded to the surface. A bioactive agent is then covalently bonded to the silane coating. In particular instances, an additional coating of bio-absorbable polymer and/or pharmaceutical agent is deposited over the bioactive agent.
Numerical optimization of composite hip endoprostheses under different loading conditions
NASA Technical Reports Server (NTRS)
Blake, T. A.; Davy, D. T.; Saravanos, D. A.; Hopkins, D. A.
The optimization of composite hip implants was investigated. Emphasis was placed on the effect of shape and material tailoring of the implant to improve the implant-bone interaction. A variety of loading conditions were investigated to better understand the relationship between loading and optimization outcome. Comparisons of the initial and optimal models with more complex 3D finite element models were performed. The results indicate that design improvements made using this method result in similar improvements in the 3D models. Although the optimization outcomes were significantly affected by the choice of loading conditions, certain trends were observed that were independent of the applied loading.
Adverse sequelae following revision of a total hip replacement for a fractured ceramic component: case report
Lee, Ling Hong; Langton, David; Green, Stephen
Revision total hip replacement following a fractured ceramic bearing component presents a challenge in the choice of the new bearing implant. A femoral head made of equal or harder material should be implanted to prevent catastrophic wear. Despite this, patients and surgeons must be wary of potential complications. PMID:27163083
Adverse sequelae following revision of a total hip replacement for a fractured ceramic component: case report.
Lee, Ling Hong; Langton, David; Green, Stephen
Revision total hip replacement following a fractured ceramic bearing component presents a challenge in the choice of the new bearing implant. A femoral head made of equal or harder material should be implanted to prevent catastrophic wear. Despite this, patients and surgeons must be wary of potential complications. PMID:27163083
Wigner, E.P.; Ohlinger, L.A.
Reactors of the heterogeneous, graphite moderated, fluid cooled type and shielding and spacing plugs for the coolant channels thereof are reported. In this design, the coolant passages extend horizontally through the moderator structure, accommodating the fuel elements in abutting end-to-end relationship, and have access openings through the outer shield at one face of the reactor to facilitate loading of the fuel elements. In the outer ends of the channels which extend through the shields are provided spacers and shielding plugs designed to offer minimal reslstance to coolant fluid flow while preventing emanation of harmful radiation through the access openings when closed between loadings.
[Are the cobalt hip prosthesis dangerous?].
Mistretta, Virginie; Kurth, William; Charlier, Corinne
The placement of a hip prosthesis is one of the most common orthopedic surgical procedures. Some implants contain metal and are therefore capable of releasing metal particles like cobalt in patients who wear metal prostheses. Cobalt can be responsible of local toxicity (including metallosis, hypersensitivity reaction, and benign tumor) or systemic toxicity (including cardiomyopathy, polycythemia, hypothyroidism, and neurological disorders). To monitor potential toxicity of metal hip prostheses, an annual monitoring of patients implanted is recommended and includes clinical examination, radiological examination and blood cobalt determination. The cobalt concentration in blood allows to estimate the risk of toxicity and to evaluate the performance of the implant. The currently recommended threshold value is equal to 7 µg of cobalt per liter of blood. Our study, conducted on 251 patients over a period of 4 years, has shown that the cobalt concentration average was 2.51 µg/l in blood, with 51 patients having a cobaltemia higher than the threshold of 7 µg/l. PMID:27615181
Lessons from retrievals: Retrievals help understand the reason for revision of coated hip arthroplasties.
de Villiers, Danielle; Hothi, Harry; Khatkar, Harman; Meswania, Jayantilal; Blunn, Gordon; Skinner, John; Hart, Alister
Coatings have been applied to all surfaces of hip implants with the majority performing well in the laboratory, but there are few reports of their performance in humans. The rationale for coating the metal-on-metal bearing surfaces includes a reduction in metal ion release and risk of adverse reaction to metal debris; yet there are no reports of retrieved coated metal-on-metal hip implants despite the concern that they may delaminate. The aim of this study was to better understand the performance of coated hip implants in humans through findings of three coated metal-on-metal hip resurfacings, retrieved after failure for unexplained pain. Analysis of these implants included quantification of the amount and mechanism of coating loss which was correlated with clinical, imaging and blood data. In all cases, there were large areas of complete coating loss in which the metal substrate was exposed and found to be rougher than the coated areas. The coating loss gave rise to third body abrasive wear of the coating and the exposed metal, the latter of which led to high blood levels of cobalt and chromium. Coating of the bearing surfaces of metal-on-metal hip resurfacings, therefore, do not prevent metal ion release when implanted into humans. This is an example of a need for increased retrieval analysis of newly introduced implants and expansion of laboratory testing regulations to better reflect the clinical environment. PMID:26503841
Metal sensitivity before and after total hip arthroplasty.
Deutman, R; Mulder, T J; Brian, R; Nater, J P
Of 212 patients undergoing total hip replacement who were tested preoperatively for sensitivity to nickel, chromium, and cobalt, fourteen showed sensitivity. No sensitivity to the bone cement was recorded. Of 173 patients who had never had a metal implant before, 5.8 per cent showed a positive reaction. Two patients out of fifteen with a failed McKee-Farrar prosthesis were found to be sensitive. Of six patients who had a stable McKee-Farrar prosthesis in the other hip, none showed sensitivity to the metal. In four of sixty-six patients, sensitivity to nickel or cobalt developed after the implantation of a metal-to-plastic prosthesis. No patients were sensitized to the cement. The consequences of proved hypersensitivity in patients with metal-to-plastic prostheses, either present prior to insertion of the prosthesis or evoked by the implant material, are not known. PMID:908716
The Symmetry of Adverse Local Tissue Reactions in Patients with Bilateral Simultaneous and Sequential ASR Hip Replacement.
Madanat, Rami; Hussey, Daniel K; Donahue, Gabrielle S; Potter, Hollis G; Wallace, Robert; Bragdon, Charles R; Muratoglu, Orhun K; Malchau, Henrik
The purpose of this study was to evaluate whether patients with bilateral metal-on-metal (MoM) hip replacements have symmetric adverse local tissue reactions (ALTRs) at follow-up. An MRI of both hips was performed at a mean time of six years after surgery in 43 patients. The prevalence and severity of ALTRs were found to be similar in simultaneous hips but differences were observed in sequential hips. The order and timing of sequential hip arthroplasties did not affect the severity of ALTRs. Thus, in addition to metal ion exposure from an earlier MoM implant other factors may also play a role in the progression of ALTRs. Bilateral implants should be given special consideration in risk stratification algorithms for management of patients with MoM hip arthroplasty. PMID:26055146
The Effect of Dislocation Type (Crowe Types I-IV) on Pelvic Development in Developmental Dysplasia of the Hip: A Radiologic Study of Anatomy.
Bilgen, Ömer Faruk; Salar, Necmettin; Bilgen, Muhammet Sadık; Mutlu, Müren; Kara, Gökhan Kürşat; Gürsel, Enis
Classification of hip pathology in developmental dysplasia of the hip (DDH) helps in appropriate placement of implants during total hip arthroplasty. We examined preoperative unilateral and bilateral pelvic radiographs of 57 patients (114 hips) undergoing total hip arthroplasty because of DDH. Both sides of the pelvis were visually separated into 3 areas for comparison. When area ratios of hips with Crowe types II, III, and IV DDH were compared with ratios for healthy hips, values in hips with DDH were significantly low for the iliac wings, significantly high for the acetabular regions, and significantly low for the ischial area. Using a line crossing the healthy hip's teardrop and parallel to a line joining the distal sacroiliac joints is useful for calculating limb-length discrepancy. PMID:25499171
Hip arthroscopy in the setting of hip dysplasia
Yeung, M.; Kowalczuk, M.; Simunovic, N.
Objective Hip arthroscopy in the setting of hip dysplasia is controversial in the orthopaedic community, as the outcome literature has been variable and inconclusive. We hypothesise that outcomes of hip arthroscopy may be diminished in the setting of hip dysplasia, but outcomes may be acceptable in milder or borderline cases of hip dysplasia. Methods A systematic search was performed in duplicate for studies investigating the outcome of hip arthroscopy in the setting of hip dysplasia up to July 2015. Study parameters including sample size, definition of dysplasia, outcomes measures, and re-operation rates were obtained. Furthermore, the levels of evidence of studies were collected and quality assessment was performed. Results The systematic review identified 18 studies investigating hip arthroscopy in the setting of hip dysplasia, with 889 included patients. Criteria used by the studies to diagnose hip dysplasia and borderline hip dysplasia included centre edge angle in 72% of studies but the range of angles were quite variable. Although 89% of studies reported improved post-operative outcome scores in the setting of hip dysplasia, revision rates were considerable (14.1%), with 9.6% requiring conversion to total hip arthroplasty. Conclusion The available orthopaedic literature suggests that although improved outcomes are seen in hip arthroscopy in the setting of hip dysplasia, there is a high rate of re-operation and conversion to total hip arthroplasty. Furthermore, the criteria used to define hip dysplasia vary considerably among published studies. Cite this article: M. Yeung, M. Kowalczuk, N. Simunovic, O. R. Ayeni. Hip arthroscopy in the setting of hip dysplasia: A systematic review. Bone Joint Res 2016;5:225–231. DOI: 10.1302/2046-3758.56.2000533. PMID:27313136
21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.
Code of Federal Regulations, 2010 CFR
... uncemented acetabular component, prosthesis. 888.3330 Section 888.3330 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...
21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.
Code of Federal Regulations, 2011 CFR
... uncemented acetabular component, prosthesis. 888.3330 Section 888.3330 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...
... a hip replacement and need antibiotics before any dental work. When to Call Your Doctor Call your health care provider if you have: A sudden increase in pain Chest pain or shortness of breath Frequent urination ...
Preventing venous thromboembolic disease in patients undergoing elective hip and knee arthopolasty: Evidence-based guideline and evidence report. American Association of Orthopaedic Surgeons. 2011. Harkess JW, Crockarell JR. Arthroplasty of ...
Arthroscopic hip labral repair.
Philippon, Marc J; Faucet, Scott C; Briggs, Karen K
Labral tears in the hip may cause painful clicking or locking of the hip, reduced range of motion, and disruption to sports and daily activities. The acetabular labrum aids stabilization of the hip joint, particularly during hip motion. The fibrocartilaginous structure extends the acetabular rim and provides a suction seal around the femoroacetabular interface. Treatment options for labral tears include debridement, repair, and reconstruction. Repair of the labrum has been shown to have better results than debridement. Labral refixation is achieved with sutures anchored into the acetabular rim. The acetabular rim is trimmed either to correct pincer impingement or to provide a bleeding bed to improve healing. Labral repair has shown excellent short-term to midterm outcomes and allows patients to return to activities and sports. Arthroscopic rim trimming and labral refixation comprise an effective treatment for labral tears with an underlying diagnosis of femoroacetabular impingement and are supported by the peer-reviewed literature. PMID:23875153
... hemiarthroplasty to replace the ball part of your hip joint. You should have received physical therapy while you were in the hospital or at a rehabilitation center before going home from the hospital.
... hip area, and images are recorded on a computer. The black-and-white images show the internal ... the images can be seen clearly on the computer screen. A technician (sonographer) trained in ultrasound imaging ...
... such as sprinting, kicking, and changing direction while running or moving, can stretch and tear the hip flexors. Runners, people who do martial arts, and football, soccer, and hockey players are more likely to have ...
Minimally invasive hip replacement
... Smits SA, Swinford RR, Bahamonde RE. A randomized, prospective study of 3 minimally invasive surgical approaches in total hip arthroplasty: comprehensive gait analysis. J Arthroplasty . 2008;23:68-73. PMID: 18722305 ...
Anderson, A
Hip dysplasia is a common orthopaedic developmental disorder of dogs. This paper reviews the treatment options available for management of the condition in the skeletally immature and adult dog. PMID:21906059
Harris, E Clare; Coggon, David
Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by the elimination or redesign of processes and the use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on the capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242
Harris, E Clare; Coggon, David
Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by elimination or redesign of processes and use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age, and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242
Hip fusion as hip salvage procedure in cerebral palsy.
Fucs, Patricia M De Moraes Barros; Yamada, Helder H
The treatment of the spastic hip in Cerebral Palsy (CP) remains a challenge especially in cases of advance changes. Many options are available and the key for a good outcome is to find the best surgical procedure to an individualized patient. The hip fusion is one of the surgical options. The authors presented a group of spastic CP with painful chronic hip subluxation and dislocation treated with hip fusion with a mean follow-up period of 14.5 years. Surgical technique, post-operative management and outcomes were shown, also with the observations done regarding the evolution of the contralateral hip after the hip fusion. They concluded that the hip arthrodesis is an option for patients with spastic CP with painful subluxation or dislocated hips with the goal of pain relief maintain or improve functional status, and facilitating the care. The best candidate is a young ambulatory patient with normal contralateral hip and normal spinal alignment. PMID:25207734
Fixation using alternative implants for the treatment of hip fractures (FAITH): design and rationale for a multi-centre randomized trial comparing sliding hip screws and cancellous screws on revision surgery rates and quality of life in the treatment of femoral neck fractures
Background Hip fractures are a common type of fragility fracture that afflict 293,000 Americans (over 5,000 per week) and 35,000 Canadians (over 670 per week) annually. Despite the large population impact the optimal fixation technique for low energy femoral neck fractures remains controversial. The primary objective of the FAITH study is to assess the impact of cancellous screw fixation versus sliding hip screws on rates of revision surgery at 24 months in individuals with femoral neck fractures. The secondary objective is to determine the impact on health-related quality of life, functional outcomes, health state utilities, fracture healing, mortality and fracture-related adverse events. Methods/Design FAITH is a multi-centre, multi-national randomized controlled trial utilizing minimization to determine patient allocation. Surgeons in North America, Europe, Australia, and Asia will recruit a total of at least 1,000 patients with low-energy femoral neck fractures. Using central randomization, patients will be allocated to receive surgical treatment with cancellous screws or a sliding hip screw. Patient outcomes will be assessed at one week (baseline), 10 weeks, 6, 12, 18, and 24 months post initial fixation. We will independently adjudicate revision surgery and complications within 24 months of the initial fixation. Outcome analysis will be performed using a Cox proportional hazards model and likelihood ratio test. Discussion This study represents major international efforts to definitively resolve the treatment of low-energy femoral neck fractures. This trial will not only change current Orthopaedic practice, but will also set a benchmark for the conduct of future Orthopaedic trials. Trial registration The FAITH trial is registered at ClinicalTrials.gov (Identifier NCT00761813). PMID:24965132
Exchange of Spacer Regions between Rrna Operons in Escherichia Coli
Harvey, S.; Hill, C. W.
The Escherichia coli rRNA operons each have one of two types of spacer separating the 16S and 23S coding regions. The spacers of four operons encode tRNA(Glu2) and the other three encode both tRNA(Ile) and tRNA(Ala 1 B). We have prepared a series of mutants in which the spacer region of a particular rrn operon has been replaced by the opposite type. Included among these were a mutant retaining only a single copy of the tRNA(Glu2) spacer (at rrnG) and another retaining only a single copy of the tRNA(Ile)-tRNA(Ala 1 B) spacer (at rrnA). While both mutants grew more slowly than controls, the mutant deficient in tRNA(Glu2) spacers was more severely affected. At a frequency of 6 X 10(-5), these mutants phenotypically reverted to faster growing types by increasing the copy number of the deficient spacer. In most of these phenotypic revertants, the deficient spacer type appeared in a rrn operon which previously contained the surplus type, bringing the ratio of spacer types closer to normal. In a few cases, these spacer changes were accompanied by an inversion of the chromosomal material between the donor and recipient rrn operons. Two examples of inversion of one-half of the E. coli chromosome between rrnG and rrnH were observed. The correlation of spacer change with inversion indicated that, in these particular cases, the change was due to an intrachromatid gene conversion event accompanied by a reciprocal crossover rather than reciprocal exchange between sister chromatids. PMID:2168847
Polesello, Giancarlo Cavalli; Keiske Ono, Nelson; Bellan, Davi Gabriel; Honda, Emerson Kiyoshi; Guimarães, Rodrigo Pereira; Junior, Walter Riccioli; Do Val Sella, Guilherme
To confirm the therapeutic importance of hip arthroplasty in athletes whose pain precludes sportive function of the hip joint, being able to minimize it to the extent of helping on the return of sports practice at satisfactory levels. Methods: 49 athlete patients (51 hips) submitted to hip arthroscopy complaining of pain and inability to practice sports were assessed. Follow-up time ranged from 12 to 74 months (mean: 39.0 months). Preoperatively, pain site, severity according to Facial Expression Scale (FES) and the degree of disability using the modified Harris Hip Score (HHS) were assessed. Different diagnoses were provided, which led to the indication of arthroscopy, such as femoralacetabular impact, acetabular lip injury not secondary to femoral-acetabular impact, etc. Postoperatively, the patients were assessed by using the same methods as used at baseline and by the subjective analysis of return to sports activities. Results: Based on pre-and postoperative HHS and FES, the statistical analysis showed significance between values. We found some improvement in all cases and return to sports activities at a satisfactory level in most of the cases. Conclusion: As a result of our study, we confirm that arthroscopy in athletes with local hip injuries is an effective technique, able to promote the return to sports practice in most of the cases, without pain, and with an effective joint function, provided well indicated. PMID:26998449
Roos, Bruno Dutra; Roos, Milton Valdomiro; Júnior, Antero Camisa; Lampert, Henrique Bonotto; da Silva, Matheus Luis
Objective: To evaluate the clinical and radiographic results from patients who underwent femoral reconstruction secondary to loosening of total hip arthroplasty, using circumferential proximal femoral allografts and cemented implants. Methods: A retrospective study was conducted on 32 patients (33 hips) who underwent femoral reconstruction secondary to loosening of total hip arthroplasty, using circumferential proximal femoral allografts and cemented implants. Among these patients, 28 (29 hips) fulfilled all the requirements for this study. The mean follow-up was five years and two months. The clinical evaluation was done in accordance with the Harris Hip Score. Radiographically, the patients were assessed regarding reabsorption and consolidation of the allograft, migration of the greater trochanter, stability of the femoral component and heterotypic calcification. Results: The average preoperative Harris Hip Score was 32 points. At the last postoperative follow-up, the average score was 82 points. Allograft resorption of some degree was seen in nine hips (31%). Regarding consolidation, 24 cases (82.8%) showed full consolidation, three (10.3%) showed partial consolidation and two (6.9%) showed pseudarthrosis. All femoral components were stable. According to the criteria established, 27 cases (93.1%) were considered to be successful reconstructions after a mean follow-up of five years and two months. Conclusion: From the results obtained, it was concluded that use of circumferential proximal femoral allografts in selected cases of femoral reconstruction secondary to loosening of arthroplasty presented a high survival rate from the reconstruction over an average follow-up of five years and two months. PMID:27047896
The pathogenesis of osteolysis in two different cementless hip replacements.
Learmonth, I D; Smith, E J; Cunningham, J L
Wear of ultra-high molecular weight polyethylene has been incriminated in the osteolysis associated with aseptic loosening of hip implants. A variety of different factors can contribute to accelerated patterns of polyethylene wear and subsequent osteolysis. This paper examines the incidence of osteolysis observed in two different well-matched cohorts of cementless total hip arthroplasties. The patterns of osteolysis observed, which are ascribed to the generation of polyethylene debris, are interpreted with reference to the design of the individual prostheses. PMID:9141891
Improvement of inhaler efficacy by home-made spacer.
Sritara, P; Janvitayanuchit, S
The delivery of aerosol from a metered dose inhaler (MDI) was reported to be more efficient with a spacer. Hence, a home-made spacer modified from a 950 ml low cost plastic bottle, was compared with a MDI and with a 750 ml imported spacer (Nebuhaler). On three consecutive days, at the same time of day, 20 adult patients with chronic asthma inhaled two puffs of terbutaline sulphate (0.5 mg), delivered from MDI alone, MDI with a 750 ml Nebuhlaer and MDI with a home-made spacer. The following measurements were made: forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and pulse rate. These measurements were carried out immediately before and at 5, 20, 60 min after inhalation of terbutaline. FEV1 was significantly increased (P < 0.05) at 5, 20 and 60 min after administration of terbutaline with MDI via either spacers than with MDI alone but no significant difference was observed between Nebuhaler and the home-made spacer. FVC and pulse rate showed no significant change with each method of administration. In conclusion, terbutaline delivered by MDI and home-made spacer was more effective in bronchodilatation than by MDI alone and was just as effective as MDI and Nebuhaler. The home-made spacer therefore offers a simple, inexpensive and more effective method for delivering aerosol drug. PMID:7798822
Orthognathic model surgery with LEGO key-spacer.
Tsang, Alfred Chee-Ching; Lee, Alfred Siu Hong; Li, Wai Keung
A new technique of model surgery using LEGO plates as key-spacers is described. This technique requires less time to set up compared with the conventional plaster model method. It also retains the preoperative setup with the same set of models. Movement of the segments can be measured and examined in detail with LEGO key-spacers. PMID:24045189
Molecular recordings by directed CRISPR spacer acquisition.
Shipman, Seth L; Nivala, Jeff; Macklis, Jeffrey D; Church, George M
The ability to write a stable record of identified molecular events into a specific genomic locus would enable the examination of long cellular histories and have many applications, ranging from developmental biology to synthetic devices. We show that the type I-E CRISPR (clustered regularly interspaced short palindromic repeats)-Cas system of Escherichia coli can mediate acquisition of defined pieces of synthetic DNA. We harnessed this feature to generate records of specific DNA sequences into a population of bacterial genomes. We then applied directed evolution so as to alter the recognition of a protospacer adjacent motif by the Cas1-Cas2 complex, which enabled recording in two modes simultaneously. We used this system to reveal aspects of spacer acquisition, fundamental to the CRISPR-Cas adaptation process. These results lay the foundations of a multimodal intracellular recording device. PMID:27284167
Metal-on-metal total hip arthroplasty: the concerns.
MacDonald, S J
The metal-on-metal bearing couple is having a resurgence in clinical applications seen in total hip and hip resurfacing technologies. The most noteworthy advantage of a metal-on-metal implant is the improved wear characteristics seen in vitro on wear simulators and in vivo with retrieved implants. All bearings have disadvantages, and a metal-on-metal bearing is no exception. Concerns exist regarding the generation of metal ions seen in the blood and urine of patients with metal-on-metal implants. These elevated metal ions have theoretical, although not proven, risks related to carcinogenic and biologic concerns. Additionally, concerns exist regarding hypersensitivity, increased incidence of instability and increased costs. Specific patient selection issues arise with metal-on-metal implants. The current generation of implants has only early and mid-term results available, with no long-term series yet published. Therefore, although a metal-on-metal bearing may be considered a viable alternative to either polyethylene or ceramic implants, outstanding and unresolved issues continue to exist with this bearing, as they do with the alternatives. PMID:15577471
[Spinal column: implants and revisions].
Krieg, S M; Meyer, H S; Meyer, B
Non-fusion spinal implants are designed to reduce the commonly occurring risks and complications of spinal fusion surgery, e.g. long duration of surgery, high blood loss, screw loosening and adjacent segment disease, by dynamic or movement preserving approaches. This principle could be shown for interspinous spacers, cervical and lumbar total disc replacement and dynamic stabilization; however, due to the continuing high rate of revision surgery, the indications for surgery require as much attention and evidence as comparative data on the surgical technique itself. PMID:26779646
SU-E-J-230: Effect of Metal Hip Prosthesis On the Accuracy of Electromagnetic Localization and Tracking
Butler, W; Merrick, G; Kurko, B; Bittner, N
Purpose: To quantify the effect of metal hip prosthesis on the ability to track and localize electromagnetic transponders. Methods: Three Calypso transponders were implanted into two prostate phantoms. The geometric center of the transponders were identified on computed tomography and set as the isocenter. With the phantom stationary on the treatment table and the tracking array 14-cm above the isocenter, data was acquired by the Calypso system at 10 Hz to establish the uncertainty in measurements. Transponder positional data was acquired with unilateral hip prostheses of different metallic compositions and then with bilateral hips placed at variable separation from the phantom. Results: Regardless of hip prosthesis composition, the average vector displacement in the presence of a unilateral prosthesis was < 0.5 mm. The greatest contribution to overall vector displacement occurred in the lateral dimension. With bilateral hip prosthesis, the average vector displacement was 0.3 mm. The displacement in the lateral dimension was markedly reduced compared with a unilateral hip, suggesting that there was a countervailing effect with bilateral hip prosthesis. The greatest average vector displacement was 0.6 mm and occurred when bilateral hip prostheses were placed within 4 cm of the detector array. Conclusion: Unilateral and bilateral hip prostheses did not have any meaningful effect on the ability to accurately track electromagnetic transponders implanted in a prostate phantom. At clinically realistic distances between the hip and detection array, the average tracking error is negligible.
Preventing Leg Length Discrepancy and Instability After Total Hip Arthroplasty.
Sculco, Peter K; Austin, Matthew S; Lavernia, Carlos J; Rosenberg, Aaron G; Sierra, Rafael J
Restoration of equal leg lengths and dynamic hip stability are essential elements of a successful total hip arthroplasty. A careful clinical examination, a preoperative plan, and appropriate intraoperative techniques are necessary to achieve these goals. Preoperative identification of patients at risk for residual leg length discrepancy allows surgeons to adjust the surgical approach and/or the type of implant and provide better preoperative patient education. The use of larger femoral heads, high-offset stem options, and enhanced soft-tissue repairs have improved impingement-free range of motion as well as dynamic hip stability and have contributed to an overall reduction in dislocation. Methods for accurate leg length restoration and component positioning include anatomic landmarks, intraoperative radiographs, intraoperative calipers, stability testing, and computer-assisted surgery. If recurrent instability occurs after total hip arthroplasty, the underlying cause for dislocation should be identified and treated; this may include the use of semiconstrained dual-mobility or fully constrained liners, depending on abductor function. Surgeons should be aware of the clinical and surgical techniques for achieving leg length equalization and dynamic hip stability in total hip arthroplasty. PMID:27049193
Bearing surfaces in hip replacement – Evolution and likely future
Kumar, Narinder; Arora, Gen N.C.; Datta, Barun
Total hip arthroplasty has evolved from the first total hip arthroplasty in 1938, through the revolutionization of hip arthroplasty by principles of low friction arthroplasty introduced by Sir John Charnley in 1960s to the present state of the art implants and techniques. The main concern regarding failure of total hip arthroplasty has been the biological response to particulate polyethylene debris generated by conventional metal on polyethylene bearing surfaces leading to osteolysis and aseptic loosening of the prosthesis. Therefore, recent research has been focussing on alternative bearing surfaces to reduce the particulate debris generated. These bearing surfaces include ceramic-polyethylene, metal–metal as well as ceramic–ceramic articulations and have demonstrated lesser friction rates as well as significantly lower wear rates as compared to widely used metal on polyethylene surfaces. Clinical experience until now has shown that metal on metal articulations have significant safety concerns whereas metal-on-highly crosslinked polyethylene, ceramic on ceramic and ceramic on highly crosslinked polyethylene articulations have shown encouraging results to hold promise for wider use in younger and more active patients. This review article discusses positives and drawbacks of various bearing surfaces in current clinical use in total hip arthroplasty as well as briefly explores the newer technologies on the horizon which may even further decrease wear and improve total hip arthroplasty survivorship. PMID:25382913
Weber, Alexander E.; Bedi, Asheesh; Tibor, Lisa M.; Zaltz, Ira; Larson, Christopher M.
Context: Dance, gymnastics, figure skating, and competitive cheerleading require a high degree of hip range of motion. Athletes who participate in these sports use their hips in a mechanically complex manner. Evidence Acquisition: A search of the entire PubMed database (through December 2013) and additional searches of the reference lists of pertinent articles. Study Design: Systematic review. Level of Evidence: Level 3. Results: Whether innate or acquired, dancers and gymnasts have some hypermobility that allows their hips to be placed in potentially impinging or unstable positions required for their given activity. Such extremes of motion can result in both intra-articular and extra-articular impingement as well as compensatory osseous and muscular pathology. In addition, dancers and gymnasts are susceptible to impingement-induced instability. Dancers with innate generalized hyperlaxity are at increased risk of injury because of their activities and may require longer recovery times to return to play. Both nonoperative and operative treatments (arthroscopic and open) have an important role in returning flexibility athletes to their preoperative levels of sport and dance. Conclusion: Because of the extreme hip motion required and the compensatory soft tissue laxity in dancers and gymnasts, these athletes may develop instability, impingement, or combinations of both. This frequently occurs in the setting of subtle pathoanatomy or in patients with normal bony anatomy. With appropriate surgical indications and the correct operative technique, the treating surgeon can anticipate high levels of return to play for the gymnast and dancer with hip pain. PMID:26137181
Chang, Qing; Liu, Shubing; Guan, Changyong; Yu, Fangyuan; Wu, Shenguang; Jiang, Changliang
Our aim was to compare hip arthroplasty with internal screw fixation in the repair of intertrochanteric fractures in elderly patients with osteoporosis. Of 112 included patient, 70 (81.81 ± 4.88 years) received hip arthroplasty with a prosthesis specially designed for intertrochanteric fractures, and 42 (83.46 ± 5.11 years) underwent plate-screw fixation. The hip arthroplasty group had significantly longer operation time, intraoperative blood loss, and total volume of blood transfused but had shorter time to beginning weight-bearing (5.94 ± 2.76 vs 23.68 ± 22.01 days) and higher postoperative Harris hip score (91.37 ± 4.80 vs 86.14 ± 5.46). In the arthroplasty group, there were 2 dislocations; and in the plate-screw fixation group, there were 5 internal fixation failures. Hip arthroplasty is preferable to internal fixation in elderly patients (age >80 years) with osteoporosis. PMID:21530148
Ten different hip resurfacing systems: biomechanical analysis of design and material properties
Kleinhans, Jennifer A.; Menge, Michael; Kretzer, Jan Philippe
This study gives an overview of the main macro- and microstructural differences of ten commercially available total hip resurfacing implants. The heads and cups of resurfacing hip implants from ten different manufacturers were analysed. The components were measured in a coordinate measuring machine. The microstructure of the heads and cups was inspected by scanning electron microscopy. The mean radial clearance was 84.86 μm (range: 49.47–120.93 μm). The implants were classified into three groups (low, medium and high clearance). All implants showed a deviation of roundness of less than 10 μm. It was shown that all implants differ from each other and a final conclusion about the ideal design and material combination cannot be given based on biomechanical data. Widespread use of specific designs can only be recommended if clinical long-term follow-up studies are performed and analysed for each design. PMID:18600323
Modular noncemented total hip arthroplasty for congenital dislocation of the hip. Case report and design rationale.
Gorski, J M
The highest rate of failure and the greatest technical difficulty in total hip arthroplasty occurs with congenital dislocation of the hip (CDH). Predisposing factors are failure to secure special femoral components to fit an extremely narrow and straight medullary cavity with space for only a very thin mantle of cement. The acetabulum is usually atrophic, and bone grafts are commonly required to support a small-diameter cup. The young age of the average patient and high levels of activity contribute to cement failure. A new modular cementless prosthesis provides excellent immediate skeletal fixation and pain relief in CDH patients. Five modular components are screwed or press-fit into bone. The modular approach facilitates implantation, reduces inventory, and is adaptable to unforeseen problems. These advantages are ordinarily absent with standard or custom cemented components. Modular components may also permit easier revision. The prosthesis is made of titanium alloy for its superalloy strength, elastic modulus, and bioinertness. By omitting the cement mantle, press-fit is obtained with the largest possible implant. The large size minimizes stem breakage in these young, small bones. Excellent short-term results suggest that modular cementless implants are indicated in some patients with CDH. PMID:3342552
Hip joint replacement - series (image)
... hip socket. The socket is usually made of metal. A liner that fits inside the socket. It ... usually plastic, but some surgeons use ceramic and metal. The liner allows the hip to move smoothly. ...
