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An Educational Module for Pavlik Harness Application for Developmental Dysplasia of the Hip: Study in a Greek Population

Summary: Introduction : The success of Pavlik harness therapy is based, among other things, upon the correct reapplication by parents. This prospective study assesses the effectiveness of a validated Objective Structured Assessment of Technical Skill (OSATS) educational module for Pavlik harness application among Greek parents. Methods : Forty consecutive parents of newborns with developmental dysplasia of the hip (DDH), who were treated with Pavlik harness, were divided into two groups. Twenty parents (group 1) were educated with the Greek OSATS version, while the rest (group 2) served as the control. The OSATS score, quality of the final product (Global Rating Scale - GRS) and sonographic imaging of the hips were evaluated during follow-up. Results : Post-intervention evaluation revealed significant higher means of OSATS score (p < 0.01), GRS of performance (p < 0.05) and GRS of final product (p < 0.05) for group 1. At every retention time point, OSATS was significantly higher for group 1, however there were no significant differences between either GRS score between groups. There was no significant difference in radiographic evaluation and successful outcome. Conclusions : This educative module increased the parents’ skill level on application of Pavlik harness. However, this module revealed no significant effect in clinical and radiological evaluation of the hips, in this population.


INTRODUCTION
Developmental dysplasia of the hip (DDH) includes a wide spectrum of clinical and imaging findings, ranging from mild instability of the hip joint, as well as developmental variations to dislocation [1,2]. Its definition, even nowadays, is not entirely agreed upon. The term most commonly refers to patients born with dysplasia or instability of the hip, which may lead to hip dislocation. More broadly, DDH is defined as abnormal growth of the hip. Abnormal development of the hip joint encompasses osseous structures, such as the acetabulum and proximal femur, as well as the soft tissues, such as the labrum and capsule. More specific terms have been used in order to describe aspects of this clinical entity, such as subluxation, dislocation, instability and teratologic dislocation of the hip [3].
The frequency of DDH is reported to be approximately 1/1000 newborns. During infancy DDH remains asymptomatic. Screening of newborns has been established as standard neonatal medical act for more than seven decades. It involves universal neonatal clinical examination (Ortolani and Barlow maneuvers) with the addition of sonographic imaging of the hip joint [3,4]. Hip ultrasonography provides early detection of DDH by visualizing the osseous, as well as the cartilaginous parts of the hip joint. Graf was the first to describe the ultrasonography of newborns' hips for the early detection of DDH in the early 1980s [5]. According to Graf, bony roof (alpha) angle mainly determines the hip type. Cartilaginous roof (beta) angle, age of the patient and the course of the perichondrium are additional determining issues of ultrasonographic hip typing [5].
The achievement of concentric reduction and as a result normal development of proximal femur and acetabulum, as soon as possible, represents the main goal of DDH treatment [4]. Pavlik introduced a "harness with stirrups" device in the 1940s, as a functional treatment of DDH, since active movement while hips and knees were kept in flexion and the hips also in abduction results in spontaneous and painless repositioning and centralization of the femoral head in the hip joint [4,6,7].
The Pavlik harness, since its introduction, has been widely used as a first-line treatment in newborns <6 months with DDH. Successful outcomes are based upon the correct application and reapplication of the device [8]. Parents are usually responsible for removing and reapplying the Pavlik harness, for everyday bathing and harness weaning. It seems, therefore, to be of paramount importance to educate parents on reapplication of the harness. In 2015, twenty five steps, through international consensus, were established in a validated objective structured assessment of technical skill (OSATS) for the application of the Pavlik harness ( Figure 1) [9]. OSATS has been used among health care personnel, while very few studies exist regarding parents' assessment [8].
The present prospective study represents the first attempt in Greece to assess whether a Greek language OSATS for the application of the Pavlik harness had an effect on the skill levels of parents regarding reapplication of the device, as well as the outcome of DDH.

