骨表面再造数值模拟在人工股骨头假体优化设计中的应用

人工股骨头假体植入技术目前存在的主要问题之一是：植入假体存在远期等工发症，从而导致手术失败。对于引起松动的主要原因，通常人们认为是磨损磨屑和应力遮挡所造成的骨质吸收。因此，对人工股骨头假体植入物的结构进行优化是具有特别重要的意义，本文采用骨再造理论与有限元结合的方法，用计算机模拟人工股骨头假体植入股骨的再造行为，用截面吸收率和抗弯截面模量损失率定量分析假体所产生的应力遮挡效应，骨再造理论采用变能密度作控制变量的表面再造理论，有限单元采用二十节点等参数等单元。结果表明：在所讨论的假体模型中，三种围领形式的假体产生的骨吸收仅相差4％。三种长度直柄的假体所产生的骨吸收相差近30％，直柄长度的变化对应力遮挡效应有更显著的影响。

THE APPLICATION OF BONE SURFACE REMODELING SIMULATION IN OPTIMIZATION OF ARTIFICIAL FEMUR PROSTHESIS

One of the primary problems exits in the technology of implanting artificial femur is : There are syndromes such as long-term loosing, which cause the operation failure. It is general considered that the main reason of the loosing is bone absorption caused by abrasion fragments and the effect of stress shielding. So it is no doubt that optimizing the structure of artificial femur is very important. Based on bone remodeling theory and finite element method, computer simulation was used to bone remodeling behavior after artificial femur prosthesis embedding. Computer according with section absorptive rate and losing ratio of bending resistance section module also did quantitative analysis of the effect of stress shielding brought by prosthesis. During the simulation and analysis, surface-remodeling theory with strain energy density as controlling variation was taken as bone remodeling theory, and 20-node isoparametric element was used as finite element. The results have shown that among all prosthesis model discussed in this paper, there is only 4 percent discrepancy of absorption among the three collar type prostheses and 30 percent for the three straight handle type ones with different length. The length variation of straight handle has distinct influence on the effect of stress shielding.