人工髋关节置换前后股骨及假体的生物力学分析

Biomechanical analysis of prosthesis and femur before and after hip replacement

目的:研究人工髋关节置换前后股骨及假体的应力分布以及假体设计参数对应力的影响。方法:建立股骨和假体有限元模型,分析在步行峰值关节载荷和主要肌肉载荷作用下,完整股骨和置换后股骨及假体的应力水平。结果:完整股骨中上部内侧受压应力,外侧受张应力,中下部外侧受压应力,内侧受张应力,股骨应力峰值位于中下部;置换后股骨受力总体模式不变,近端应力遮挡显著。随颈干角增加,假体及股骨应力水平降低;柄长对假体应力影响不大,股骨上的应力随柄长增大略有增加。结论:假体设计时可适当增大颈干角,在骨组织条件允许的情况下可适当增加假体柄长,以减轻术后的应力遮挡效应。

Objective： To determine stress distribution of prosthesis and femur before and after hip replacement and the effect of design parameters on the stress. Methods： The finite element models of an intact femur and a femur implanted with a femoral prosthesis were developed and stress analysis were carried out when both joint contact forces and muscle forces were included in the loading. Results： The peak stresses of intact femur were presented at the middle and lower regions of femur with compressive stress in lateral side and tensile stress in medial side, which was on the contrary at the upper femur. The stress pattern of implanted femur was similar to the one of intact femur with the obvious stress shielding at proximal femur. With increasing neck-shaft angle, the stress of femur and prosthesis decreased. The increased length of the stem brought the increased stress of femur slightly, but had little effect on the stress of prosthesis. Conclusions： Neck-shaft angle could be increased properly and stem length could be increased in certain conditions to reduce the stress shielding in implanted femur.