Baumann角测量预测肱骨髁上骨折肘内翻的研究

The measurement of baumann's angle to predict the complicated cubitus varus in supracondylar fracture of the humerus

目的研究Ｂａｕｍａｎｎ角的正常值及影响因素，并应用于临床，降低肱骨髁上骨折肘内翻的发生率．方法分别测量２～１２岁正常儿童１１０人，２０４肘的Ｂａｕｍａｎｎ角（Ｂ角）和提携角（Ｃ角）．在肱骨髁上骨折模型上，肱骨远端在内倾、屈曲、旋转三维状态下分别摄Ｘ线片测Ｂ角改变．并前瞻性研究５５例儿童肱骨髁上骨折，对整复后Ｂ角增大预测可能会发生肘内翻的病人，重新进行整复直至满意．结果Ｂ角平均７０．５±５．３５°，Ｃ角平均９．８１±４．２９°．Ｂ角与Ｃ角有非常显著的负相关（ｒ＝－０．３０８，Ｐ＜０．０１）．Ｂ角增加０．５～０．７°，Ｃ角约减少１°．骨折远端在三维状态下，远端内倾对Ｂ角影响最大，屈曲次之，旋转最小．５５例中２４例整复后Ｂ角增大１～１４°，平均８．８°．对增大５°以上２０例，均重新进行了整复固定．随访发现Ｃ角较对侧减小２～４°４例，４～６°３例，１５°１例，仅１例出现６°肘内翻畸形（１．８１％）．结论测量Ｂ角能准确预测提携角，对早期诊断肱骨髁上骨折肘内翻，降低肘内翻发生率具有重大意义．

Objective:To investigate the normal value of Baumann's angle and its affecting factors to decrease the complicated cubitus varus in supracondylar fracture of the humerus.Methods:Baumann's angle (angle B) and carrying angle (angle C) were measured in 110 normal children (aged 2～12 years,204 elbows).In the model of supracondylar fracture of humerus,angle B was collected on X-ray films in trimentional conditions of medial tilting,flexion and rotation of the distal fragment.Reposition was performed in 20 of 55 supracondylar fracture of the humerus in children,whose angle was reduced until it was satisfying.Results:The average value of angle B was 70.5±5.35° and angle C 9.81±4.29°.There was significant negative correlation between angle B and C (r=-0.308,P<0.01).For each increase of 0.5～0.7° of angle B,angle C decreased by 1°.The sequence of factors influencing angle B was medial titling,flexion and rotation of the distal fragment.Angle B in 24 cases of the 55 increased 1～14° after the reposition(average 8.8°).Those 20 patients whose angle B increased by more than 5°after the reduction were reduced anew.Only one patient had a cubitus varus for 6° in the following-up.Conclusion:The change of angle B can be used as reference to predict the complicated cubitus varus in supracondylar fracture of the humerus.