PREVALENCE OF PREVIOUSLY UNDETECTED OSTEONECROSIS OF THE FEMORAL-HEAD IN RENAL-TRANSPLANT RECIPIENTS

PURPOSE: To determine the prevalence of osteonecrosis (ON) of the femoral head in renal transplant recipients and determine the natural history of previously undetected lesions. MATERIALS AND METHODS: The hips of 132 renal transplant recipients were examined with magnetic resonance (MR) imaging, with radiographs obtained only in the patients with positive MR images. RESULTS: Ten patients (15 hips) were considered to have ON (prevalence, 7.6%). Eleven of the hips had Ficat stage O disease (asymptomatic, preradiographic) and were followed up with serial radiography and MR imaging. Over an average follow-up of 22 months, only one of these lesions showed progression. The other 10 hips did not show progression at MR imaging or radiography. CONCLUSION: Previously undetected ON may have a benign course in many eases. Although a substantial number of patients have previously unsuspected disease, further study is necessary to assess the need for ''prophylactic'' surgery in such cases.