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Long term survival of Hydroxyapatite ceramic coated threaded cup uncemented hip arthroplasty in presence of high polythene wear rate at 10 year follow-up

S Datir, P Angus, Dewsbury

Category: Furlong Clinical Results

The Dewsbury District General Hospital

Abstract

The aim of this study was to review the long term clinical results and the polythene wear rate of uncemented total hip arthroplasty performed using the Furlong H-A.C. coated threaded acetabular cup. In this retrospective cross-sectional survivorship study we reviewed the results of 144 uncemented total hip arthroplasties in 118 patients (Male: Female-65: 53, Mean age: 52.8 years(range 21-78 years) performed between 1988 and 2000, with a minimum of 5 year follow up. The mean duration of follow-up for the group was 10.2 years (range: 5-17.5, median: 9.7). Data was collected on demographics, complications, revision surgery, clinical scores. Radiographic mesurement of wear was performed using dual circle technique. Kaplan-Meier survival analysis was performed to evaluate 10-year survival. Four patients were lost to follow-up and 11 patients (12 hips) had died due to unrelated causes. Two femoral stems were revised, one due to intaoperative fracture and one due to stem fracture. Two acetabular shells were revised due to aseptic loosening. One patient underwent two-staged revision of both components due to deep infection. Nine hips (6.2%) underwent polyethylene liner exchange for asymptomatic polythene wear at mean interval of 13 years after the primary procedure. Mean Engh’s score for fixation and stability of the stem was 9.7 out of 10 and 14.5 out of 17 respectively. There was no evidence of osteolysis around the femoral or acetabular components in spite of relatively high polythene wear rate (0.24mm/year). Ten-year survival for the acetabular and femoral component with radiological evidence of aseptic loosening as an end point was 99.15 (CI: 98.3-99.9) and 99.28 (CI: 98.5-99.9). Our study demonstrates excellent survival of threaded HAC coated acetabular sockets at 10 year interval in a young population in spite of relatively higher polythene wear rate.

Data displayed at the British Orthopaedic Association Annual Congress, Liverpool, September 16th – 19th, 2008.