金属对金属髋关节动态边缘接触力学行为

目的研究球面共型接触人工髋关节在股骨头动态位移条件下的边缘接触力学行为。方法基于所发展的有限元球面网格数据模型,动态模拟分析金属对金属人工髋关节在给定生理位移工况条件下的接触行为和可能诱发的边缘接触现象。结果数值模拟表明,随着动态位移载荷的增加,关节接触面压力合力的垂直分力和水平分力都有上升趋势;在边缘接触过程中压力合力的垂直分力比非边缘接触情况变化趋势要缓慢,但相应的水平分力增大趋势更显著。此外,边缘接触与非边缘接触对应的接触压力分布形态与接触区域也各不相同。结论金属对金属人工关节髋臼相对股骨头过大的倾斜状态极易引起边缘接触,动态边缘接触情况下,将导致股骨头向髋臼内侧产生相对滑动及附加磨损的可能,这对临床人工髋关节磨损评估与关节制造发展提供了分析依据。

Dynamic edge contact behavior of metal-on-metal hip joint replacements

Objective To investigate the edge contact behavior of conformal spherical hip joint replacements under the given dynamic contact displacement condition.Methods Based on the developed spherical-grid-data-model,the contact behavior and corresponding edge contact behavior of a typical metal-on-metal hip joint replacement was simulated under the increasing displacement between the acetabular cup and femoral head.Results It was found from the obtained results that the vertical and horizontal component of the support force due to contact pressure increased with the dynamic contact displacement increasing.The vertical component of support force for the edge contact showed a slower variation tendency than that for the non-edge contact,while the corresponding horizontal component of support force increased more significantly with the dynamic displacement.In addition,the corresponding contact pressure distributions and the contact areas of hip joint replacements for edge contact and non-edge contact were different.Conclusions The significant edge contact behavior of hip joint replacements with bigger cup inclination angle occurrs with the increasing displacement of femoral head to the acetabular cup,which will cause the sliding between contact surfaces and additional wear since the horizontal support force increases.This provides a reference for the wear assessment and manufacturing of hip joint replacements.