髋表面置换股骨侧假体外翻位植入后股骨近端应力变化的有限元分析

目的 探讨髋表面置换股骨侧假体外翻位植入后股骨近端的应力变化,并寻求最佳外翻植入角度.方法 建立正常股骨近端髋表面置换股骨侧假体(Wright假体)三维模型,其中股骨假体按解剖颈干角(本文选用股骨模型的生理解剖颈干角为135°)、外翻5°、10°、15°植入,加载关节合力及相关肌肉的肌力负荷,分析假体植入前后股骨近端的应力分布变化,并对股骨近端假体周围区域骨质应力分布进行分区量化研究.结果 股骨假体轻度外翻植入降低了股骨头颈交界处上方(2、8区)的应力,5°外翻植入股骨头上方假体杯下缘(1、7区)应力遮挡最小,股骨颈下方(4、10区)应力分布更接近正常股骨.结论 外翻5°植入假体股骨近端应力更接近正常股骨,降低了股骨颈骨折和假体松动的危险.

A finite element analysis of stress distribution on proximal femur after vulgus implantation in hip resurfacing arthroplasty

Objective To determine an ideal angle for prosthesis implantation after analyzing the stress distribution on the proximal femur after valgus implantation of hip resurfacing arthroplasty.Methods A three-dimensional finite element model of intact femur was developed for implantation of the Wright hip resudaeing prosthesis at valgus degrees of 0°,5°,10°,and 15°.After articular resultant forces and related muscles' forces were loaded,changes in stresses on the proximal femur before and after implantation were analyzed.Results A slightly valgus orientation reduced the stress on the superior neck around the head-neck junction (sections 2 & 8).In the implantation at valgus degrees of 5°,the stress shielding in the proximal sections (sections 1 & 7) was the minimum,and the stress distribution in sections 4 and 10 were close to that in the case of an intact femur.Conclusion A valgus 5° implantation in hip resudacing arthroplasty may result in a stress distribution on the proximal femur similar to the normal value and thus may decrease the risks of femoral neck fracture and aseptic loosening of the femoral component.