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

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