We performed a retrospective study of a consecutive series of patients who had had a primary total hip replacement with so-called hybrid fixation of the components (an acetabular component inserted without cement and a femoral component inserted with cement) between September 1985 and June 1989. Clinical data were available for 114 patients (125 hips), of whom 110 (121 hips) also had radiographic data. The minimum duration of follow-up was fifty-six months or until revision, and the average duration was seventy-two months. The average Harris hip score improved from 47 points preoperatively to 91 points postoperatively (for the 109 patients who did not have a subsequent revision of the femoral component). Only three patients who did not have a revision had more than slight pain in the hip. Four hips (3 per cent) were revised for aseptic loosening of the femoral component at an average of fifty-five months; two of these four had a fracture of the femoral component. One patient had a resection arthroplasty for late infection. One patient had disassembly of an acetabular polyethylene liner, and another had dissociation of a modular femoral head; both patients had a reoperation. Radiographically, two femoral components were definitely loose, as determined by subsidence of the component in one patient and a fracture of the cement in the other. Ten hips (8 per cent) had endosteal lysis of the femur. Over-all, 5 per cent (six) of 121 femoral components were either revised for loosening or had definite radiographic evidence of loosening, but no acetabular component was loose. The clinical results in the 104 patients (115 hips) for whom clinical and radiographic data were available were excellent at the time of intermediate follow-up. Since few hips had progressive radiolucent lines about the acetabular or femoral component, we are optimistic that the long-term results will also be satisfactory.
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‡Stanford University Medical Center, Stanford, California 94305.