New experience with alumina-on-alumina ceramic bearings for total hip arthroplasty.
D'Antonio, James; Capello, William; Manley, Michael; Bierbaum, Benjamin
A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release. In a prospective randomized study, 514 hips were implanted. All patients (average age, 53 years) received the same press-fit hydroxyapatite coated femoral stem; two thirds (345 hips) received alumina ceramic bearings, and one third (169 hips) received a cobalt-chrome-on-polyethylene bearing. At a mean follow-up of 35.2 months (range, 24-48 months), there was no significant difference in clinical performance between the patient cohorts. No ceramic fracture or alumina ceramic bearing failure occurred. This new experience involves the use of improved ceramic materials and new design considerations that eliminate the risks and complications of past experiences with ceramic implants and provides a safe bearing option for young patients. PMID:12066265
Use of Cemented Spacer with a Handmade Stem to Treat Acute Periprosthetic Tibial Fracture Infection: A Case Report
Font-Vizcarra, LluÍs; Izquierdo, Oscar; GarcÍa-NuÑo, Laura; GonzÁlez, Araceli; Diaz-Brito, VicenÇ; Castellanos, Juan
We report an 85-year-old woman with dementia and dependent for normal life activities who was admitted due to a left periprosthetic tibial fracture. The tibial component was replaced by one with a long stem and she was discharged. Four weeks after the intervention the patient was re-admitted due to an acute prosthetic joint infection. All the components were removed and a bone-cement spacer with a handmade stem with a metal core was implanted. Radiological signs of fracture consolidation were observed after 3 months of follow-up. Due to the previous health status of the patient, it was decided to keep the spacer as a definitive treatment. After 24 months, the patient was able to sit without pain and to stand up with help using a knee brace. There were no radiological or clinical signs of infection. PMID:24551027
Hip impingement: beyond femoroacetabular
Bardakos, Nikolaos V.
In the last 20 years, femoroacetabular impingement has been at the forefront of clinical practice as a cause of hip pain in young adults. As arthroscopic techniques for the hip continue to evolve, the possible presence of a new group of conditions creating mechanical conflict in and around the hip joint (ischiofemoral, subspine and iliopsoas impingement) has recently been elucidated whilst interest in already known 'impingement' syndromes (pelvic-trochanteric and pectineofoveal impingement) is now revived. This article attempts to increase awareness of these relatively uncommon clinical entities by describing their pathomorphology, contact mechanics, treatment and published results available to present. It is hoped that such knowledge will diversify therapeutic options for the clinician, thereby improving outcomes in a small but not negligible portion of patients with previously unexplained persistent symptoms. PMID:27011843
Pervasive generation of oppositely oriented spacers during CRISPR adaptation
Shmakov, Sergey; Savitskaya, Ekaterina; Semenova, Ekaterina; Logacheva, Maria D.; Datsenko, Kirill A.; Severinov, Konstantin
During the process of prokaryotic CRISPR adaptation, a copy of a segment of foreign deoxyribonucleic acid referred to as protospacer is added to the CRISPR cassette and becomes a spacer. When a protospacer contains a neighboring target interference motif, the specific small CRISPR ribonucleic acid (crRNA) transcribed from expanded CRISPR cassette can protect a prokaryotic cell from virus infection or plasmid transformation and conjugation. We show that in Escherichia coli, a vast majority of plasmid protospacers generate spacers integrated in CRISPR cassette in two opposing orientations, leading to frequent appearance of complementary spacer pairs in a population of cells that underwent CRISPR adaptation. When a protospacer contains a spacer acquisition motif AAG, spacer orientation that generates functional protective crRNA is strongly preferred. All other protospacers give rise to spacers oriented in both ways at comparable frequencies. This phenomenon increases the repertoire of available spacers and should make it more likely that a protective crRNA is formed as a result of CRISPR adaptation. PMID:24728991
... electrodes are inserted. The electronic device at the base of the electrode array is then placed under ... FDA approval for implants The Food and Drug Administration (FDA) regulates cochlear implant devices for both adults ...
Goserelin implant is used in combination with radiation therapy and other medications to treat localized prostate cancer and is ... treatment of abnormal bleeding of the uterus. Goserelin implant is in a class of medications called gonadotropin- ...
A cochlear implant is a small, complex electronic device that can help to provide a sense of sound. People who are ... of-hearing can get help from them. The implant consists of two parts. One part sits on ...
Carmustine implant is used along with surgery and sometimes radiation therapy to treat malignant glioma (a certain type of ... Carmustine implant comes as a small wafer that is placed in the brain by a doctor during surgery to ...
... antenna. This part of the implant receives the sound, converts the sound into an electrical signal, and sends it to ... implants allow deaf people to receive and process sounds and speech. However, these devices do not restore ...
... Updated Safety Information (Consumer Article) FDA Provides Updated Safety Data on Silicone Gel-Filled Breast Implants (Press Announcement) [ARCHIVED] Breast Implant Guidance for Industry (2006) Post Approval Studies Webpage Freedom of Information ...
Inhalational drug delivery from seven different spacer devices.
Barry, P. W.; O'Callaghan, C.
BACKGROUND: A study was performed to determine in vitro the difference in drug output of seven currently available spacer devices when used with different inhaled medications. METHODS: A glass multistage liquid impinger (MSLI) was used to determine the amount of disodium cromoglycate (DSCG, 5 mg), salbutamol (100 micrograms), or budesonide (200 micrograms) obtained in various particle size ranges from metered dose inhalers (MDIs) actuated directly into the MSLI or via one of seven different spacer devices; the Fisonair, Nebuhaler, Volumatic, Inspirease, Aerochamber, Aerosol Cloud Enhancer, and Dynahaler. RESULTS: In particles smaller than 5 microns in diameter the dose of DSCG recovered from the Fisonair and Nebuhaler was 118% and 124%, respectively, of that recovered using the MDI alone. The dose recovered from the smaller volume spacers was 90% (Inspirease), 36% (Aerochamber), 33% (Aerosol Cloud Enhancer), and 21% (Dynahaler) of that from the MDI alone. The Volumatic increased the amount of salbutamol in particles smaller than 5 microns to 117% of that from the MDI, and the Inspirease and Aerochamber spacers decreased it by nearly 50%. The amount of budesonide in small particles recovered after use of the Nebuhaler, Inspirease, and the Aerochamber was 92%, 101%, and 78%, respectively, of that from the MDI alone. CONCLUSIONS: Under the test conditions used, large volume spacers such as the Fisonair, Nebuhaler, and Volumatic delivered significantly more DSCG and salbutamol than the smaller spacers tested. The differences between spacers were less for budesonide than the other medications studied. This study shows that there are significant differences in the amount of drug available for inhalation when different spacers are used as inhalational aids with different drugs. Spacer devices need to be fully evaluated for each drug prescribed for them. Images PMID:8795674
Sammarco, G J
Conditions that occur in the dancer's hip fall into the following categories: poor training; conditions that occur as the result of normal use; overuse syndromes, including tendinitis and myositis; and conditions referring pain to the hip. Dancers are highly motivated and goal oriented and often suppress symptoms for long periods, making diagnosis and treatment difficult. Observing the dancer at work and understanding his art are emphasized, and a practical guide to therapy is presented. Development of proper dance technique and a proper flexibility program can decrease the incidence of injuries. PMID:6652698
[Complications of hip arthroscopies].
Dienst, M; Grün, U
Surgical complications of hip arthroscopies are rare in the hands of experienced hip arthroscopists. However, when performed by beginners and in more demanding situations such as marginal distraction of the head and socket and technically advanced procedures, the risk increases. This report describes possible complications which may happen during positioning and traction, portal placement, and diagnostic and therapeutic procedures. Possible causes of soft tissue lesions of the portal area, perineum and foot, intra-articular lesions of the labrum and cartilage, direct and traction-related indirect neurovascular lesions, and other rare complications are analyzed. PMID:18854972
Fitzpatrick, Daniel C; Sheerin, Daniel V; Wolf, Brian R; Wuest, Thomas K
Objective To evaluate the clinical performance of the Dynamic Helical Hip System (DHHS) spiral blade relative to the Dynamic Hip Screw (DHS) lag screw. Design Randomized prospective study. Setting One level-2 trauma center and one level-3 trauma center. Patients Fifty-one consecutive patients were recruited into the trial. Inclusion criteria included patients over 50 years of age with AO/OTA 31A1 or 31A2 fracture. Intervention Surgeries were performed by one of 15 participating community orthopaedic surgeons. The patients were randomized to either a DHHS or DHS implant. Follow-up occurred at two weeks and six weeks and then at six-week intervals until healing occurred. Main Outcome Measures Primary outcome variables included sliding of die implant on the final AP radiographs, failure by cut-out and implant failure. Results There were 24 patients in the DHS group and 27 in the DHHS group. There was no difference in age, gender, ASA score, fracture classification or in the quality of reduction measured on the immediate postoperative radiographs (p=0.28) between the two groups. The tip apex distance was 18.7 mm in the DHHS group and 18.5 mm in the DHS group (p=0.40). The DHHS group had average blade sliding of 7.4 mm while the DHS group had an average lag-screw sliding of 7.7 (p=0.45). The DHHS group had two failures by central protrusion of the blade through the femoral head without significant varus collapse or superior migration. One was revised to a DHS and healed, the other was revised to a proximal femoral locking plate, which also failed and eventually required revision to a total hip arthroplasty. Investigation of the implants post failure showed evidence of binding of the blade shaft in the barrel as a mechanism of failure in both cases. No DHS implants cut out in this series, although one patient was revised to a total hip arthroplasty for symptomatic segmental osteonecrosis. Conclusion Both implants performed well in a majority of cases. The higher
The possible introduction of anti-osteoporosis drugs as an integrated treatment in total hip arthroplasty.
Marchese, Marcella; Zarattini, Guido; Pazzaglia, Ugo E
The anchorage of cementless total hip arthroplasty relies on a direct bone to implant bonding. Several factors including material properties and surface treatment determine the interfacial response of the host bone to a foreign material. Another factor that must be taken into account is the bone remodeling after the prosthesis introduction. Considering this bone remodeling, in the last few years the possibility of using anti-osteoporotic drugs has been introduced as a supplementary and integrated treatment in total hip replacement. PMID:21970916
Management of the 'young' patient with hip disease.
Ritterman, Scott A; Rubin, Lee E
Although hip arthritis typically affects older patients, there is a rapidly growing population of "young" patients experiencing debilitating symptoms from hip disease. Most commonly, osteoarthritis and avascular necrosis affect this population, but a variety of other primary structural and metabolic causes can also occur. The expectations of these younger patients are often distinct from geriatric patients, and the challenges in optimizing their care are unique in this demanding population. Selection of the implant, bearing surface, and surgical technique can all impact the success and longevity of total hip replacement. A consideration for respecting the native bone stock is an important consideration that can potentially reduce some of the future challenges of revision arthroplasty in this young population. PMID:23641435
Total hip arthroplasty in young patients with osteoarthritis.
Daras, Mariza; Macaulay, William
Total hip arthroplasty (THA), an effective treatment for patients with end-stage arthritic hip conditions, provides dramatic pain relief, enhances mobility, and restores function.The success of THA in older patients, in concert with improvements in techniques and biomaterials, has stimulated demand for this procedure in younger, more active patients hoping to regain full activity. Although young age remains a relative contraindication to THA, the weight of this factor has diminished. Several investigators have reported results of low-friction arthroplasty in young patients. Unfortunately, the value of these studies is limited because of heterogeneous hip pathology in the younger groups, particularly given that preoperative pathology has proved to significantly affect implant survival. In this review of the literature, we focus on THA survival in young, active patients with a preoperative diagnosis of noninflammatory osteoarthritis. PMID:19377644
Impingement in Total Hip Replacement: Mechanisms and Consequences
Brown, Thomas D.; Callaghan, John J.
The occurrence of total hip impingement, whether or not accompanied by frank dislocation, holds substantial untoward clinical consequences, especially as less-forgiving advanced bearing implant designs come into ever more widespread use. Biomechanical aspects of impingement and dislocation have historically received relatively little scientific attention, although that situation is now rapidly changing. The present article reviews contemporary laboratory and clinical research on the impingement/dislocation phenomena, focusing particularly on how implant design variables, surgical implantation factors and patient activity each act individually and in concert to pose impingement and dislocation challenges. In recent years, several powerful new research methodologies have emerged that have greatly expanded the scope for clinical translation of systematic laboratory study. Transferring the findings from such research into yet better implant designs, and even better surgical procedures, offers encouragement that the clinical impact of this troublesome complication can be further reduced. PMID:19956356
Preclinical Evaluation of Bioabsorbable Polyglycolic Acid Spacer for Particle Therapy
Akasaka, Hiroaki; Sasaki, Ryohei; Miyawaki, Daisuke; Mukumoto, Naritoshi; Sulaiman, Nor Shazrina Binti; Nagata, Masaaki; Yamada, Shigeru; Murakami, Masao; Demizu, Yusuke; Fukumoto, Takumi
Purpose: To evaluate the efficacy and safety of a polyglycolic acid (PGA) spacer through physical and animal experiments. Methods and Materials: The spacer was produced with surgical suture material made of PGA, forming a 3-dimensional nonwoven fabric. For evaluation or physical experiments, 150-MeV proton or 320-MeV carbon-ion beams were used to generate 60-mm width of spread-out Bragg peak. For animal experiments, the abdomens of C57BL/6 mice, with or without the inserted PGA spacers, were irradiated with 20 Gy of carbon-ion beam (290 MeV) using the spread-out Bragg peak. Body weight changes over time were scored, and radiation damage to the intestine was investigated using hematoxylin and eosin stain. Blood samples were also evaluated 24 days after the irradiation. Long-term thickness retention and safety were evaluated using crab-eating macaques. Results: No chemical or structural changes after 100 Gy of proton or carbon-ion irradiation were observed in the PGA spacer. Water equivalency of the PGA spacer was equal to the water thickness under wet condition. During 24 days' observation after 20 Gy of carbon-ion irradiation, the body weights of mice with the PGA spacer were relatively unchanged, whereas significant weight loss was observed in those mice without the PGA spacer (P<.05). In mice with the PGA spacer, villus and crypt structure were preserved after irradiation. No inflammatory reactions or liver or renal dysfunctions due to placement of the PGA spacer were observed. In the abdomen of crab-eating macaques, thickness of the PGA spacer was maintained 8 weeks after placement. Conclusions: The absorbable PGA spacer had water-equivalent, bio-compatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to stop proton or carbon-ion beams and to separate normal tissues from the radiation field.
The Finnish Arthroplasty Register: report of the hip register.
Puolakka, T J; Pajamäki, K J; Halonen, P J; Pulkkinen, P O; Paavolainen, P; Nevalainen, J K
The Finnish Arthroplasty Register was established in 1980. Between 1980 and 1999, 62,841 primary and 12,224 revision total hip arthroplasties (THA) were recorded. The annual number of both primary and revision THA has increased: in 1999, the incidence of primary THAs was 93/100,000. 174 implant designs have been used, but the 6 commonest implants comprised 82% in 1999. Since the late 1980s, more than 40% of the hips were inserted without cement. Over 47% of the cementless primary hip prostheses were used in patients younger than 60 years and over 93% of the cemented primary hips were used in patients 60 years or older. The 10-year survival rate was 72 (95% CI 67-76)% in patients younger than 55 years and 90 (89-91)% in patients older than 70 years. The commonest reasons for revision were aseptic loosening (65%), dislocation (9%) and infection (7%). In revisions, the 5-year survival of the cementless hip prosthesis improved over time: it was 85 (82-87)% in 1985-1989, 89 (88-91)% in 1990-1994 and 92 (88-95)% in 1995-1999. There are striking differences between the Arthroplasty Registers of Scandinavia as regards the end-point definition of survival. The Finnish Arthroplasty Register considers all reasons for revisions as the end-point of survival, but the Swedish register takes into account only aseptic loosening, so direct comparisons between registers are not possible. Recent data from the Finnish Arthroplasty Register indicate that the results of total hip replacements are improving in Finland. With the civic registration number, one can link and match data files. For example, with use of the Finnish Cancer Register, we found no increase in the risk of cancer after a THA. PMID:11728068
Hip resurfacing: a large, US single-surgeon series.
Brooks, P J
Hip resurfacing has been proposed as an alternative to traditional total hip arthroplasty in young, active patients. Much has been learned following the introduction of metal-on-metal resurfacing devices in the 1990s. The triad of a well-designed device, implanted accurately, in the correct patient has never been more critical than with these implants. Following Food and Drug Administration approval in 2006, we studied the safety and effectiveness of one hip resurfacing device (Birmingham Hip Resurfacing) at our hospital in a large, single-surgeon series. We report our early to mid-term results in 1333 cases followed for a mean of 4.3 years (2 to 5.7) using a prospective, observational registry. The mean patient age was 53.1 years (12 to 84); 70% were male and 91% had osteoarthritis. Complications were few, including no dislocations, no femoral component loosening, two femoral neck fractures (0.15%), one socket loosening (0.08%), three deep infections (0.23%), and three cases of metallosis (0.23%). There were no destructive pseudotumours. Overall survivorship at up to 5.7 years was 99.2%. Aseptic survivorship in males under the age of 50 was 100%. We believe this is the largest United States series of a single surgeon using a single resurfacing system. PMID:26733633
Early Attempts at Hip Arthroplasty
Gomez, Pablo F; Morcuende, Jose A
Over the last three centuries, treatment of hip arthritides has evolved from rudimentary surgery to modern total hip arthroplasty (THA), which is considered one of the most successful surgical interventions ever developed. We here review the history of the early hip arthroplasty procedures for hip arthritis that preceded Charley total hip arthroplasty. An evaluation of such past enterprises is relevant, and reminds us of the ephemeral nature of human industriousness, and how medical research and procedures are not isolated developments, but correlate to the social, economical, and cultural framework of their time. PMID:16089067
Hip Arthroscopy in The Athlete
Sports related injuries to the hip have received relatively little attention, in the part because the clinical assessment, imaging studies, and surgical techniques are less sophisticated. The evolution of hip arthroscopy has offered a less invasive technique that allows for recognition and treatment of hip pathologies that previously went unrecognized. The success of hip arthoscopy is dependent on proper patient selection based on the patient's history and diagnosis. The purpose of this clinical commentary is to outline mechanisms of injury and specific lesions that can be addresses using hip arthoscopy. PMID:21509141
Tammareddi, Kumar; Morelli, Vincent; Reyes, Miguel
Groin and hip injuries are seen in athletes who perform quick directional changes and cutting movements. Because forces generated through athletic performance are transferred through the hip, injuries to these areas may limit athletes with mild pain or lead to career-ending injuries. The anatomy of the hip and groin is complex and symptoms often overlap. This article discusses some athletic causes, but other medical conditions may be associated with hip and groin pain as well. Updates in evaluation and treatment are discussed for adductor strains, hip osteoarthritis, femoroacetabular impingement, sports hernia, osteitis pubis, and obturator nerve entrapment. PMID:23668647
Hip Arthroscopy: A Brief History.
Kandil, Abdurrahman; Safran, Marc R
Hip arthroscopy is a fast-growing and evolving field. Like knee and shoulder arthroscopy, hip arthroscopy began as a diagnostic procedure and then progressed to biopsy and resection of abnormalities. Subsequently, it has evolved to repair of various tissues and treatment of underlying causes. As the understanding of the hip joint and its associated pathophysiology grows, indications will continue to expand for this diagnostic and therapeutic modality. This article outlines the historic developments of hip arthroscopy, including advancements in instrumentation and techniques from the days of the first hip arthroscopies to the present day. PMID:27343387
B. H. Park; C. R. Clark; J. F. Jue
This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.
Hip Morphology Characterization
Barrientos, Cristián; Diaz, Jorge; Brañes, Julian; Chaparro, Felipe; Barahona, Maximiliano; Salazar, Alfonso; Hinzpeter, Jaime
Background: Femoroacetabular impingement (FAI) is the result of a mechanical conflict in the hip joint, and its diagnosis is based on clinical and radiological parameters. To our knowledge, there are no published studies describing the radiologic characteristics of FAI in Latin American populations. Purpose: To describe the radiological features associated with FAI in an asymptomatic Chilean population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We prospectively recruited asymptomatic patients with no history or symptoms of hip pathology who underwent abdomen-pelvis computed tomography (CT) for a nonorthopaedic indication. The acetabular and femoral parameters related to FAI were measured. Results: We studied 101 subjects (202 hips) with a mean age of 36.8 ± 14.4 years. The mean center-edge angle was 39.4° ± 7.2°. The crossover sign was present in 34 cases (33.7%). The mean alpha angle was 49.7° ± 8.3°. Depending on the cut points chosen for FAI-related parameters, between 39.6% and 69.3% of an asymptomatic Chilean population were found to have morphological features related to FAI. Conclusion: Our findings suggest that the proposed pathological threshold values in the literature cannot be extrapolated to a Chilean population, and this must be taken into consideration when evaluating Latin American patients with hip pain. PMID:26535273
Congenital hip dislocation (image)
... by a blow, fall, or other trauma, a dislocation can also occur from birth. The cause is unknown but genetic factors may play a role. Problems resulting from very mild developmental dysplasia of the hip may not become apparent until the person is ...
Contreras, Marcos Emílio Kuschnaroff; Hoffmann, Rafael Barreiros; de Araújo, Lúcio Cappelli Toledo; Dani, William Sotau; José Berral, Francisco
Objectives: To determine the prevalence of complications in a series of consecutive cases of hip arthroscopy; to assess the progression of the sample through a learning curve; and to recognize the causes of complications in arthroscopic hip operations. Method: 150 consecutive cases that underwent hip arthroscopy between May 2004 and December 2008 were evaluated. The complications encountered were classified in three ways: organic system affected, severity and groups of 50 consecutive cases. The data were analyzed by means of descriptive statistics and Fisher's exact test. Results: We observed 15 complications in this study (10%): ten were neurological, two were osteoarticular, one was vascular-ischemic and two were cutaneous. In the classification of severity, three were classified as major, 12 as intermediate and none as minor. The incidence of complications over the course of the learning curve did not present any statistically significant difference (p = 0.16). Conclusions: Hip arthroscopy is a surgical procedure that involves low morbidity, but which presents complications in some cases. These complications are frequently neurological and transitory, and mainly occur because of joint traction. The complication rate did not decrease with progression of our sample. PMID:27022521
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
14. TYPICAL WORK DECK SHOWING RING SPACERS, CABLE DRUMS AND OTHER SPECIALIZED HARDWARE; VIEW TO SOUTH. - Cape Canaveral Air Station, Launch Complex 17, Facility 28416, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL
Ilizarov bone transport combined with antibiotic cement spacer for infected tibial nonunion
Peng, Jing; Min, Li; Xiang, Zhou; Huang, Fuguo; Tu, Chongqi; Zhang, Hui
Purpose: To evaluate the curative effect of Ilizarov bone transport combined with antibiotic cement spacer for infected tibial nonunion with bone defect. Methods: We retrospectively reviewed the outcomes of 58 patients with infected tibial nonunion from January 2008 to March 2011 at our institution. Patients were treated with complete debridement, radical sequestrectomy, antibiotic cement spacer implantation, bone transport using the Ilizarov external fixator, and soft tissue reconstruction. Clinical efficacy was assessed using Paley's grading system and patient satisfaction at the last follow-up. Results: Follow-up ranged from 24 to 63 months (average, 31.6 months). Mean size of the tibial defect was 9.2 cm (range, 6-15 cm). The soft tissue defect was closed successfully in all cases. Patients eventually achieved union with a mean bone union index of 1.2 months/cm at an average of 10.6 months (range, 8-31 months). In terms of Paley grade, 30 patients had excellent results, 23 good, and 5 fair. Functional results were excellent in 28 patients, good in 18, and fair in 12. Thirty-five patients felt extremely satisfied, 18 satisfied, and 5 acceptable with the functional outcome. Complications included pin site infection in 18 cases, limb length discrepancy less than 1.5 cm in 10, knee stiffness in 5, equinus deformity in 4, infectious recurrence in 1 and pin breakage in 1. There was no refracture at the reconstruction site. Conclusion: Ilizarov bone transport combined with antibiotic cement spacer is a versatile and effective method for treatment of infected tibial nonunion. PMID:26309700
Efficacy of Debridement for Early Periprosthetic Joint Infection after Hip Arthroplasty
Kim, Jong Hoon; Chun, Sung Kwang; Yoon, Yong Cheol; Lakhotia, Devendra
Purpose In early prosthetic joint infection after hip arthroplasty, debridement with prosthesis retention may be performed for implant salvage, but the reported success rates are highly variable. Hence we reviewed the outcome of radical debridement and retention of prosthesis using established diagnostic criteria and surgical procedures in relation to significant variables including clinical characteristics, pathogenicity, and antibiotic treatment. Materials and Methods We retrospectively reviewed 20 patients (11 men and 9 women) with early prosthetic joint infection after unilateral hip arthroplasty, treated by radical debridement with retention of prosthesis from January 2000 to May 2011. Average follow-up period was 55 months (12-178 months). The outcome was evaluated and analyzed based on recurrence of infection and clinical (Harris hip score) and radiological criteria. Results Pathogens were isolated from 11 hips (methicillin-resistant Staphylococcus aureus [MRSA] in three, methicillin-resistant Staphylococcus epidermidis [MRSE] in two, methicillin-sensitive Staphylococcus aureus [MSSA] in one, Acinetobacter baumannii in two, Enterococcus faecalis in two patients, and Enterococcus, Citrobacter species in one). The mean duration of antibiotic administration was 43.5 days. Recurrence of infection was not observed in any case. Average Harris hip score was 91 points at the last follow-up. Revision surgery was not required for any reason including implant failure. Dislocation occurred in two hips after debridement and was treated conservatively. Conclusion Radical debridement with prosthesis retention is an effective procedure for early prosthetic joint infection after hip arthroplasty in carefully selected patients and with early diagnosis.
Small diameter acetabulum and femoral head in total hip arthroplasty for developmental dysplasia of the hip, with no femoral osteotomy.
Verettas, Dionysios-Alexandros; Chloropoulou, Pelagia; Xarchas, Konstantinos; Drosos, Georgios; Ververidis, Athanasios; Kazakos, Konstantinos
We present the results of 66 total hip arthroplasties in 62 patients of mean age 46 years (24-74 years), with developmental dysplasia of the hip. In all cases the centre of rotation of the new hip was positioned at the site of the true acetabulum. In all patients cementless press fit acetabular components of small diameter (42-44 mm) were used, articulating exclusively with a 22.25 mm modular metal femoral head, without the use of bone grafts or shortening osteotomies of the femur. Despite the use of small diameter femoral heads the rate of dislocation was 3%. After an average follow-up period of 9 years (4-18 years), no revisions were required for infection, loosening or wear or implant migration. Osteolytic lesions were seen in the periacetabular region in 3 patients who were symptom free. A total of 2 revisions were required for instability and 2 patients had the wires of their trochanteric osteotomy removed because of bursitis. Leg length inequality was improved in 55% of the patients and one postoperative transient sciatic nerve lesion settled within 4 months. We believe that in patients with painful dysplastic hips, the use of small diameter implants with the centre of rotation at the true acetabulum, can give very satisfactory results, without any supplementary procedures. PMID:25907394
Spacer process and alignment assessment for SADP process
NASA Astrophysics Data System (ADS)
Lattard, L.; McCallum, M.; Morton, R.; Fujiwara, T.; Makino, K.; Tokui, A.; Takahashi, N.; Sasamoto, S.
Self Aligned Double Patterning (SADP) is now widely accepted as a viable technology for the further extension of 193nm immersion lithography towards the 22nm /18nm technology nodes. SADP was primary introduced for the manufacturing of flash memory due to its 1D design geometry. However, SADP is now becoming a main stream technology for advanced technology nodes for logic product. SADP results in alignment marks with reduced image contrast after completion of spacer patterning. Consequently there is an elevated risk that the alignment performance of the cut lithography layer on the spacer [1] may be negatively impacted. Initial studies indicate that it may be necessary to consider new mark designs. In this paper, we will evaluate different types of SADP processes with the alignment system of the Nikon S620D and S621D immersion scanner. We will discuss the performances and the differences observed due to the SADP materials. Included in this study is an intensive characterization of the morphology of the spacer after SADP process. We will use for this a 3D-AFM from Insight, and characterize the spacer profile of the spacer. Using a standard AFM microscope, we can characterize the surface roughness in the inner and the outer part of the wafer. The self aligned spacer process results in asymmetric spacers. Two types of surface (inside and outside) of the spacer are formed. The impact of this asymmetry is also assessed. The roughness difference, between the two parts, will play an important roll in the alignment contrast.
Nuclear reactor spacer grid and ductless core component
Christiansen, David W.; Karnesky, Richard A.
The invention relates to a nuclear reactor spacer grid member for use in a liquid cooled nuclear reactor and to a ductless core component employing a plurality of these spacer grid members. The spacer grid member is of the egg-shell type and is constructed so that the walls of the cell members of the grid member are formed of a single thickness of metal to avoid tolerance problems. Within each cell member is a hydraulic spring which laterally constrains the nuclear material bearing rod which passes through each cell member against a hardstop in response to coolant flow through the cell member. This hydraulic spring is also suitable for use in a water cooled nuclear reactor. A core component constructed of, among other components, a plurality of these spacer grid members, avoids the use of a full length duct by providing spacer sleeves about the sodium tubes passing through the spacer grid members at locations between the grid members, thereby maintaining a predetermined space between adjacent grid members.
Sidewall spacer optimization for steep switching junctionless transistors
NASA Astrophysics Data System (ADS)
Gupta, Manish; Kranti, Abhinav
In this work, we analyze the impact of a high permittivity (high-κ) sidewall spacer and gate dielectric on the occurrence of sub-60 mV/decade subthreshold swing (S-swing) in symmetrical junctionless (JL) double gate (DG) transistors. It is shown that steep S-swing values (≤10 mV/decade) can be achieved in JL devices with a combination of a high permittivity (high-κ) gate dielectric and a narrow low permittivity (low-κ) sidewall spacer. Implementation of a wider high-κ spacer will diminish the degree of impact ionization by the influence of the fringing component of the gate electric field, and will not be useful for steep off-to-on current transition. A wider spacer with low-κ and a narrow spacer with high-κ permittivity will be useful to limit the latching effect that can occur at lower temperatures (250 K). For high temperature operation, the decrease in the impact ionization rate can be compensated by designing a JL transistor with a thicker silicon film. The work demonstrates opportunities to enhance impact ionization at sub bandgap voltages, and proposes optimal guidelines for selecting a sidewall spacer to facilitate steep switching in JL transistors.
Effect of high hip center on stress for dysplastic hip.
Nie, Yong; Pei, Fuxing; Li, Zongming
High hip center reconstruction has been advocated in treating deficient acetabulum. However, there is no consensus on the clinical outcome of this technique. In addition, it remains unclear to what extend this technique restores the normal hip biomechanics. The goal of this study was to investigate stress above the acetabular dome in response to a range of high hip center positioning for Crowe type I and II hip dysplasia. This study consisted of 2 main parts, radiologic and biomechanical. Pelvic radiographs of 18 patients were studied to determine the amount of displacement of the hip center in the superior direction compared with the normal side. Second, qualitative and quantitative changes in stress on cortical and trabecular bone in the region of the acetabular dome as a result of superior displacement of the hip center were analyzed with subject-specific finite element models. The results showed that the range of the hip center position in the superior direction for Crowe type I and II hip dysplasia was 0 to 15 mm above the contralateral femoral head center. When superior displacement of the hip center exceeded 5 mm above the anatomic hip center, cortical bone mass on the 2 thickest cross-sections above the acetabular dome decreased quickly and the stress value on posterolateral cortical bone was obviously lower than the normal level. This study showed that to restore the normal load above the acetabular dome, there is a limit of 5 mm above the anatomic hip center for high hip center acetabular reconstruction for Crowe type I and II hip dysplasia. PMID:24992059
Bone cement implantation syndrome: a delayed postoperative presentation.
