肱骨髁间骨折不同双钢板固定方式的有限元分析

目的利用有限元分析双钢板平行固定和垂直固定对不同类型肱骨髁间骨折的生物力学影响。方法 CT扫描获得肱骨远端断层图像,利用软件Mimics及Ansys建立正常肱骨远端有限元模型,并在此基础上制成六种肱骨髁间骨折模型（高T型、低T型、H型、Y型、内侧λ型和外侧λ型）。在骨折模型的内侧柱和外侧柱分别模拟7孔解剖型锁定钢板固定,根据其固定的方式分为平行固定组和垂直固定组。各模型均施加300 N压缩载荷。结果各模型加载后的最大位移均位于肱骨外侧髁。垂直固定均较平行固定的位移大,在低T型和H型骨折模型中更显著,垂直固定较平行固定的位移大44.47%和34.08%。von Mises应力在接近肱骨髁上骨折断端的螺钉及钉孔周围最高。在除Y型外的其余五种骨折模型中,平行固定均较垂直固定的最大应力值更小,应力分布相对均匀。结论两种不同双钢板固定方式对肱骨髁间骨折稳定性的影响与骨折的类型有关,低T型和H型骨折模型中,选用平行固定方式有更大优势。

Comparison of Different Two Plate Fixation of Intercondylar Humeral Fractures:a Finite Element Study

Objective To use finite element analysis to study the biomechanical properties of the perpendicular and parallel double plate fixation in different types of intercondylar humeral fractures.Methods Thin layer images of the distal humerus were obtained by spiral CT scan.The analysis model of the normal distal humerus was constructed using the Mimics software and ANSYS software.Six different intercondylar humeral fracture models(high T,low T,H,Y,medial λ and lateral λ) were made on the basis of the normal model.Fractures were fixed with double 7 holes anatomic locking plates in the medial column and lateral column of the distal humerus.According to the plating method,all models were divided into parallel group and perpendicular group.All models were simulated to impose 300N compressive load.Results The maximum displacement of each model with the applied load was located in the humeral lateral condyle.The perpendicular plating group were demonstrated greater displacement than the parallel,and this was significant in the low T-and H-type fracture models(0.818 vs 1.183,44.47%;0.847 vs 1.137,34.08%).The maximum von Mises stresses were on the screws and holes near the supracondylar fracture gap.In all models except Y-type,parallel configurations were shown lower von Mises stress values and a more uniform stress distribution than the perpendicular configurations.Conclusion The stability of the intercondylar humeral fractures is associated with the double plate configuration and the type of fracture.Using two plates parallel configuration in low T-and H-type intercondylar humeral fractures has more obvious advantages.