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.