Singh, Vikash; Bhakta, Pradipta; Zietak, Edyta; Hussain, Ashfaq
Bone cement implantation syndrome (BCIS) is a well-known entity but is poorly understood and rarely reported. It is an important cause of perioperative morbidity and mortality in the patient undergoing cemented hip arthroplasty. BCIS is characterized by hypotension, hypoxia, cardiac arrhythmias, and increased pulmonary vascular resistance and can lead to eventual cardiac arrest if not managed properly. We hereby report a case of delayed presentation of BCIS following cemented right hip arthroplasty. PMID:27185726
Clinical outcome of Zweymüller total hip arthroplasty for patients with high congenital hip dislocation.
Chen, Dongyang; Xu, Zhihong; Shi, Dongquan; Qiu, Xusheng; Dai, Jin; Yuan, Tao; Weng, Wenjie; Jiang, Qing
Treatment of high congenital dislocation of the hip (CDH) remains controversial. We report the outcome of hip arthroplasty using a cementless threaded cup and a cementless straight stem in patients with high congenital hip dislocation. Between January 2001 and August 2004, 17 patients with high congenital hip dislocation were treated. During surgery, at least 25% of the cup was anchored in bone. By monitoring somatosensory-evoked potentials (SEPs) of the common peroneal nerve we were able to reduce the femoral head into position in the true acetabulum by releasing soft tissues. A bulk autogenous femoral head bone graft was implanted in 5 patients to achieve at least 75% bony coverage of the acertabular component. Follow-up ranged from 48 months to 91 months with an average of 69.7 months. The mean Harris hip score increased from 43 points preoperatively to 89 points at the time of final follow-up (P<0.001). Radiographic analysis showed bony union of the bone graft in all cases. PMID:21279967
Impact of hydrogel spacer injections on interfraction prostate motion during prostate cancer radiotherapy.
Picardi, Cristina; Rouzaud, Michel; Kountouri, Melpomeni; Lestrade, Laetitia; Vallée, Jean Paul; Caparrotti, Francesca; Dubouloz, Angèle; Miralbell, Raymond; Zilli, Thomas
Background The dosimetric advantage of prostate-rectum spacers to displace the anterior rectal wall outside of the high-dose radiation regions has been clearly established in prostate cancer radiotherapy (RT). The aim of this study was to assess the impact of hydrogel spacer (HS) in the interfraction prostate motion in patients undergoing RT for prostate cancer. Material and methods Twenty prostate cancer patients implanted with three fiducial markers (FM) with (n = 10) or without (n = 10) HS were analyzed. Displacements between the prostate isocenter based on the FM's position and the bony anatomy were quantified in the left-right (LR), anterior-posterior (AP), superior-inferior (SI) axes by offline analyses of 122 cone beam computed tomography scans. Group systematic (M), systematic (Σ) and random (σ) setup errors were determined. Results In patients with or without HS, the overall mean interfraction prostate displacements were 0.4 versus -0.4 mm (p = 0.0001), 0.6 versus 0.6 mm (p = 0.85), and -0.6 mm versus -0.3 mm (p = 0.48) for the LR, AP, and SI axes, respectively. Prostate displacements >5 mm in the AP and SI directions were similar for both groups. No differences in M, Σ and σ setup errors were observed in the three axes between HS + or HS- patients. Conclusions HS implantation does not significantly influence the interfraction prostate motion in patients treated with RT for prostate cancer. The major expected benefit of HS is a reduction of the high-dose levels to the rectal wall without influence in prostate immobilization. PMID:26796870
Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun
Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications.
Drug-Eluting Nasal Implants: Formulation, Characterization, Clinical Applications and Challenges
Parikh, Ankit; Anand, Utkarshini; Ugwu, Malachy C.; Feridooni, Tiam; Massoud, Emad; Agu, Remigius U.
Chronic inflammation and infection of the nasal sinuses, also referred to as Chronic Rhinosinusitis (CRS), severely affects patients' quality of life. Adhesions, ostial stenosis, infection and inflammation relapses complicate chronic sinusitis treatment strategies. Drug-eluting stents, packings or implants have been suggested as reasonable alternatives for addressing these concerns. This article reviewed potential drug candidates for nasal implants, formulation methods/optimization and characterization methods. Clinical applications and important considerations were also addressed. Clinically-approved implants (Propel™ implant, the Relieva stratus™ MicroFlow spacer, and the Sinu-Foam™ spacer) for CRS treatment was an important focus. The advantages and limitations, as well as future considerations, challenges and the need for additional research in the field of nasal drug implant development, were discussed. PMID:24871904
Drug-eluting nasal implants: formulation, characterization, clinical applications and challenges.
Parikh, Ankit; Anand, Utkarshini; Ugwu, Malachy C; Feridooni, Tiam; Massoud, Emad; Agu, Remigius U
Chronic inflammation and infection of the nasal sinuses, also referred to as Chronic Rhinosinusitis (CRS), severely affects patients' quality of life. Adhesions, ostial stenosis, infection and inflammation relapses complicate chronic sinusitis treatment strategies. Drug-eluting stents, packings or implants have been suggested as reasonable alternatives for addressing these concerns. This article reviewed potential drug candidates for nasal implants, formulation methods/optimization and characterization methods. Clinical applications and important considerations were also addressed. Clinically-approved implants (Propel™ implant, the Relieva stratus™ MicroFlow spacer, and the Sinu-Foam™ spacer) for CRS treatment was an important focus. The advantages and limitations, as well as future considerations, challenges and the need for additional research in the field of nasal drug implant development, were discussed. PMID:24871904
High Productivity Implantation ''PARTIAL IMPLANT''
Hino, Masayoshi; Miyamoto, Naoki; Sakai, Shigeki; Matsumoto, Takao
The patterned ion implantation 'PARTIAL IMPLANT' has been developed as a productivity improvement tool. The Partial Implant can form several different ion dose areas on the wafer surface by controlling the speed of wafer moving and the stepwise rotation of twist axis. The Partial Implant system contains two implant methods. One method is 'DIVIDE PARTIAL IMPLANT', that is aimed at reducing the consumption of the wafer. The Divide Partial Implant evenly divides dose area on one wafer surface into two or three different dose part. Any dose can be selected in each area. So the consumption of the wafer for experimental implantation can be reduced. The second method is 'RING PARTIAL IMPLANT' that is aimed at improving yield by correcting electrical characteristic of devices. The Ring Partial Implant can form concentric ion dose areas. The dose of wafer external area can be selected to be within plus or minus 30% of dose of wafer central area. So the electrical characteristic of devices can be corrected by controlling dose at edge side on the wafer.
21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.
Code of Federal Regulations, 2014 CFR
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip)...
21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.
Code of Federal Regulations, 2014 CFR
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...
21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.
Code of Federal Regulations, 2012 CFR
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...
21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.
Code of Federal Regulations, 2012 CFR
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip)...
21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.
Code of Federal Regulations, 2013 CFR
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip)...
21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.
Code of Federal Regulations, 2013 CFR
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...
Constrained components for the unstable hip following total hip arthroplasty: a literature review
Ragland, P. S.; Clarke, S.
Patients with chronic instability or late dislocation following total hip arthroplasty often require operative management. Unfortunately, there is an increased risk of recurrent dislocation following revision in these patients. Over the past decade the use of constrained devices for patients with chronic instability has gained increased interest; however, there is a paucity of studies available in the literature regarding the use of these devices. The purpose of this study was to analyze the available literature over the past 15 years, focusing on larger, long-term studies, to obtain recommendations from the respective articles for indications and contraindications for the use of constrained devices. Our review of eight reports included 1,199 hips in 1,148 patients with a total mean follow-up of 51 months (range, 24 to 124 months). The mean rate of dislocation following revision with a constrained liner was 10% and the mean re-operation rate for reasons other than dislocation was 4%. We concluded that constrained liners are an option for patients who have failed management of instability with other implants, those with instability of unclear etiology, those with cognitive problems who are unable to follow dislocation precautions, those with deficient abductors, and elderly or low-demand individuals with well-positioned implants requiring revision. PMID:16927089
Correlative analysis of MRI-evident abductor hip muscle degeneration and power after minimally invasive versus conventional unilateral cementless THA.
Vasilakis, Ioannis; Solomou, Ekaterini; Vitsas, Vasilis; Fennema, Peter; Korovessis, Panagiotis; Siamblis, Dimitrios K
The 2 main null hypotheses of this study were: (1) the 4-year surgical trauma-related degeneration within the hip abductor muscles after a minimally invasive approach to total hip arthroplasty would be similar to that following a conventional approach; and (2) no differences in perioperative blood loss or postoperative hip pain would be observed between the minimally invasive and conventional approaches.In 40 consecutive randomly selected adult patients with unilateral primary hip osteoarthritis, a cementless Zweymüller-Plus THA (Smith & Nephew Orthopaedics, Baar, Switzerland) was implanted by a single surgeon in 1 institution during the same period. Twenty patients underwent a minimally invasive approach (group A), and 20 patients underwent a conventional anterolateral approach (group B). Four years postoperatively, the operated and contralateral nonoperated hips of 37 available patients from both groups were examined with magnetic resonance imaging to show any changes in the gluteus medius and tensor fascia latae. Simultaneously, hip abductor power was measured bilaterally in both groups. Anthropometric data, blood loss, Short Form 36 self-assessment questionnaire, visual analog pain score, and walking distance were also analyzed.The reliability of magnetic resonance imaging and hip abductor power measurements was high. No difference was found in hip abductor power on the operated side between the 2 groups, whereas hip abductor power on the nonoperated side was significantly higher in both groups. This study revealed no mechanical and functional benefits in favor of patients undergoing minimally invasive vs conventional total hip arthroplasty. PMID:23218622
Mechanical testing and modelling of the Universal 2 implant.
Gislason, M K; Foster, E; Main, D; Fusiek, G; Niewczas, P; Bransby-Zachary, M; Nash, D H
Understanding the load mechanics of orthopaedic implants is important to be able to predict their behaviour in-vivo. Much research, both mechanical and clinical, has been carried out on hip and knee implants, but less has been written about the mechanics of wrist implants. In this paper, the load mechanics of the Universal 2 wrist implant have been measured using two types of measuring techniques, strain gauges and Fibre Bragg Grating measurements to measure strains. The results were compared to a finite element model of the implant. The results showed that the computational results were in good agreement with the experimental results. Better understanding of the load mechanics of wrist implants, using models and experimental results can catalyse the development of future generation implants. PMID:27083120
Modified Girdlestone arthroplasty and hip arthrodesis using the Ilizarov external fixator as a salvage method in the management of severely infected total hip replacement
Kliushin, Nikolai M; Ababkov, Yuri V; Ermakov, Artem M; Malkova, Tatiana A
Background: Resection arthroplasty or hip arthrodesis after total hip replacement (THR) can be used to salvage the limb in case with deep infection and severe bone loss. The Ilizarov fixator provides stability, axial correction, weight-bearing and good fusion rates. Materials and Methods: We retrospectively assessed the outcomes of 37 patients with severe periprosthetic infection after THR treated between 1999 and 2011. The treatment included implant removal, debridement and a modified Girdestone arthroplasty (29 cases) or hip arthrodesis (seven cases) using the Ilizarov fixator. The Ilizarov fixation continued from 45 to 50 days in the modified arthroplasty group and 90 days in the arthrodesis group. One case was treated using the conventional resection arthroplasty bilaterally. Results: Eighteen months after treatment, infection control was seen in 97.3% cases. Six hips were fused as one patient died in this group. Limb length discrepancy (LLD) averaged 5.5 cm. The Harris hip score ranged from 35 to 92 points. Hip joint motion ranged from 10° to 30° in the modified arthroplasty group. All subjects could walk independently or using support aids. No subluxation or LLD progression was observed. Conclusion: The modified Girdlestone arthroplasty and hip arthrodesis using the Ilizarov apparatus results in sufficient ability for ambulation and good infection control in cases of failed THR associated with severe infection. PMID:26955173
Heterotopic ossification after hip arthroscopy
Amar, Eyal; Sharfman, Zachary T.; Rath, Ehud
Heterotopic ossification (HO) after hip arthroscopy is the abnormal formation of mature lamellar bone within extra skeletal soft tissues. HO may lead to pain, impaired range of motion and possibly revision surgery. There has been a substantial amount of recent research on the pathophysiology, prophylaxis and treatment of HO associated with open and arthroscopic hip surgery. This article reviews the literature on the aforementioned topics with a focus on their application in hip arthroscopy. PMID:27011859
Heterotopic ossification after hip arthroscopy.
Amar, Eyal; Sharfman, Zachary T; Rath, Ehud
Heterotopic ossification (HO) after hip arthroscopy is the abnormal formation of mature lamellar bone within extra skeletal soft tissues. HO may lead to pain, impaired range of motion and possibly revision surgery. There has been a substantial amount of recent research on the pathophysiology, prophylaxis and treatment of HO associated with open and arthroscopic hip surgery. This article reviews the literature on the aforementioned topics with a focus on their application in hip arthroscopy. PMID:27011859
Capsular Management in Hip Arthroscopy.
Harris, Joshua D
The hip capsule is a highly complex anatomic structure, which influences normal hip motion and biomechanics. A dynamic stabilizing capsular contribution exists in the iliocapsularis and gluteus minimus, among other musculotendinous structures crossing the joint. Variable types and sizes of capsulotomy are necessary to sufficiently visualize and address the bony and soft tissue pathologic source of symptoms. Unrepaired capsulotomies may leave the hip significantly unstable to variable degrees. Capsular closure is a necessary part of a comprehensive arthroscopic hip preservation procedure. Greater titration of the degree of plication may be performed for patients with risk factors for postoperative instability. PMID:27343391
Infant hip sonography: current concepts.
Harcke, H T; Grissom, L E
Sonography of the infant hip has gained wide acceptance in the decade since its introduction. The two principle techniques of Graf and Harcke have been combined with the proposal of a Dynamic Standard Minimum Examination. Whereas sonography is used increasingly to manage developmental dislocation and/or displasia of the hip, there is no agreement on the use of sonography for universal newborn screening. This article describes in detail the Dynamic Standard Minimum Sonographic Examination of the infant hip. In addition, this article reviews the classification and management of infant hip disorders. PMID:7946476
Space Station Long Spacer Element begins processing at KSC
NASA Technical Reports Server (NTRS)
The Long Spacer, a component of the International Space Station, arrives and is moved to its test stand in the northeast corner of the high bay in KSC's Space Station Processing Facility. The Long Spacer provides structural support for the outboard Photovoltaic Modules that supply power to the station. Now just a structure, the Long Spacer will have attached to it as part of processing a heat dissipation radiator and two Pump and Flow Control subassemblies that circulate ammonia to cool the solar array electronics. Also to be mounted are ammonia fluid lines as part of the cooling system and the cabling necessary for power and control of the station. The Long Spacer becomes an integral part of a station truss segment when it is mated with the Integrated Equipment Assembly, which stores the electrical power generated by the solar arrays for use by the station modules. The Long Spacer is being processed in preparation for STS-97, currently planned for launch aboard Discovery in April 1999.
Gas-insulated substation spacer surface degradation analysis
Chu, F.Y.; Braun, J.M. )
The objective of the project was to develop surface analysis techniques which can correlate the performance of spacers in SF{sub 6} insulated switchgear with changes in their dielectric and chemical characteristics after exposure to SF{sub 6} arcing byproducts and low energy flashovers. Critical material parameters responsible for spacer performance were investigated by optical and scanning electron microscopy, electron spectroscopy for chemical analysis, thermogravimetric analysis and electrical surface resistance measurements. Results related to arc byproduct resistance and tracking resistance of seven types of filled epoxy spacer materials are presented. Degradation mechanisms have been proposed to explain the differing material behaviour. The study shows that the interaction of certain types of filler and resin systems with the SF{sub 6} spark and the decomposed gas is responsible for the degradation in impulse withstand performance. A practical technique using surface electrical resistance to detect degraded spacer after exposure to large quantities of arc byproducts has been developed and the construction of a probe for spacer surface assessment was described. 15 refs., 28 figs., 8 tabs.
Impact of spacer thickness on biofouling in forward osmosis.
Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S
Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. PMID:24726992
[Prostate-rectum spacers: optimization of prostate cancer irradiation].
Zilli, T; Benz, E; Miralbell, R
In the curative radiotherapy of localized prostate cancer, improvements in biochemical control observed with dose escalation have been counterbalanced by an increase in radiation-induced toxicity. The injection of biodegradable spacers between prostate and rectum represents a new frontier in the optimization of radiotherapy treatments for patients with localized disease. Transperineal injection of different types of spacers under transrectal ultrasound guidance allows creating a 7-to-20 mm additional space between the prostate and the anterior rectal wall lasting 3 to 12 months. Dosimetrically, a relative reduction in the rectal volume receiving at least 70 Gy (V70) in the order of 43% to 84% is observed with all types of spacers, regardless of the radiotherapy technique used. Preliminary clinical results show for all spacers a good tolerance and a possible reduction in the acute side effects rate. The aim of the present systematic review of the literature is to report on indications as well as dosimetric and clinical advantages of the different types of prostate-rectum spacers commercially available (hydrogel, hyaluronic acid, collagen, biodegradable balloon). PMID:24746454
Surface and Subsurface Analyses of Metal-on-Polyethylene Total Hip Replacement Retrievals.
Vuong, Vicky; Pettersson, Maria; Persson, Cecilia; Larsson, Sune; Grandfield, Kathryn; Engqvist, Håkan
Metal-on-polyethylene (MoP) articulations are one of the most reliable implanted hip prostheses. Unfortunately, long-term failure remains an obstacle to the service life. There is a lack of higher resolution research investigating the metallic surface component of MoP hip implants. This study investigates the surface and subsurface features of metallic cobalt chromium molybdenum alloy (CoCrMo) femoral head components from failed MoP retrievals. Unused prostheses were used for comparison to differentiate between wear-induced defects and imperfections incurred during implant manufacturing. The predominant scratch morphology observed on the non-implanted references was shallow and linear, whereas the scratches on the retrievals consisted of largely nonlinear, irregular scratches of varying depth (up to 150 nm in retrievals and up to 60 nm in reference samples). Characteristic hard phases were observed on the surface and subsurface material of the cast samples. Across all samples, a 100-400 nm thick nanocrystalline layer was visible in the immediate subsurface microstructure. Although observation of the nanocrystalline layer has been reported in metal-on-metal articulations, its presence in MoP retrievals and unimplanted prostheses has not been extensively examined. The results suggest that manufacturing-induced surface and subsurface microstructural features are present in MoP hip prostheses prior to implantation and naturally, these imperfections may influence the in vivo wear processes after implantation. PMID:26399989
Anterior Hip Joint Force Increases with Hip Extension, Decreased Gluteal Force, or Decreased Iliopsoas Force
Lewis, Cara L.; Sahrmann, Shirley A.; Moran, Daniel W.
Abnormal or excessive force on the anterior hip joint may cause anterior hip pain, subtle hip instability and a tear of the acetabular labrum. We propose that both the pattern of muscle force and hip joint position can affect the magnitude of anterior joint force and thus possibly lead to excessive force and injury. The purpose of this study was to determine the effect of hip joint position and of weakness of the gluteal and iliopsoas muscles on anterior hip joint force. We used a musculoskeletal model to estimate hip joint forces during simulated prone hip extension and supine hip flexion under 4 different muscle force conditions and across a range of hip extension and flexion positions. Weakness of specified muscles was simulated by decreasing the modeled maximum force value for the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion. We found that decreased force contribution from the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion resulted in an increase in the anterior hip joint force. The anterior hip joint force was greater when the hip was in extension than when the hip was in flexion. Further studies are warranted to determine if increased utilization of the gluteal muscles during hip extension and of the iliopsoas muscle during hip flexion, and avoidance of hip extension beyond neutral would be beneficial for people with anterior hip pain, subtle hip instability, or an anterior acetabular labral tear. PMID:17707385
Developmental Dislocation (Dysplasia) of the Hip (DDH)
... developmental dysplasia (dislocation) of the hip (DDH), the hip joint has not formed normally. The ball is loose ... be taken to provide detailed pictures of the hip joint. Treatment When DDH is detected at birth, it ...
Graphitic Tribological Layers in Metal-on-Metal Hip Replacements
NASA Astrophysics Data System (ADS)
Liao, Y.; Pourzal, R.; Wimmer, M. A.; Jacobs, J. J.; Fischer, A.; Marks, L. D.
Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris.
Thomas, P; Thomsen, M
An increasing number of patients receive and benefit from osteosynthesis materials or artificial joint replacement. The most common complications are mechanical problems or infection. Metals like nickel, chromium and cobalt as well as bone cement components like acrylates and gentamicin are potential contact allergens which can cause intolerance reactions to implants. Eczema, delayed wound/bone healing, recurrent effusions, pain and implant loosening all have been described as manifestation of implant allergy. In contrast to the high incidence of cutaneous metal allergy, allergies associated with implants are rare. Diagnosis of metal implant allergy is still difficult. Thus differential diagnoses--in particular infection--have to be excluded and a combined approach of allergologic diagnostics by patch test and histopathology of peri-implant tissue is recommended. It is still unknown which conditions induce allergic sensitization to implants or trigger peri-implant allergic reactions in the case of preexisting cutaneous metal allergy. Despite the risk of developing complications being unclear, titanium based osteosynthesis materials are recommended for metal allergic patients and the use of metal-metal couplings in arthroplasty is not recommended for such patients. If the regular CoCr-polyethylene articulation is employed, the patient should give informed written consent. PMID:20204719
Optimal acetabular orientation for hip resurfacing.
Grammatopoulos, G; Pandit, H; Glyn-Jones, S; McLardy-Smith, P; Gundle, R; Whitwell, D; Gill, H S; Murray, D W
Pseudotumours are a rare complication of hip resurfacing. They are thought to be a response to metal debris which may be caused by edge loading due to poor orientation of the acetabular component. Our aim was to determine the optimal acetabular orientation to minimise the risk of pseudotumour formation. We matched 31 hip resurfacings revised for pseudotumour formation with 58 controls who had a satisfactory outcome from this procedure. The radiographic inclination and anteversion angles of the acetabular component were measured on anteroposterior radiographs of the pelvis using Einzel-Bild-Roentgen-Analyse software. The mean inclination angle (47 degrees, 10 degrees to 81 degrees) and anteversion angle (14 degrees, 4 degrees to 34 degrees) of the pseudotumour cases were the same (p = 0.8, p = 0.2) as the controls, 46 degrees (29 degrees to 60 degrees) and 16 degrees (4 degrees to 30 degrees) respectively, but the variation was greater. Assuming an accuracy of implantation of +/- 10 degrees about a target position, the optimal radiographic position was found to be approximately 45 degrees of inclination and 20 degrees of anteversion. The incidence of pseudotumours inside the zone was four times lower (p = 0.007) than outside the zone. In order to minimise the risk of pseudotumour formation we recommend that surgeons implant the acetabular component at an inclination of 45 degrees (+/- 10) and anteversion of 20 degrees (+/- 10) on post-operative radiographs. Because of differences between the radiographic and the operative angles, this may be best achieved by aiming for an inclination of 40 degrees and an anteversion of 25 degrees. PMID:20675749
Wheeze in childhood: is the spacer good enough?
Rajkumar, Veena; Rajendra, Barathi; How, Choon How; Ang, Seng Bin
Max was treated with SABA using an MDI and spacer with facemask and responded well to the initial treatment. You explained to the parents that nebulisers are neither required nor recommended in the treatment of wheezing in their child's situation. You advised the parents on the proper technique of MDI use with spacer and facemask, as well as care of the equipment. You also gave them a clearly written action plan regarding the efficient management of the next episode of wheeze with MDI and spacer. You further explained the side effects of oral bronchodilators and nebulisers, and why you refrained from using them. Max was given a follow-up appointment to assess his progress, and his parents were advised on the situations when they should go to a doctor or the emergency department. PMID:25631964
Strontium in the bone-implant interface.
Vestermark, Marianne Toft
Total hip replacement surgery is being performed on an increasingly large part of the population and at increasingly younger age. Because we live and stay physically active longer, and since hip replacement surgery has become quite successful, the treatment is being offered to progressively more patients. Unfortunately, about 17% of hip replacement surgeries currently involve revisions. Consequently, the longevity of both the primary and revision implant is an issue and warrants further investigation. Implants undergoing early instability or even subsidence correlate with an increased risk of aseptic loosening, subsequently requiring revision. Thus, the goal is early fixation by osseointegration of the implant. For revision implants, this is an even greater challenge since an allograft is often needed during surgery to obtain immediate stability of the implant. Bone grafts are rapidly resorbed. Thus, instability of the prosthesis may develop before new bone formation is well established and can mechanically secure the prosthesis. Strontium is a dual action drug; being both bone anabolic and anti-catabolic. In the form of strontiumranelate, it is used in the treatment of osteoporosis. Strontium may potentially improve the early osseointegration and fixation of implants. This dissertation consists of three studies investigating the effect of strontium at the bone-implant interface. The questions were firstly, what is the optimal delivery method for strontium to the interface, and secondly, can strontium exercise its dual action at the interface? The studies were performed in a cementless, experimental gap model in canine. The effects of strontium were evaluated by histomorphometrical analysis of the osseointegration and mechanical push-out test of implant fixation. Different stereological methods were used for the histomorphometrical analysis of each study. The methods used were reviewed critically and found valid. Study I compared a 5% strontium
Compatibility of the totally replaced hip. Reduction of wear by amorphous diamond coating.
Santavirta, Seppo
Particulate wear debris in totally replaced hips causes adverse local host reactions. The extreme form of such a reaction, aggressive granulomatosis, was found to be a distinct condition and different from simple aseptic loosening. Reactive and adaptive tissues around the totally replaced hip were made of proliferation of local fibroblast like cells and activated macrophages. Methylmethacrylate and high-molecular-weight polyethylene were shown to be essentially immunologically inert implant materials, but in small particulate form functioned as cellular irritants initiating local biological reactions leading to loosening of the implants. Chromium-cobalt-molybdenum is the most popular metallic implant material; it is hard and tough, and the bearings of this metal are partially self-polishing. In total hip implants, prerequisites for longevity of the replaced hip are good biocompatibility of the materials and sufficient tribological properties of the bearings. The third key issue is that the bearing must minimize frictional shear at the prosthetic bone-implant interface to be compatible with long-term survival. Some of the approaches to meet these demands are alumina-on-alumina and metal-on-metal designs, as well as the use of highly crosslinked polyethylene for the acetabular component. In order to avoid the wear-based deleterious properties of the conventional total hip prosthesis materials or coatings, the present work included biological and tribological testing of amorphous diamond. Previous experiments had demonstrated that a high adhesion of tetrahedral amorphous carbon coatings to a substrate can be achieved by using mixing layers or interlayers. Amorphous diamond was found to be biologically inert, and simulator testing indicated excellent wear properties for conventional total hip prostheses, in which either the ball or both bearing surfaces were coated with hydrogen-free tetrahedral amorphous diamond films. Simulator testing with such total hip prostheses
Spacer effect on nanostructures and self-assembly in organogels via some bolaform cholesteryl imide derivatives with different spacers
In this paper, new bolaform cholesteryl imide derivatives with different spacers were designed and synthesized. Their gelation behaviors in 23 solvents were investigated, and some of them were found to be low molecular mass organic gelators. The experimental results indicated that these as-formed organogels can be regulated by changing the flexible/rigid segments in spacers and organic solvents. Suitable combination of flexible/rigid segments in molecular spacers in the present cholesteryl gelators is favorable for the gelation of organic solvents. Scanning electron microscopy and atomic force microscopy observations revealed that the gelator molecules self-assemble into different aggregates, from wrinkle and belt to fiber with the change of spacers and solvents. Spectral studies indicated that there existed different H-bond formations between imide groups and assembly modes, depending on the substituent spacers in molecular skeletons. The present work may give some insight into the design and character of new organogelators and soft materials with special molecular structures. PMID:24083361
Relvas, Carlos; Reis, Joana; Potes, José Alberto Caeiro; Fonseca, Fernando Manuel Ferreira; Simões, José Antonio Oliveira
This study, aimed the development of a methodology for rapid manufacture of orthopedic implants simultaneously with the surgical intervention, considering two potential applications in the fields of orthopedics: the manufacture of anatomically adapted implants and implants for bone loss replacement. This work innovation consists on the capitation of the in situ geometry of the implant by direct capture of the shape using an elastomeric material (polyvinylsiloxane) which allows fine detail and great accuracy of the geometry. After scanning the elastomeric specimen, the implant is obtained by machining using a CNC milling machine programmed with a dedicated CAD/CAM system. After sterilization, the implant is able to be placed on the patient. The concept was developed using low cost technology and commercially available. The system has been tested in an in vivo hip arthroplasty performed on a sheep. The time increase of surgery was 80 minutes being 40 minutes the time of implant manufacturing. The system developed has been tested and the goals defined of the study achieved enabling the rapid manufacture of an implant in a time period compatible with the surgery time. PMID:27004181
Relvas, Carlos; Reis, Joana; Potes, José Alberto Caeiro; Fonseca, Fernando Manuel Ferreira; Simões, José Antonio Oliveira
This study, aimed the development of a methodology for rapid manufacture of orthopedic implants simultaneously with the surgical intervention, considering two potential applications in the fields of orthopedics: the manufacture of anatomically adapted implants and implants for bone loss replacement. This work innovation consists on the capitation of the in situ geometry of the implant by direct capture of the shape using an elastomeric material (polyvinylsiloxane) which allows fine detail and great accuracy of the geometry. After scanning the elastomeric specimen, the implant is obtained by machining using a CNC milling machine programmed with a dedicated CAD/CAM system. After sterilization, the implant is able to be placed on the patient. The concept was developed using low cost technology and commercially available. The system has been tested in an in vivo hip arthroplasty performed on a sheep. The time increase of surgery was 80 minutes being 40 minutes the time of implant manufacturing. The system developed has been tested and the goals defined of the study achieved enabling the rapid manufacture of an implant in a time period compatible with the surgery time. PMID:27004181
Hip dysplasia in the skeletally mature patient.
Goldstein, Rachel Y; Kaye, Ian David; Slover, James; Feldman, David
Abnormal hip development causes one-quarter to one-half of all hip disease. Dysplastic hips typically share characteristic anatomic abnormalities. The dysplastic acetabulum is typically shallow, lateralized, and anteverted with insufficient coverage anteriorly, superiorly, and laterally. The dysplastic proximal femur has a small femoral head with excessive femoral neck anteversion and a short neck with an increased neck shaft angle. These characteristic changes result in intraarticular pathology leading to hip arthritis. A variety of treatment options exist based on the degree of dysplasia and the amount of concomitant hip arthritis. Treatment options include hip arthroscopy, acetabular or femoral osteotomies, hip arthrodesis, and total hip arthroplasty. PMID:25150325
Metal-on-Metal Total Hip Resurfacing Arthroplasty
Executive Summary Objective The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population. Clinical Need Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years. Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries. The Technology Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup. Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a
Effect of Hip Angle on Anterior Hip Joint Force during Gait
Lewis, Cara L.; Sahrmann, Shirley A.; Moran, Daniel W.
