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 0 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 cases. Although a substantial number of patients have previously unsuspected disease, further study is necessary to assess the need for "prophylactic" surgery in such cases.