经皮逆行拉力螺钉固定髋臼后柱骨折的有限元对比研究

目的：通过有限元法，对经坐骨结节和坐骨小切迹两种不同逆行拉力螺钉内固定方案的生物学稳定性进行比较，为临床应用提供理论依据。方法利用三维有限元软件，建立经坐骨结节（A组）和坐骨小切迹（B组）两种不同逆行拉力螺钉固定髋臼后柱骨折的有限元模型，模拟双足站立位和坐位，分别对其进行力学稳定性比较。结果对比站立位和坐位下两种内固定方案髋臼关节面骨折线节点位移均数及拉力螺钉最大应力，站立位位移均数A组＜B组（ P＝0．932＞0．05），差值无明显统计学意义；坐位位移均数A组＞B组（P＝0．004＜0．05），差值具有统计学意义。在坐位时拉力螺钉取得最大应力36．053Mpa。结论两种逆行拉力螺钉方案均可为髋臼后柱骨折提供坚强内固定，经坐骨小切迹置入后柱逆行拉力螺钉表现出更好的坐位生物力学稳定性。

Comparative finite element analysis of percutaneous retrograde lag screw fixation of the fractures in the posterior column of acetabulum

Objective Finite element method was used to compare the biomechanical stability for internal fixation by percutaneous retrograde lag screw for acetabular posterior column fractures via the ischial tuberosity( group A) and lesser sciatic notch( group B) ,so as to provide the reference for its clinical application.Methods Three-di-visional finite element modeling software was used to build two internal fixation models for treating posterior column ac-etabulum fracture,including retrograde lag screw via the ischial tuberosity and via lesser sciatic notch.Finite element analysis was carried out in sitting postion and standing position.Results In the sitting and standing position,the av-erage node displacement on the fracture line and the maximum force on the lag screw were compared.The node dis-placement on the fracture line between group A and group B showed statistically significant differences in the sitting position( group A>group B, P=0.004 <0.05 ) and no statistically significant difference in the standing position (group A0.05).The maximum force on the lag screw in sitting position was 36.053 Mpa. Conclusion Both methods of retrograde lag screw can provide rigid internal fixation for posterior column acetabulum fracture.The lag screw inserted via lesser sciatic notch shows better biomechanical stability in the sitting position.