Anterior hip or groin pain is a common complaint for which people are referred for physical therapy. We have observed that people with anterior hip pain often walk in greater hip extension than people without anterior hip pain, and that the pain is reduced when they walk in less hip extension. Therefore, we investigated anterior hip joint forces which may contribute to anterior hip pain and examined the effect of end range hip extension on the anterior hip joint force during gait. To do this, we used a 6 degree of freedom, 3-dimensional musculoskeletal model to estimate hip joint forces during gait. Within subjects, the maximum anterior hip joint force for gait trials with the most hip extension was compared to the anterior hip joint force for gait trials with the least hip extension. The musculoskeletal model indicated that increasing the maximum end range hip extension when walking results in an increase in the anterior hip joint force when compared to walking in less hip extension. Walking in greater hip extension may result in an increase in the anterior hip joint force, and thereby contribute to anterior hip pain. The findings of this study provide some evidence supporting the use of gait modification to reduce anterior hip force when treating people with anterior hip pain. PMID:20934338
Effect of strontium-containing hydroxyapatite bone cement on bone remodeling following hip replacement.
Ni, Guo X; Lin, Jian H; Chiu, Peter K Y; Li, Zhao Y; Lu, William W
It is uncertain whether the use of bioactive bone cement has any beneficial effect on local bone adaptation following hip replacement. In this study, twelve goats underwent cemented hip hemiarthroplasty unilaterally, with either PMMA bone cement or strontium-containing hydroxyapatite (Sr-HA) bioactive bone cement. Nine months later, the femoral cortical bones at different levels were analyzed by microhardness testing and micro-CT scanning. Extensive bone remodeling was found at proximal and mid-levels in both PMMA and Sr-HA groups. However, with regard to the differences of bone mineral density, cortical bone area and bone hardness between implanted and non-implanted femur, less decreases were found in Sr-HA group than PMMA group at proximal and mid-levels, and significant differences were shown for bone area and hardness at proximal level. The results suggested that the use of Sr-HA cement might alleviate femoral bone remodeling after hip replacement. PMID:19728042
[Complications after hip osteotomy].
Renner, L; Perka, C; Zahn, R
Complex deformities of the acetabulum are one of the most common reasons for secondary pelvic osteoarthritis. One option of treatment is osteotomy of the acetabulum close to the joint. The correction of the spatially reduced roof of the femoral head resulting from pelvic dysplasia can minimize the risk of developing secondary osteoarthritis or reduce the progression of an already existing osteoarthritis. The Ganz periacetabular osteotomy (PAO) and Tönnis triple osteotomy procedures are the predominant methods used to correct hip dysplasia in adolescents. Both are complex procedures which bear specific risks and complications, thus requiring very experienced surgeons. PMID:24356819
Mechanical properties of femoral cortical bone following cemented hip replacement.
Ni, G X; Lu, W W; Chiu, P K Y; Wang, Y; Li, Z Y; Zhang, Y G; Xu, B; Deng, L F; Luk, K D K
Femoral bone remodeling following total hip replacement is a big concern and has never been examined mechanically. In this study, six goats underwent unilateral cemented hip hemiarthroplasty with polymethyl methacrylate (PMMA) bone cement. Nine months later animals were sacrificed, and the femoral cortical bone slices at different levels were analysed using microhardness testing and microcomputed tomography (micro-CT) scanning. Implanted femurs were compared to contralateral nonimplanted femurs. Extensive bone remodeling was demonstrated at both the proximal and middle levels, but not at the distal level. Compared with the nonimplanted side, significant decreases were found in the implanted femur in cortical bone area, bone mineral density, and cortical bone hardness at the proximal level, as well as in bone mineral density and bone hardness at the middle level. However, no significant difference was observed in either variable for the distal level. In addition, similar proximal-to-distal gradient changes were revealed both in cortical bone microhardness and bone mineral density. From the mechanical point of view, the results of the present study suggested that stress shielding is an important mechanical factor associated with bone adaptation following total hip replacement. PMID:17506504
ERIC Educational Resources Information Center
Hall, Marcella Runell
Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.…
Ultrasound-Guided Hip Procedures.
Payne, Jeffrey M
This article describes the techniques for performing ultrasound-guided procedures in the hip region, including intra-articular hip injection, iliopsoas bursa injection, greater trochanter bursa injection, ischial bursa injection, and piriformis muscle injection. The common indications, pitfalls, accuracy, and efficacy of these procedures are also addressed. PMID:27468669
The impact of proximal femoral morphology on failure strength with a mid-head resection short-stem hip arthroplasty.
Olsen, Michael; Al Saied, Mohamed; Morison, Zachary; Sellan, Michael; Waddell, James P; Schemitsch, Emil H
Mid-head resection short-stem hip arthroplasty is a conservative alternative to conventional total hip replacement and addresses proximal fixation challenges in patients not suitable for hip resurfacing. It is unclear whether proximal femoral morphology impacts the ultimate failure load of mid-head resection implanted femurs, thus the aim of this study was to investigate the effect of native neck-shaft angle (NSA) and coronal implant alignment on proximal femoral strength. In total, 36 synthetic femurs with two different proximal femoral morphologies were utilized in this study. Of them, 18 femurs with a varus NSA of 120° and 18 femurs with a valgus NSA of 135° were each implanted with a mid-head resection prosthesis. Femurs within the two different femoral morphology groups were divided into three equal coronal implant alignment groups: 10° valgus, 10° varus or neutral alignment. Prepared femurs were tested for stiffness and to failure in axial compression. There was no significant difference in stiffness nor failure load between femurs implanted with valgus-, varus- or neutrally aligned implants in femurs with a NSA of 120° (p = 0.396, p = 0.111, respectively). Femurs implanted in valgus orientation were significantly stiffer and failed at significantly higher loads than those implanted in varus alignment in femurs with a NSA of 135° (p = 0.001, p = 0.007, respectively). A mid-head resection short-stem hip arthroplasty seems less sensitive to clinically relevant variations of coronal implant alignment and may be more forgiving upon implantation in some femoral morphologies, however, a relative valgus component alignment is recommended. PMID:25515228
Cup position alone does not predict risk of dislocation after hip arthroplasty.
Esposito, Christina I; Gladnick, Brian P; Lee, Yuo-Yu; Lyman, Stephen; Wright, Timothy M; Mayman, David J; Padgett, Douglas E
We used a large prospective institutional registry to determine if there is a 'safe zone' that exists for acetabular component position within which the risk of hip dislocation is low and if other patient and implant factors affect the risk of hip dislocation. Patients who reported a dislocation event within six months after hip arthroplasty surgery were identified, and acetabular component position was measured with anteroposterior radiographs. The frequency of dislocation was 2.1% (147 of 7040 patients). No significant difference was found in the number of dislocated hips among the radiographic zones (±5°,±10°,±15° boundaries). Dislocators <50 years old were less active preoperatively than nondislocators (P=0.006). Acetabular component position alone is not protective against instability. PMID:25249516
Outcomes of total hip arthroplasty in patients with osteonecrosis of the femoral head-a current review.
Pierce, Todd P; Elmallah, Randa K; Jauregui, Julio J; Verna, Daniel F; Mont, Michael A
The purpose of this review was to analyze (1) patient-reported outcomes and implant survivorship of osteonecrosis (ON) patients following total hip arthroplasty (THA), (2) if prior hip-preserving procedures influence these outcomes, (3) if resurfacing procedures alter outcomes; and (4) how these outcomes may have been impacted by the choice of different bearing surfaces. Today, with implant innovations such as cementless constructs, ceramic bearing surfaces, and highly cross-linked polyethylene, ON patients derive great benefit and have high survivorship following THA. Most studies have shown that previous hip-preserving procedures do not have a deleterious effect on outcomes. Literature on the use of ceramic and highly cross-linked polyethylene bearing surfaces have shown that these implant designs are useful in younger and more active patients. Future research should evaluate the long-term outcomes and survivorship of these new THA constructs. PMID:26045086
CoCrMo Metal-on-Metal Hip Replacements
Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence
After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in-vivo and in-vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425
CoCrMo metal-on-metal hip replacements.
Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence
After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in vivo and in vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425
Calculating the hip center of rotation using contralateral pelvic anatomy.
Durand-Hill, Matthieu; Henckel, Johann; Satchithananda, Keshthra; Sabah, Shiraz; Hua, Jia; Hothi, Harry; Langstaff, Ronald J; Skinner, John; Hart, Alister
Failure to place an artificial hip in the optimal center of rotation results in poor hip function and costly complications. The aim of this study was to develop robust methodology to estimate hip center of rotation (hCoR) from preoperative computed tomography (CT) scans, using contralateral anatomy, in patients with unilateral diseased hips. Ten patients (five male, five female) with normal pelvic anatomy, and one patient with a unilateral dysplastic acetabulum were recruited from the London Implant Retrieval center image bank. 3D models of each pelvis were generated using commercial software. Two methods for estimation of hCoR were compared. Method 1 used a mirroring technique alone. Method 2 utilized mirroring and automatic alignment. Predicted versus actual hCoR co-ordinates were compared using intraclass correlation coefficients and paired T-tests. Both methods predicted hCoR with excellent agreement to original co-ordinates (>0.9) in all axes. Both techniques allowed prediction of the hCoR within ± 5 mm in all axes. Both techniques provided useful clinical information for planning acetabular reconstruction in patients with unilateral defects. Method 1 was less complex and is suitable for patients with developmental and degenerative pathologies. Method 2 may provide greater accuracy in a discrete group of patients with normal development prior to pathology (e.g., acetabular fractures). © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1077-1083, 2016. PMID:26630078
Transparency to Reduce Surgical Implant Waste
Dilisio, Matthew F.; Patti, Brianna; Fening, Stephen D.; Junko, Jeffrey T.
Background Rising health care costs and emphasis on value have placed the onus of reducing healthcare costs on the surgeon. Methods Financial data from 3,973 hip, knee, and shoulder arthroplasties performed at a physician owned orthopedic hospital was retrospectively reviewed over a two-year period. A wasted implant financial report was posted starting the second year of the study. Each surgeon's performance could be identified by his peers. Results After posting of the financial report, 1.11% of all hip and knee arthroplasty cases had a waste event compared to 1.50% during the control year. Shoulder arthroplasty waste events occurred twice as often than that observed in hip and knee arthroplasty during the study period. A decrease in waste events was observed but was not statistically significant (p = 0.30). Conclusions Posting a non-blinded wasted implant data sheet was associated with a reduction in the number of wasted orthopedic surgical implants in this series, although the reduction was not statistically significant. PMID:26217467
Fabricating specialised orthopaedic implants using additive manufacturing
NASA Astrophysics Data System (ADS)
Unwin, Paul
It has been hypothesised that AM is ideal for patient specific orthopaedic implants such as those used in bone cancer treatment, that can rapidly build structures such as lattices for bone and tissues to in-grow, that would be impossible using current conventional subtractive manufacturing techniques. The aim of this study was to describe the adoption of AM (direct metal laser sintering and electron beam melting) into the design manufacturing and post-manufacturing processes and the early clinical use. Prior to the clinical use of AM implants, extensive metallurgical and mechanical testing of both laser and electron beam fabrications were undertaken. Concurrently, post-manufacturing processes evaluated included hipping, cleaning and coating treatments. The first clinical application of a titanium alloy mega-implant was undertaken in November 2010. A 3D model of the pelvic wing implant was designed from CT scans. Novel key features included extensive lattice structures at the bone interfaces and integral flanges to fix the implant to the bone. The pelvic device was implanted with the aid of navigation and to date the patient remains active. A further 18 patient specific mega-implants have now been implanted. The early use of this advanced manufacturing route for patient specific implants has been very encouraging enabling the engineer to produce more advanced and anatomical conforming implants. However, there are a new set of design, manufacturing and regulatory challenges that require addressing to permit this technique to be used more widely. This technology is changing the design and manufacturing paradigm for the fabrication of specialised orthopaedic implants.
Metal release and corrosion effects of modular neck total hip arthroplasty
Jakubowitz, Eike; Krachler, Michael; Thomsen, Marc; Heisel, Christian
Modular neck implants are an attractive treatment tool in total hip replacement. Concerns remain about the mechanical stability and metal ion release caused by the modular connection. Five different implant designs were investigated in an experimental set-up. In vivo conditions were simulated and the long-term titanium release was measured. Finally, the modular connections were inspected for corrosion processes and signs of fretting. No mechanical failure or excessive corrosion could be identified for the implants tested. The titanium releases measured were extremely low compared to in vivo and in vitro studies and were not in a critical range. PMID:19219434
Hip Abduction Can Prevent Posterior Edge Loading of Hip Replacements
van Arkel, Richard J; Modenese, Luca; Phillips, Andrew TM; Jeffers, Jonathan RT
Edge loading causes clinical problems for hard-on-hard hip replacements, and edge loading wear scars are present on the majority of retrieved components. We asked the question: are the lines of action of hip joint muscles such that edge loading can occur in a well-designed, well-positioned acetabular cup? A musculoskeletal model, based on cadaveric lower limb geometry, was used to calculate for each muscle, in every position within the complete range of motion, whether its contraction would safely pull the femoral head into the cup or contribute to edge loading. The results show that all the muscles that insert into the distal femur, patella, or tibia could cause edge loading of a well-positioned cup when the hip is in deep flexion. Patients frequently use distally inserting muscles for movements requiring deep hip flexion, such as sit-to-stand. Importantly, the results, which are supported by in vivo data and clinical findings, also show that risk of edge loading is dramatically reduced by combining deep hip flexion with hip abduction. Patients, including those with sub-optimally positioned cups, may be able to reduce the prevalence of edge loading by rising from chairs or stooping with the hip abducted. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1172–1179, 2013. PMID:23575923
The effect of dynamic hip motion on the micromotion of press-fit acetabular cups in six degrees of freedom.
Crosnier, Emilie A; Keogh, Patrick S; Miles, Anthony W
The hip joint is subjected to cyclic loading and motion during activities of daily living and this can induce micromotions at the bone-implant interface of cementless total hip replacements. Initial stability has been identified as a crucial factor to achieve osseointegration and long-term survival. Whilst fixation of femoral stems achieves good clinical results, the fixation of acetabular components remains a challenge. In vitro methods assessing cup stability keep the hip joint in a fixed position, overlooking the effect of hip motion. The effect of hip motion on cup micromotion using a hip motion simulator replicating hip flexion-extension and a six degrees of freedom measurement system was investigated. The results show an increase in cup micromotion under dynamic hip motion compared to Static Flexion. This highlights the need to incorporate hip motion and measure all degrees of freedom when assessing cup micromotion. In addition, comparison of two press-fit acetabular cups with different surface coatings suggested similar stability between the two cups. This new method provides a basis for a more representative protocol for future pre-clinical evaluation of different cup designs. PMID:27210567
... additional visits are needed for activating, adjusting, and programming the various electrodes that have been implanted. Also, ... to the center for checkups once the final programming is made to the speech processor. Both children ...
... bone growth and development of sexual characteristics) in girls usually between 2 and 8 years of age ... MRI scans (radiology techniques designed to show the images of body structures) to find the implant when ...
... which the type of tissue that lines the uterus [womb] grows in other areas of the body ... with the treatment of abnormal bleeding of the uterus. Goserelin implant is in a class of medications ...
NASA Astrophysics Data System (ADS)
Langouche, G.; Yoshida, Y.
In this tutorial we describe the basic principles of the ion implantation technique and we demonstrate that emission Mössbauer spectroscopy is an extremely powerful technique to investigate the atomic and electronic configuration around implanted atoms. The physics of dilute atoms in materials, the final lattice sites and their chemical state as well as diffusion phenomena can be studied. We focus on the latest developments of implantation Mössbauer spectroscopy, where three accelerator facilities, i.e., Hahn-Meitner Institute Berlin, ISOLDE-CERN and RIKEN, have intensively been used for materials research in in-beam and on-line Mössbauer experiments immediately after implantation of the nuclear probes.
MedlinePlus Videos and Cool Tools
... facts so you can make an informed decision as to whether dental implants are right for your ... the jaw bone. It's obviously not the same as the original connection , but functions just the same. ...
Image-guided, navigation-assisted Relieva Stratus MicroFlow Spacer insertion into the ethmoid sinus.
Taulu, Rami; Numminen, Jura; Bizaki, Argyro; Rautiainen, Markus
Anatomical complexity presents the main challenge in the administration of topical corticosteroid therapy to the paranasal sinus mucosa. This often leads to suboptimal drug delivery due to low concentrations of the therapeutic agent to the intended target area. The Relieva Stratus™ MicroFlow Spacer (Relieva Stratus) is a drug-eluting stent that is temporarily implanted into the ethmoid sinus. The reservoir of the stent is filled with triamcinolone acetonide, which is then slowly released from the device into the ethmoid sinus mucosa. The Relieva Stratus provides local and targeted delivery of the anti-inflammatory agent to the diseased mucosa. This minimally invasive implant is an option when treating ethmoid sinusitis. From January 2011 to November 2013, a total of 52 Relieva Stratus implantations into the ethmoidal cells were performed at the Department of Ear and Oral Diseases at Tampere University Hospital, Finland. C-arm fluoroscopy guidance was employed for 26 sinuses (13 patients) and optical image-guided surgery (IGS)-assisted insertions were performed on another 26 sinuses (13 patients). The accuracy of fluoroscopic insertion is not optimal, but this method is accurate enough to prevent the violation of the skull base and lamina papyracea. IGS enables the precise treatment of the diseased cells. From a technical perspective, IGS-guided insertion is a faster, safer and more exact procedure that guarantees the optimal positioning and efficacy of the implant. Moreover, IGS guidance does not entail the use of ionizing radiation. PMID:25325931
Total Hip Arthroplasty Using the S-ROM-A Prosthesis for Anatomically Difficult Asian Patients
Hozumi, Akira; Kobayashi, Kyousuke; Tsuru, Nobuhisa; Miyamoto, Chikara; Maeda, Jyunichiro; Chiba, Ko; Goto, Hisataka; Osaki, Makoto
Background. The S-ROM-A prosthesis has been designed for the Asian proximal femur with a small deformed shape and narrow canal. In this study, the clinical and radiological results using the S-ROM-A prosthesis for Japanese patients with severe deformity due to dysplasia and excessive posterior pelvic tilt were examined. Methods. 94 hips were followed up for a mean of 55 months, with a mean age at surgery of 61 years. The primary diagnoses were 94 coxarthritis cases, including 51 dysplasia and 37 primary OA, 1 avascular necrosis, 2 traumatic arthritis, and 3 Perthes disease. Thirty-one hips had been treated with osteotomy of the hip joints. Preoperative intramedullary canal shapes were stovepipe in 23 hips, normal in 51 hips, and champagne-flute in 5 hips. The maximum pelvic inclination angle was 56°. Results. The mean JOA score improved from 46 points preoperatively to 80 points at final follow-up. On radiological evaluation of the fixation of the implants according to the Engh classification, 92 (97%) hips were classified as "bone ingrown fixation." Conclusion. In primary THA, using the S-ROM-A prosthesis for Asian patients with proximal femoral deformity, even after osteotomy and with posterior pelvic tilt, provided good short- to midterm results. PMID:26582575
Theoretical and practical aspects in total uncemented hip arthroplasty by using short femoral stem prosthesis
Moga, M; Pogarasteanu, ME; Barbilian, A
Hip arthrosis, primary or secondary, is an osteoarthritic degenerative process that affects the hip joint. Primary hip arthrosis has an unknown etiology, and secondary hip arthrosis has well defined causes; of these causes, some are known to lead to arthrosis of the hip in the young age patient. The surgical treatment aims either to preserve the patient's hip joint, or to replace the joint. The most commonly used procedure at this time is the total hip arthroplasty. The femoral component may have a short or a long stem. The short femoral stem prosthesis is usually impacted by using a unique technique and unique instruments, according to the manufacturer's specifications. There are several models of short stem femoral prosthesis, but no matter which one is chosen, the surgical indication, the surgical technique and a well-conducted recovery program are important. The choosing of each arthroplastic implant must be made with care, taking into consideration the patient's benefit, his expectations, and also the surgeon's experience. PMID:26103643
CRISPR interference and priming varies with individual spacer sequences
Xue, Chaoyou; Seetharam, Arun S.; Musharova, Olga; Severinov, Konstantin; J. Brouns, Stan J.; Severin, Andrew J.; Sashital, Dipali G.
CRISPR–Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems allow bacteria to adapt to infection by acquiring 'spacer' sequences from invader DNA into genomic CRISPR loci. Cas proteins use RNAs derived from these loci to target cognate sequences for destruction through CRISPR interference. Mutations in the protospacer adjacent motif (PAM) and seed regions block interference but promote rapid 'primed' adaptation. Here, we use multiple spacer sequences to reexamine the PAM and seed sequence requirements for interference and priming in the Escherichia coli Type I-E CRISPR–Cas system. Surprisingly, CRISPR interference is far more tolerant of mutations in the seed and the PAM than previously reported, and this mutational tolerance, as well as priming activity, is highly dependent on spacer sequence. We identify a large number of functional PAMs that can promote interference, priming or both activities, depending on the associated spacer sequence. Functional PAMs are preferentially acquired during unprimed 'naïve' adaptation, leading to a rapid priming response following infection. Our results provide numerous insights into the importance of both spacer and target sequences for interference and priming, and reveal that priming is a major pathway for adaptation during initial infection. PMID:26586800
Filter holder assembly having extended collar spacer ring
Alvin, Mary Anne; Bruck, Gerald J.
A filter holder assembly is provided that utilizes a fail-safe regenerator unit with an annular spacer ring having an extended metal collar for containment and positioning of a compliant ceramic gasket used in the assembly. The filter holder assembly is disclosed for use with advanced composite, filament wound, and metal candle filters.
Psoas muscle pyogenic abscess in association with infected hip arthroplasty: a rare case of simultaneous bilateral presentation.
Volpin, Andrea; Kini, Sunil Gurpur; Berizzi, Antonio
Simultaneous bilateral presentation of psoas abscess with prosthetic joint involvement is extremely rare. A 68-year-old woman presented to us with bilateral dull aching groin pain of 6 months' duration, which flared up in the past month, associated with pyrexial symptoms. She had undergone bilateral hip replacements in the past with uneventful recovery. MRI showed bilateral psoas muscle collection in communication with the hip joints. Preoperative hip aspirate demonstrated frank pus with positivity on Gram stain and radiographs confirmed prosthetic loosening of bilateral hips. The patient subsequently underwent two-stage revision arthroplasty of both infected hip implants. At 5-year follow-up, the patient remains asymptomatic with good functional outcome and no recurrence on serial MRI. PMID:25994433
A Novel Murine Model of Established Staphylococcal Bone Infection in the Presence of a Fracture Fixation Plate to Study Therapies Utilizing Antibiotic-laden Spacers after Revision Surgery
Inzana, Jason A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.
Mice are the small animal model of choice in biomedical research due to the low cost and availability of genetically engineered lines. However, the devices utilized in current mouse models of implant-associated bone infection have been limited to intramedullary or trans-cortical pins, which are not amenable to treatments involving extensive debridement of a full-thickness bone loss and placement of a segmental antibiotic spacer. To overcome these limitations, we developed a clinically faithful model that utilizes a locking fracture fixation plate to enable debridement of an infected segmental bone defect (full-thickness osteotomy) during a revision surgery, and investigated the therapeutic effects of placing an antibiotic-laden spacer in the segmental bone defect. To first determine the ideal time point for revision following infection, a 0.7 mm osteotomy in the femoral mid-shaft was stabilized with a radiolucent PEEK fixation plate. The defect was inoculated with bioluminescent Staphylococcus aureus, and the infection was monitored over 14 days by bioluminescent imaging (BLI). Osteolysis and reactive bone formation were assessed by X-ray and micro-computed tomography (micro-CT). The active bacterial infection peaked by 5 days post-inoculation, however the stability of the implant fixation became compromised by 10–14 days post-inoculation due to osteolysis around the screws. Thus, day 7 was defined as the ideal time point to perform the revision surgery. During the revision surgery, the infected tissue was debrided and the osteotomy was widened to 3 mm to place a poly-methyl methacrylate spacer, with or without vancomycin. Half of the groups also received systemic vancomycin for the remaining 21 days of the study. The viable bacteria remaining at the end of the study were measured using colony forming unit assays. Volumetric bone changes (osteolysis and reactive bone formation) were directly measured using micro-CT image analysis. Mice that were treated with
Modular hybrid total hip arthroplasty. Experimental study in dogs
Background This prospective experimental study evaluated the surgical procedure and results of modular hybrid total hip arthroplasty in dogs. Methods Ten skeletally mature healthy mongrel dogs with weights varying between 19 and 27 kg were used. Cemented modular femoral stems and uncemented porous-coated acetabular cups were employed. Clinical and radiographic evaluations were performed before surgery and at 30, 60, 90, 120, 180 and 360 days post-operation. Results Excellent weight bearing was noticed in the operated limb in seven dogs. Dislocation followed by loosening of the prosthesis was noticed in two dogs, which were therefore properly treated with a femoral head osteotomy. Femoral fracture occurred in one dog, which was promptly treated with full implant removal and femoral osteosynthesis. Conclusions The canine modular hybrid total hip arthroplasty provided excellent functionality of the operated limb. PMID:21736758
21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.
Code of Federal Regulations, 2013 CFR
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...
21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.
Code of Federal Regulations, 2010 CFR
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...
21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.
Code of Federal Regulations, 2011 CFR
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...
21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.
Code of Federal Regulations, 2012 CFR
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...
21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.
Code of Federal Regulations, 2014 CFR
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...
Electrochemical instrumentation of a hip simulator: a new tool for assessing the role of corrosion in metal-on-metal hip joints.
Yan, Y; Neville, A; Dowson, D; Williams, S; Fisher, J
Polyethylene wear debris induced osteolysis has triggered investigations to find alternative material combinations to the well-established metal-on-polyethylene hip implants. Owing to some early successful clinical cases, metal-on-metal (MoM) hip replacements have been attracting more and more interest. There is, however, considerable concern about the propensity of MoM hip replacements to release metal ions and fine, nanometre-scale metallic wear debris. The long-term effect from released metal ions and wear particles is still not clear. To date, all the work on hip simulators focused on assessing mass losses damage has been referred to as 'wear'. However, it is known in the field of tribocorrosion that mechanical removal of the passive layer on Co-Cr alloys can significantly enhance corrosion activity. In total joint replacements, it is possible that corrosion plays a significant role. However, no one has ever tried to extract, on a hip simulator, what proportion of the damage is due to mechanical processes and the corrosion processes. This paper describes the first instrumentation of an integrated hip joint simulator to provide in-situ electrochemical measurements in real time. The open circuit potential results are reported to assess the corrosion regime in the absence and presence of movement at the bearing surfaces. The importance of these measurements is that the real damage mechanisms can be assessed as a function of the operating cycle. PMID:21218689
Arthroscopic Treatment of Traumatic Hip Dislocation.
Begly, John P; Robins, Bryan; Youm, Thomas
Traumatic hip dislocations are high-energy injuries that often result in considerable morbidity. Although appropriate management improves outcomes, associated hip pathology may complicate the recovery and lead to future disability and pain. Historically, open reduction has been the standard of care for treating hip dislocations that require surgical intervention. The use of hip arthroscopy to treat the sequelae and symptoms resulting from traumatic hip dislocations recently has increased, however. When used appropriately, hip arthroscopy is a safe, effective, and minimally invasive treatment option for intra-articular pathology secondary to traumatic hip dislocation. PMID:27007728
Future Bearing Surfaces in Total Hip Arthroplasty
One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements
Future bearing surfaces in total hip arthroplasty.
Chang, Jun-Dong
One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements
Impingement and Dislocation in Total HIP Arthroplasty: Mechanisms and Consequences
Brown, Thomas D; Elkins, Jacob M; Pedersen, Douglas R; Callaghan, John J
In contemporary total hip arthroplasty, instability has been a complication in approximately 2% to 5% of primary surgeries and 5% to 10% of revisions. Due to the reduction in the incidence of wear-induced osteolysis that has been achieved over the last decade, instability now stands as the single most common reason for revision surgery. Moreover, even without frank dislocation, impingement and subluxation are implicated in a set of new concerns arising with advanced bearings, associated with the relatively unforgiving nature of many of those designs. Against that backdrop, the biomechanical factors responsible for impingement, subluxation, and dislocation remain under-investigated relative to their burden of morbidity. This manuscript outlines a 15-year program of laboratory and clinical research undertaken to improve the scientific basis for understanding total hip impingement and dislocation. The broad theme has been to systematically evaluate the role of surgical factors, implant design factors, and patient factors in predisposing total hip constructs to impinge, sublux, and/or dislocate. Because this class of adverse biomechanical events had not lent itself well to study with existing approaches, it was necessary to develop (and validate) a series of new research methodologies, relying heavily on advanced finite element formulations. Specific areas of focus have included identifying the biomechanical challenges posed by dislocation-prone patient activities, quantifying design parameter effects and component surgical positioning effects for conventional metal-on-polyethylene implant constructs, and the impingement/dislocation behavior of non-conventional constructs, quantifying the stabilizing role of the hip capsule (and of surgical repairs of capsule defects), and systematically studying impingement and edge loading of hard-on-hard bearings, fracture of ceramic liners, confounding effects of patient obesity, and subluxation-mediated worsening of third body
O'Kane, J W
Anterior hip pain is a common complaint with many possible causes. Apophyseal avulsion and slipped capital femoral epiphysis should not be overlooked in adolescents. Muscle and tendon strains are common in adults. Subsequent to accurate diagnosis, strains should improve with rest and directed conservative treatment. Osteoarthritis, which is diagnosed radiographically, generally occurs in middle-aged and older adults. Arthritis in younger adults should prompt consideration of an inflammatory cause. A possible femoral neck stress fracture should be evaluated urgently to prevent the potentially significant complications associated with displacement. Patients with osteitis pubis should be educated about the natural history of the condition and should undergo physical therapy to correct abnormal pelvic mechanics. "Sports hernias," nerve entrapments and labral pathologic conditions should be considered in athletic adults with characteristic presentations and chronic symptoms. Surgical intervention may allow resumption of pain-free athletic activity. PMID:10537384
Effects of spacer length and terminal group on the crystallization and morphology of biscarbamates: a longer spacer does not reduce the melting temperature.
Khan, Mostofa Kamal; Sundararajan, Pudupadi R
The effects of alkyl side chain and spacer lengths and the type of terminal group on the morphology and crystallization of a homologous series of biscarbamates (model compounds for polyurethanes) were investigated. Biscarbamates were synthesized with alkyl side chains of various lengths ranging from C4 to C18 and an alkyl spacer group with 12 CH2 units (C12 spacer) between the two hydrogen bonding motifs. The crystallization and morphological features are compared with the previously studied biscarbamates with a C6 spacer. As a token example, we also studied a biscarbamate molecule in which the terminal methyl group was replaced by a phenyl group. We stress four important conclusions of the study: (1) A number of studies in the literature found that the longer alkyl spacers reduced the thermal transition temperatures of the molecules, and such behavior was attributed to an increase in the flexibility of the alkyl spacer. However, the results of the present study are to the contrary. With the biscarbamates studied here, the hydrogen-bonding groups on both sides of the C12 spacer act as "anchors", and the longer spacer does not reduce the melting temperatures compared with those with the C6 spacer. (2) The melt viscosity measurements show shear-thinning behavior, which has been mostly observed with polysaccharides and hydrogen-bonded polymers. (3) Avrami analysis shows a two-stage crystallization, which is not commonly observed in organic small molecule systems. (4) The phenyl end group does not add another self-assembly code in terms of π-stacking but acts as a defect. While formation of crystals was observed for biscarbamates with short alkyl side chains with a C6 spacer, an increase in spacer length to C12 induces spherulitic morphology. Although the overall sizes of the spherulites are the same for both spacers, the rate of spherulite growth was higher and the crystallization rate was lower with the C12 spacer compared with the C6 spacer. In contrast with the
Primary total hip replacement versus hip resurfacing - hospital considerations.
