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Alumina-on-alumina total hip arthroplasty. A five-year minimum follow-up study.

BACKGROUND
Ceramic-on-ceramic couplings are attractive alternative bearing surfaces that have been reported to eliminate or reduce problems related to polyethylene wear debris. Disappointing experiences with alumina ceramic bearings in the past have led to many improvements in the manufacture and design of ceramic implants. The purpose of the present study was to report the results of contemporary alumina-on-alumina total hip arthroplasties with regard to wear, osteolysis, and fracture of the ceramic after a minimum duration of follow-up of five years.


METHODS
We evaluated the results of a consecutive series of 100 primary alumina-on-alumina total hip arthroplasties that had been performed with use of a metal-backed socket and a cementless stem in eighty-four patients. All of the patients were sixty-five years of age or younger (mean age, forty-one years), and a single surgeon performed all of the procedures. After a minimum duration of follow-up of sixty months, one patient (one hip) had died and four patients (six hips) had been lost to follow-up, leaving a total of seventy-nine patients (ninety-three hips) available for study. All of these patients were evaluated clinically and radiographically with special attention to wear, periprosthetic osteolysis, and ceramic failure.


RESULTS
The mean Harris hip score was 97 points at the time of the latest follow-up evaluation. All prostheses demonstrated radiographic evidence of bone ingrowth. No implant was loose radiographically, and no implant was revised. Ceramic wear was not detectable in the thirty-seven hips in which the femoral head could be differentiated from the cup on radiographs. Periprosthetic osteolysis was not observed in any hip. A fracture of the alumina femoral head and a peripheral chip fracture of the alumina insert occurred in one hip following a motor-vehicle accident.


CONCLUSIONS
The results of contemporary alumina-on-alumina total hip arthroplasty with a metal-backed socket and a cementless stem were encouraging after a minimum duration of follow-up of five years. We believe that these improved alumina-on-alumina bearing implants offer a promising option for younger, active patients.