Cemented revision of failed uncemented femoral components of total hip arthroplasty.

Abstract

The long-term results of revision of failed primary cemented femoral components with use of cement have been reported, but there is little information about the results of revision of failed uncemented femoral components with use of cement. The purpose of the present study was to examine the minimum five-year results for patients in whom a failed uncemented primary femoral component was revised with use of modern cementing techniques. Forty-eight consecutive hips (forty-seven patients) in which a failed primary uncemented femoral component was revised with use of cement at one institution from 1985 to 1992 were followed prospectively and reviewed retrospectively. The mean age of the patients at the time of revision was sixty-seven years. Only seven revisions were performed with a long-stem femoral component. The postoperative cement mantle was classified, according to the system of Mulroy and Harris, as grade A in four hips, grade B in twenty-five, grade C1 in seven, grade C2 in twelve, and grade D in none. Eleven femoral components were removed or revised because of aseptic loosening (ten) or deep infection (one). An additional four unrevised femoral components had evidence of probable or definite loosening at the time of the final radiographic follow-up. Thus, fourteen (29%) of the forty-eight femoral implants demonstrated aseptic loosening during the study period. Five of the twenty-nine hips in which the postoperative cement mantle was classified as grade A or B had mechanical failure at the time of the final follow-up, compared with nine of the nineteen hips in which the postoperative cement mantle was classified as grade C1 or C2 (p < 0.05). Among the hips with surviving prostheses, 79% had had moderate or severe pain preoperatively whereas 25% had moderate or severe pain at the time of the final follow-up. The six-year rate of survival of the femoral component was 72% with revision for aseptic loosening as the end point and 67% with mechanical failure (revision for aseptic loosening or radiographic loosening) as the end point. While revision of a failed uncemented femoral implant with use of cement provided pain relief and improved function for most patients, the rate of loosening at the time of intermediate-term follow-up was higher than that commonly reported after revision of failed cemented implants with use of cement and also was higher than that commonly reported after revision with use of uncemented extensively porous-coated implants. Bone removal at the time of the initial implantation of the stem and bone loss due to subsequent failure of the uncemented implant often left little intramedullary cancellous bone, which may explain the high rate of loosening observed in the first decade after revision in this series.