金属对金属人工髋关节边缘接触效应

目的 研究金属对金属人工髋关节不同行走姿态下的接触力学行为，特别是大幅度运动可能导致的边缘接触效应。方法 建立球面共型接触的髋关节有限元模型，通过改变髋臼相对股骨头的倾斜状态和对股骨头施加恒定竖直方向载荷相结合，等效模拟分析人工髋关节不同行走姿态下的接触状态。结果 髋臼相对股骨头倾角在小于约60°范围内增加时，其对应的最大接触压力呈下降趋势，接触面积有所增大；当倾角超过80°范围时，关节接触区域因靠近髋臼边缘，最大接触压力位置由初始接触点向髋臼倾斜方向移动了约6°~9°的位置，用以满足压力分布合力与外载荷的平衡，接触压力和分布范围有所增加。结论 髋臼相对股骨头较大倾斜状态极易引起不同的边缘接触现象，置换人体髋关节产生的边缘接触问题需要引起临床外科和关节制造上的重视。

Effect of edge contact on metal-on-metal hip joint replacements

Objective To study the contact mechanics of metal-on-metal hip joint replacements under different walking conditions, particularly for the edge contact behavior between the cup and the head of the bearing due to large range movement. Methods The finite element model of a typical hip joint replacement with conformal spherical bearing was established to simulate the edge contact of hip joint replacement under the given cup inclination angles and vertical loads. Results The maximum contact pressure decreased slightly and the contact area increased when the cup inclination angles increased within the range of 0°~60°. When the cup inclination angles were more than 80°, the corresponding contact area moved to the cup edge, the maximum contact pressure and distribution range increased, but the position of the maximum contact pressure moved from the initial contact point to the new point with 6°~9° in the direction of the increasing cup inclination angle to balance the corresponding contact pressure distribution and the loaded human weight. Conclusions Different edge contact behavior of hip joint replacements tends to occur due to the bigger cup inclination angle. Therefore, much attention should be paid to the problem of edge contact for both the clinical surgery and the manufacturing of hip joint replacements.