The present study describes the lubrication mechanisms within artificial hip joints considering real conformity of rubbing surfaces. Part I is focused on hard-on-soft material combination, introducing the fundamentals of lubrication performance. These pairs have not been explored in terms of in situ observation before. The contact of metal femoral component articulating with transparent polymer acetabular cup was studied using a hip joint simulator. The film formation was evaluated by fluorescent microscopy method. Various model synovial fluids were employed while the key constituents, i.e. albumin, γ-globulin, and hyaluronic acid were fluorescently stained to determine its role in film formation process. Two types of the tests were performed. The first dynamic test aimed on the development of film thickness under constant load during motor driven swinging motion mimicking flexion-extension. Subsequently, a combined test was designed consisting of the three phases; static part with loading/unloading phase (1), pendulum swinging till spontaneous damping of the motion due to friction (2), and static observation under the constant load (3). The results clearly confirmed that the interaction of constituents of synovial fluid plays a dominant role and substantially influences the lubrication conditions. In particular, the main finding coming from the present study is that γ-globulin together with hyaluronic acid form relatively thin stable boundary layer enabling the enhanced adsorption of albumin, thus increasing the lubricant film. Part II of the present study is focused on hard-on-hard pairs while the main differences in film formation process are highlighted among others.

本研究描述了人工髋关节内的润滑机制，考虑了摩擦表面的真实一致性。第一部分着重于软硬材料组合，介绍了润滑性能的基本原理。这些对以前从未进行过原位观察的探讨。使用髋关节模拟器研究了与透明聚合物髋臼杯铰接的金属股骨组件的接触。通过荧光显微镜法评价膜的形成。使用各种模型滑液，同时对关键成分即白蛋白，γ-球蛋白和透明质酸进行荧光染色，以确定其在成膜过程中的作用。进行了两种类型的测试。第一个动态测试旨在在模仿弯曲-延伸的电机驱动的摆动运动过程中，在恒定负载下形成膜厚。随后，设计了一个包含三个阶段的组合测试。带有加载/卸载阶段的静态零件（1），摆动摆动直至由于摩擦而自发地衰减运动（2），以及在恒定负载下进行静态观察（3）。结果清楚地证实，滑液成分之间的相互作用起主要作用，并显着影响润滑条件。特别地，来自本研究的主要发现是γ-球蛋白与透明质酸一起形成相对薄的稳定边界层，从而使得白蛋白的吸附增强，从而增加了润滑膜。