PREVALENCE OF PREVIOUSLY UNDETECTED OSTEONECROSIS OF THE FEMORAL-HEADIN RENAL-TRANSPLANT RECIPIENTS

PURPOSE: To determine the prevalence of osteonecrosis (ON) of the femo ral head in renal transplant recipients and determine the natural hist ory of previously undetected lesions. MATERIALS AND METHODS: The hips of 132 renal transplant recipients were examined with magnetic resonan ce (MR) imaging, with radiographs obtained only in the patients with p ositive MR images. RESULTS: Ten patients (15 hips) were considered to have ON (prevalence, 7.6%). Eleven of the hips had Ficat stage O disea se (asymptomatic, preradiographic) and were followed up with serial ra diography and MR imaging. Over an average follow-up of 22 months, only one of these lesions showed progression. The other 10 hips did not sh ow progression at MR imaging or radiography. CONCLUSION: Previously un detected ON may have a benign course in many eases. Although a substan tial number of patients have previously unsuspected disease, further s tudy is necessary to assess the need for ''prophylactic'' surgery in s uch cases.