Development of Optimum Design, Trial Production and Evaluation Systems for Knee Joint Prostheses with High Performace Similar to Natural Synovial Joints

本研究的目的是开发高性能膝关节假体的优化设计、试制和评估系统。采用了以下方法：【自然膝关节三维几何分析】利用激光位移仪对自然膝关节模型进行几何测量，进行几何分析。在站立和摆动阶段显示股骨表面半径的变化。接触分析表明，在严重阶段发生了滚动运动。分析了从磁共振图像中提取的表面轮廓。采用应变能最小化的方法进行表面重构。在对天然膝关节进行几何分析的基础上，提出了几种不同的几何模型。圆柱形。以丙烯酸树脂和超高分子量聚乙烯为原料，采用微机控制的数控机床制作了双圆柱形、球形和重塑模型。采用成型-解冻法制备PVA（聚乙烯醇）水凝胶胫骨组分。为评估膝关节假体的动态特性，研制了一种模拟行走运动的新型膝关节模拟器。观察了流体膜的形成和摩擦行为。【基于自适应多模态润滑的优化设计】在总结本课题的基础上，提出了膝关节假体自适应多模态润滑的设计理念。结果表明，采用较好的一致性几何设计或适当的半径设计，以及采用具有边界润滑能力的柔顺材料均可提高润滑性能。为临床应用指明了设计方向。

The object of this research is to develop the systems for optimum design, trial production and evaluation of knee prostheses with high performance.The following methods were carried out.[Three-dimensional geometrical analysis of natural knee joints] Geometrical analysis was carried out based on geometrical measurement of natural knee joint model by laser displacement meter. Changes in radius of femoral surfaces between stance and swing phases were shown. Contact analysis indicated the occurrence of rolling motion during severe phase. Surface profiles extracted from the Magnetic Resonance Images were analyzed. Surface remodeling were proposed by minimizing the strain energy.[Trial production and evaluation] Several kinds of geometrical models were proposed on the basis of geometrical analysis of natural knee joint. Cylindrical.duo-cylindrical, spherical and remodeling models were produced from acrylic resin and ultrahigh molecular weight polyethylene by personal computer controlled NC machine. The tibia component of PVA (polyvinylalcohol) hydrogel were prepared by molding-thawing method. New type of knee joint simulator to simulate walking motion was manufactured to evaluate of dynamic characteristics of knee prostheses. Fluid film formation and frictional behavior were observed.[Optimum design with adaptive multimode lubrication] The design concept of adaptive multimode lubrication for knee prostheses was proposed from the summarization of this research project. It was shown that geometrical design with better congruity or with appropriate radius, and the application of compliant materials accompanied with boundary lubricating ability enhance the lubricating performance. The design direction was shown for clinical application.