Abstract: Objective To study the correlation of mechanical changes after supracondylar fracture of the humerus. Methods Fifty-four children with supracondylar fracture of the humerus who were treated in our hospital from 2019 to 2022 were selected. All patients underwent closed reduction and Kirschner wire fixation and were followed up for 6 months. The children with valgus and tebitus varus at 6 months of follow-up were assigned to malunion group （n=10）, and those without cubitus valgus and cubitus varus were divided into normal healing group （n=44）. anteversion angles of capitulum humerus , Baumann angle, carrying angle and torsion angle of distal humerus were measured in two groups and compared between the two groups before operation, after reduction and at 6 months of follow-up. Logistic regression analysis was used to analyze the mechanical factors affecting the malunion of elbow joint. Results The preoperative Baumann angles, distal humeral torsion angles, and carrying angles were significantly higher in the malunion group than in the normal healing group, and the differences were all statistically significant （P<0.05）. After reduction, the anteversion angles of capitulum humerus, Baumann angle and distal humeral torsion angles in the malunion group were significantly higher than those in the normal healing group, and the differences were statistically significant （P<0.05）. Spearman correlation analysis showed that Baumann angles were negatively correlated with distal humeral torsion angles and carrying angles before operation in both groups; after reduction, the anteversion angles of capitulum humeri, Baumann angles, distal humeral torsion angles and carrying angles were significantly negatively correlated with the carrying angle in both groups; at a follow-up of 6 months, there was a significant negative correlation between Baumann angle and carrier angle in both groups. Multivariate logistic regression analysis showed that anteversion angles of capitulum humerus after reduction, Bauman angle before operation and after reduction, carrying angle at 6-months of follow-up, and distal humeral torsion angles before operation were all factors influencing the malunion of children with supracondylar fracture of the humerus. Conclusion The present study showed that anteversion angles of capitulum humerus after reduction, Bauman angles before operation and after reduction, carrying angles at 6-months of follow-up, and distal humerus torsion angles before operation were related to the malunion of children with supracondylar fracture of humerus.

Key words: supracondylar fracture of the humerus, mechanical change, malunion, antebitus varus, angle of distal humerus torsion

摘要： 目的 研究肱骨髁上骨折后力学改变畸形愈合的相关性。方法 研究对象选取2019年至2022年在我院就诊的54例肱骨髁上骨折患儿,所有患者均采取闭合复位克氏针固定术,将随访6个月时并发肘外翻和肘内翻的患儿分为畸形愈合组（n=10）,未发生并发肘外翻和肘内翻的患儿分为正常愈合组（n=44）,比较2组患儿术前、复位后、随访6个月时的肱骨小头前倾角、Baumann角、提携角、肱骨远端扭转角,采用Spearman相关系数分析术前、复位后、随访6个月时提携角与肱骨小头前倾角、Baumann角、肱骨远端扭转角的相关性。采用logistic回归分析影响肘关节畸形愈合的力学因素。结果 术前畸形愈合组中Baumann角、肱骨远端扭转角、提携角均明显高于正常愈合组,差异均有统计学意义（P<0.05）;复位后,畸形愈合组肱骨小头倾角、Baumann角、肱骨远端扭转角明显高于正常愈合组,差异均有统计学意义（P<0.05）;Spearman相关性分析结果显示,两组术前Baumann角与肱骨远端扭转角与提携角呈明显负相关（P<0.05）;复位后,两组的肱骨小头倾角、Baumann角、肱骨远端扭转角与提携角均呈明显负相关（P<0.05）;随访6个月时,Baumann角与提携角呈明显负相关（P<0.05）。多因素logistic回归分析结果显示,两组复位后的肱骨小头倾角、术前Bauman角、复位后Bauman角、随访6个月时提携角、术前肱骨远端扭转角均是肱骨髁上骨折患儿发生畸形愈合的影响因素（P<0.05）。结论 复位后肱骨小头倾角、术前Bauman角、复位后Bauman角、随访6个月时提携角、术前肱骨远端扭转角与肱骨髁上骨折患儿发生畸形愈合有关。

关键词: 肱骨髁上骨折, 力学改变, 畸形愈合, 肘内翻, 肱骨远端扭转角