肘关节有限元模型模拟碰撞损伤的生物力学特性分析

Establishment of 3-D finite element model of elbow joint and its application for analysis of impact injury

目的利用有限元法建立肘关节的三维有限元模型,动态模拟肘关节以不同角度撞击地面,分析肘关节的生物力学特性。方法选取1名健康青年男性志愿者,肘关节屈曲90°行CT扫描,应用Mimics、Geomagic、UG、Hypermesh等软件对所得数据进行三维重建,建立肘关节的三维有限元模型;在Abaqus软件中模拟肘关节以不同角度(前臂与地面呈30°、60°、90°)撞击地面时,计算骨皮质破裂的临界速度及显著破裂时的速度,分析应力传导及其大小、分布等的变化规律。结果肘关节屈曲90°状态发生正面碰撞时应力传导主要集中在肱骨髁、肱骨滑车及尺骨鹰嘴等部位,而桡骨头应力传导较小;当肘关节与地面撞击(前臂与地面分别呈30°、60°、90°)时,骨皮质破裂临界速度分别为11.4、9.3、13.8 m/s;前臂与地面分别呈30°、60°撞击,撞击速度分别达15.0、13.0 m/s时,尺骨鹰嘴呈粉碎性骨折;前臂与地面呈90°撞击,撞击速度达18.0 m/s时,肱骨远端呈明显横行骨折。结论应用有限元建模分析软件构建的人体肘关节有限元模型可用于外力作用下肘关节损伤机制的研究,也可用于肘关节损伤时暴力的大小、速度、方向的推断。

Objective To establish a 3-D finite element model （FEM） of elbow joint, and analyze the biomechanical changes of the elbow joint in impact injury by dynamical simulation of elbow joint to impact the ground at different angels. Methods The finite element model of the elbow joint was established based on CT images of a young health male with his elbow joint bent at 90°, with aid of Mimics, Geomagic, UG and other softwares. Abaqus and Hypermesh softwares were used to simulate the injuries of the elbow joint impacting the ground at different angles （the angle of the forearm and the ground were 30°, 60° and 90°, respectively）. The critical velocities of cortical bone fracture and obvious fracture were calculated, and the patterns of conduction, intensity and distribution of the stress force were analyzed during impact process. Results When the elbow joint bent at 90° impacted the ground frontally, the conduction of the impact stress mainly concentrated in the humerus condyle, humerus trochlear and olecranon, but little in the radius. The critical velocities of cortical rupture were 11.4, 9.3, and 13.8 m/s respectively, when the angulations were 30°, 60°, and 90°. When the angulations were 30° and 60°, the impact velocities speeded up to 15.0 and 13.0 m/s, the olecranon had obvious fracture. Obvious transverse fracture was found in the distal humerus at the condition of angulations of 90° and velocity of 18.0 m/s. Conclusion The established FEM of elbow joint can be used in the biomechanical studies on mechanism of elbow injuries. It also provides new means to infer the intensity, velocity and direction of violence when the elbow joint is injured.