预防股骨头坏死塌陷的内置物设计及有限元分析

Design of implant and finite element analysis for preventing collapse in osteonecrosis of the femoral head

目的基于目前股骨头植入装置对股骨头支撑不足的问题,设计一种帽形股骨头内置物并运用有限元分析探讨植入后对股骨应力分布的影响,评估其在临床应用的可能性。方法股骨头内置物由弧形帽和柱形短柄组成,弧形帽采用多孔材料;选取一名健康成人股骨为研究对象,根据CT扫描图像建立正常股骨头模型和植入术后远期有限元模型;根据骨密度分区设置材料属性,施加双足站立生理载荷条件,计算分析植入内置物前后股骨应力分布。结果术后内置物弧形帽下方骨组织节点应力均值低于术前模型,差异具有统计学意义;股骨颈部应力峰值及接触内置物柄部末端的区域应力水平增加,股骨其他结构的应力无显著变化。结论帽形内置物植入后能够降低股骨头应力水平并形成稳固支撑结构,有希望应用于股骨头坏死早期的临床治疗。

Objective To provide sufficient mechanical support for the femoral head,a cap-shaped titanium alloy implant was designed and finite element analysis was applied to investigate the biomechanical behaviour in the treatment for osteonecrosis of the femoral head(ONFH).Methods The implant consisted of a porous cap and a stem.Based on CT imaging data of a healthy volunteer,three-dimensional femur models before and after implantation were developed.Material properties were assigned by bone density and the stresses of the femoral head and femoral shaft were calculated before and after operation in weight-bearing state.Results After the implantation,Von Mises stress of the femoral head underside the cap decreased significantly,peak stress of femoral neck and the region around the stem increased,other region of the femur remained unchanged.Conclusions The cap-shaped implant is conducive to reduce the stress inside the femoral head and provide sufficient biomechanical support which might be a promising substitute for the treatment of early stage ONFH.