Total hip arthroplasty after renal transplantation. Long-term follow-up study and assessment of metabolic bone status.

Twenty-two patients had 36 total hip arthroplasties for painful osteonecrosis of the femoral head. At a mean of 86 months after operation, a complete follow-up evaluation, including physical examination, was obtained in 24 hips in 15 patients. An additional 12 hips in seven patients were followed by telephone interview and radiographic evaluation. Although most patients experienced improved hip function and symptomatic relief from pain as a result of the operation, 10 hips developed heterotopic bone, 5 hips dislocated after operation, 6 hips failed due to aseptic loosening, and 1 hip developed a deep infection, and one patient died due to pulmonary embolism. Neither sex, preoperative steroid dose, nor postoperative mean alternate-day steroid dose could be related to aseptic loosening. However, histologic examination of transilial bone biopsy specimens (7 patients, 13 hips) revealed steroid-induced osteoporosis, by the presence of hyperosteoidosis (increased unmineralized osteoid) and increased bone resorption. Bilateral hip involvement, osteoporosis, and high turnover skeletal remodelling at the cement-bone interface potentially contributed to a failure rate that was higher in this group than that reported for primary hip arthroplasty for other diagnoses. The existence of steroid-induced metabolic bone disease and preexisting renal osteodystrophy may pose a significant threat to the long-term survival of a total hip implant.