臼蓋形成不全股における大腿骨頭中心の位置変化

Translation of Hip Center at the Dysplastic Hip

　背景：正常股，前股関節症の大腿骨頭中心位置について調査を行ったので報告する．

　対象と方法：立位正面X線写真で正常股または前股関節症と診断された女性患者38症例57関節を対象に大腿骨頭中心位置とSharp角，center-edge(CE)角，acetabular head index(AHI)との相関を調査した．

　結果：大腿骨頭中心はAHIが10％，CE角が10°減少するごとに2.0mm外方化し，Sharp角が10°増加するごとに5.3mm上方化する．正常の骨頭中心は涙痕下端より16.8mm上方，34.2mm外側にあると算出された．

　まとめ：CE角，AHIが小さくSharp角が大きい前股関節症の患者では大腿骨頭が上方化，外方化している．

　Background： We report the femoral head position of the normal or pre-coxarthrosis.

　Method：We measured 57 female hip centers with X-ray pictures of normal or pre-coxarthrosis stage, and investigated the correlation between the center position and Sharp angle, center-edge (CE) angle, and acetabular head index (AHI).　The average age of cases was 34.7 (17-58 y.o).　The horizontal distance was strongly correlated with AHI.　The vertical distance was correlated with Sharp angle.

　Outcome：As AHI decreased 10% or CE angle decreased 10 degree, the center position moved 2.0mm laterally, and as Sharp angle increased 10 degree, 5.3mm superiorly.　Normal hip center position was estimated as 34.2mm lateral and 16.8mm superior from tip of tear drop.

　Conclusion：Hip center translated laterally and superiorly at pre-coxarthrosis stage.