摩擦热对人工髋关节假体松动失效的作用机理研究

Higher frictional heat will be produced during the service process of artificial joint prosthesis in vivo than natural joint. The loosening failure mechanism of prosthesis will be changed by the elevated temperature of prosthesis and synovial fluid. But in this process, the specific mechanism of frictional heat has not been put forward. In this study, the frictional heat generated on the interface of joint head/acetabulum in the friction process of prosthesis is studied. First of all, the temperature distribution model of prosthesis and synovial fluid under the effect of frictional heat will be established by using the experimental measurement, numerical solution and finite element simulation, and the process of frictional heat generation and diffusion will be elucidated. Secondly, the effect of frictional heat on the prosthesis friction and wear behavior will be studied by analyzing the interfacial tribological property and the synovial fluid lubrication, and constructing the coupling relationship between frictional heat and fluid lubrication characteristics. Last, the effect of frictional heat on the pathogenesis of “wear debris disease” will be studied by analyzing the UHMWPE wear debris characteristics and the osteolysis reaction process induced by wear debris, and constructing the coupling relationship between frictional heat and interface wear debris properties. The effective mitigation method of frictional heat to accelerate prosthesis loosening failure will be presented by combining the depth analysis of the process of frictional heat generation and diffusion. The results of this study can provide a new idea for solving the loosening problems of various types of prosthesis, and provide some theoretical and data support to put forward more reasonable postoperative attention for the patients with joint replacement.

人工关节服役过程中会产生高于天然关节的摩擦热，引起假体与滑液温度上升进而改变假体的松动失效机制，但在此过程中，摩擦热的具体作用机理一直未被合理提出。本项目以髋关节假体关节头/髋臼界面产生的摩擦热为研究对象，首先，运用试验测量、数值求解及有限元模拟等方法，建立摩擦热作用下假体与滑液的温度场分布模型，阐明摩擦热产生与扩散的具体过程；然后，研究摩擦热作用下的UHMWPE耐磨特性及滑液润滑特性，构建摩擦热与滑液润滑特性间的耦合关系并探讨其对假体摩擦磨损行为的影响；最后，研究摩擦热作用下的UHMWPE磨屑性状及磨屑诱导骨溶解反应过程，构建摩擦热与界面磨屑性状间的耦合关系并探讨其对“磨屑病”发病机制的影响，结合摩擦热产生与扩散过程的深入分析，提出有效减缓摩擦热加速假体松动失效的控制方法。研究结果能为解决各类假体松动失效问题提供新的研究思路，并为关节置换患者提出更为合理的术后注意事项提供一定的理论依据。

本项目以人工关节服役过程中产生的高于天然关节的摩擦热为对象，以阐明摩擦热效应对髋关节假体服役寿命的影响机制为目标，开展了摩擦热对人工髋关节假体松动失效的作用机理研究。主要研究内容包括：基于Herz接触理论，结合数值计算与有限元仿真，构建了不同材料髋臼配副在模拟步态过程中头-窝界面接触力学模型及热力学模型，阐述了步态下界面摩擦热的产生、分配及扩散机理；研究了摩擦热作用下不同假体材料的摩擦磨损特性，阐明了摩擦热效应影响下不同材料磨屑的生成过程及表面磨损机理的变化过程，特别提出了高摩擦热作用下的UHMWPE材料的塑性变形机制；研究了摩擦热作用下生物滑液的润滑特性、润湿特性及生物学特性，结合摩擦学试验结果，阐明了平均蛋白浓度、UHMWPE润湿性及平均摩擦系数三者间的相互耦合关系，进一步解析了摩擦热效应对UHMWPE关节窝材料体内失效过程的作用机理；同时，考虑到摩擦热诱导金属基假体材料金属离子的释放对假体体内服役寿命的恶劣影响，开展了摩擦热效应影响下的金属基假体材料的电化学腐蚀行为研究，构建了摩擦热影响下金属基假体材料表面电化学腐蚀过程的物理模型。研究结果可为进一步解决假体体内的松动失效问题提供理论依据与数据支持。