全髋关节置换术中压电股骨重建的边光滑有限元分析

目的 针对传统有限元法(finite element method, FEM)分析全髋关节置换(total hip arthroplasty, THA)后压电股骨重建时精度低的问题，采用边光滑有限元法(edge-based smoothed finite element method, ES-FEM)对植入假体后压电股骨近端的骨重建进行仿真分析。方法 根据自适应骨重建理论，建立假体-压电股骨模型。基于模型的背景网格构建光滑域，引入梯度光滑技术，求解出光滑的重建刺激，进而得到术后压电股骨近端的密度分布。结果 植入假体后，受力点由股骨头转移到假体，出现应力屏蔽现象，股骨内部表观密度的分布发生明显变化。相比于FEM,ES-FEM在一定程度上能软化数值模型，提高仿真精度。在相同的网格下，电势和密度的求解精度分别提高27%和30%左右。结论 采用ES-FEM能够更精确地模拟出THA术后压电股骨近端的骨重建进程，为THA临床研究提供有效的理论依据。

Edge-Based Smoothed Finite Element Analysis of Piezoelectric Femur Remodeling in Total Hip Arthroplasty

Objective Aiming at the low accuracy problem of the traditional finite element method ( FEM) in analyzing the piezoelectric femur remodeling after total hip arthroplasty (THA), the edge-based smoothed finite element method ( ES-FEM ) was applied to simulate remodeling process of the piezoelectric femur after prosthesis implantation. Methods According to the adaptive bone remodeling theory, the prosthesis-piezoelectric femur model was established. Based on background mesh of the model, the edge-based smoothing domainswere constructed. Then, the smoothed remodeling stimuli were calculated by introducing the gradient smoothing technology. The distribution of apparent density in proximal femur could be obtained. Results After prosthesis implantation, the stress points were transferred from the femoral head to the prosthesis. Hence, the stress shielding phenomenon occurred. The apparent density distributions changed obviously. Compared with the FEM the ES-FEM could soften the numerical model and improve the simulation accuracy. Based on the same mesh, the computation accuracy of the potential and density was improved by about 27% and 30% , respectively. Conclusions The ES-FEM in this study possesses better accuracy in analyzing the bone remodeling after THA, which provides an effective theoretical basis for clinical study of artificial joint replacement.