[10-year actuarial analysis of a cohort of 156 total hip prostheses of a cemented polished aluminum/polyethylene alloy].

PURPOSE OF THE STUDY: From 1983 to 1986, 156 alumina/polyethylene combination hip arthroplasties (131 patients) were performed at the Henri Mondor Hospital. Before 1983, the stainless-steel/polyethylene combination was performed. In this follow-up study, the outcome of the first 156 consecutive alumine-polyethylene combination hip arthroplasties were analyzed with clinical and radiological features. The comparison of the two combinations was analyzed. A survival analysis was performed over a ten years interval.

MATERIAL AND METHODS: The femoral component of the prosthesis was made of Titanium alloy (TiA16V4). The femoral head was made of dense alumina (A1203). The head diameter was 32 mm. The socket was made of ultra-high-molecular-weight polyethylene (UHMWPE). Fixation of head to stem was obtained through conical sleeving. We used a posterolateral approach, and a cemented THA without pressurization. At last follow-up evaluation, 90 patients were reviewed, 9 patients were interviewed by phone. Three patients were dead and 20 patients were lost for follow-up evaluation, in the first year. Nine failures were reoperated. The major cause of failure was septic complication of the THA (8). The average age of patients at arthroplasty was 58.1 year. The clinical evaluation was performed with the Merle d'Aubigné, Postel scoring system. The radiographs of 117 hips out of the 156 were available for this evaluation. Radiolucents, failures and wear were analyzed.

RESULTS: There was a 5 per cent rate (8 hips) of deep infection due for two hips to the underlying pathology. Ten (6.5 per cent) of the 156 hips had had an episode of dislocation at last follow-up. Eighty-nine per cent of the hips were rated excellent, very good, and good; 9.3 per cent were rated fair: and 1.7 per cent were rated poor. The radiographs of the socket revealed 54 per cent of bone-cement radiolucent and three failures at last follow-up. The radiographs of the stem revealed 29 per cent of bone-cement radiolucent and one failure at last follow-up. There was no revision of the femoral stem. Survival analysis (aseptic failures) depicted 93.45 per cent durability of the arthroplasty at 10 years. The survival analysis for the socket alone, using the same criteria for failure, demonstrated 94.53 per cent survival success at 10 years, and 98.91 per cent for the stem component. The comparison of the two combinations gave us a survival analysis for the socket alone, using aseptic failure as criteria, 79.84 per cent for stainless-steel/polyethylene combination at 8 years, and 97.63 per cent for alumina/polyethylene at the same time.

CONCLUSION: The alumina/polyethylene combination with a 32 mm head diameter gave better results than the stainless-steel/polyethylene combinations. The improvement was noted on the acetabular component.