基于ANSYS的人体膝关节半月板撕裂数值模拟

目的 研究半月板在撕裂情况下膝关节应力、应变以及有效表面压力分布的情况。方法 基于CT和MR扫描图像数据，使用软件Mimics和ANSYS，应用逆向工程原理建立膝关节的三维有限元模型(包括上、下膝盖骨和半月板)，模型中处理忽略关节软骨和韧带。分析和对比健康完整膝关节、内侧半月板“V”字形撕裂膝关节和半月板纵向撕裂膝关节3种模型在承受轴向载荷时的力学响应情况。结果 在轴向载荷作用下，健康膝关节半月板要传递大部分压应力载荷，且这些载荷主要集中在半月板中部的横向侧，最大的接触压力出现在半月板中间部分的后方。半月板撕裂时，应力最大的部位出现在撕裂部位周边，且由于撕裂部位的存在，半月板的接触应力分布有显著变化。结论 半月板撕裂对膝关节各部件的应力分布和峰值有很大影响，医生可根据半月板的撕裂形状，通过确定半月板上应力集中的位置，有效、准确地确定半月板撕裂患者最需要重点修复治疗的地方。
Objective To study the distribution of stress, strain and effective surface pressure in the knee joint. Methods Based on CT/MR scan image data and using the Mimics/ANSYS software, a three-dimensional finite element model of the knee joint (including the upper/lower knee and the meniscus) was established with the principle of reverse engineering, and the treatment of articular cartilage and ligament was ignored in this model. The mechanical responses of the three models, i.e., the healthy knee joint, the knee joint with V-shape medial meniscal tears, the knee joint with longitudinal meniscal tears under axial loading were analyzed and compared. Results Under axial loading, the healthy knee joint would transfer the majority of the compressive stress loads, which were mainly concentrated in the lateral side of the middle part of the meniscus, and the maximum contact pressure appeared in the rear area of the middle part of the meniscus. When the meniscus was torn, the maximum stress appeared at the periphery of the tear, and the contact stress distribution of the meniscus was significantly changed due to the presence of the tear. Conclusions The meniscal tears have a significant influence on the stress distribution and peak stress of the knee joint. According to the shape of the meniscus, the doctor can determine the position of the stress concentration in the meniscus, and to determine the most important point in the treatment of the meniscus tear.