Aseptic avascular necrosis of the femoral condyles in renal transplant patients: clinical and radiological aspects on 69 knees.

The purpose of this study was to analyze clinical and radiological aspects of aseptic avascular necrosis (AVN) of the femoral condyles in renal transplant patients. Forty-five renal transplant patients were followed between 1971 and 1993, and 69 knees have been studied. The immunosuppressive protocol comprised in all cases corticosteroids, with aziathioprine and since 1983 cyclosporin in 80% of patients. Episodes of rejection were treated with bolus doses of methylprednisolone. In 53.3% of patients, both knees were involved. The necrosis was bicondylar in 60.8% of knees. In the case of an unicondylar lesion, the lateral condyle was involved in 24.7% of knees vs 14.5% for the medial condyle. Symptoms occurred on average 4.9 years after transplantation (range 3 months-10.5 years). This period appeared significantly shorter for patients who had suffered an episode of rejection. In only 24.4% of patients was the knee involvement isolated. Pain was the initial symptom for 83% of patients. Other symptoms included locked knee (20.7%), effusion (49.2%), instability (14.5%), and loss of motion (15.9%). The diagnosis was established by standard radiographs, and in 8 patients by magnetic resonance imaging. Aseptic AVN of the femoral condyles in renal transplant patients is not rare even if it is less frequent than femoral head necrosis. Medication with corticosteroids is the main risk factor.