旋后外旋型踝关节损伤有限元模型的建立与力学分析

Finite element modeling and mechanical analysis on supination-external rotation ankle injury

目的模拟旋后外旋型踝关节损伤,建立踝关节三维有限元模型。方法基于正常人体踝关节CT图像,建立包含韧带的踝关节三维数值模型;采用有限元方法对Lauge-Hanson分型4种不同程度的旋后外旋型踝关节损伤进行分析,得到踝关节应力及胫距关节面的压力分布。结果施加旋后外旋载荷时,应力最大值位于胫腓前韧带胫骨附着点;断裂胫腓前韧带后,则位于骨间膜;继续断裂骨间膜后,应力较大值位于踝关节后韧带;再断裂胫腓后韧带后,应力较大值位于三角韧带。压力较大值则位于腓骨远端、胫距下关节面后部。结论建立的踝足部三维数值模型可用于旋后外旋型踝关节损伤的的力学机理分析,计算出的踝关节应力及胫距关节面的压力分布符合临床中Lauge-Hanson分型的描述。

Objective To simulate the supination-external rotation ankle injury and establish a 3D finite element model of the ankle. Methods Based on CT images of the normal human ankle joint, the 3D model of the ankle with ligaments was established. The supination-extemal rotation ankle injuries with four different degrees of Lauge-Hanson were analyzed by finite element method. Distributions of the ankle joint stress and tibial articular surface pressure were obtained. Results The maximum stress was at the anterior tibiofibular ligament attach- ment point of the tibial under supination-external rotation loading. When the anterior tibiofibular ligament was rup- tured, the maximum stress was at the interosseous membrane. After the interosseous membrane was ruptured, the high stress was at the posterior ligament of the ankle. When the posterior tibiofibular ligament was ruptured, the high stress was at the deltoid ligament. The high pressure was at the distal fibula or the rear of tibial articular surface. Conclusions The established ankle-foot 3D numerical model can be used for the mechanical analysis of supination-externalrotation ankle injury. The calculated distributions of the ankle stress and the tibial articular surface pressure were in agreement with the description of Lauge-Hanson classification.