TRANSIENT OSTEOPOROSIS OF THE HIP AND SUBCHONDRAL INSUFFICIENCY FRACTURE
Yamamoto T, Miyanishi K, Nakashima Y, Shuto T, Jingushi S, Iwamoto Y
Kyushu University, Fukuoka, Japan

The purpose of this study is to re-evaluate the subchondral changes in transient osteoporosis of the hip (TOH).

MRI findings of 19 consecutive cases with TOH were retrospectively studied. There were 15 men and 4 women. The age ranges from 26 to 63 (average 44). Pathologic specimens were available in 5 cases. On MRI, all 19 hips showed a bone marrow edema pattern in the femoral head and/or neck. In addition, linear patterns of very-low-signal intensity were identified on T1 in the subchondral area in all 19 hips. These linear patterns were thought to represent subchondral fracture lines. Pathology showed thin bone trabeculae with associated serous exudate and interstitial hemorrhage. Fractures with associated callus formation were clearly observed in one case.

The presence of subchondral fracture seems to be important in considering the pathophysiology of TOH