Ward, William G; Carter, Christina J; Barone, Marisa; Jinnah, Riyaz
Multiple factors regarding surgical procedures and patient selection affect hospital staffing needs as well as hospital revenues. In order to better understand the potential impact on hospitals that hip arthroplasty device selection (standard total hip arthroplasty vs. resurfacing) creates, a review of all primary hip arthroplasties performed at one institution was designed to identify factors that impacted hospital staffing needs and revenue generation. All primary hip arthroplasties undertaken over three fiscal years (2008 to 2010) were reviewed, utilizing only hospital business office data and medical records data that had been previously extracted prior for billing purposes. Analysis confirmed differing demographics for two hip arthroplasty populations, with the resurfacing patients (compared to the conventional total hip arthroplasty population) consisting of younger patients (mean age, 50 vs. 61 years), who were more often male (75% vs. 45%), were more likely to have osteoarthritis as their primary diagnosis (83 vs. 67%) and were more often covered by managed care or commercial insurance (83 vs. 34%). They also had shorter hospital stays (mean length of stay, 2.3 vs. 4.1 days) and consequently provided a more favorable financial revenue stream to the hospital on a per patient basis. Several trends appeared during the study periods. There was a steady increase in all procedures in all groups except for the resurfacings, which decreased 26% in males and 53% in females between 2009 and 2010. Differences were observed in the demographics of patients presenting for resurfacing, compared to those presenting for conventional total hip arthroplasty. In addition to the revenue stream considerations, institutions undertaking a resurfacing program must commit the resources and planning in order to rehabilitate these patients more expeditiously than is usually required with conventional hip arthroplasty patients. PMID:22035493
Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study
Nevitt, Michael C; Niu, Jingbo; Clancy, Mary M; Lane, Nancy E; Link, Thomas M; Vlad, Steven; Tolstykh, Irina; Jungmann, Pia M.; Felson, David T; Guermazi, Ali
Study question Is there concordance between hip pain and radiographic hip osteoarthritis? Methods In this diagnostic test study, pelvic radiographs were assessed for hip osteoarthritis in two cohorts: the Framingham Osteoarthritis Study (community of Framingham, Massachusetts) and the Osteoarthritis Initiative (a multicenter longitudinal cohort study of osteoarthritis in the United States). Using visual representation of the hip joint, participants reported whether they had hip pain on most days and the location of the pain: anterior, groin, lateral, buttocks, or low back. In the Framingham study, participants with hip pain were also examined for hip pain with internal rotation. The authors analysed the agreement between radiographic hip osteoarthritis and hip pain, and for those with hip pain suggestive of hip osteoarthritis they calculated the sensitivity, specificity, positive predictive value, and negative predictive value of radiographs as the diagnostic test. Study answer and limitations In the Framingham study (n=946), only 15.6% of hips in patients with frequent hip pain showed radiographic evidence of hip osteoarthritis, and 20.7% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of radiographic hip osteoarthritis for hip pain localised to the groin was 36.7%, specificity 90.5%, positive predictive value 6.0%, and negative predictive value 98.9%. Results did not differ much for hip pain at other locations or for painful internal rotation. In the Osteoarthritis Initiative study (n=4366), only 9.1% of hips in patients with frequent pain showed radiographic hip osteoarthritis, and 23.8% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of definite radiographic hip osteoarthritis for hip pain localised to the groin was 16.5%, specificity 94.0%, positive predictive value 7.1%, and negative predictive value 97.6%. Results also did not differ much for hip pain at other locations. What this
Investigating stress shielding spanned by biomimetic polymer-composite vs. metallic hip stem: A computational study using mechano-biochemical model.
Tavakkoli Avval, Pouria; Samiezadeh, Saeid; Klika, Václav; Bougherara, Habiba
Periprosthetic bone loss in response to total hip arthroplasty is a serious complication compromising patient's life quality as it may cause the premature failure of the implant. Stress shielding as a result of an uneven load sharing between the hip implant and the bone is a key factor leading to bone density decrease. A number of composite hip implants have been designed so far to improve load sharing characteristics. However, they have rarely been investigated from the bone remodeling point of view to predict a long-term response. This is the first study that employed a mechano-biochemical model, which considers the coupling effect between mechanical loading and bone biochemistry, to investigate bone remodeling after composite hip implantation. In this study, periprosthetic bone remodeling in the presence of Carbon fiber polyamide 12 (CF/PA12), CoCrMo and Ti alloy implants was predicted and compared. Our findings revealed that the most significant periprosthetic bone loss in response to metallic implants occurs in Gruen zone 7 (-43% with CoCrMo; -35% with Ti) and 6 (-40% with CoCrMo; -29% with Ti), while zone 4 has the lowest bone density decrease with all three implants (-9%). Also, the results showed that in terms of bone remodeling, the composite hip implant is more advantageous over the metallic ones as it provides a more uniform density change across the bone and induces less stress shielding which consequently results in a lower post-operative bone loss (-9% with CF/PA12 implant compared to -27% and -21% with CoCrMo and Ti alloy implants, respectively). PMID:25460403
Ceramic-on-Ceramic Total Hip Arthroplasty in a Twelve-Year-Old Patient: Case Report with a 27-Year Follow-Up.
Save, Ameya V; Varthi, Arya; Talusan, Paul G; Gala, Raj; Nelson, Stephen; Keggi, Kristaps J
Total hip arthroplasty in the juvenile patient with a severely diseasedjoint can provide long-term pain relief and improvement in function. We present a patient with juvenile rheumatoid arthritis who underwent a Mittelmeier ceramic-on-ceramic total hip arthroplasty at age 12 in 1986. The implant provided the patient with a functioning hip for 24 years, but subsequently required revision due to femoral component loosening. This case report represents the longest reported clinical follow-up of noncemented, ceramic-on-ceramic total hip arthroplasty in a juvenile patient and depicts an excellent outcome at 27 years. Our case is also unique in that the Mittelmeier ceramic acetabulum was left in place during revision surgery. In this report, we also describe the senior author's choice of the Mittelmeier hip prosthesis within its historical context and provide a brief review of the literature as it relates to total hip arthroplasty in the juvenile patient. PMID:27509640
Hip Surgery Candidates: A Comparative Study of Hip Osteoarthritis and Prior Hip Fracture Patient Characteristics
Marks, Ray
Aim: To assess similarities and differences in patient-related characteristics before and after surgery for painful disabling hip osteoarthritis among elderly subgroups with and without a trauma history. Method: First, a cohort of 1000 hospitalized patients were assessed for trends in: perceived duration of the condition, pain intensity, functional performance ability, walking distance, body mass, and comorbidity characteristics among other factors. Then, the most salient of these patient-related characteristics were compared between 42 cases of hip osteoarthritis without a trauma history and 42 cases with a trauma history matched for age and gender, using medical records and standard data recording and analysis procedures. Results: Hip osteoarthritis cases with a prior hip fracture history had a longer duration of disability, and were more impaired functionally before surgery (p < 0.05) than those with no such history. They also had lower leg muscle strength and used more assistive devices. Conclusion: Patients undergoing hip replacement surgery for painful hip osteoarthritis who have a hip fracture history are likely to be more impaired and disabled than those with no such history. PMID:19478931
Fracture After Total Hip Replacement
... er Total Hip Replacement cont. • Dislocation • Limb length inequality • Poor fracture healing • Repeat fracture • Lack of in- ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Page ( 5 ) AAOS does ...
Anchor-induced chondral damage in the hip
Matsuda, Dean K.; Bharam, Srino; White, Brian J.; Matsuda, Nicole A.; Safran, Marc
The purpose of this study is to investigate the outcomes from anchor-induced chondral damage of the hip, both with and without frank chondral penetration. A multicenter retrospective case series was performed of patients with chondral deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, hip outcome scores and descriptions of arthroscopic treatment in cases requiring revision surgery and anchor removal are reported. Five patients (three females) of mean age 32 years (range, 16–41 years) had documented anchor-induced chondral damage with mean 3.5 years (range, 1.5–6.0 years) follow-up. The 1 o'clock position (four cases) and anterior and mid-anterior portals (two cases each) were most commonly implicated. Two cases of anchor-induced acetabular chondral deformation without frank penetration had successful clinical and radiographic outcomes, while one case progressed from deformation to chondral penetration with clinical worsening. Of the cases that underwent revision hip arthroscopy, all three had confirmed exposed hard anchors which were removed. Two patients have had clinical improvement and one patient underwent early total hip arthroplasty. Anchor-induced chondral deformation without frank chondral penetration may be treated with close clinical and radiographic monitoring with a low threshold for revision surgery and anchor removal. Chondral penetration should be treated with immediate removal of offending hard anchor implants. Preventative measures include distal-based portals, small diameter and short anchors, removable hard anchors, soft suture-based anchors, curved drill and anchor insertion instrumentation and attention to safe trajectories while visualizing the acetabular articular surface. PMID:27011815
Increased Long-Term Cardiovascular Risk After Total Hip Arthroplasty
Gordon, Max; Rysinska, Agata; Garland, Anne; Rolfson, Ola; Aspberg, Sara; Eisler, Thomas; Garellick, Göran; Stark, André; Hailer, Nils P.; Sköldenberg, Olof
Abstract Total hip arthroplasty is a common and important treatment for osteoarthritis patients. Long-term cardiovascular effects elicited by osteoarthritis or the implant itself remain unknown. The purpose of the present study was to determine if there is an increased risk of late cardiovascular mortality and morbidity after total hip arthroplasty surgery. A nationwide matched cohort study with data on 91,527 osteoarthritis patients operated on, obtained from the Swedish Hip Arthroplasty Register. A control cohort (n = 270,688) from the general Swedish population was matched 1:3 to each case by sex, age, and residence. Mean follow-up time was 10 years (range, 7–21). The exposure was presence of a hip replacement for more than 5 years. The primary outcome was cardiovascular mortality after 5 years. Secondary outcomes were total mortality and re-admissions due to cardiovascular events. During the first 5 to 9 years, the arthroplasty cohort had a lower cardiovascular mortality risk compared with the control cohort. However, the risk in the arthroplasty cohort increased over time and was higher than in controls after 8.8 years (95% confidence interval [CI] 7.0–10.5). Between 9 and 13 years postoperatively, the hazard ratio was 1.11 (95% CI 1.05–1.17). Arthroplasty patients were also more frequently admitted to hospital for cardiovascular reasons compared with controls, with a rate ratio of 1.08 (95% CI 1.06–1.11). Patients with surgically treated osteoarthritis of the hip have an increased risk of cardiovascular morbidity and mortality many years after the operation when compared with controls. PMID:26871792
Anchor-induced chondral damage in the hip.
Matsuda, Dean K; Bharam, Srino; White, Brian J; Matsuda, Nicole A; Safran, Marc
The purpose of this study is to investigate the outcomes from anchor-induced chondral damage of the hip, both with and without frank chondral penetration. A multicenter retrospective case series was performed of patients with chondral deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, hip outcome scores and descriptions of arthroscopic treatment in cases requiring revision surgery and anchor removal are reported. Five patients (three females) of mean age 32 years (range, 16-41 years) had documented anchor-induced chondral damage with mean 3.5 years (range, 1.5-6.0 years) follow-up. The 1 o'clock position (four cases) and anterior and mid-anterior portals (two cases each) were most commonly implicated. Two cases of anchor-induced acetabular chondral deformation without frank penetration had successful clinical and radiographic outcomes, while one case progressed from deformation to chondral penetration with clinical worsening. Of the cases that underwent revision hip arthroscopy, all three had confirmed exposed hard anchors which were removed. Two patients have had clinical improvement and one patient underwent early total hip arthroplasty. Anchor-induced chondral deformation without frank chondral penetration may be treated with close clinical and radiographic monitoring with a low threshold for revision surgery and anchor removal. Chondral penetration should be treated with immediate removal of offending hard anchor implants. Preventative measures include distal-based portals, small diameter and short anchors, removable hard anchors, soft suture-based anchors, curved drill and anchor insertion instrumentation and attention to safe trajectories while visualizing the acetabular articular surface. PMID:27011815
A concept for hip prosthesis identification using ultra wideband radar.
Lui, Hoi-Shun; Shuley, Nicholas; Crozier, Stuart
Ultra wideband (UWB) radar has been extensively investigated both theoretically and practically for the identification buried artifacts. Ground probe radar (GPR) concentrates on the identification of lightly buried land mines, unexploded ordnance (UXO) and archeological targets. The same technology is proposed in a similar context for the rapid identification of in vivo implanted metallic prostheses. The technique is based on resonance based target identification and the paper investigates UWB scattering from a metallic hip prosthesis in free space as a first step in the identification process. PMID:17271965
"In vivo" determination of hip joint separation and the forces generated due to impact loading conditions.
Dennis, D A; Komistek, R D; Northcut, E J; Ochoa, J A; Ritchie, A
Numerous supporting structures assist in the retention of the femoral head within the acetabulum of the normal hip joint including the capsule, labrum, and ligament of the femoral head (LHF). During total hip arthroplasty (THA), the LHF is often disrupted or degenerative and is surgically removed. In addition, a portion of the remaining supporting structures is transected or resected to facilitate surgical exposure. The present study analyzes the effects of LHF absence and surgical dissection in THA patients. Twenty subjects (5 normal hip joints, 10 nonconstrained THA, and 5 constrained THA) were evaluated using fluoroscopy while performing active hip abduction. All THA subjects were considered clinically successful. Fluoroscopic videos of the normal hips were analyzed using digitization, while those with THA were assessed using a computerized interactive model-fitting technique. The distance between the femoral head and acetabulum was measured to determine if femoral head separation occurred. Error analysis revealed measurements to be accurate within 0.75mm. No separation was observed in normal hips or those subjects implanted with constrained THA, while all 10 (100%) with unconstrained THA demonstrated femoral head separation, averaging 3.3mm (range 1.9-5.2mm). This study has shown that separation of the prosthetic femoral head from the acetabular component can occur. The normal hip joint has surrounding capsuloligamentous structures and a ligament attaching the femoral head to the acetabulum. We hypothesize that these soft tissue supports create a passive, resistant force at the hip, preventing femoral head separation. The absence of these supporting structures after THA may allow increased hip joint forces, which may play a role in premature polyethylene wear or prosthetic loosening. PMID:11311703
[Pseudotumors caused by hip prostheses].
Helkamaa, Teemu; Lohman, Martina; Alberty, Anne
More than 100000 hip replacements have been performed in Finland. In the hip replacement operations performed due to osteoarthritis, the artificial joint surfaces are made of metal, plastic or ceramics. Pseudotumors associated with metal-on-metal (MoM) sliding surfaces have received worldwide attention. Soft issue lesions, not always symptomatic, may develop around the joint replacements. These may even require joint revision surgery. PMID:26237883
Effect of cement fill ratio in loosening of hip implants
Gunn, Elizabeth; Gundapaneni, Dinesh; Goswami, Tarun
Femoral loosening is one of the most prevalent causes of revision orthopedic surgeries. Cement mantle thickness has been directly correlated with femoral loosening. If the mantle is too thick, there is an increased risk of radiolucent lines and inconsistent densities. Also, the more bone that is reamed out during the procedure can lead to instability, especially if the quality of the bone is compromised due to osteoporosis. Too thin of a mantle can lead to a higher probability for cement fracture, loosening the prosthetic even further. This study has shown that there is an ideal thickness range between two to five that should be kept. From radiographic images one can measure the thickness of the cement mantle showing the loosening characteristics. PMID:23507806
Good outcome of total hip replacement in patients with cerebral palsy
King, Garry; Hunt, Linda P; Wilkinson, J Mark; Blom, Ashley W
Background and purpose — People with cerebral palsy (CP) often have painful deformed hips, but they are seldom treated with hip replacement as the surgery is considered to be high risk. However, few data are available on the outcome of hip replacement in these patients. Patients and methods — We linked Hospital Episode Statistics (HES) records to the National Joint Registry for England and Wales to identify 389 patients with CP who had undergone hip replacement. Their treatment and outcomes were compared with those of 425,813 patients who did not have CP. Kaplan-Meier estimates were calculated to describe implant survivorship and the curves were compared using log-rank tests, with further stratification for age and implant type. Reasons for revision were quantified as patient-time incidence rates (PTIRs). Nationally collected patient-reported outcomes (PROMS) before and 6 months after operation were compared if available. Cumulative mortality (Kaplan-Meier) was estimated at 90 days and at 1, 3, and 5 years. Results — The cumulative probability of revision at 5 years post-surgery was 6.4% (95% CI: 3.8–11) in the CP cohort as opposed to 2.9% (CI 2.9–3%) in the non-CP cohort (p < 0.001). Patient-reported outcomes showed that CP patients had worse pain and function preoperatively, but had equivalent postoperative improvement. The median improvement in Oxford hip score at 6 months was 23 (IQR: 14–28) in CP and it was 21 (14–28) in non-CP patients. 91% of CP patients reported good or excellent satisfaction with their outcome. The cumulative probability of mortality for CP up to 7 years was similar to that in the controls after stratification for age and sex. Interpretation — Hip replacement for cerebral palsy appears to be safe and effective, although implant revision rates are higher than those in patients without cerebral palsy. PMID:26863583
Guarniero, Roberto
The term "developmental dysplasia of the hip" (DDH) includes a wide spectrum of abnormalities that affect the hip during its growth, ranging from dysplasia to joint dislocation and going through different degrees of coxofemoral subluxation. The incidence of DDH is variable, and depends on a number of factors, including geographical location. Approximately one in 1,000 newborn infants may present hip dislocation and around 10 in 1,000 present hip instability. Brazil has an incidence of five per 1,000 in terms of findings of a positive Ortolani sign, which is the early clinical sign for detecting the disorder. The risk factors for DDH include: female sex, white skin color, primiparity, young mother, breech presentation at birth, family history, oligohydramnios, newborns with greater weight and height, and deformities of the feet or spine. Hip examinations should be routine for newborns, and should be emphasized in maternity units. Among newborns and infants, the diagnosis of DDH is preeminently clinical and is made using the Ortolani and Barlow maneuvers. Conventional radiography is of limited value for confirming the diagnosis of DDH among newborns, and ultrasound of the hip is the ideal examination. The treatment of DDH is challenging, both for pediatric orthopedists and for general practitioners. The objectives of the treatment include diagnosis as early as possible, joint reduction and stabilization of the hip in a secure position. Classically, treatment options are divided according to different age groups, at the time of diagnosis. PMID:27022528
Bleck, E E
Orthopedic surgery can alleviate the hip flexion, adduction, and medial rotation deformities of the hip and improve the function and appearance of gait. To accomplish this, however, careful examination and prudence in the operative procedure to avoid overdoing and overcorrecting are important. Orthopedic surgery can prevent subluxation and dislocation of the hip before the age of seven years, and consequently repetitive radiographic examinations of the hip in children who have spastic paralysis of the hip musculature should be a routine procedure. Subluxation and dislocation of the hip, when established, can be successfully treated with orthopedic surgical procedures. Physicians must keep in mind that the spastic paralysis of cerebral palsy originates in the brain, and therefore the spasticity cannot be eliminated. The best that can be done is to weaken or remove some muscles as deforming forces and to achieve compromises for continued function. The goal should be optimal independence for the child and adolescent during development, and freedom from pain with deteriorating function due to degenerative arthritis in the adult. PMID:7360505
Long-duration metal-on-metal total hip arthroplasties with low wear of the articulating surfaces.
Schmalzried, T P; Peters, P C; Maurer, B T; Bragdon, C R; Harris, W H
The 20-year performance of metal-on-metal hip articulations has not been reported. Five McKee-Farrar total hip prostheses and one Sivash prosthesis were obtained at revision surgery after a mean implantation time of 21.3 years. A radiographic, histologic, implant, and wear analysis was performed on these total hip implants with cobalt-chrome metal-on-metal articulations. All cases were associated with femoral component loosening, but the bearing surfaces performed remarkably well. The worst case estimate of combined femoral and acetabular linear wear was 4.2 microns per year, about 25 times less than that typically seen with polyethylene. Metal particles and foreign-body inflammation were seen in all cases, but the volume of reactive tissue was small compared with what is generally seen at revision of hips with a polyethylene acetabular bearing. This may be due to a reduced particle burden or a decreased inflammatory reaction to particulate metal, or both. In addition to articular wear, other sources of metal particles included femoral neck impingement on the acetabular rim, stem burnishing, and corrosion. Prosthetic hip reconstructions can fail for many reasons, including suboptimal femoral stem and/or acetabular cup design and/or fixation. By today's standards, the McKee-Farrar and Sivash stem and acetabular component designs are suboptimal; however, after more than 20 years of use, the metal-on-metal bearing surfaces in these cases demonstrated low wear and do not appear to be the cause of failure. Recent advances in total hip arthroplasty, which include improved implant design, materials, manufacturing, and fixation, combined with a better understanding of the mechanisms of implant loosening and failure, suggest that the cobalt-chrome metal-on-metal bearing be reexamined as an alternative to polyethylene when exceptional durability is required. PMID:8713913
SPACER: server for predicting allosteric communication and effects of regulation
Goncearenco, Alexander; Mitternacht, Simon; Yong, Taipang; Eisenhaber, Birgit; Eisenhaber, Frank; Berezovsky, Igor N.
The SPACER server provides an interactive framework for exploring allosteric communication in proteins with different sizes, degrees of oligomerization and function. SPACER uses recently developed theoretical concepts based on the thermodynamic view of allostery. It proposes easily tractable and meaningful measures that allow users to analyze the effect of ligand binding on the intrinsic protein dynamics. The server shows potential allosteric sites and allows users to explore communication between the regulatory and functional sites. It is possible to explore, for instance, potential effector binding sites in a given structure as targets for allosteric drugs. As input, the server only requires a single structure. The server is freely available at http://allostery.bii.a-star.edu.sg/. PMID:23737445
Flows through sequential orifices with heated spacer reservoirs
NASA Technical Reports Server (NTRS)
Hendricks, R. C.; Stetz, T. T.
Flow rates and pressure thermal profiles for two phase choked flows of fluid nitrogen were studied theoretically and experimentally in a four sequential orifice configuration. Both theory and experimental evidence demonstrate that heat addition in the first spacer-reservoir adjacent to the inlet orifice is most effective in reducing the flow rate and that heat addition in the last spacer-reservoir is least effective. The flows are choked at the exit orifice for large spacings and at the inlet orifice for small spacings. The moderate addition of heat available for this experiment did not materially alter this result for large spacings; however, significant heat addition for the small spacings tended to shift the choke point to the exit orifice. Nitrogen is used as the working fluid over a range of states from liquid to gas with a reduced inlet stagnation pressure range to P sub r, o = 2.
Pathologic ligamentous constraint of the hip.
Crowninshield, R D; Johnston, R C; Brand, R A; Pedersen, D R
A mathematic model of the hip capsule and lower extremity musculature was utilized to predict the forces present in the hip ligaments during locomotion. The results demonstrate principles and trends (rather than absolute results) in hip mechanics, the details of which are affected by the associated modeling assumptions. The active stretching of a hip joint capsule tightened by scarring or surgical transfer may appreciably increase the hip contact force. Capsular elements that prevent hip flexion and adduction play a major role in hip contact force exaggeration during common activities. The positive effect of maintaining the hip capsule to reduce total hip component dislocation contrasts with the potential negative effects of restricting joint motion and increasing the joint contact force. Increased joint loading due to capsular restriction may contribute to prosthetic component loosening. PMID:6641064
Diagnosis of adverse local tissue reactions following metal-on-metal hip arthroplasty.
Chalmers, Brian P; Perry, Kevin I; Taunton, Michael J; Mabry, Tad M; Abdel, Matthew P
Metal-on-metal (MOM) bearing surfaces in hip arthroplasty have distinct advantages that led to the increase in popularity in North America in the early 2000s. However, with their increased use, concerns such as local cytotoxicity and hypersensitivity reactions leading to soft tissue damage and cystic mass formation (known collectively as adverse local tissue reactions (ALTR)) became apparent. The clinical presentation of ALTR is highly variable. The diagnosis of ALTR in MOM articulations in hip arthroplasty can be challenging and a combination of clinical presentation, physical examination, implant track record, component positioning, serum metal ion levels, cross-sectional imaging, histopathologic analysis, and consideration of alternative diagnoses are essential. PMID:26816329
Magnetic resonance imaging features of complications following hip replacement: A pictorial review
Pilania, Khushboo; Jankharia, Bhavin
Hip replacement surgery helps millions of people worldwide walk painlessly each year. With increasing life spans and decreased clinical threshold for surgery, this number will continue to rise. With the increase in the number of surgeries and the longevity of implants, the need for early and prompt diagnosis of complications is also rising. This essay underlines the fact that magnetic resonance imaging on a 1.5T scanner with specialized metal artefact reduction sequences is a viable technique to image the post-arthroplasty hip and has vast potential in the prompt and early diagnosis of complications in these patients.
Improving electricity production in tubular microbial fuel cells through optimizing the anolyte flow with spiral spacers.
Zhang, Fei; Ge, Zheng; Grimaud, Julien; Hurst, Jim; He, Zhen
The use of spiral spacers to create a helical flow for improving electricity generation in microbial fuel cells (MFCs) was investigated in both laboratory and on-site tests. The lab tests found that the MFC with the spiral spacers produced more electricity than the one without the spiral spacers at different recirculation rates or organic loading rates, likely due to the improved transport/distribution of ions and electron mediators instead of the substrates because the organic removal efficiency was not obviously affected by the presence of the spiral spacers. The energy production in the MFC with the spiral spacers reached 0.071 or 0.073 kWh/kg COD in either vertical or horizontal installment. The examination of the MFCs installed in an aeration tank of a municipal wastewater treatment plant confirmed the advantage of using the spiral spacers. Those results demonstrate that spiral spacers could be an effective approach to improve energy production in MFCs. PMID:23500582
Increased antibiotic release and equivalent biomechanics of a spacer cement without hard radio contrast agents.
Bitsch, R G; Kretzer, J P; Vogt, S; Büchner, H; Thomsen, M N; Lehner, B
We compared a novel calcium carbonate spacer cement (Copal® spacem) to well-established bone cements. Electron microscopic structure and elution properties of the antibiotics ofloxacin, vancomycin, clindamycin, and gentamicin were examined. A knee wear simulator model for articulating cement spacers was established. Mechanical tests for bending strength, flexural modulus, and compressive and fatigue strength were performed. The electron microscopic analysis showed a microporous structure of the spacer cement, and this promoted a significantly higher and longer antibiotic elution. All spacer cement specimens released the antibiotics for a period of up to 50days with the exception of the vancomycin loading. The spacer cement showed significantly less wear scars and fulfilled the ISO 5833 requirements. The newly developed spacer cement is a hydrophilic antibiotic carrier with an increased release. Cement without hard radio contrast agents can improve tribological behaviour of spacers, and this may reduce reactive wear particles and abrasive bone defects. PMID:26219491
Structural design feasibility study of Space Station long spacer truss
NASA Technical Reports Server (NTRS)
Armand, Sasan C.; Funk, Gregory P.; Dohogne, Caroline A.
The structural design and configuration feasibility of the long spacer truss assembly that will be used as part of the Space Station Freedom is the focus of this study. The structural analysis discussed herein is derived from the transient loading events presented in the Space Transportation System Interface Control Document (STS ICD). The transient loading events are liftoff, landing, and emergency landing loads. Quasi-static loading events were neglected in this study since the magnitude of the quasi-static acceleration factors is lower than that of the transient acceleration factors. Structural analysis of the proposed configuration of the long spacer truss with four longerons indicated that negative safety margins are possible. As a result, configuration changes were proposed. The primary configuration change suggested was to increase the number of truss longerons to six. The six-longeron truss appears to be a more promising structure than the four-longeron truss because it offers a positive margin of safety and more volume in its second bay (BAY2). This additional volume can be used for resupply of some of the orbital replacement units (such as a battery box). Note that the design effort on the long spacer truss has not fully begun and that calculations and reports of the negative safety margins are, to date, based on concept only.
Spacers' role in the dynamics of hyperbranched polymers
NASA Astrophysics Data System (ADS)
Satmarel, C.; von Ferber, C.; Blumen, A.
We investigate hyperbranched polymers (HBPs) and highlight the relation between their architecture and their viscoelastic behavior, while paying special attention to the role of the chainlike spacer segments between branching points. For this we study the dynamics of HBP in solution, based on the generalized Gaussian structure formalism, an extension of the Rouse model, which disregards hydrodynamical and excluded volume effects. For HBP the dynamical effects display, beside the obvious contributions of localized modes on the spacers, also remarkable features, as we highlight based on the exact renormalization procedure recently developed by us in J. Chem. Phys. 123, 034907 (2005). We exemplify these features by analyzing the dynamics of randomly linked star polymers and study the impact both of the length and of the spacers' mobility on the normal modes' spectra. We compute these modes both by numerical diagonalization and also by employing our renormalization procedure; the excellent agreement between these methods allows us to extend the range of investigations to very large HBP.
Structural design feasibility study of Space Station long spacer truss
NASA Astrophysics Data System (ADS)
Armand, Sasan C.; Funk, Gregory P.; Dohogne, Caroline A.
The structural design and configuration feasibility of the long spacer truss assembly that will be used as part of the Space Station Freedom is the focus of this study. The structural analysis discussed herein is derived from the transient loading events presented in the Space Transportation System Interface Control Document (STS ICD). The transient loading events are liftoff, landing, and emergency landing loads. Quasi-static loading events were neglected in this study since the magnitude of the quasi-static acceleration factors is lower than that of the transient acceleration factors. Structural analysis of the proposed configuration of the long spacer truss with four longerons indicated that negative safety margins are possible. As a result, configuration changes were proposed. The primary configuration change suggested was to increase the number of truss longerons to six. The six-longeron truss appears to be a more promising structure than the four-longeron truss because it offers a positive margin of safety and more volume in its second bay (BAY2). This additional volume can be used for resupply of some of the orbital replacement units (such as a battery box). Note that the design effort on the long spacer truss has not fully begun and that calculations and reports of the negative safety margins are, to date, based on concept only.
... outside of the body, behind the ear. A second part is surgically placed under the skin. An implant does not restore normal hearing. It can help a person understand speech. Children and adults can benefit from them. National Institute on Deafness and Other Communication Disorders
... are sent along the auditory nerve to the brain. A deaf person does not have a functioning inner ear. A cochlear implant tries to replace the function of the inner ear by ... signals to the brain. Sound is picked up by a microphone worn ...
Eponymous hip joint approaches.
Somford, Matthijs P; Hoornenborg, Daniël; Wiegerinck, Johannes I; Bolder, Stefan B T; Schreurs, Berend W
After the low friction arthroplasty by John Charnley was no longer confined to specialized hospitals but commonplace in the general orthopedic practice, the issue remained how to most optimally reach the hip. The names of the authors of these approaches remain in a lot of cases connected to the approach. By evaluating the original articles in which the approaches are described we ascertain the original description and technique. By various sources we obtained the (short) biography of the people whose name is connected to the approach. Our research covers the biographies of colleagues Smith-Petersen, Watson-Jones, Hardinge, Charnley, Moore and Ludloff. The eponymous approaches are shown and described after the short biography on each individual. This study shows that without the work of our colleagues we cannot proceed in our profession. An understanding and knowledge of the people who dedicated themselves to developing the orthopedic surgery to the high standard it has today is the least honour we should give them. PMID:27139185
Kinematic radiography of the hip joint after hip resurfacing arthroplasty.
