移植隧道对股骨力学性能的影响

EFFECTS OF FEMORAL TUNNELS ON MECHANICAL PROPERTIES OF HUMAN FEMUR

该文应用Mimics 8.1软件由膝关节螺旋CT数据重构3D股骨模型。基于该模型依据单束、双束韧带重建手术的要求,建立了膝关节正常股骨、含单移植、双移植隧道股骨的三种近似三维有限元模型。根据股骨在关节屈伸中承受载荷的性质提取压缩、弯曲和扭转三种作用力,分别加载到上述三种有限元股骨模型上,进行有限元仿真。该文提出截面应力比较法,从股骨截面应力云图中提取最大有效应力值与最大第一主应力值为指标来评定隧道对股骨承载性能的影响,通过对比分析表明:无论采用前交叉韧带重建的哪种方法,在正常压缩、弯曲和扭转的三种负载下,隧道对ACL重建后的截面应力分布状态影响不明显,对股骨最大有效应力值的影响较弱(应力变化量≤5.06%),对股骨第一主应力值的影响也较小(变化量≤6.85%)。总之,ACL重建移植隧道对股骨承载应力的影响较小。在临床手术中医生对股骨隧道的视点只需放在起止点的准确选取上。该文提出的截面应力比较法丰富了ACL重建术后的股骨力学性能评定的技术与方法。

Firstly in this paper,a three dimensional model of human femur was built based on spiral CT images utilizing the software Mimics 8.1.Based on this femur model and according to the demand of the ligament reconstruction surgery,three approximately 3D finite element models corresponding to intact femur model,the femur model with a signal tunnel and femur model with double tunnels are built.Then,the loads received by the femur in joint movement are decomposed into three forces：namely compress,bend and torsion forces and are applied to the three finite element femur models to carry out the finite element simulation.This paper introduces the sectional stress comparison method,which extract the max virtual stress and max primary stress from stress nephogram of femur sections to evaluate the tunnels’ effects on femur＇s mechanical properties.The results show that,the femoral tunnels affect the distribution of femur section stress insignificantly after ACL reconstruction,with the max virtual stress and max primary stress change less than 5.06% and 6.85% respectively.Therefore,surgeons can only concentrate their attentions on considering the precise sites of the femoral tunnels in the surgery.Also,the section stress comparison method proposed in this work suggests a new way to evaluate femur＇s mechanical properties after ACL reconstruction.