上胫腓关节三维有限元模型的建立及对两型关节脱位的生物力学分析

Establishment of three-dimensional finite element model of proximal tibiofibular joint and biomechanic analysis of horizontal and oblique joint dislocation

背景:上胫腓关节是一个容易让人忽视的关节,临床上许多膝部的顽疾是由上胫腓关节的外伤或病变引起,研究其生物力学很重要。目前,新型高效的有限元研究方法尚未应用于上胫腓关节脱位的生物力学研究中。目的:通过正常人的上胫腓关节CT扫描图像,建立两型(水平型和倾斜型)上胫腓关节的三维有限元模型,分析躯体受到由远端向近端的纵向作用力下,上胫腓关节处的应力分布,提供对活体上胫腓关节评估的新方法。方法:选择2名(水平型和倾斜型各1名)均无上胫腓关节及膝关节外伤史的正常健康志愿者,进行64排CT扫描其上胫腓关节,运用逆向工程原理,通过三维有限元建模软件建立两型三维有限元模型。以上胫腓关节最常受力——沿纵轴受力,分别在两型三维有限元模型上进行力学加载,研究上胫腓关节处的应力分布,记录胫骨和腓骨出现明显相对位移(脱位)的作用力大小。结果:成功建立了两型上胫腓关节的三维有限元模型,其加载后的应力主要分布于两型上胫腓关节的腓骨内侧部分及腓骨头中部偏外上的区域,沿纵轴作用力引起两型关节脱位的作用力为:倾斜型关节1250 N,水平型关节1850 N。结论:倾斜型上胫腓关节较水平型上胫腓关节更易发生脱位,与文献的结果相一致。研究所用的两型上胫腓关节的三维有限元模型具有有效性,可作为力学分析的基础模型。

Background：Proximal tibiofibular joint is easily ignored. Many knee problems, in fact, are related to the trauma or disease of the proximal tibiofibular joint. As a new fashioned and high-efficiency method, the finite element, so far, has not been used in the biomechanical study of proximal tibiofibular joint dislocation. Objective： Through the proximal tibiofibular joint CT scanning images of normal people, two types of （horizontal and oblique） three dimensional finite element models of proximal tibiofibular joint were established. Stress distribution was eval-uated when longitudinal force was applied from the distal to the proximal end of tibiofibular joint so as to provide a new method to evaluate proximal tibiofibular joint in vivo. Methods：Two （1 horizontal and 1 oblique type） healthy volunteers who did not have trauma of proximal tibiofibular joint or knee joint received 64-slice CT scanning of tibiofibular joint. According to the principle of reverse engineering, three-dimen-sional finite element models were established by finite element modeling software. The most common force affected on proximal tibiofibular joint （along the longitudinal axis） was applied in the two types of three-dimensional finite element model, and the stress distribution was observed. The force leading to dislocation was recorded. Results：Both horizontal and oblique finite element models of proximal tibiofibular joint were established. Stresses were main-ly distributed in the medial part of the fibula and outside the central region of the fibular head. The dislocation of oblique joint occurred when longitudinal force was 1250 N and the dislocation of horizontal joint appeared under 1850 N longitudinal force. Conclusions： Oblique proximal tibiofibular joint is more prone to dislocation than horizontal one in finite element models, which is consistent with the literature. The models established in the study are effective and can be used for mechanical analysis.