全髋关节置换前后股骨侧应力的理论分析

采用复合梁基本理论来构建骨水泥和非骨水泥型全髋关节置换前后假体周围骨质应力分布的解析理论模型，通过将假体周围股骨分成等距的11个断层，并将每个断层分成前、后、内、外四个象限，分别计算每个象限的解析解和有限元分析值，做直线回归并相关分析。结果显示解析理论模型能有效的用于全髋关节置换前后力学环境变化的研究，利用该模型不仅有助于理解并解释临床相关的力学问题，而且有助于对全髋关节置换相关的涉及患者自身、假体设计和手术等多方面因素进行规律性研究。

Theoretical Analysis of Changes in Femoral Stresses after Total Hip Arthroplasty

Changes in bone stress in the proximal femur following implantation can be estimated with the use of composite beam theory. The aim of this study was to construct the mathematical analytical models for predicting the degree of stress shielding and to test the validity of the predictions using finite element simulation. To define the periprosthetic bone stress values, the proximal femur was divided into eleven equidistant cross sections, then each section was divided into four quadrants corresponding to the anterior, posterior, medial and lateral aspects of the femur. Bone stress values were calculated by both mathematical analytical models and finite element analysis, then linear regression analyses produced slopes and R-values that show numerical and finite element results corresponding well to intact femur and both the types of fixation with/without cement. And the results also showed that femoral bone stress shielding by both the prostheses occurred in most periprosthetic zones. The most serious regions occurred in the proximal medial quadrant. This study has succeeded in creating the mathematical analytical models to predict the bone, cement and prostheses stress values, and thus can help us to evaluate the mechanical behavior of total hip replacement, to further understand the distinction between different fixation, and to make advances in implant design, surgical technique and long-term results.