不同骨密度下松质骨螺钉生物力学性能的三维有限元分析

Three-dimensional finite element analysis of biomechanical characteristics of cancellous screw in different bone densities

目的研究不同骨密度下松质骨螺钉拔出过程中的应力分布和拔出强度,为临床骨外科螺钉植入提供生物力学依据。方法使用Solidworks建立松质骨螺钉植入模型,导入Abaqus有限元软件模拟螺钉拔出过程,计算分析低、中、高3种骨密度下模型的应力分布和拔出力变化过程。结果拔出过程中,骨的应力集中在外螺纹与骨接触处,螺钉应力主要集中于尾侧3个螺纹的尾侧螺纹面,整体应力分布沿螺钉长轴递减;螺钉在3种密度松质骨中的拔出力随拔出位移增加而增加,拔出强度分别为208.90、431.45、648.80N。结论在松质骨螺钉拔出过程中,应力集中在螺钉尾侧,拔出强度与骨密度呈正相关。

Objective To predict the cancellous screw stress distributions and pull-out strength in cancellous bone with different densities using 3-D finite element analysis and provide biomechanical evidence for screw implant in clinical practices.Methods Three-dimensional models of bones with low,medium and high bone density and a fixation screw were generated in Solidworks.Finite element analysis was performed after importing these models to Abaqus to simulate the pullout process.Results Stress concentrated both at the surfaces where major diameter of the screw connected the bone and at the proximal half angle of the 3 proximal screw threads.Maximum Von Mises stress of the threads decreased along the long axis of the screw.The pull-out strengths of the cancellous screw were 208.9 N,431.45 N,and 648.80 N in low,medium and high bone density,respectively.Conclusion During the pull-out process of cancellous screw,stress concentrates at the proximal end of the screw and the pull-out strengths are proportional to the cancellous bone density.