MATERIAL AND METHODS
The translation of the OSATS checklist in Greek was performed according to the translation protocol guidelines of Beaton et al [10]. Two Greek speaking expert Orthopaedic Surgeons with excellent knowledge of English translated the OSATS into Greek. Two new checklists were made: OSATS-GR no 1 and OS-ATS-GR no 2. The translators compared these two and combined them into one checklist: OSATS-GR no1,2. The final checklist was translated back to English and was compared by a committee, comprised from the two translators, one statistician and one English language professor, to the original checklist. The committee did not find any differences between the two checklists. The final translation was approved and named OSATS-GR.
A total of 40 consecutive parents without any experience in applying a Pavlik harness were enrolled in this prospective randomized study at Athens General Children's Hospital "Pan. & Aglaia Kyriakou". All parents were shown by an expert Orthopaedic Surgeon how to apply the device using a doll. At that point two content experts used the OSATS-GR and a global rating scale (GRS) for the assessment of performance and final product, which are specific to Pavlik harness application (baseline testing).
The study population was then divided randomly into two groups (1 and 2; 20 participants each). Group 1 was presented the instructional video by Moktar J et al [11] and the OSATS-GR was analyzed. Group 2, serving as control, was not given any additional training. After 1 hour the two groups were re-assessed with the OSATS-GR and GRS. The video and the OSATS-GR were given to the group 1 (post-intervention).
Follow-ups were performed at 1,2 and 4-months after the Pavlik harness application. At the 1 and 2 months follow-up the infants were examined with sonographic imaging and the parents were assessed with the OSATS-GR, while at the 4-month follow-up infants were examined with X-rays and the parents' assessment with the OSATS-GR.
Parents could remove and reapply the Pavlik harness only after 4 weeks of initial treatment, while all infants were 6 to 8 weeks old at the beginning of treatment. Treatment lasted 4 months. General Children's Hospital "Pan. & Aglaia Kyriakou" is a 600-bed general hospital covering mainly urban and suburban pediatric population of Athens, the capital of Greece.
Statistical analysis of skill acquisition and sonographic outcomes were conducted using t tests and analysis of variance (ANOVA).
The present study was approved by the hospital's bioethics and scientific committee, and informed written consent was received from all participants.
Acetabular index at 4 months post intervention was 31° (SD=4) in group 1, compared to 30° (SD=4; p-value= 0.9) in group 2. Treatment was successful (at the 4-months followup) in 95% of cases in both groups. The remaining patients were treated operatively.

DISCUSSION
DDH has been related to familial predisposition, prenatal and postnatal mechanical factors, racial predilection and female gender [12]. Pavlik harness represents the most common orthosis used in everyday practice for DDH treatment of children under the age of 6 months. This non-invasive treatment method has gained overall acceptance. However, its improper use has been associated with complications, such as avascular femoral head necrosis, brachial plexus palsy and femoral nerve palsy [9,13].
During the treatment course with Pavlik harness, parents are required to reapply the device at home. Therefore, treatment relies upon parental cooperation, including the understanding of how to correctly apply the orthotic device [9]. It seems that the education of parents in Pavlik harness application may play a significant role for successful treatment. The present prospective study explored whether a validated Greek language OSATS (OSATS-GR) for the application of the Pavlik harness had an effect on the skill levels of parents regarding reapplication of the device by assessing the OSATS-GR and GRS among a group of parents receiving this additional education and a control group. Furthermore, the study evaluated whether the validated in the Greek language OSATS for the application of the Pavlik harness had an effect on the final outcome, by comparing sonographic findings (α-angle) and acetabulum index during the follow-up.
The study has shown that the studied parameters (OSATS-GR and GRS) were significantly higher in the group of parents receiving the learning module, when compared to the control group. OSATS-GR was statistically higher in the intervention group throughout the follow-up (up to 4 months). Similar findings have already been reported by Gargan et al for the OS-ATS score in English [8]. Gargan et al showed that parents, following intervention (educational process) and for a whole month after, had similar OSATS scores to those of experts [8].
The GRS product had no statistically significant difference between the 2 groups from the first followup (1 month). Therefore, although parents in the intervention group were better able to apply the Pavlik harness immediately after the intervention, the final EDUCATIONAL MODULE FOR PAVLIK HARNESS product from the initial 1-month follow-up did not differ between the two groups. Furthermore, sonographic and radiographic evaluation (α-angle and acetabular index) revealed no statistically significant difference throughout the follow-up among the two groups. Out-come was also similar (90% successful treatment in both groups).These results exhibit that exposure to the harness alone (standard demonstration with a doll) can alter the outcome of the application process, since the control group showed similar GRS at all follow-ups. An educative module, such as the one performed in the present study, offers parents a detailed overview of the procedures that should be followed. Parents gain confidence and a higher degree of understanding that their cooperation is of utmost importance for a successful outcome.
Although it seems that such an educative module does not affect the final outcome of DDH, it has short term advantages that have to do with answering most of the parents' questions in a systematic way. It is of paramount importance that healthcare providers still retain a significant role in parental education, particularly in assisting with setting of the required hip angles [11].

CONCLUSIONS
Simulated learning is gaining worldwide acceptance in medical and healthcare training. However, very few studies exist regarding the evaluation of this mode of teaching with parents. The present study represents the first attempt to use a validated Greek simulated learning module for correct Pavlik harness application. The skill levels of parents were increased after completion of this module. However, the study revealed that this had no significant impact on clinical outcome. More experience and data are needed from prospective studies with control groups evaluating the efficacy of such learning modules. Simulated learning may also become essential in teaching parents the correct application of Pavlik harness. However, it is of utmost importance to be under supervision with close follow-ups.