Subchondral changes in transient osteoporosis of the hip.
OBJECTIVE
To review the subchondral changes on MR imaging in transient osteoporosis of the hip (TOH) and to consider the pathophysiology.


METHODS
MR images of 12 hips of 11 consecutive patients with TOH were retrospectively studied. The diagnoses of TOH were confirmed on the basis of previously published criteria, including decreased bone density of the femoral head and/or neck on radiographs, bone marrow edema (BME) pattern on MR images, spontaneous resolution of the symptoms and a return to normal radiodensity.


RESULTS
All 12 hips showed a BME pattern in the femoral head and/or neck. Linear patterns of very low signal intensity were identified on T1-weighted images in the subchondral area within the diffuse low signal intensity area in all 12 hips. On T2-weighted images, a low signal intensity line was observed in the corresponding area in eight hips only. These linear patterns were thought to represent subchondral fracture lines.


CONCLUSIONS
The presence of a subchondral fracture may be important when considering the pathophysiology of TOH.
Miyanishi
K
K
Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Yamamoto
T
T
Nakashima
Y
Y
Shuto
T
T
Jingushi
S
S
Noguchi
Y
Y
Iwamoto
Y
Y
D000328:Adult; D005260:Female; D005270:Femur Head / Q000473:pathology*; D005272:Femur Neck / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000473:pathology*; D012189:Retrospective Studies