The uncemented porous-coated anatomic total hip prosthesis. Two-year results of a prospective consecutive series.
Fifty uncemented porous-coated total hip prostheses were implanted in forty-seven patients whose mean age was fifty-eight years. Clinical hip-rating scores, as described by Harris, were determined and anteroposterior and frog-leg lateral radiographs were made preoperatively, shortly postoperatively, and at three months, six months, one year, and two years postoperatively. The mean hip-rating score was 92 points (range, (range, 74 to 100 points) at one year and 92 points (range, 69 to 100 points) at two years. The thigh was slightly painful in nine patients (18 per cent) at one year and in eight (16 per cent) at two years. Fourteen hips (28 per cent) (in thirteen patients) caused a moderate or severe limp two years postoperatively; however, this complication appears to have been related more to the direct lateral approach that was used than to the prosthesis. Six (13 per cent) of the patients walked with a cane at one year and five (11 per cent) still required a cane at two years. Serial radiographic evaluations revealed that, between the first and second postoperative years, a progressive radiodense femoral line developed in twenty hips (41 per cent); a progressive acetabular line, in four hips (8 per cent); and progressive femoral sclerosis, in twelve hips (24 per cent). There was progressive loosening of beads from twelve (24 per cent) of the femoral components and from nine (18 per cent) of the acetabular components. The position of one acetabular and one femoral component changed. Two femoral shafts fractured, one intraoperatively and one fourteen months postoperatively. We concluded that the clinical results were encouraging in these patients at the end of two years. We are concerned, however, about the progressive radiodense lines, sclerosis, and loosening of beads as well as the slight, but persistent, pain in the thigh in eight patients.