Optimum Design of Knee Prostheses with High Performance Similar to Natural Knee Joints

本研究的目的是开发与天然膝关节相似的高性能膝关节假体的优化设计方法。我们的目标是建立自适应多模态润滑系统。采用了以下方法：1。通过将铝颗粒掺入润滑剂中，对柔性材料（如人工软骨）与透明板之间形成的液膜进行了光学可视化。利用CCD相机和图像处理系统分析了液膜分布和接触区域。用明胶溶液润滑明胶模型，观察到凝胶膜的低摩擦行为。为评估膝关节假体在行走状态下的液膜形成情况，研制了膝关节模拟器，并将其用于测量股骨与胫骨构件之间的电阻和摩擦力。在具有高黏度润滑剂润滑的弹性胫骨部件的膝关节假体中，即使在加载站立阶段，弹性流体动力学膜也相当形成。实验结果表明，聚乙烯胫骨假体需要自适应多模态润滑来建立其持久耐用性，或者使用低粘度润滑剂进行润滑。全膝关节置换术的临床优化从假体几何设计、假体内固定及术后界面固定角度评价4种非骨水泥全膝关节假体的临床效果。

The object of this research is to develop the approaches for the optimum design of knee prostheses with high performance similar to natural knee joints. What we are aiming at is to establish the adaptive multimode lubrication.The following methods were carried out.1. Three-dimensional analysis for the contact conditions in knee jointsThe optical visualization of fluid film formation between compliant material as artificial cartilage and transparent plate was carried out by mixing aluminium particles into lubricants. The fluid film profiles and contact zones were analyzed by means of CCD camera and image processing system. The low frictional behavior of gel film was observed for gelatin models lubricated with gelatin solution.2. Knee joint simulator testTo evaluate the fluid film formation in knee prostheses under walking condition, the knee joint simulator was developed and used for the measurement of electric resistance and friction between femoral and tibial components. In a knee prosthesis with an elastomeric tibial component lubricated with high visosity lubricatns, the elastohydrodynamic film was considerably formed even during the loading stance phase. It is suggested from the experimental results that the adaptive multimode lubrication is required to establish the long durability of the knee prosthesis with polyethylene tibial component, or lubricated with low viscosity lubricants.3. Clinical optimization in total knee replacementThe clinical results of four types of uncemented total knee prostheses were evaluated from the viewpoint of the geometrical design, instrumentations and postoperative fixation at the interface.