特発性大腿骨頭壊死症に対するBipolar人工骨頭置換術の成績とその適応について

Clinical Results of Bipolar Hemiarthroplasty in Idiopathic Necrosis of the Femoral Head

　抄録：特発性大腿骨頭壊死症に対してBipolar人工骨頭置換術を施行し，術後5年以上経過観察可能であった29例30関節を対象として，臨床成績に関与する因子について検討した．経過観察期間が10年以上の15関節の長期成績は最終経過観察時のJOAスコアが平均65.1点と満足すべきものではなかった．臨床成績に関与する因子としては，病期，臼底リーミング，outer headの上方移動，stemの沈下が挙げられた．最終経過観察時のJOAスコアが80点以上の成績良好例は12例13関節で，臼底リーミングを行った例は2関節のみであった．特発性大腿骨頭壊死症に対するBipolar人工骨頭置換術の適応は限定すべきと思われるが，臼底リーミングを要さない，stageⅢまでの例には適応が残されている可能性が示唆された．

　The clinical results of 29 patients (30 hips) who had undergone Bipolar hemiarthroplasty for idiopathic necrosis of the femoral head between 5 and 18.5 years earlier were reviewed. The performance of 15 hips at follow-up times of 10 years or more was found to have been unsatisfactory based on JOA scores averaging 65.1 points. Factors affecting the clinical results included disease stage, reaming of the acetabulum, proximal migration of the outer head, and sinking of the stem. Twelve patients (13 hips) had satisfactory results based on JOA scores of 80 points or more, and reaming of the acetabulums had been performed in only 2 hips. We conclude that the indications for Bipolar hemiarthroplasty for idiopathic necrosis of the femoral head should be limited to cases that do not require reaming of the acetabulum and are diagnosed before the necrosis exceeds stage Ⅲ.