Kawashima, Hiroki; Kajino, Yoshitomo; Kabata, Tamon; Tsuchiya, Hiroyuki; Sanada, Shigeru; Ichikawa, Katsuhiro
This study aimed to evaluate the usefulness of dynamic radiography using a dynamic flat-panel detector (FPD) system after hip resurfacing arthroplasty (HRA). A total of 32 hips of 26 patients who underwent HRA were included. Sequential images of active abduction in the supine position and flexion in the 45° semilateral position were obtained using the FPD system. We examined the imaging findings of impingement between the acetabular component and femoral neck with cooperative motion at maximal exercise. Moreover, the central component coordinate of the acetabulum and femoral head sides was measured. For abduction motion, impingement was detected in two (6.3 %) hips between the superior portion of the femoral neck and acetabular component. For flexion motion, impingement was detected in 19 (59.4 %) hips. There were no findings of subluxation between the acetabular component and femoral neck after impingement, but cooperative motion of lumbar and pelvic flexion was observed. There was no significant difference in the center-to-center distance regardless of the presence or absence of impingement. Detailed postoperative kinematics of the hips after HRA showed that the proposed dynamic FPD system could reveal acquired impingement and cooperative motion as dynamic images and possibly reveal findings that would be unobservable using static images. PMID:27207072
Development and characterization of 3D-printed feed spacers for spiral wound membrane systems.
Siddiqui, Amber; Farhat, Nadia; Bucs, Szilárd S; Linares, Rodrigo Valladares; Picioreanu, Cristian; Kruithof, Joop C; van Loosdrecht, Mark C M; Kidwell, James; Vrouwenvelder, Johannes S
Feed spacers are important for the impact of biofouling on the performance of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane systems. The objective of this study was to propose a strategy for developing, characterizing, and testing of feed spacers by numerical modeling, three-dimensional (3D) printing of feed spacers and experimental membrane fouling simulator (MFS) studies. The results of numerical modeling on the hydrodynamic behavior of various feed spacer geometries suggested that the impact of spacers on hydrodynamics and biofouling can be improved. A good agreement was found for the modeled and measured relationship between linear flow velocity and pressure drop for feed spacers with the same geometry, indicating that modeling can serve as the first step in spacer characterization. An experimental comparison study of a feed spacer currently applied in practice and a 3D printed feed spacer with the same geometry showed (i) similar hydrodynamic behavior, (ii) similar pressure drop development with time and (iii) similar biomass accumulation during MFS biofouling studies, indicating that 3D printing technology is an alternative strategy for development of thin feed spacers with a complex geometry. Based on the numerical modeling results, a modified feed spacer with low pressure drop was selected for 3D printing. The comparison study of the feed spacer from practice and the modified geometry 3D printed feed spacer established that the 3D printed spacer had (i) a lower pressure drop during hydrodynamic testing, (ii) a lower pressure drop increase in time with the same accumulated biomass amount, indicating that modifying feed spacer geometries can reduce the impact of accumulated biomass on membrane performance. The combination of numerical modeling of feed spacers and experimental testing of 3D printed feed spacers is a promising strategy (rapid, low cost and representative) to develop advanced feed spacers aiming to reduce the impact of
Independent tuning of double plasmonic waves in a free-standing graphene-spacer-grating-spacer-graphene hybrid slab.
Chen, Ying; Yao, Jin; Song, Zhengyong; Ye, Longfang; Cai, Guoxiong; Liu, Qing Huo
The independent excitation and tuning of double plasmonic waves are realized in a free-standing graphene-spacer-grating-spacer-graphene (GSGSG) hybrid slab, which consists of two graphene field effect transistors placed back-to-back to each other. Resulted from the high transparency and the tight confinement of surface plasmonic mode for the graphene, double plasmonic waves can be independently excited by guided-mode resonances (GMRs). Theoretical and numerical investigations are performed in the mid-infrared band. Furthermore, the tuning of individual GMR resonant wavelengths with respect to the system parameters is studied. The results provide opportunities to engineer the proposed hybrid slab for wavelength selective and multiplexing applications. PMID:27464148
In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators.
Yan, Yu; Dowson, Duncan; Neville, Anne
The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces. PMID:23182693
Favorable outcome of a total hip arthroplasty with insufficient bone coverage of the roof reinforcement ring
Judas, Fernando M.; Lucas, Francisco M.; Fonseca, Ruben L.
Introduction Total hip arthroplasty in patients with developmental dysplasia of the hip can be a complex procedure due to acetabular and proximal femoral deformities. Presentation of case A 59-year-old male patient underwent a total hip arthroplasty for the treatment of end-stage dysplastic osteoarthritis. A roof reinforcement ring, a cemented polyethylene cup, and a cementless stem were used. A portion of the superior rim of the ring was uncovered by the host bone. Morsellized autogenous femoral-head graft was impacted to fill the space between the superior rim of the ring and the superior part of the dysplastic acetabulum. At the follow-up after 5-years, the patient had no complaints and was very satisfied with the operation result. The hip radiograph revealed no signs of instability of the acetabular component, and no bone graft resorption. Discussion Favorable results were described using metal rings and conical femoral stems for the treatment of the developmental dysplasia of the hip. The superior rim of the metal ring should be against host bone for 60% of its support. Despite the suboptimal implantation of the ring compromising, apparently, mechanical stability of the arthroplasty, the outcome was favorable. Conclusion This result can be supported by the good fixation of the metal ring to the pelvis with screws, the adequate orientation of both components of the total hip arthroplasty, and the bone graft incorporation. PMID:26453941
Scientific evaluation of spinal implants: an ethical necessity.
Moojen, Wouter A; Bredenoord, Annelien L; Viergever, Roderik F; Peul, Wilco C
The clinical introduction of novel medical devices often occurs without evidence of good methodological quality and with relatively little oversight and regulation. As a consequence, the safety, efficacy, and long-term effects of devices are frequently insufficiently known upon device approval. Recent controversies surrounding the Poly Implant Prothèse (PIP) breast implants, metal-on-metal hip implants, and interspinous implants underscore the need to reconsider how innovation in medical devices can adhere to sound ethical standards without inhibiting surgical research and development. In this article, the introduction of spinal implants is taken as an example to firstly discuss the scientific and ethical challenges of developing, testing, and introducing novel medical devices and to secondly identify avenues for improving the existing regulatory frameworks for such innovation. Two measures for improvement are most feasible in the short term: demanding prospective studies before device introduction and developing registries to monitor and evaluate new medical devices. Level of evidence: 5. PMID:25514748
Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty
Anwander, H.; Cron, G. O.; Rakhra, K.
Objectives Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. Methods In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters. Results There was no significant difference between the two bearing types with both genders combined. However, dividing patients by THA bearing and gender, women with MoM bearings had the highest Ktrans values, exceeding those of women with MoP bearings (0.067 min−1 versus 0.053 min−1; p-value < 0.05) and men with MoM bearings (0.067 min−1 versus 0.034 min−1; p-value < 0.001). Considering only the men, patients with MoM bearings had lower Ktrans than those with MoP bearings (0.034 min−1 versus 0.046 min−1; p < 0.05). Conclusion DCE-MRI is feasible to perform in tissues surrounding THA. Females with MoM THA show high Ktrans values in DCE-MRI, suggesting altered tissue perfusion kinematics which may reflect relatively greater inflammation. Cite this article: Dr P. E. Beaule. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot stud. Bone Joint Res 2016;5:73–79. DOI: 10
Stabilising effect of dynamic interspinous spacers in degenerative low-grade lumbar instability.
Holinka, Johannes; Krepler, Petra; Matzner, Michael; Grohs, Josef G
The aim of the study was to investigate the stabilising effect of dynamic interspinous spacers (IS) in combination with interlaminar decompression in degenerative low-grade lumbar instability with lumbar spinal stenosis and to compare its clinical effect to patients with lumbar spinal stenosis in stable segments treated by interlaminar decompression only. Fifty consecutive patients with a minimum age of 60 years were scheduled for interlaminar decompression for clinically and radiologically confirmed lumbar spinal stenosis. Twenty-two of these patients (group DS) with concomitant degenerative low-grade lumbar instability up to 5 mm translational slip were treated by interlaminar decompression and additional dynamic IS implantation. The control group (D) with lumbar spinal stenosis in stable segments included 28 patients and underwent only interlaminar decompression. The mean follow-up was 46 months in group D and 44 months in group DS. A visual analogue scale (VAS), Oswestry Disability Index (ODI) and walking distance were evaluated pre- and postoperatively. The segmental instability was evaluated in flexion-extension X-rays. The implantation of an IS significantly reduced the lumbar instability on flexion-extension X-rays. At the time of follow-up walking distance, VAS and ODI showed a significant improvement in both groups, but no statistical significance between groups D and DS. Four patients each in groups D and DS had revision surgery during the period of evaluation. The stabilising effect of dynamic IS in combination with interlaminar decompression offers an opportunity for an effective treatment for degenerative low-grade lumbar instability with lumbar spinal stenosis. PMID:20419452
In-vivo degradation of poly(carbonate-urethane) based spine implants
Cipriani, E.; Bracco, P.; Kurtz, S.M.; Costa, L.; Zanetti, M.
Fourteen explanted Dynesys® spinal devices were analyzed for biostability and compared with a reference, never implanted, control. Both poly(carbonate-urethane) (PCU) spacers and polyethylene-terephthalate (PET) cords were analyzed. The effect of implantation was evaluated through the observation of physical alterations of the device surfaces, evaluation of the chemical degradation and fluids absorption on the devices and examination of the morphological and mechanical features. PCU spacers exhibited a variety of surface damage mechanisms, the most significant being abrasion and localized, microscopic surface cracks. Evidence of oxidation and chain scission were detected on PCU spacers ATR–FTIR. ATR–FTIR, DSC and hardness measurements also showed a slight heterogeneity in the composition of PCU. The extraction carried out on the PCU spacers revealed the presence of extractable polycarbonate segments. One spacer and all PET cords visually exhibited the presence of adherent biological material (proteins), confirmed by the ATR–FTIR results. GC/MS analyses of the extracts from PET cords revealed the presence of biological fluids residues, mainly cholesterol derivatives and fatty acids, probably trapped into the fiber network. No further chemical alterations were observed on the PET cords. Although the observed physical and chemical damage can be considered superficial, greater attention must be paid to the chemical degradation mechanisms of PCU and to the effect of byproducts on the body. PMID:24043907
Evaluation of the patient with hip pain.
Wilson, John J; Furukawa, Masaru
Hip pain is a common and disabling condition that affects patients of all ages. The differential diagnosis of hip pain is broad, presenting a diagnostic challenge. Patients often express that their hip pain is localized to one of three anatomic regions: the anterior hip and groin, the posterior hip and buttock, or the lateral hip. Anterior hip and groin pain is commonly associated with intra-articular pathology, such as osteoarthritis and hip labral tears. Posterior hip pain is associated with piriformis syndrome, sacroiliac joint dysfunction, lumbar radiculopathy, and less commonly ischiofemoral impingement and vascular claudication. Lateral hip pain occurs with greater trochanteric pain syndrome. Clinical examination tests, although helpful, are not highly sensitive or specific for most diagnoses; however, a rational approach to the hip examination can be used. Radiography should be performed if acute fracture, dislocations, or stress fractures are suspected. Initial plain radiography of the hip should include an anteroposterior view of the pelvis and frog-leg lateral view of the symptomatic hip. Magnetic resonance imaging should be performed if the history and plain radiograph results are not diagnostic. Magnetic resonance imaging is valuable for the detection of occult traumatic fractures, stress fractures, and osteonecrosis of the femoral head. Magnetic resonance arthrography is the diagnostic test of choice for labral tears. PMID:24444505
Alumina-on-alumina total hip prostheses in patients 40 years of age or younger.
Bizot, P; Banallec, L; Sedel, L; Nizard, R
To avoid the consequences of polyethylene wear in a high-risk population, 128 alumina-on-alumina total hip arthroplasties have been done in 104 consecutive patients. The maximum age of patients was 40 years. The main preoperative diagnoses were osteonecrosis and sequellae of congenital hip dislocation (71% of the hips). The same titanium alloy cemented stem was implanted in all of the hips. Four types of alumina acetabular component fixations were used: a cemented plain alumina socket (41 hips), a screw-in ring with an alumina insert (22 hips), a press-fit plain alumina socket (32 hips), and a press-fit titanium metal back with an alumina insert (33 hips). Eight patients (11 hips) died during the followup period. Sixteen revisions have been documented, 12 for acetabular aseptic loosening, three for bipolar loosening (two of which were septic), and one for unexplained pain. Eighty-eight hips in 74 patients have been followed up radiologically for 2 to 22 years. Wear was unmeasurable. Four additional sockets showed definite migration. The respective survival rates after 7 years were 94.1% for the cemented cup, 88.8% for the screw-in ring, 95.1% for cementless press-fit plain alumina socket and 94.3% for the metal-back press-fit component. The 10-year survival rate was 90.4% for the cemented socket and 88.8% for the screw-in ring. The 15-year survival rate was 78.9% for the cemented socket. Grafting was the only prognostic factor, with a survival rate of 62.6% after 10 years for the hips with a bone graft and of 90.1% for hips without a graft. The alumina-on-alumina bearing surfaces seem to be a valuable alternative to the standard metal-on-polyethylene system for young patients. However, an improvement in socket fixation is required to lengthen the life span of the prosthesis to match the life expectancy of this demanding population. PMID:11039794
Neonatal Incidence of Hip Dysplasia
Peled, Eli; Eidelman, Mark; Katzman, Alexander
The advantages of sonographic examination are well known, but its main disadvantage is that it might lead to overdiagnosis, which might cause overtreatment. Variations in the incidence of developmental dysplasia of the hip are well known. We ascertained the incidence of neonatal sonographic developmental dysplasia of the hip without considering the development of those joints during followup. All 45,497 neonates (90,994 hips) born in our institute between January 1992 and December 2001 were examined clinically and sonographically during the first 48 hours of life. Sonography was performed according to Graf's method, which considers mild hip sonographic abnormalities as Type IIa. We evaluated the different severity type incidence pattern and its influence on the total incidence during and between the investigated years. According to our study, sonographic Type IIa has major effects on the incidence of overall developmental dysplasia of the hip with a correlation coefficient of 0.95, whereas more severe sonographic abnormalities show relatively stable incidence patterns. Level of Evidence: Level I, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18288551
Alternative process for thin layer etching: Application to nitride spacer etching stopping on silicon germanium
Posseme, N. Pollet, O.; Barnola, S.
Silicon nitride spacer etching realization is considered today as one of the most challenging of the etch process for the new devices realization. For this step, the atomic etch precision to stop on silicon or silicon germanium with a perfect anisotropy (no foot formation) is required. The situation is that none of the current plasma technologies can meet all these requirements. To overcome these issues and meet the highly complex requirements imposed by device fabrication processes, we recently proposed an alternative etching process to the current plasma etch chemistries. This process is based on thin film modification by light ions implantation followed by a selective removal of the modified layer with respect to the non-modified material. In this Letter, we demonstrate the benefit of this alternative etch method in term of film damage control (silicon germanium recess obtained is less than 6 A), anisotropy (no foot formation), and its compatibility with other integration steps like epitaxial. The etch mechanisms of this approach are also addressed.
[Total hip replacement with isoelastic prosthesis in animals (author's transl)].
Muhr, O; Stockhusen, H; Müller, O
Uncemented fixation and low-fraction materials are the basis of this experiment. Plastics with an elasticity similar to the bone ("isoelasticity") show very propitious material qualities. The direct cementless incorporation of test bodies must be checked. In 63 sheep isoelastic total hip joints were implanted. After 2 till 51 weeks the animals were sacrificed and 44 specimen of hips and organs were explored macroscopically, radiologically, spherimetrically and histologically. The result was: 1. Plastic hip prosthesis are incorporated in the bone, but the boundary layer is built by a collagenous fiber tissue. 2. Loosening brings resoption of the bone and expansion of the structural changed soft tissue. 3. The transformation of the femoral cortex to osteoporosis is considered possibly as the consequence of an insufficient biological transfer of the weight. 4. Fractures of the femoral prosthesis-stem could not be observed. 5. The radiology allows at the pelvis prosthesis a concret statement concerning stability, on the femoral part a probable one. 6. The abrasion is minimal, the tissue reaction to abrasion products is unessential. 7. Small abrasion particles are carried of by the lymph tract and stored in the first regional gland. A more distant spreading is not demonstrable. PMID:985179
Basic Science Considerations in Primary Total Hip Replacement Arthroplasty
Mirza, Saqeb B; Dunlop, Douglas G; Panesar, Sukhmeet S; Naqvi, Syed G; Gangoo, Shafat; Salih, Saif
Total Hip Replacement is one of the most common operations performed in the developed world today. An increasingly ageing population means that the numbers of people undergoing this operation is set to rise. There are a numerous number of prosthesis on the market and it is often difficult to choose between them. It is therefore necessary to have a good understanding of the basic scientific principles in Total Hip Replacement and the evidence base underpinning them. This paper reviews the relevant anatomical and biomechanical principles in THA. It goes on to elaborate on the structural properties of materials used in modern implants and looks at the evidence base for different types of fixation including cemented and uncemented components. Modern bearing surfaces are discussed in addition to the scientific basis of various surface engineering modifications in THA prostheses. The basic science considerations in component alignment and abductor tension are also discussed. A brief discussion on modular and custom designs of THR is also included. This article reviews basic science concepts and the rationale underpinning the use of the femoral and acetabular component in total hip replacement. PMID:20582240
In vivo biostability of polymeric spine implants: retrieval analyses from a United States investigational device exemption study.
Shen, Ming; Zhang, Kai; Koettig, Petra; Welch, William C; Dawson, John M
The Dynesys System for stabilizing the lumbar spine was first surgically implanted in Europe in 1994. In 2003, a prospective, randomized, investigational device exemption clinical trial of the system for non-fusion dynamic stabilization began. Polycarbonate urethane (PCU) and polyethylene terephthalate (PET) components explanted from four patients who had participated in the study were analyzed for biostability. Components had been implanted 9-19 months. The explanted components were visually inspected and digitally photographed. Scanning electron microscopy was used to analyze the surface of the spacers. The chemical and molecular properties of the retrieved spacers and cords were quantitatively compared with lot-matched, shelf-aged, components that had not been implanted using attenuated total reflection Fourier transform infrared (FTIR) and gel permeation chromatography (GPC). FTIR analyses suggested that the explanted spacers exhibited slight surface chemical changes but were chemically unchanged below the surface and in the center. New peaks that could be attributed to biodegradation of PCU were not observed. The spectral analyses for the cords revealed that the PET cords were chemically unchanged at both the surface and the interior. Peaks associated with the PET biodegradation were not detected. GPC results did not identify changes to the distributions of molecular weights that might be attributed to biodegradation of either PCU spacers or PET cords. The explanted condition of the retrieved components demonstrated the biostability of both PCU spacers and PET cords that had been in vivo for up to 19 months. PMID:21538208
Characterization of wear in composite material orthopaedic implants. Part II: The implant/bone interface.
Albert, K; Schledjewski, R; Harbaugh, M; Bleser, S; Jamison, R; Friedrich, K
Carbon fiber/PEEK polymer (C/PEEK) composite materials are being developed for use as orthopaedic implant materials. Wear is an issue of increasing importance in orthopaedic implants; particulate debris generated by the wearing of biomaterials may be a causal factor leading to osteolysis and implant loosening. Therefore, numerical and experimental studies were completed to characterize the wear of C/PEEK composite materials in comparison to current orthopaedic implant materials. Finite element analyses (FEA) of a composite material hip stem implanted in a femur and loaded at 890 N determined that peak contact stresses will occur at the proximal-medial and distal regions of the implant. These contact stresses were found to be below 1.0 MPa over most of the implant surface; however the peak stress in the proximal-medial region was 1.8 MPa and higher still at the distal portion of the stem. In vivo forces result in contact stress values up to 9.0 MPa. The composite implant exhibited 10-40% lower contact stresses in the distal region compared to a titanium-alloy implant of identical design. Composite material wear samples were slid against porous hydroxylapatite (HA) to simulate the stem/bone interface. An identical series of experiments was run for comparison to a current orthopaedic implant material--Ti6A14V titanium alloy. Two domains of motion were studied; a composite ring-on-HA disc large amplitude sliding wear test; and a composite pin-on-HA disc small amplitude fretting regimen. Nominal contact pressures during testing were 1.4 MPa and 7.6 MPa for sliding and fretting tests, respectively. Fretting and sliding abrasive wear tests resulted in the composite material exhibiting a lower wear rate than the titanium-alloy. The magnitude of the difference was greatly dependent on the contact pressures, sliding amplitudes, and counterface material properties. PMID:7950869
Effect of component design in retrieved bipolar hip hemiarthroplasty systems.
Hess, Matthew D; Baker, Erin A; Salisbury, Meagan R; Kaplan, Lige M; Greene, Ryan T; Greene, Perry W
Primary articulation of bipolar hemiarthroplasty systems is at the femoral head-liner interface. The purpose of this study was to compare observed damage modes on 36 retrieved bipolar systems with implant, demographic, intraoperative, and radiographic data to elucidate the effects of component design, specifically locking mechanism, on clinical performance. Retrieved bipolar hip hemiarthroplasty systems of 3 different design types were obtained, disassembled, and evaluated macro- and microscopically for varying modes of wear, including abrasion, burnishing, embedding, scratching, and pitting. Clinical record review and radiographic analysis were performed by a senior orthopedic surgery resident. Average bipolar hip hemiarthroplasty system term of service was 46 months (range, 0.27-187 months). All devices contained wear debris captured within the articulating space between the femoral head and liner. In 31% of patients without infection, lucency was observed on immediate prerevision radiographs. The system with a leaf locking mechanism showed significantly increased radiographically observed osteolysis (P=.03) compared with a system with a stopper ring locking mechanism. In addition, implant design and observed damage modes, including pitting and third-body particle embedding, were significantly associated with radiographically observed osteolysis. PMID:24025011
Hip replacement in femoral head osteonecrosis: current concepts
Scaglione, Michelangelo; Fabbri, Luca; Celli, Fabio; Casella, Francesco; Guido, Giulio
Summary Osteonecrosis of the femoral head is a destructive disease that usually affects young adults with high functional demands and can have devastating effects on hip joint. The treatment depends on extent and location of the necrosis lesion and on patient's factors, that suggest disease progression, collapse probability and also implants survival. Non-idiopathic osteonecrosis patients had the worst outcome. There is not a gold standard treatment and frequently it is necessary a multidisciplinary approach. Preservation procedures of the femoral head are the first choice and can be attempted in younger patients without head collapse. Replacement procedure remains the main treatment after failure of preserving procedures and in the late-stage ONFH, involving collapse of the femoral head and degenerative changes to the acetabulum. Resurfacing procedure still has good results but the patient selection is a critical factor. Total hip arthroplasties had historically poor results in patients with osteonecrosis. More recently, reports have shown excellent results, but implant longevity and following revisions are still outstanding problems. PMID:27134633
21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.
Code of Federal Regulations, 2010 CFR
... uncemented prosthesis. 888.3360 Section 888.3360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...
21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.
Code of Federal Regulations, 2011 CFR
... uncemented prosthesis. 888.3360 Section 888.3360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...
Deciding to have knee or hip replacement
... patientinstructions/000368.htm Deciding to have knee or hip replacement To use the sharing features on this page, ... make a decision. Who Benefits From Knee or hip Replacement Surgery? The most common reason to have a ...
Risks of hip and knee replacement
... is normal to lose blood during and after hip or knee replacement surgery. Some people need a blood transfusion during ... clot form are higher during and soon after hip or knee replacement surgery. Sitting or lying down for long periods ...
[Ceramic-on-ceramic bearings in total hip arthroplasty (THA)].
Sentürk, U; Perka, C
The main reason for total hip arthroplasty (THA) revision is the wear-related aseptic loosening. Younger and active patients after total joint replacement create high demands, in particular, on the bearings. The progress, especially for alumina ceramic-on-ceramic bearings and mixed ceramics have solved many problems of the past and lead to good in vitro results. Modern ceramics (alumina or mixed ceramics containing alumina) are extremely hard, scratch-resistant, biocompatible, offer a low coefficient of friction, superior lubrication and have the lowest wear rates in comparison to all other bearings in THA. The disadvantage of ceramic is the risk of material failure, i.e., of ceramic fracture. The new generation of mixed ceramics (delta ceramic), has reduced the risk of head fractures to 0.03-0.05 %, but the risk for liner fractures remains unchanged at about 0.02 %. Assuming a non-impinging component implantation, ceramic-on-ceramic bearings have substantial advantages over all other bearings in THA. Due to the superior hardness, ceramic bearings produce less third body wear and are virtually impervious to damage from instruments during the implantation process. A specific complication for ceramic-on-ceramic bearings is "squeaking". The high rate of reported squeaking (0.45 to 10.7 %) highlights the importance of precise implant positioning and the stem and patient selection. With precise implant positioning this problem is rare with many implant designs and without clinical relevance. The improved tribology and the presumable resulting implant longevity make ceramic-on-ceramic the bearing of choice for young and active patients. PMID:25874400
Total Hip Arthroplasty around the Inception of the Interface Bioactive Bone Cement Technique
Oonishi, Hiroyuki; Kawahara, Ikuo
Background To augment cement-bone fixation, Dr. Hironobu Oonishi attempted additional physicochemical bonding through interposition of osteoconductive crystal hydroxyapatite (HA) granules at the cement-bone interface in 1982. He first used the interface bioactive bone cement (IBBC) technique in 12 selected patients (12 hips) in 1982 (first stage) and followed them for 2 years. In 1985, the technique was applied in 25 total hip arthroplasty (THA) patients (second stage) and the effects were investigated by comparing the side with the IBBC technique and the other side without the IBBC technique. He has employed this technique in all THA patients since 1987 (third stage). Methods In the IBBC technique, HA granules (2 to 3 g) were smeared on the bone surface just before the acetabular and femoral components were cemented. In the first stage, 12 hips were operated using the IBBC technique in 1982. In the second stage, THA was performed without the IBBC technique on one side and with the IBBC technique on the other side within 1 year in 25 patients. In the third stage, THA was performed with the IBBC technique in 285 hips in 1987. Results In the first stage patients, implant loosening was not detected at 30 years after operation. In the second stage patients, revision was required in 7 hips without the IBBC technique due to cup loosening (5 hips) and stem loosening (2 hips), whereas no hip was revised after THA with the IBBC technique at 26 years after operation. In the third stage patients, the incidence of radiolucent lines and osteolysis was very few at 25 years after operation. Conclusions The long-term follow-up of THA performed around the inception of the IBBC technique has revealed low incidences of radiolucent lines, osteolysis, and revision surgery. PMID:27583104
[Traumatic hip dislocation in childhood].
Stachel, P; Hofmann-v Kap-herr, S; Schild, H
The article reports on eight cases of traumatic dislocation of the hip in children. Six of these were genuine dislocations and two dislocation fractures. The children were between 5 and 13 years of age at the time of injury. Seven of these 8 children could be followed up one to 21 years after the accident. All 7 children were free from complaints at the time of follow-up examination; in one case only we found a moderate loss of function in the injured hip joint. In this patient the x-ray film showed deformation of the head of the femur after partial necrosis of the femoral head, as well as initial signs of coxarthrosis. Prognosis of this rare injury in children is favourable if repositioning is performed in time and if relief of the hip is effected for the proper period of time, depending on the individual case. PMID:2665382
Subspine Hip Impingement: An Unusual Cause of Hip Pain in an Elite Weightlifter.
Nabhan, Dustin C; Moreau, William J; McNamara, Shannen C; Briggs, Karen K; Philippon, Marc J
Anterior hip pain can be difficult to diagnose due to the many pathologies and overlapping pain patterns that exist in the hip region. Clinical findings of pain at the anterior inferior iliac spine with passive hip flexion, proximal quadriceps pain and weakness, and painful impingement tests of the hip may be indicative of subspine hip impingement. This report describes the diagnosis and treatment of anterior hip pain, including subspine impingement and femoroacetabular impingement in an elite weightlifter. This case also describes how with the correct diagnosis and treatment, the athlete returned to play to her previous level of sport 11 months after a complex hip injury. PMID:27618239
The use of hip arthroscopy in the management of the pediatric hip.
Roy, Dennis R
Arthroscopy of the pediatric hip began in 1977 with a publication by Gross. Interest was relatively slow to develop in the 1980s and 1990s. Coupled with the success of hip arthroscopy in the adult, interest heightened in applying the procedure to a variety of pediatric hip disorders, given that the alternative was an open surgical hip dislocation. The success of this initial group of pediatric hip arthroscopist's has further expanded the application of hip arthroscopy as the primary or adjunct procedure for the management of intra-articular problems of the pediatric hip. PMID:27583144
The use of hip arthroscopy in the management of the pediatric hip
Roy, Dennis R.
Arthroscopy of the pediatric hip began in 1977 with a publication by Gross. Interest was relatively slow to develop in the 1980s and 1990s. Coupled with the success of hip arthroscopy in the adult, interest heightened in applying the procedure to a variety of pediatric hip disorders, given that the alternative was an open surgical hip dislocation. The success of this initial group of pediatric hip arthroscopist's has further expanded the application of hip arthroscopy as the primary or adjunct procedure for the management of intra-articular problems of the pediatric hip. PMID:27583144
Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants.
Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark
Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform. PMID:27069363
Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants
Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark
Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform. PMID:27069363
Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?
Mason, James; Baker, Paul; Gregg, Paul J; Porter, Martyn; Deehan, David J; Reed, Mike R
Background and purpose The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. Methods We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. Results In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. Interpretation In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients. PMID:25285617
Femoral head diameter considerations for primary total hip arthroplasty.
Girard, J
The configuration of total hip arthroplasty (THA) implants has constantly evolved since they were first introduced. One of the key components of THA design is the diameter of the prosthetic femoral head. It has been well established that the risk of dislocation is lower as the head diameter increases. But head diameter impacts other variables beyond joint stability: wear, cam-type impingement, range of motion, restoration of biomechanics, proprioception and groin pain. The introduction of highly cross-linked polyethylene and hard-on-hard bearings has allowed surgeons to implant large-diameter heads that almost completely eliminate the risk of dislocation. But as a result, cup liners have become thinner. With femoral head diameters up to 36 mm, the improvement in joint range of motion, delay in cam-type impingement and reduction in dislocation risk have been clearly demonstrated. Conversely, large-diameter heads do not provide any additional improvements. If an "ecologically sound" approach to hip replacement is embraced (e.g. keeping the native femoral head diameter), hip resurfacing with a metal-on-metal bearing must be carried out. The reliability of large-diameter femoral heads in the longer term is questionable. Large-diameter ceramic-on-ceramic bearings may be plagued by the same problems as metal-on-metal bearings: groin pain, squeaking, increased stiffness, irregular lubrication, acetabular loosening and notable friction at the Morse taper. These possibilities require us to be extra careful when using femoral heads with a diameter greater than 36 mm. PMID:25596984
Bone sarcoma diagnosed at the time of reconstructive hip surgery
Dowdy, Paul A.; Griffin, Anthony M.; White, Lawrence M.; Wunder, Jay S.; Bell, Robert S.
