大腿骨頭軟骨下脆弱性骨折後に発症した急速破壊型股関節症の1例

Rapidly Destructive Coxopathy after Subchondral Insufficiency Fracture : Case Report

　抄録：われわれは単純X線像では異常を認めない発症早期にMRIで大腿骨頭軟骨下脆弱性骨折を認め，保存的に加療したが急速に股関節の破壊が進み，発症12カ月後にTHAを行った症例を経験した．患者は誘因なく発症した右股関節の違和感のため発症2週後に当院を受診した．発症3週後のMRIのT2強調像で大腿骨頭軟骨下に関節面と平行な低信号強度帯がみられ大腿骨頭軟骨下脆弱性骨折と診断した．以後，急速に股関節の破壊が進み手術したが，摘出標本の組織所見でも急速な骨破壊像を認めた．

　We report a case with subchondral insufficiency fracture of the femoral head. The patient came to our clinic complaining of dull pain in the right hip of 2 weeks duration. X-rays did not show any abnormal findings, but an MRI scan 1 week later showed a clear low-intensity band in the subchondral area of the femoral head. Despite strict restriction of weight bearing, the femoral head rapidly collapsed. Total hip arthoplasty (THA) was performed 12 months after the onset of symptoms. Both the macro-and microscopic examinations and the radiologic findings clearly demonstrated extensive bone destruction.