Transient epiphyseal lesions in renal transplant recipients: presumed insufficiency stress fractures.

PURPOSE: To determine epiphyseal abnormalities in renal transplant recipients.

MATERIALS AND

METHODS

Initial and final findings on serial conventional radiographs and magnetic resonance (MR) images obtained in symptomatic joints of transplant recipients were determined and correlated.

RESULTS

In 42 of 47 joints, T1-weighted MR images depicted 106 ill-delimited areas of low signal intensity. At 1-year follow-up, all lesions had disappeared. T1-weighted MR images depicted nine well-delimited regions of normal signal intensity delineated by a rim of low signal intensity in seven joints. No lesion had completely disappeared at follow-up. Initial radiographs either were normal or showed patchy osteoporosis (13 joints). Follow-up radiographs showed epiphyseal collapse of two femoral heads, with well-delimited lesions on MR images, and subtle subchondral sclerosis in 21 noncollapsed epiphyses.

CONCLUSION

Initial MR imaging patterns of transient lesions (92% of lesions) are different from those of irreversible lesions. Transient lesions suggest insufficiency stress fractures, while irreversible lesions suggest avascular osteonecrosis.