Objective To describe the clinical course of a group of patients in whom sarcoma of the proximal femur was diagnosed at the time of reconstructive hip surgery. Design A retrospective case series. Setting Final management of all patients took place at a tertiary care centre. Patients and Interventions Six consecutive patients with sarcoma of the proximal femur diagnosed at the time of reconstructive hip surgery. The mistaken diagnoses made before surgery were benign tumour (2 patients), avascular necrosis (2 patients), subtrochanteric fracture due to metastasis (1 patient) and granuloma from a loose hip implant (1 patient). The final diagnosis was osteosarcoma in 3 patients and chondrosarcoma in 3. Three patients with high-grade sarcoma received neoadjuvant chemotherapy followed by femoral or pelvic resection, or both, and reconstruction. Two patients with chondrosarcoma underwent wide excision of the tumour with allograft or modular implant reconstruction. One patient with widespread metastasis received only palliative chemotherapy. Main outcome measures Overall survival with respect to oncologic and functional results of treatment. Results Two patients (1 who received only palliative chemotherapy) died after 5 and 21 months' follow-up, respectively. Average follow-up for the remaining 4 patients was 65.2 months (range from 51 to 75 months). They were disease free at latest follow-up. One patient required amputation for septic complications related to the reconstruction. Conclusions Limb salvage surgery for sarcoma of the proximal femur is challenging when the diagnosis is made at the time of reconstructive surgery rather than through an appropriately planned biopsy. However, this series suggests that limb preservation is feasible and that hindquarter amputation is not the only solution. PMID:9711160
Spontaneous modular femoral head dissociation complicating total hip arthroplasty.
Talmo, Carl T; Sharp, Kinzie G; Malinowska, Magdalena; Bono, James V; Ward, Daniel M; LaReau, Justin
Modular femoral heads have been used successfully for many years in total hip arthroplasty. Few complications have been reported for the modular Morse taper connection between the femoral head and trunnion of the stem in metal-on-polyethylene bearings. Although there has always been some concern over the potential for fretting, corrosion, and generation of particulate debris at the modular junction, this was not considered a significant clinical problem. More recently, concern has increased because fretting and corrosive debris have resulted in rare cases of pain, adverse local tissue reaction, pseudotumor, and osteolysis. Larger femoral heads, which have gained popularity in total hip arthroplasty, are suspected to increase the potential for local and systemic complications of fretting, corrosion, and generation of metal ions because of greater torque at the modular junction. A less common complication is dissociation of the modular femoral heads. Morse taper dissociation has been reported in the literature, mainly in association with a traumatic event, such as closed reduction of a dislocation or fatigue fracture of the femoral neck of a prosthesis. This report describes 3 cases of spontaneous dissociation of the modular prosthetic femoral head from the trunnion of the same tapered titanium stem because of fretting and wear of the Morse taper in a metal-on-polyethylene bearing. Continued clinical and scientific research on Morse taper junctions is warranted to identify and prioritize implant and surgical factors that lead to this and other types of trunnion failure to minimize complications associated with Morse taper junctions as hip implants and surgical techniques continue to evolve. PMID:24972443
Ion implantation and laser annealing
NASA Astrophysics Data System (ADS)
Three ion implantation and laser annealing projects have been performed by ORNL through the DOE sponsored Seed Money Program. The research has contributed toward improving the characteristics of wear, hardness, and corrosion resistance of some metals and ceramics, as well as the electrical properties of semiconductors. The work has helped to spawn related research, at ORNL and elsewhere, concerning the relationships between microstructure and materials properties. ORNL research has resulted in major advances in extended life and non-corrosive artificial joints (hip and knee), high performance semiconductors, failure resistant ceramics (with potential energy applications), and solar cells. The success of the seed money projects was instrumental in the formation of ORNL's Surface Modification and Characterization Facility (SMAC). More than 60 universities and companies have participated in SMAC programs.
[Hip fracture: call the geriatrician? ].
Coutaz, M
Hip fracture management by the geriatrician demands a close cooperation with orthopedic surgeons and a interdisciplinary approach with the implementation of protocole-driven care to standardize the care of most patients. From admission to discharge this orthogeriatric management is based on the comprehensive geriatric assessment to reduce the delays in surgery, the occurence of delirium or the most postoperative complications. This collaborative model of care seems to have the potential to improve function, admissions to nursing homes and mortality outcomes compared with usual care of geriatric patient with hip fracture. PMID:25536828
Hip-Hop and the Academic Canon
ERIC Educational Resources Information Center
Abe, Daudi
Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's…
Diagnosis of infected total hip arthroplasty.
Enayatollahi, Mohammad A; Parvizi, Javad
Despite the battery of available tests, the diagnosis of periprosthetic joint infection (PJI) remains a challenge. A comprehensive medical history and physical examination with appropriate radiographs followed by erythrocyte sedimentation rate and serum C-reactive protein are the first-line screening test for patients with suspected hip PJI. The second line of investigation of patients with abnormal serology or a strong suspicion for PJI, is joint aspiration. Aspirates should be sent for assessment of white blood cell count, polymorphonuclear percentage, leukocyte esterase strip test, and microbiology. If the first attempt fails, the joint should be re-aspirated at a different time. The International Consensus recommends against infiltration of saline or other fluids into a "dry" joint. In patients not planned for surgery but need further evaluation for PJI, a nuclear imaging study may help. In others with a planned revision surgery, intraoperative samples for frozen section and culture study are the best measures available. Treatment strategies for PJI are well established in the literature. Poor surgical candidates receive oral suppressive antibiotic therapy alone. Acute PJI, presenting within 4 weeks of the index surgery, or as a result of bacteraemia, may be treated with irrigation and debridement and implant retention. Chronic PJI, occurring more than 4 weeks after initial surgery, is treated with 1-stage or 2-stage revision arthroplasty. In some persistent infections or patients who refuse to undergo revision surgery, salvage procedures may be needed. PMID:26044538
Cement applicator use for hip resurfacing arthroplasty.
Jaeger, Sebastian; Rieger, Johannes S; Obermeyer, Beate; Klotz, Matthias C; Kretzer, J Philippe; Bitsch, Rudi G
We compared the manufacturer recommended cementing technique for a femoral hip resurfacing implant (BHR, S&N) to a newly designed cement applicator on 20 porous carbon foam specimens. Substantial design changes and improvements of the cement applicator were necessary: The diameter and number of the cement escaping holes at the top of the applicator were optimized for medium viscosity cement. It was necessary to add four separate air inlet holes with large diameters. The inner shape of the applicator had to be adapted to the BHR design with a circular extending chamfer in the proximal region, a parallel inner wall and a second chamfer distally. The interface temperatures showed no risk for heat necrosis using both techniques. The cement penetration depth was more uniform and significantly reduced for the applicator cementing technique (4.34 ± 1.42 mm, 6.42 ± 0.43 mm, p = 0.001). The cement-applicator showed no cement defects compared to a large defect length (0.0 ± 0.0 mm, 10.36 ± 1.10 mm, p < 0.001) with the manufacturer recommended cementing technique. The cement applicator technique appears to be effective for a homogenous cement distribution without cement defects and safe with a lower risk of polar over-penetration. PMID:25772262
Musculoskeletal-based finite element analysis of femur after total hip replacement.
Meena, Vijay K; Kumar, Mohit; Pundir, Amit; Singh, Suman; Goni, Vijay; Kalra, Parveen; Sinha, Ravindra K
This article evaluates the effect of stress variation on adult femur following total hip replacement using musculoskeletal-based finite element analysis. The aim was to study the changes in stress distribution in the femur after total hip replacement by providing simulated in vivo loading and boundary conditions. The loading and boundary conditions were generated using a musculoskeletal modelling software 'AnyBody' and were applied on femur model, generated from the computed tomography (CT) scan data for standing posture of male patient. The results showed considerable variation in stress distribution pattern in the femur before and after total hip replacement, the metallic implant taking major loads of human body and transferring very less loads to the femur. PMID:27006421
MODULUS Stem for Developmental Hip Dysplasia: Long-term Follow-up.
Benazzo, Francesco M; Piovani, Lucio; Combi, Alberto; Perticarini, Loris
Between October 2001 and December 2010, 143 patients with developmental dysplasia underwent hip arthroplasty surgery using a conical stem with modular necks (MODULUS system, Lima Corporate, Villanova di San Daniele del Friuli, Italy). Thirty (21.0%) patients had both hips replaced, for a total of 173 implants. The mean age at the time of surgery was 55 years (range: 22-81 years). The mean follow-up was 87 months (range: 36-146 months); average Harris Hip Score increased from 42 (range: 23-65) preoperatively to 92 (range: 76-100) at the last follow-up. Stem revision was required in two cases. The MODULUS stem showed good long-term clinical and radiographic results, with a Kaplan-Meier survivorship of 97.6% (95% CI: 94.8-100.0%) at 8 years. PMID:25980775
Failure of a novel ceramic-on-ceramic hip resurfacing prosthesis.
Matharu, Gulraj S; Daniel, Joseph; Ziaee, Hena; McMinn, Derek J W
We report the early failure of five ceramic-on-ceramic hip resurfacings (CoCHRs). The ceramic used for the acetabular liner was a novel ceramic-composite (two thirds polyurethane and one third alumina ceramic). All cases were revised for increasing metal ion levels (blood cobalt 3.93-208.0 μg/l and chromium 1.57-17.5 μg/l) due to ceramic liner fracture and/or accelerated wear of the ceramic femoral head coating. Patients underwent bearing exchange and revision using primary hip arthroplasty implants at a mean of 3.0 years following CoCHR. Intraoperatively all patients had metallosis. At 1 to 2 years of follow-up blood metal ions normalized with no complications. We do not recommend this particular type of ceramic-on-ceramic bearing for hip resurfacing. PMID:25453631
Aggregation behavior of a gemini surfactant with a tripeptide spacer.
Wang, Meina; Han, Yuchun; Qiao, Fulin; Wang, Yilin
A peptide gemini surfactant, 12-G(NH2)LG(NH2)-12, has been constructed with two dodecyl chains separately attached to the two terminals of a glutamic acid-lysine-glutamic acid peptide and the aggregation behavior of the surfactant was studied in aqueous solution. The 12-G(NH2)LG(NH2)-12 molecules form fiber-like precipitates around pH 7.0, and the precipitation range is widened on increasing the concentration. At pHs 3.0 and 11.0, 12-G(NH2)LG(NH2)-12 forms soluble aggregates because each molecule carries two positively charged amino groups at the two ends of the peptide spacer at pH 3.0, while each molecule carries one negatively charged carboxyl group in the middle of the peptide spacer at pH 11.0. 12-G(NH2)LG(NH2)-12 displays a similar concentration-dependent process at these two pHs: forming small micelles above the critical micelle concentration and transferring to fibers at pH 3.0 or twisted ribbons at pH 11.0 above the second critical concentration. The fibers formed at pH 3.0 tend to aggregate into bundles with twisted structure. Both the twisted fibers at pH 3.0 and the twisted ribbons at pH 11.0 contain β-sheet structure formed by the peptide spacer. PMID:25588349
An analysis of screw fixation of the femoral component in cementless hip arthroplasty.
Martin, J W; Sugiyama, H; Kaiser, A D; Van Hoech, J; Whiteside, L A
A cementless hip stem that allows screw fixation of the collar to cortical bone in the calcar region was found to achieve enhanced rotational stability when implanted in preserved cadaveric human femora. Although the implants with screws showed less tendency for subsidence than the implants without screws, rotational micromotion was not found to be statistically different under light loading conditions. When implanted in composite bone, the addition of screws in the configuration tested was associated with significant metal-on-metal wear during combined compression and rotational cyclic loading. This finding is of concern due to potential wear particle toxicity and possible lowered fatigue life of the prosthesis. Therefore, specific design changes are recommended. PMID:2243211
Possibility of one-stage surgery to reconstruct bone defects using the modified Masquelet technique with degradable calcium sulfate as a cement spacer: A case report and hypothesis
In addition to autologous bone graft, vascularized fibular autograft and Ilizarov bone transfer, the Masquelet technique is another effective method to reconstruct bone defects. This technique was initially proposed in 1986 and consists of two stages. At the first stage, radical debridement is required and subsequently, a polymethylmethacrylate (PMMA) cement spacer is implanted at the site of the bone defects. At the second stage, when the PMMA-induced membrane is formed 6–8 weeks later, the cement spacer is carefully removed in order to not disturb the induced membrane and the bone graft is performed to fill the bone defects. Although this technique has resulted in satisfactory outcomes in the reconstruction of bone defects, the PMMA spacer used to induce membrane is not degradable and requires surgical removal. In recent years, calcium sulfate has been used as a localized antibiotic delivery vehicle and bone substitute due to its superiorities over PMMA, particularly its completely degradable nature. The present study identified that calcium sulfate can also induce the formation of a membrane. In addition, we hypothesized that the degradability of calcium sulfate may allow one-stage reconstruction of bone defects. The current study presents a clinical case report and review of the literature. PMID:26998279
Enhancing Asthma Medication Delivery: Spacers and Valved Holding Chambers.
Schoessler, Sally; Winders, Tonya
Asthma is one of the most prevalent chronic diseases managed by school nurses, and its management often includes the administration of bronchodilators delivered via a metered dose inhaler (MDI). The use of an MDI requires coordination and mastery of steps that must be performed correctly and in the proper order. These steps are greatly enhanced, especially in the pediatric population, through the use of medical devices-spacers and valved holding chambers. The purpose of this article is to review the rationale and implications for the use of these devices in the school setting. PMID:27194239
Contact pressures in the human hip joint measured in vivo.
Hodge, W A; Fijan, R S; Carlson, K L; Burgess, R G; Harris, W H; Mann, R W
The pressures on human articular cartilage have been measured in vivo. An instrumented femoral head prosthesis that telemeters interarticular pressure at 10 discrete locations 253 times per second was implanted in apposition to natural acetabular cartilage. Data were acquired during surgery, recovery, rehabilitation, and normal activity, for longer than 1 year after surgery. Pressure magnitudes were synchronized with body-segment kinematic data and foot-floor force measurements so as to locate transduced pressure areas on the natural acetabulum and correlate movement kinematics and dynamics with local cartilage pressures. The data reveal very high local (up to 18 MPa) and nonuniform pressures, with abrupt spatial and temporal gradients, that correlate well both in magnitude and distribution with in vitro data and computer simulations of synovial joint mechanics. Peak pressures in vivo are, however, considerably higher than pressures measured in vitro under the putative forces experienced by the joint in life, particularly in normal movements where cocontraction occurs in agonist and antagonist muscles across the hip joint. Thus, extant gait-analysis studies which apply inverse Newtonian calculations to infer joint forces establish the lower limit on such forces, since such analyses include only the net muscular torques about the joint and cannot account for the contribution of the increment in joint force due to muscular cocontraction. Our data also contribute to the understanding of normal synovial joint tribology and the possible role of mechanical factors in the deterioration evident in osteoarthritis. Further, design criteria for both partial and total hip replacement prostheses and specific aspects of rehabilitation protocols following hip surgery (e.g., the extent to which crutches and canes unload the hip joint) warrant reconsideration in light of the extraordinary high pressures measured during the activities of daily living. Images PMID:3458248
Soft-tissue balance in short and straight stem total hip arthroplasty.
Windhagen, Henning; Chincisan, Andra; Choi, Hon Fai; Thorey, Fritz
The growing numbers of short stem hip implants have redefined total hip arthroplasty with new stem geometries and possible functional differences. Several systematic reviews have reported good clinical results with this new class of stems, although kinematic alterations are still unclear in many aspects. The good clinical results obtained at the authors' institution led to the current study. The authors hypothesized that the geometric alignment of the prosthetic components may be closer to the anatomy of the healthy hip joint, thus leading to better function and clinical satisfaction. An examination via finite element analysis was chosen to model the hip joint and virtually implant a short and a standard straight stem. Findings indicated that anchoring of the short stem allowed favorable positioning in the proximal femur, with the femoral head already in the center of the cup. This positioning was not possible for the straight stem, which required further reduction of the femur by a significant translation into the cup, leading to abnormal soft-tissue balancing. The results from the simulation showed an absolute average deviation of ligamentous fiber strains of 6% for the short stem in 30° of flexion and extension versus 29% and 36% for the standard straight stem in 30° of flexion and extension, respectively. A femoral neck guided orientation of the short stem implant seems to allow a more anatomical reconstruction and thus a more balanced hip in terms of the modeled soft tissues. In contrast, the straight stem alters the head position and induces nonphysiological capsular strains. PMID:25826627
Simulation of Anti-Galloping Effects of Phase-to-Phase Spacers in Transmission Line
NASA Astrophysics Data System (ADS)
Liu, Chao-Qun; Chen, Hua-Ling; Liu, Bin; Liu, Cao-Lan; Sun, Na; Yang, Jia-Lun
Currently, the application of phase-to-phase spacers can effectively prevent and control line faults caused by conductor galloping and is one of the most effective methods to prevent galloping of transmission lines. The installation layout scheme of phase-to-phase spacers directly affects the anti-galloping effect. Moreover, the common empirical formula can not accurately assess the anti-galloping effect of phase-to-phase spacers. In this paper, the nonlinear finite element method is employed to establish an accurate analysis model of phase-to-phase spacers for conductors. And the anti-galloping effects of phase-to-phase spacers installed in different ways are analyzed, with the aim of providing an effective method for the installation of phase-to-phase spacers used in practical transmission lines.
Intraoperative measurement of rotational stability of femoral components of total hip arthroplasty.
Harris, W H; Mulroy, R D; Maloney, W J; Burke, D W; Chandler, H P; Zalenski, E B
High out-of-plane forces acting on the hip joint can produce important rotational micromotion of the femoral component. This micromotion at the prosthesis interface may be detrimental to the stability of the implant. In cementless femoral implants this could prevent bone ingrowth, and in the cemented component this could cause generation of particulate debris, lysis, and loosening. The introduction of the torque wrench micrometer for assessment of intraoperative femoral component stability can quantify the initial stability of primary cementless femoral components and critically evaluate the stability (at either the initial or revision arthroplasty) of both cemented and cementless femoral components. It allows the surgeon to produce a known torque in the direction and magnitude of the out-of-plane forces that load the hip in vivo. PMID:2019039
Molecular Mechanisms of HipA Mediated Multidrug Tolerance and its Neutralization by HipB
Schumacher, Maria A.; Piro, Kevin M.; Xu, Weijun; Hansen, Sonja; Lewis, Kim; Brennan, Richard G.
Summary Bacterial multidrug tolerance is largely responsible for the inability of antibiotics to eradicate infections and is caused by a small population of dormant bacteria called persisters. HipA is a critical Escherichia coli persistence factor that is normally neutralized by HipB, a transcription repressor, which also regulates hipBA expression. Here we report multiple structures of HipA and a HipA-HipB-DNA complex. HipA has a eukaryotic Ser/Thr kinase-like fold and can phosphorylate the translation factor, EF-Tu, suggesting a persistence mechanism via cell stasis. The HipA-HipB-DNA structure reveals the HipB-operator binding mechanism, ~70° DNA bending and unexpected HipA-DNA contacts. Dimeric HipB interacts with two HipA molecules to inhibit its kinase activity through sequestration and conformational inactivation. Combined, these studies suggest mechanisms for HipA-mediated persistence and its neutralization by HipB. PMID:19150849
Balancing innovation and medical device regulation: the case of modern metal-on-metal hip replacements.
Howard, Jason J
Due to problems with wear particle generation and subsequent loosening using conventional metal-on-polyethylene total hip replacements, there has been a shift toward alternative bearing systems, including metal-on-metal (MoM), for younger, more active patients with degenerative joint disease. Based on positive results from early short-term clinical studies, MoM hip replacements were readily adopted by orthopedic surgeons with thousands being implanted worldwide over the past decade. Unacceptably high revision rates reported by two national joint registries called into question the rigorousness of the regulatory approval process for these implants, particularly with respect to premarket data requirements to prove safety, effectiveness, and the appropriateness of the regulatory pathway chosen. The purpose of this review was to investigate the balance between facilitating the introduction of new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment. The case of MoM hip replacement devices was used to frame the investigation and subsequent discussions. The regulatory approval processes and post-market surveillance requirements associated with three common MoM hip replacements (two resurfacings: the Birmingham and articular surface replacement and the articular surface replacement XL total hip replacement) were investigated. With respect to modern MoM hip replacement devices, the balance between facilitating the introduction of these new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment was not achieved. The lessons learned from these experiences have application beyond joint replacements to the introduction of new medical technologies in general, particularly for those who have a significant potential for harm. In this regard, a series of recommendations have been developed to contribute to the evolution of the medical device regulatory process
Balancing innovation and medical device regulation: the case of modern metal-on-metal hip replacements
Howard, Jason J
Due to problems with wear particle generation and subsequent loosening using conventional metal-on-polyethylene total hip replacements, there has been a shift toward alternative bearing systems, including metal-on-metal (MoM), for younger, more active patients with degenerative joint disease. Based on positive results from early short-term clinical studies, MoM hip replacements were readily adopted by orthopedic surgeons with thousands being implanted worldwide over the past decade. Unacceptably high revision rates reported by two national joint registries called into question the rigorousness of the regulatory approval process for these implants, particularly with respect to premarket data requirements to prove safety, effectiveness, and the appropriateness of the regulatory pathway chosen. The purpose of this review was to investigate the balance between facilitating the introduction of new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment. The case of MoM hip replacement devices was used to frame the investigation and subsequent discussions. The regulatory approval processes and post-market surveillance requirements associated with three common MoM hip replacements (two resurfacings: the Birmingham and articular surface replacement and the articular surface replacement XL total hip replacement) were investigated. With respect to modern MoM hip replacement devices, the balance between facilitating the introduction of these new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment was not achieved. The lessons learned from these experiences have application beyond joint replacements to the introduction of new medical technologies in general, particularly for those who have a significant potential for harm. In this regard, a series of recommendations have been developed to contribute to the evolution of the medical device regulatory process
How do metal ion levels change over time in hip resurfacing patients? A cohort study.
Savarino, Lucia; Cadossi, Matteo; Chiarello, Eugenio; Fotia, Caterina; Greco, Michelina; Baldini, Nicola; Giannini, Sandro
Metal-on-metal hip resurfacing (MOM-HR) is offered as an alternative to traditional hip arthroplasty for young, active adults with advanced osteoarthritis. Nevertheless, concerns remain regarding wear and corrosion of the bearing surfaces and the resulting increase in metal ion levels. We evaluated three cohorts of patients with Birmingham hip resurfacing (BHR) at an average follow-up of 2, 5, and 9 years. We asked whether there would be differences in ion levels between the cohorts and inside the gender. Nineteen patients were prospectively analyzed. The correlation with clinical-radiographic data was also performed. Chromium, cobalt, nickel, and molybdenum concentrations were measured by atomic absorption spectrophotometry. Chromium and cobalt levels demonstrated a tendency to decrease over time. Such tendency was present only in females. An inverse correlation between chromium, implant size, and Harris hip score was present at short term; it disappeared over time together with the decreased ion levels. The prospective analysis showed that, although metal ion levels remained fairly constant within each patient, there was a relatively large variation between subjects, so mean data in this scenario must be interpreted with caution. The chronic high exposure should be carefully considered during implant selection, particularly in young subjects, and a stricter monitoring is mandatory. PMID:25580456
How Do Metal Ion Levels Change over Time in Hip Resurfacing Patients? A Cohort Study
Savarino, Lucia; Cadossi, Matteo; Chiarello, Eugenio; Fotia, Caterina; Greco, Michelina; Baldini, Nicola; Giannini, Sandro
Metal-on-metal hip resurfacing (MOM-HR) is offered as an alternative to traditional hip arthroplasty for young, active adults with advanced osteoarthritis. Nevertheless, concerns remain regarding wear and corrosion of the bearing surfaces and the resulting increase in metal ion levels. We evaluated three cohorts of patients with Birmingham hip resurfacing (BHR) at an average follow-up of 2, 5, and 9 years. We asked whether there would be differences in ion levels between the cohorts and inside the gender. Nineteen patients were prospectively analyzed. The correlation with clinical-radiographic data was also performed. Chromium, cobalt, nickel, and molybdenum concentrations were measured by atomic absorption spectrophotometry. Chromium and cobalt levels demonstrated a tendency to decrease over time. Such tendency was present only in females. An inverse correlation between chromium, implant size, and Harris hip score was present at short term; it disappeared over time together with the decreased ion levels. The prospective analysis showed that, although metal ion levels remained fairly constant within each patient, there was a relatively large variation between subjects, so mean data in this scenario must be interpreted with caution. The chronic high exposure should be carefully considered during implant selection, particularly in young subjects, and a stricter monitoring is mandatory. PMID:25580456
[An unusual early complication in cementless replacement of the hip joint. Case report].
Kauschke, T; Zilch, H
This is the first description of a dislocation of the polyethyleninlay from the cup of a cementless hip prosthesis. Due to a fall of the patient 8 months after the implantation an unspecific complaint arised. In spite of detailed diagnostic no reason could have been found. During the renewed operation we saw the dislocated inlay by mechanical anchorage of the cup and the shaft. Retrospective there were made suggestions how the described complication could be recognized earlier. PMID:7871611
[Congenital hip dysplasia, screening and therapy].
Kolb, A; Windhager, R; Chiari, C
Congenital hip dysplasia and hip dislocation are relatively common pathological conditions of the musculoskeletal system in infants. An early and certain diagnosis can now be achieved by sonographic hip screening within the framework of screening examination programs. This early diagnostic procedure in infants is essential particularly for a conservative treatment strategy. Therefore, apart from possessing in-depth knowledge, training of the examiner in specialist courses is of central importance. This article presents an overview of the entity of congenital hip dysplasia and hip dislocation, the diagnostics and treatment with special emphasis on recent developments. PMID:26489825
Hip pain and childhood malignancy.
Wong, M; Chung, C H; Ngai, W K
In children, neuroblastoma can mimic various orthopaedic pathologies and this may create difficulties for doctors in reaching the correct diagnosis. Stage IV neuroblastoma was initially diagnosed as transient synovitis in this case report of a 7-year-old girl presenting with hip and low back pain. PMID:12459605
ERIC Educational Resources Information Center
Talley, Clarence, Sr.
Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…
Neurovascular Injury in Hip Arthroplasty
Neurological and vascular complications following hip arthroplasty are uncommon, and their impact ranges from transient and trivial to permanent and devastating. The proximity of neural and vascular structures makes any operation on the hip potentially hazardous. Direct or indirect injuries of these structures may occur during operative exposure and subsequent procedures. Thus, complete awareness of the anatomy of the pelvis and proximal femur is required. Peripheral nerve injuries can involve either distant sites or nerves in the immediate vicinity of the hip joint. Sciatic nerve injury is the most common nerve injury following total hip arthroplasty. Femoral nerve injury is much less common and is associated with an anterior approach. Its diagnosis is often delayed, but the prognosis is generally better than with sciatic nerve injury. The superior gluteal nerve is at risk during the direct lateral approach. Obturator nerve injury is the least common type of injury and has the least functional consequences. Vascular injuries are less common but more immediately life threatening. The mechanisms of vascular injury include occlusion associated with preexisting peripheral vascular disease and vascular injury during removal of cement during screw fixation of acetabular components, cages, or structural grafts. It is critical to avoid the anterior quadrants for acetabular screw fixation. All acetabular and femoral defects should be bone-grafted to avoid inadvertent cement migration. Following these guidelines, surgeons should be able to offer the most appropriate treatment and counseling to the patients.
Influence of hydrophobic and hydrophilic spacer-containing enzyme conjugates on functional parameters of steroid immunoassay.
Nara, Seema; Tripathi, Vinay; Chaube, Shail K; Rangari, Kiran; Singh, Harpal; Kariya, Kiran P; Shrivastav, Tulsidas G
Introduction of spacers in coating steroid antigen or enzyme conjugates or immunogen is known to exert an influence on the sensitivity of steroid enzyme immunoassays. We have introduced hydrophobic and hydrophilic spacers between enzyme and steroid moieties and studied their effects on functional parameters of enzyme immunoassays, using cortisol as a model steroid. Cortisol-3-O-carboxymethyloxime-bovine serum albumin (F-3-O-CMO-BSA) was used as immunogen to raise the antiserum in New Zealand white rabbits. Three enzyme conjugates were prepared using cortisol-21-hemisuccinate (F-21-HS) as carboxylic derivative of cortisol and horseradish peroxidase (HRP) as an enzyme label. These were F-21-HS-HRP (without spacer), F-21-HS-adipic acid dihydrazide-HRP (adipic acid dihydrazide as hydrophobic spacer), and F-21-HS-urea-HRP (urea as hydrophilic spacer). The influence of hydrophobic and hydrophilic spacers on the functional parameters of assays such as lower detection limit, ED50, and specificity was studied with reference to enzyme conjugate without spacer. The results of the present investigation revealed that the presence of a hydrophilic spacer in the enzyme conjugate decreases the lower detection limit, decreases the ED50, and marginally improves the specificity of assays. These improvements in functional parameters of assays may be due to the decreased magnitude of the overall hydrophobic interactions existing between the spacer in enzyme conjugate and the antigen binding site of the antibody. PMID:18023401
Predicting electrical measurements by applying scatterometry to complex spacer structures
NASA Astrophysics Data System (ADS)
Sendelbach, Matthew; Ayala, Javier; Herrera, Pedro
The comparison of scatterometry measurements of complex spacer structures to electrical test measurements is discussed. Details of the NFET and PFET structures are presented, along with a summary of the scatterometry models used to represent the structures. Before comparison data are shown, a methodology and set of metrics are presented that assist in the analysis and interpretation of comparison data. The methodology, called Prediction Analysis, has its roots in TMU analysis, where both measurements are subject to error. But in Prediction Analysis, an "apples-to-apples" comparison of the measurements is not the goal, and the measurements may be reported in different units. The goal of Prediction Analysis is to analyze the components of error in a correlation and use this analysis to predict a measurement based on the knowledge of another measurement, such that the predicted measurement is bounded. This method is used in this work to determine how well scatterometry measurements of certain parameters correlate to electrical measurements of gate resistance, gate Lpoly, and transistor current Ion. Clear correlations are demonstrated, and physical explanations that explain these correlations are presented. Due to the correlations, the scatterometry measurements can be used as a predictor of electrical performance significantly before the electrical test occurs. Because of this, scatterometry can be a reliable measurement technique for improving spacer controls and reducing the mean time to detect (MTTD) some profile abnormalities.
Sports hip injuries: assessment and management.
Kelly, Bryan T; Maak, Travis G; Larson, Christopher M; Bedi, Asheesh; Zaltz, Ira
Over the past 10 years, the understanding, assessment, and management of hip pain and injuries in the athlete have improved. Traditionally, the evaluation of hip pain and injuries was limited to obvious disorders, such as hip arthritis and fractures, or disorders that were previously considered to be simply soft-tissue strains and contusions, such as groin pulls, hip pointers, and bursitis. Two parallel tracks of progress have improved understanding of the complexities of hip joint athletic injuries and the biomechanical basis of early hip disease. In the field of sports medicine, improved diagnostic skills now allow better interpretation of debilitating intra-articular hip disorders and their effects on core performance. In the field of hip preservation, there has been an evolution in understanding the effects of biomechanical mismatches between the femoral head and the acetabulum on the development of early hip damage, injury, and arthritis. The integration of these two parallel fields has accelerated the understanding of the importance of hip biomechanics and early hip injury in human performance and function. PMID:23395055
Hip Imaging in Athletes: Sports Imaging Series.
Agten, Christoph A; Sutter, Reto; Buck, Florian M; Pfirrmann, Christian W A
Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016. PMID:27429142
Techniques and Results for Open Hip Preservation
Levy, David M.; Hellman, Michael D.; Haughom, Bryan; Stover, Michael D.; Nho, Shane J.
