REVISION TOTAL HIP-ARTHROPLASTY WITH THE BIAS FEMORAL COMPONENT - 3 TO 6-YEAR RESULTS

The BIAS femoral component was used for most of the revision total hip arthroplasties performed during a four-year period by one surgeon. Forty-one BIAS femoral components were implanted in thirty-nine patients and were followed prospectively for a mean of five years (range, three to six years). The mean age of the patients was fifty-seven years. Twenty-eight (68 per cent) of the femora were classified preoperatively as having severe loss of bone distal to the intertrochanteric line. Cancellous autogenous graft from the iliac crest or fresh-frozen cancellous allograft was used in all hips to fill the proximal defects. Weight-bearing was delayed for three months after the operation. Clinical and radiographic evaluation was performed with the use of accepted criteria. The mean preoperative Harris hip score was 36 points (range, 0 to 71 points) and improved postoperatively to 85 points (range, 53 to 100 points). Thirty-two (78 per cent) of the hips had a good or excellent result at the most recent follow-up examination. Thirty-six patients (thirty-eight hips [93 per cent]) had no or slight pain, and twenty-nine patients (thirty hips [73 per cent]) walked with a slight or no limp. There was an association between one or more previous revisions of the femoral component and an increased prevalence of pain in the thigh or hip (p < 0.009). Radiographic analysis showed that thirteen components (32 per cent) subsided, but eleven of them stabilized and subsidence was not associated with less satisfactory clinical results. The hip scores were not notably lower in this group. No component was revised, and no patient had clinical symptoms for which revision was indicated at the most recent examination. Revision total hip arthroplasty with use of this implant, which has a partial proximal porous coating and which is inserted without cement, provided similar clinical results but inferior fixation, as seen on radiographs, compared with reported revisions in which components were implanted with modern cementing techniques. However, the apparent reconstitution of femoral bone structure in areas of previous osteolysis or cortical thinning is encouraging. The senior one of us no longer routinely uses this specific implant for revision arthroplasty done without cement, but does use a similar, revised version of the prosthesis.