Total hip arthroplasty in juvenile rheumatoid arthritis. Two to eleven-year results.

From 1971 to 1980, forty-five patients with juvenile rheumatoid arthritis had eighty-three cemented total hip replacements at The Hospital for Special Surgery and North Carolina Memorial Hospital. Thirty-four of these patients, with sixty-two involved hips, returned for examination and radiographs. The average age of these thirty-four patients at the time of surgery was twenty-six years, and twenty-seven of them, with forty-nine involved hips, were thirty years old or less. The average length of follow-up was six years (range, two to eleven years), with forty-one hips having been followed for five to eleven years. According to The Hospital for Special Surgery hip-rating system, thirty hips were rated excellent; nineteen, good; nine, fair; and four, poor. Of the four hips with a poor result, two (in the same patient) had severe heterotopic ossification with ankylosis postoperatively, and two had required revision: one for acetabular loosening six years after replacement and the other for a broken stem of the femoral component ten years postoperatively. Radiographic review of the sixty-two hips demonstrated progressive radiolucencies or migration of 26 per cent of the acetabular components and 8 per cent of the femoral components. The frequency of acetabular migration or progressive radiolucencies was related to the postoperative position of the component relative to the position of the true acetabulum. These results were somewhat better than those in other reports on cemented total hip replacement in young patients. The difference is probably related to the lower average weight and decreased activity level of patients with juvenile rheumatoid arthritis.