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[Total hip replacement in treatment of patients with deformity of the hip caused by ankylosing spondylitis].

BACKGROUND
Total hip replacement (THR) is at present an accepted treatment in patients with severe deformity of the hip caused by advanced ankylosing spondylitis. The aim of this paper is to evaluate the results of THR in patients suffering from ankylosing spondylitis, operated from 1987 to 2007 at the Orthopaedic and Traumatologic Department of Poznan University of Medical Sciences. Material. Material included 26 patients, 2 females and 24 males, on whom 34 THR were performed, lateral approach was used in all cases. At the time of operation, the age of patients ranged from 27 to 77 years (mean 57). Follow-up ranged from 3 to 21 years (mean 10.5 years). The operative treatment was a multistage process (during one operation only one joint was replaced). Cemented totalhip arthroplasty was used during 16 of the THR, 17 of them were cementless and 1 as a hybrid.


METHOD
The patients were clinically and radiologically evaluated preoperatively, postoperatively, and at final examination. The clinical state was evaluated with Harris hip score and WOMAC scale. We based our radiological examination on Hip Society system.


RESULTS
The average preoperative Harris score for the group of patients was 27.3, WOMAC score 78.5. After an average of 10 years follow-up all hips and knees were considered excellent, with average Harris score of 91.4, WOMAC Score of 5.0. All patients had increased function and decreased pain. The radiograms of all patients revealed that the acetabular and femoral components were correctly positioned with no radiographic evidence of loosening in the last examination. No ectopic ossification concentrations were found.


CONCLUSION
Clinical and radiological evaluation of our material showed that total hip replacement in the treatment of severe deformity of the hip caused by advanced ankylosing spondylitis allows regaining good lower limb function, which helps the patients staying less dependant on the surrounding environment. Ectopic ossification is not the clinical problem during THR in patients who suffer from spondylytis deformans.