While hip arthroscopy grows in popularity, there are still many circumstances under which open hip preservation is the most appropriately indicated. This article specifically reviews open hip preservation procedures for a variety of hip conditions. Femoral acetabular impingement may be corrected using an open surgical hip dislocation. Acetabular dysplasia may be corrected using a periacetabular osteotomy. Acetabular protrusio may require surgical hip dislocation with rim trimming and a possible valgus intertrochanteric osteotomy. Legg–Calve–Perthes disease produces complex deformities that may be better served with osteotomies of the proximal femur and/or acetabulum. Chronic slipped capital femoral epiphysis may also benefit from a surgical hip dislocation and/or proximal femoral osteotomy. PMID:26649292
The use of primary total hip arthroplasty in university hospitals of the European Union.
Scheerlinck, Thierry; Druyts, Pieter; Casteleyn, Pierre-Paul
Current practice in primary total hip replacement was investigated by postal survey in 125 university hospitals of the European Union (EU). Most hospitals (78.4%) use a hip register and implant cemented as well as uncemented stems (72.0%) and cups (68.8%). In Scandinavian & Anglo-Saxon countries, 42.9% of the departments implant cemented stems in all their patients, and 16.7% implant cemented cups in all their patients. In these countries, modern cementing techniques are commonly used and therapeutic choices are strongly influenced by hip registers. In Southern Europe, cemented cups have been abandoned in 31.1% and modern cementing techniques are less common. Benelux & Germanic countries have a practice in between. Three cemented (Exeter, Charnley, Lubinus) and three uncemented stems (Zweymüller, ABG, Bi-contact) represent 41.9% and 25.3% of stem types in use. Most departments (70.4%) have adopted alternative bearings. Ceramic-ceramic and metal-metal are both used in almost half of the hospitals. Metal-polyethylene has been abandoned in 15.2%. These trends are taught to new generations of surgeons in the EU and could become common practice in a near future. PMID:15287402
Improved mechanical long-term reliability of hip resurfacing prostheses by using silicon nitride.
Zhang, Wen; Titze, M; Cappi, B; Wirtz, D C; Telle, R; Fischer, H
Although ceramic prostheses have been successfully used in conventional total hip arthroplasty (THA) for many decades, ceramic materials have not yet been applied for hip resurfacing (HR) surgeries. The objective of this study is to investigate the mechanical reliability of silicon nitride as a new ceramic material in HR prostheses. A finite element analysis (FEA) was performed to study the effects of two different designs of prostheses on the stress distribution in the femur-neck area. A metallic (cobalt-chromium-alloy) Birmingham hip resurfacing (BHR) prosthesis and our newly designed ceramic (silicon nitride) HR prosthesis were hereby compared. The stresses induced by physiologically loading the femur bone with an implant were calculated and compared with the corresponding stresses for the healthy, intact femur bone. Here, we found stress distributions in the femur bone with the implanted silicon nitride HR prosthesis which were similar to those of healthy, intact femur bone. The lifetime predictions showed that silicon nitride is indeed mechanically reliable and, thus, is ideal for HR prostheses. Moreover, we conclude that the FEA and corresponded post-processing can help us to evaluate a new ceramic material and a specific new implant design with respect to the mechanical reliability before clinical application. PMID:20725769
Microscopical analysis of synovial fluid wear debris from failing CoCr hip prostheses
NASA Astrophysics Data System (ADS)
Ward, M. B.; Brown, A. P.; Cox, A.; Curry, A.; Denton, J.
Metal on metal hip joint prostheses are now commonly implanted in patients with hip problems. Although hip replacements largely go ahead problem free, some complications can arise such as infection immediately after surgery and aseptic necrosis caused by vascular complications due to surgery. A recent observation that has been made at Manchester is that some Cobalt Chromium (CoCr) implants are causing chronic pain, with the source being as yet unidentified. This form of replacement failure is independent of surgeon or hospital and so some underlying body/implant interface process is thought to be the problem. When the synovial fluid from a failed joint is examined particles of metal (wear debris) can be found. Transmission Electron Microscopy (TEM) has been used to look at fixed and sectioned samples of the synovial fluid and this has identified fine (< 100 nm) metal and metal oxide particles within the fluid. TEM EDX and Electron Energy Loss Spectroscopy (EELS) have been employed to examine the composition of the particles, showing them to be chromium rich. This gives rise to concern that the failure mechanism may be associated with the debris.
High Re-Operation Rates Using Conserve Metal-On-Metal Total Hip Articulations
Mogensen, S.L.; Jakobsen, T.; Christoffersen, H.; Krarup, N.
Introduction: Metal-on-metal hip articulations have been intensely debated after reports of adverse reactions and high failure rates. The aim of this study was to retrospectively evaluate the implant of a metal-on.metal total hip articulation (MOM THA) from a single manufacture in a two-center study. Materials and Methods: 108 CONSERVE® MOM THA were implanted in 92 patients between November 2005 and December 2010. Patients had at time of retrospective evaluation their journals reviewed for re-operations and adverse reactions. Results: 20 hips were re-operated (18.4%) at a mean follow up of 53 months. 4 pseudotumors were diagnosed at time of follow up but no substantiated link was made between adverse reactions and re-operations. Conclusion: The high re-operation rates found in this study raised concern about the usage of the MOM THA and subsequently lead to the termination of implantation of this MOM THA at the two orthopaedic departments. PMID:27099640
Dislocation of a dual mobility total hip replacement following fracture of the polyethylene liner.
Vedrine, Bertrand; Guillaumot, Pierre; Chancrin, Jean-Luc
An eight-year-old male English Setter was referred for management of a dislocation of a cemented dual mobility canine total hip prosthesis that occurred four months after the initial surgery. Revision surgery showed that the dislocation was associated with fracture of the ultra-high molecular weight polyethylene liner. The dislocation was successfully reduced after replacing the liner. A dual mobility acetabular component is composed of a mobile polyethylene liner inside a metallic cemented cup. Chronic wear of the components of a canine dual mobility total hip replacement has not been described previously. The use of this type of implant is fairly recent and limited long term follow-up of the implanted cases may be the explanation. Acute rupture of a polyethylene liner has never been described in humans, the only case of rupture of a polyethylene liner occurred 10 years after implantation. The case presented here of rupture of the polyethylene liner of a dual mobility total hip replacement is a hitherto unreported failure mode in this model of acetabular cup in the dog. PMID:26991949
Corrosion of the Head-neck Junction After Total Hip Arthroplasty.
Jennings, Jason M; Dennis, Douglas A; Yang, Charlie C
Corrosion of the head-neck junction of implants used in total hip arthroplasty is a complex problem. Clinical severity appears to be multifactorial, and the predictive variables have yet to be consistently identified in the literature. Corrosion should be considered in the differential diagnosis of hip pain following total hip arthroplasty regardless of the type of bearing surface used. The most common presentation, pain followed by instability, is similar to complications associated with metal-on-metal articulations. The diagnosis of implant corrosion of the head-neck junction can be challenging; an infection workup should be performed along with analysis of serum metal ion levels and cross-sectional imaging. In the short term, a well-fixed stem may be retained, and the exchange of an isolated head with a ceramic femoral head seems to be a promising option for certain implants. Further research with longer follow-up is warranted, and high levels of evidence are needed to determine whether this approach is generalizable. PMID:27213620
Biological Therapies for Cartilage Lesions in the Hip: A New Horizon.
Chahla, Jorge; LaPrade, Robert F; Mardones, Rodrigo; Huard, Johnny; Philippon, Marc J; Nho, Shane; Mei-Dan, Omer; Pascual-Garrido, Cecilia
Treatment of hip cartilage disease is challenging, and there is no clear algorithm to address this entity. Biomarkers are arising as promising diagnostic tools because they could play a role in the early assessment of the prearthritic joint and as a prognostic factor before and after treatment. The potential effect of biomarkers may be used to categorize individuals at risk of evolving to severe osteoarthritis, to develop new measures for clinical progression of the disease, and to develop new treatment options for the prevention of osteoarthritis progression. A trend toward a less invasive biological treatment will usher in a new treatment era. With the growth of surgical skills in hip arthroscopy, cartilage restoration techniques are evolving in a fast and exponential manner. Biological and surgical treatments have been proposed to treat these pathologies. Biological treatments include platelet-rich plasma, stem cells or bone marrow aspirate concentration, hyaluronic acid, losartan, and fish oil. Surgical treatments include microfracture alone or augmented, direct repair, autologous chondrocyte implantation, matrix-induced chondrocyte implantation, autologous matrix-induced chondrogenesis, mosaicplasty, osteochondral allograft transplantation, and stem cells implanted in matrix (stem cells in membranes/expanded stem cells). This article reviews new evidence available on treatment options for chondral lesions and early osteoarthritis of the hip. [Orthopedics. 2016; 39(4):e715-e723.]. PMID:27359284
Frontal plane kinematics of the hip during running: Are they related to hip anatomy and strength?
Baggaley, Michael; Noehren, Brian; Clasey, Jody L; Shapiro, Robert; Pohl, Michael B
Excessive hip adduction has been associated with a number of lower extremity overuse running injuries. The excessive motion has been suggested to be the result of reduced strength of the hip abductor musculature. Hip anatomical alignment has been postulated to influence hip abduction (HABD) strength and thus may impact hip adduction during running. The purpose of this study was to investigate the relationship between hip anatomy, HABD strength, and frontal plane kinematics during running. Peak isometric HABD strength, 3D lower extremity kinematics during running, femoral neck-shaft angle (NSA), and pelvis width-femur length (PW-FL) ratio were recorded for 25 female subjects. Pearson correlations (p<0.05) were performed between variables. A fair relationship was observed between femoral NSA and HABD strength (r=-0.47, p=0.02) where an increased NSA was associated with reduced HABD strength. No relationship was observed between HABD strength and hip adduction during running. None of the anatomical measurements, NSA or PW-FL, were associated with hip adduction during running. Deviations in the femoral NSA have a limited ability to influence peak isometric hip abduction strength or frontal plane hip kinematics during running. Hip abduction strength does also not appear to be linked with changes in hip kinematics. These findings in healthy individuals question whether excessive hip adduction typically seen in female runners with overuse injuries is caused by deviations in hip abduction strength or anatomical structure. PMID:26364243
Simultaneous measurement of friction and wear in hip simulators.
Haider, Hani; Weisenburger, Joel N; Garvin, Kevin L
We propose and have evaluated a method to measure hip friction during wear testing on a popular multi-station hip simulator. A 6-degree-of-freedom load cell underneath the specimen sensed forces and torques during implant wear testing of simulated walking. This included internal-external and adduction-abduction rotations which are often neglected during friction testing on pendulum-type machines. Robust mathematical analysis and data processing provided friction estimates in three simultaneous orthogonal rotations, over extended multi-million cycle wear tests. We tested various bearing couples including metal-on-plastic, ceramic-on-plastic, and metal-on-metal material couples. In one test series, new and intentionally scratched CoCrMo 40-mm-diameter femoral heads were tested against conventional ultrahigh-molecular-weight polyethylene, highly cross-linked, and highly cross-linked with vitamin E versions. The scratching significantly increased friction and doubled the wear of all groups. Before scratching, friction levels for the aforementioned plastic groups were 0.056 ± 0.0060, 0.062 ± 0.0080, and 0.070 ± 0.0045, respectively, but after scratching increased to 0.088 ± 0.018, 0.076 ± 0.0066, and 0.082 ± 0.0049, respectively, all statistically significant increases (p = 0.00059, 0.00005, 0.0115, respectively). In another test series of 44-mm femoral head diameter hips, metal-on-plastic hips with conventional ultrahigh-molecular-weight polyethylene showed the lowest friction at 0.045 ± 0.0085, followed by highly cross-linked with 0.046 ± 0.0035 (not significantly different). In a ceramic-on-plastic design with conventional ultrahigh-molecular-weight polyethylene, higher friction 0.079 ± 0.0070 was measured likely due to that ceramic surface being rougher than usual. Metal-on-metal hips were compared without and with a TiN coating, resulting in 0.049 ± 0.014 and 0.097 ± 0.020 friction factors, respectively
Long-term results of the threaded Weill cup in primary total hip arthroplasty
Clarius, Michael; Jung, Alexander W.; Raiss, Patric; Streit, Marcus R.; Merle, Christian
Uncemented, threaded acetabular components with smooth surface treatment were widely used in continental Europe in the 1970s and 1980s for primary total hip arthroplasty (THA). Previously published studies showed high failure rates in the mid-term. In a consecutive series of 116 patients, 127 threaded cups with smooth surface treatment (Weill cup; Zimmer, Winterthur, Switzerland) were implanted in combination with one type of uncemented stem. Patients were followed up clinically and radiographically. Mean time of follow-up was 17 years (range 15–20). At the time of follow-up, the acetabular component had been revised or was awaiting revision in 30 hips (24%). Two hips were revised for infection and 23 for aseptic loosening. Four polyethylene liners were exchanged because of excessive wear. One hip was awaiting revision. The survival rate for all acetabular revisions including one hip awaiting revision was 75% (95%CI: 65–85%) at 17 years. These results support the view that smooth, threaded acetabular components do not provide satisfactory long-term fixation and should be abandoned. It is important to closely monitor patients with these components as the failure rate remains high in the long-term. PMID:19629480
Long-term results of the threaded Mecron cup in primary total hip arthroplasty
Clarius, Michael; Jung, Alexander W.; Streit, Marcus R.; Merle, Christian; Raiss, Patric
In the 1970s, high failure rates of cemented acetabular components, especially in young patients, in the middle- and long-term prompted a search for alternatives. The Mecring was one of the most popular first generation uncemented, threaded cups widely used in the 1980s for arthroplasty of the hip. First generation threaded cups commonly had smooth surface treatment and showed unacceptably high failure rates in the mid-term. In a consecutive series of 209 patients, 221 threaded uncemented acetabular cups with smooth surface treatment (Mecring) had been implanted in combination with one type of uncemented stem. Patients were followed up clinically and radiographically. The mean time of follow-up was 17 (range 15–20) years. In 91 (41%) hips the acetabular component had been revised or was awaiting revision: two hips for infection and 84 (38%) for aseptic loosening. Five hips were awaiting revision. The survival rate for all revisions including hips awaiting revision was 49% (95% CI: 41–57%) at 17 years. These results support the view that smooth, threaded acetabular components do not provide satisfactory long-term fixation and should be abandoned. Patients with these components must be closely monitored as the failure rate remains high in the long-term. PMID:19629481
Gait and stair function in total and resurfacing hip arthroplasty: a pilot study.
Shrader, M Wade; Bhowmik-Stoker, Manoshi; Jacofsky, Marc C; Jacofsky, David J
Standard total hip arthroplasty (THA) is the established surgical treatment for patients older than 65 years with progressive osteoarthritis but survivorship curves wane in patients younger than 50. Resurfacing hip arthroplasty (RHA) is an alternative for younger, active patients reportedly providing superior range of motion. Quantitative investigation of functional recovery following arthroplasty may elucidate limitations that aid in device selection. Although limited long-term kinematic data are available, the early rate of recovery and gait compensations are not well described. This information may aid in refining rehabilitation protocols based on limitations specific to the implant. We presumed hip motion and forces for subjects receiving RHA are more similar to age-matched controls during physically demanding tasks, such as stair negotiation, at early time points than those for THA. In a pilot study, we quantified walking and stair negotiation preoperatively and 3 months postoperatively for seven patients with RHA (mean age, 49 years), seven patients with standard THA (mean age, 52 years), and seven age-matched control subjects (mean age, 56 years). Although both treatment groups demonstrated trends toward functional recovery, the RHA group had greater improvements in hip extension and abduction moment indicating typical loading of the hip. Further investigation is needed to determine if differences persist long term or are clinically meaningful. PMID:19305961
Orthopedic medical devices: ethical questions, implant recalls and responsibility.
Racine, Jennifer
The hip replacement is a surgical procedure to replace the femoral head and acetabulum with prosthetic implants to improve function, increase mobility, and relieve pain caused by damage from disorders such as osteoarthritis and fractures. In recent years, we have seen several recalls of poorly functioning implant systems, most recently, the Johnson and Johnson (J&J) Articular Surface Replacement device. Product recalls are often the results of premature failure of implants requiring additional surgery to exchange the failed device. This raises many questions - technical, medical, regulatory, ethical, and legal - that ultimately put patients at risk, compromise confidence in medicine and regulatory agencies, and important relationships including those between the physician-patient and physician-industry. Where do the responsibilities lie for the patients' suffering, morbidity, and costs of removing the failed device? This article discusses the current recall of the J&J implant, the responsibilities of the manufacturer, surgeons, and the regulatory agency. PMID:23741723
Minimally invasive dynamic hip screw for fixation of hip fractures
Ho, Michael; Garau, Giorgio; Walley, Gayle; Oliva, Francesco; Panni, Alfredo Schiavone; Longo, Umile Giuseppe
We compared a minimally invasive surgical technique to the conventional (open approach) surgical technique used in fixation of hip fractures with the dynamic hip screw (DHS) device. Using a case-control design (44 cases and 44 controls), we tested the null hypothesis that there is no difference between the two techniques in the following outcome measures: duration of surgery, time to mobilisation and weight bearing postoperatively, length of hospital stay, mean difference of pre- and postoperative haemoglobin levels, position of the lag screw of the DHS device in the femoral head, and the tip–apex distance. The minimally invasive DHS technique had significantly shorter duration of surgery and length of hospital stay. There was also less blood loss in the minimally invasive DHS technique. The minimally invasive DHS technique produces better outcome measures in the operating time, length of hospital stay, and blood loss compared to the conventional approach while maintaining equal fixation stability. PMID:18478227
Palacos compared to Palamed bone cement in total hip replacement: a randomized controlled trial.
Meinardi, Joris E; Valstar, Edward R; Van Der Voort, Paul; Kaptein, Bart L; Fiocco, Marta; Nelissen, Rob G H H
Background and purpose - Stability and survival of cemented total hip prostheses is dependent on a multitude of factors, including the type of cement that is used. Bone cements vary in viscosity, from low to medium and high. There have been few clinical RSA studies comparing the performance of low- and high-viscosity bone cements. We compared the migration behavior of the Stanmore hip stem cemented using novel low-viscosity Palamed bone cement with that of the same stem cemented with conventional high-viscosity Palacos bone cement. Patients and methods - We performed a randomized controlled study involving 39 patients (40 hips) undergoing primary total hip replacement for primary or secondary osteoarthritis. 22 patients (22 hips) were randomized to Palacos and 17 patients (18 hips) were randomized to Palamed. Migration was determined by RSA. Results - None of these 40 hips had been revised at the 10-year follow-up mark. To our knowledge, the patients who died before they reached the 10-year endpoint still had the implant in situ. No statistically significant or clinically significant differences were found between the 2 groups for mean translations, rotations, and maximum total-point motion (MTPM). Interpretation - We found similar migration of the Stanmore stem in the high-viscosity Palacos cement group and the low-viscosity Palamed cement group. We therefore expect that the risk of aseptic loosening with the new Palamed cement would be comparable to that with the conventional Palacos cement. The choice of which type of bone cement to use is therefore up to the surgeon's preference. PMID:27329869
Anterior Hip Fracture Dislocation with Intrapelvic Retention of the Femoral Head and Ureter Fistula
Patrascanu, Calin; Cibu, Dan
Introduction: The anterior dislocation of the hip represents only a small percentage of all hip dislocations: 85% are posterior. Most commonly associated with this dislocation is a fracture of the femoral head and, in rare cases, a femoral neck fracture. We have found in literature no report of an anterior dislocation of the hip associated with femoral neck fracture, pelvic retention of the head and ureteral fistula. We report such a case of a 68 year old male. Case Report: A 68 year old male was presented to our attention, following a severe injury of the hip when falling from a high bridge, with severe pain in the hip and a clinical aspect of femoral neck fracture. The X-ray confirmed the femoral neck fracture but following an anterior dislocation with the head retained into the pelvis. The patient also had hematuria. An Austin Moore prosthesis was implanted for the femoral neck fracture and the head was extracted by the urologist by a new abdominal incision. Urological evaluation revealed a fistula of the ureter, treated by an internal drainage for three months. One month later the Moore prosthesis was extracted and the patient had a Girldestone hip for 5 months. Revision with a Muller cemented prosthesis had a normal evolution. Conclusion: The anterior fracture dislocation of the hip with pelvic retention of the femoral head and ureteral fistula is a rare condition resulting from high energy trauma. A multidisciplinary team is necessary to diagnose and treat fracture and soft tissue lesions. Early diagnosis and treatment is necessary to avoid septic complications. PMID:27298980
Thin hydroxyapatite surface layers on titanium produced by ion implantation
NASA Astrophysics Data System (ADS)
Baumann, H.; Bethge, K.; Bilger, G.; Jones, D.; Symietz, I.
In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (α,α) backscattering and the resonant nuclear reaction 1H( 15N,αγ) 12C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of marrow bone cells on the implanted sample surface with that of titanium.
Assessment of modified gold surfaced titanium implants on skeletal fixation.
Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas; Baas, Jorgen; Møller, Per; Bechtold, Joan E; Soballe, Kjeld
Noncemented implants are the primary choice for younger patients undergoing total hip replacements. However, the major concern in this group of patients regarding revision is the concern from wear particles, periimplant inflammation, and subsequently aseptic implant loosening. Macrophages have been shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti-inflammatory manner by inhibiting cellular NF-κB-DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration and increase mechanical fixation. Cylindrical porous coated Ti-6Al-4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out tests and stereological histomorphometrical analyses showed no statistically significant differences in the two groups. The unchanged parameters are considered an improvement of the coating properties, as a previous complete gold-coated implant showed inferior mechanical fixation and reduced osseointegration compared to control titanium implants in a similar model. Since sufficient early mechanical fixation is achieved with this new coating, it is reasonable to investigate the implant further in long-term studies. PMID:22847873
Assessment of modified gold surfaced titanium implants on skeletal fixation
Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas; Baas, Jorgen; Møller, Per; Bechtold, Joan E.; Soballe, Kjeld
Noncemented implants are the primary choice for younger patients undergoing total hip replacements. However, the major concern in this group of patients regarding revision is the concern from wear particles, periimplant inflammation, and subsequently aseptic implant loosening. Macrophages have been shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti-inflammatory manner by inhibiting cellular NF-κB-DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration and increase mechanical fixation. Cylindrical porous coated Ti-6Al-4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out tests and stereological histomorphometrical analyses showed no statistically significant differences in the two groups. The unchanged parameters are considered an improvement of the coating properties, as a previous complete gold-coated implant showed inferior mechanical fixation and reduced osseointegration compared to control titanium implants in a similar model. Since sufficient early mechanical fixation is achieved with this new coating, it is reasonable to investigate the implant further in long-term studies. PMID:22847873
Probabilistic analysis of an uncemented total hip replacement.
Dopico-González, Carolina; New, Andrew M; Browne, Martin
This paper describes the application of probabilistic design methods to the analysis of the behaviour of an uncemented total hip replacement femoral component implanted in a proximal femur. Probabilistic methods allow variations in factors which control the behaviour of the implanted femur (the input parameters) to be taken into account in determining the performance of the construct. Monte Carlo sampling techniques were applied and the performance indicator was the maximum strain in the bone. The random input parameters were the joint load, the angle of the applied load and the material properties of the bone and the implant. Two Monte Carlo based simulations were applied, direct sampling and latin hypercube sampling. The results showed that the convergence of the mean value of the maximum strain improved gradually as a function of the number of simulations and it stabilised around a value of 0.008 after 6200 simulations. A similar trend was observed for the cumulative distribution function of the output. The strain output was most sensitive to the bone stiffness, followed very closely by the magnitude of the applied load. The application of latin hypercube sampling with 1000 simulations gave similar results to direct sampling with 10,000 simulations in a much reduced time. The results suggested that the number of simulations and the selection of parameters and models are important for the reliability of both the probability values and the sensitivity analyses. PMID:19217340
Economic viability of geriatric hip fracture centers.
Clement, R Carter; Ahn, Jaimo; Mehta, Samir; Bernstein, Joseph
Management of geriatric hip fractures in a protocol-driven center can improve outcomes and reduce costs. Nonetheless, this approach has not spread as broadly as the effectiveness data would imply. One possible explanation is that operating such a center is not perceived as financially worthwhile. To assess the economic viability of dedicated hip fracture centers, the authors built a financial model to estimate profit as a function of costs, reimbursement, and patient volume in 3 settings: an average US hip fracture program, a highly efficient center, and an academic hospital without a specific hip fracture program. Results were tested with sensitivity analysis. A local market analysis was conducted to assess the feasibility of supporting profitable hip fracture centers. The results demonstrate that hip fracture treatment only becomes profitable when the annual caseload exceeds approximately 72, assuming costs characteristic of a typical US hip fracture program. The threshold of profitability is 49 cases per year for high-efficiency hip fracture centers and 151 for the urban academic hospital under review. The largest determinant of profit is reimbursement, followed by costs and volume. In the authors' home market, 168 hospitals offer hip fracture care, yet 85% fall below the 72-case threshold. Hip fracture centers can be highly profitable through low costs and, especially, high revenues. However, most hospitals likely lose money by offering hip fracture care due to inadequate volume. Thus, both large and small facilities would benefit financially from the consolidation of hip fracture care at dedicated hip fracture centers. Typical US cities have adequate volume to support several such centers. PMID:24579222
Total hip replacement for developmental dysplasia of hip and postoperative nursing.
Zong, S J; Wang, F; Hu, S L
This study was designed to determine the clinical effect of total hip replacement for the treatment of developmental dysplasia of the hip (DDH) and analyze the postoperative nursing. Sixty patients (78 hips) aged 18-75 years (average 58.6±2.31 years) who received total hip replacement for treatment of DDH at the Zhengzhou Peoples Hospital, Henan, China, from April 2013 to June 2016 were selected as research subjects. Twenty-four patients were male (30 hips) and 36 were female (48 hips). Of the 60 patients, according to Crowe typing, 24 were type I (30 hips), 26 were type II (34 hips), 6 were type III (8 hips) and 4 were type IV (6 hips). According to the Harris hip score system, the score of all hips was 39.46±3.56 points average (18-56 points) before treatment and resulted as 89.60±4.25 points (79-98 points) at the last follow-up, showing a statistically significant difference (P < 0.05). Complications such as wound infection, dislocation, fracture of femoral shaft, femoral nerve and injury of sciatic nerve were not found after treatment. A total of 48 cases (58 hips) obtained excellent curative results (93.33% recovery), 8 cases (14 hips) good (92.31% recovery), and 4 cases (6 hips) medium. Total hip replacement proved to be effective in treating DDH and secondary osteoarthritis. Moreover, soft tissue release and an optimum degree recovery of anatomic form and physiological function of the diseased hip is an important basis for reconstructing the acetabulum and stabilizing acetabulum prosthesis. PMID:27049089
Effect of n-implantation on the corrosive-wear properties of surgical Ti-6Al-4V alloy
Williams, J.M.; Beardsley, G.M.; Buchanan, R.A.; Bacon, R.K.
The effects of N-ion implantation on the corrosive-wear properties of Ti-6Al-4V, an alloy used for construction of the femoral component of artificial hip joints in humans, were tested. In corrosive-wear tests designed to simulate pertinent hip-joint parameters, electrochemical corrosion currents were measured for cylindrical samples in saline electrolyte in an arrangement which allowed the samples to be rotated between loaded polyethylene pads simultaneously with the current measurement. To further quantify material removal, Zr markers were ion-implanted into some samples so that, by use of Rutherford backscattering, material removal could be detected by changes in position of the marker relative to the surface. Corrosion currents were greatly reduced by implantation of approximately 20 at. % N, but even implantation of the Zr markers also reduced corrosion currents. The marker experiments confirmed the low rate of material removal for the implanted samples. 10 references, 5 figures, 1 table.
Effect of Structure on the Mechanical Behaviors of Three-Dimensional Spacer Fabric Composites
NASA Astrophysics Data System (ADS)
Li, Min; Wang, Shaokai; Zhang, Zuoguang; Wu, Boming
Three-dimensional (3-D) spacer fabric composite is a newly developed sandwich structure, the reinforcement of which is integrally woven by advanced textile technique. Two facesheets of 3-D spacer fabric are connected by continuous fibers, named pile in the core, providing excellent properties like outstanding integrity, debonding resistance, light weight, good designability and so on. Usually the 3-D spacer fabric composite without extra reinforcement is a kind of core material. In comparison with the facesheet reinforced spacer fabric composite, here the composite without additional weaves is called mono-spacer fabric composite. In this paper, two kinds of mono-spacer fabric composites with integrated hollow cores have been developed, one with 8-shaped piles and the other with corrugated piles. The mechanical characteristics and the damage modes of these mono-spacer fabric composites under different load conditions have been investigated. Besides, effects of pile height, pile distribution density and pile structure on the composites mechanical performances were analyzed. It is shown that the mechanical performances of mono-spacer fabric composites can be widely adapted to the respective requirements through the choice of the structural factors.
Effect of spacer length and type on the biological activity of peptide-polysaccharide matrices.
Kumai, Jun; Hozumi, Kentaro; Yamada, Yuji; Katagiri, Fumihiko; Kikkawa, Yamato; Nomizu, Motoyoshi
Peptide-polysaccharide matrices can mimic extracellular matrix structure and function and are useful for tissue and cell engineering. The spacer between the peptide and the polysaccharide is important for both peptide conformation and the interaction between the peptide and receptors. Here, the effect of a spacer on the biological activity of peptide-polysaccharide matrices using various lengths of spacers consisting of glycine, β-alanine, and ε-aminocaproic acid has been examined. Active laminin-derived peptides, including a syndecan-binding peptide (AG73: RKRLQVQLSIRT), an integrin αvβ3-binding peptide (A99a: ALRGDN), and an integrin α6β1-binding peptide (A2G10: SYWYRIEASRTG), were used as the peptide ligands and chitosan was used as a polysaccharide matrix. The spacers did not influence the biological activity of the AG73-chitosan matrix. In contrast, the integrin-binding peptide-chitosan matrices showed spacer-dependent activity. Hydrophobic spacers enhanced the cell attachment activity of the A99a-chitosan matrix. A four-glycine spacer showed the strongest effect for the biological activity of the A2G10-chitosan matrix. These results suggested that spacer-optimization for each peptide is important for designing effective peptide-polysaccharide matrices. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 512-520, 2016. PMID:26588050
Patterning with amorphous carbon spacer for expanding the resolution limit of current lithography tool
NASA Astrophysics Data System (ADS)
Jung, Woo-Yung; Kim, Sang-Min; Kim, Choi-Dong; Sim, Guee-Hwang; Jeon, Sung-Min; Park, Sang-Wook; Lee, Byung-Seok; Park, Sung-Ki; Kim, Ji-Soo; Heon, Lee-Sang
Double patterning technique using spacer which can avoid CD (Critical Dimension) uniformity problem mainly caused by overlay issue is one of the methods that could be applied to apply to manufacturing of memory devices. Though double exposure and etch technology (DEET) has comparative advantage in the number of process steps, it is required to dramatically improve overlay performance of current exposure tools for the realization of manufacturing. In this study, negative type-double pattering technique using spacer has been developed as the best way for the application of NAND flash memory device from the view point of CD uniformity and the number of mask layers used to complete double patterning. Negative type-double patterning technique using spacer consists of subsequent steps such as formation of poly line, spacer on sidewall of poly line, SOG gap fill into space between poly lines, SOG etch back, removal of spacer, and finally hard mask etch. We have used amorphous carbon as a spacer material to easily remove spacer from poly lines and adopted SOG material to easily fill in space between poly lines. When negative type-double patterning technique using spacer is applied to NAND flash memory device, we can expect that k1 factor of about 0.14~0.20 could be accomplished successfully.