Total hip arthroplasty using an uncemented femoral component with taper design : outcome at 10-year follow-up

The aim of this study was to assess the clinical and radiological outcome of the cementless-system (CLS) femoral component designed by Spotorno with a taper design. Ninety-four patients (107 hips) were operated on from January 1987 to December 1988. The female/male ratio was 2/1, the mean age was 51 years (range 20-77 years). Clinical follow-up was obtained in 89 hips (83%). Five patients (7 hips, 6.5%) could not be traced. Nine patients (11 hips, 10%) had died before the minimum time of follow-up required for this study (10 years). All these hips still had their stem in place at the time of the last intermediate inquiry. The mean follow-up was 10.3 +/- 0.3 years. No stem required revision. According to the Harris score, 84% of hips were rated good or excellent, 14% fair, and 2% poor. The average Harris hip score was 88 at the time of the last follow-up. Fifteen patients (17%) reported occasional thigh pain. All patients reported complete relief of pain within the first 6 months after the operation. Radiologically, 95% of stems showed stable fixation by bony ingrowth, 5% by fibrous ingrowth. Seven (9%) uncemented acetabular components showed progressive migration. Three of those cups had been replaced in the meantime. Fifty-one (65%) of the CLS stems induced either no change in femoral bone density or only patchy loss of bone density localized to zone 1 or 7 according to Gruen, while 27 (35%) of the hips showed some reduction of bone density in the proximal diaphysis of the femur (zone 2 or 6). Severe progressive osteolysis of the femoral cortex underneath the lesser trochanter was found in 4 hips (5%) with coexistent loosening of the cup. In all of these hips, the Mecron cup had been used. At a mean follow-up of 10 years, the results of the CLS femoral component are comparable with those of modern techniques of cementing in primary total hip arthroplasty and with the long-term outcomes of other uncemented stems with tapered design. The long-term fixation of the cup remains an unsolved problem.