站立位下骨盆与骨折内固定稳定性分析

目的 构建骨盆与骨折内固定三维有限元模型并验证其有效性。方法 基于骨盆CT扫描图像，利用Mimics、 ANSYS ICEM、 Hypermesh 与ABAQUS软件构建骨盆三维有限元模型，并在S1椎体上垂直向下加载600 N均布载荷，模拟站立位时骨盆受力环境，验证骨盆模型的有效性；同时建立3种不同内固定形式的T型骨折模型，验证3种内固定方式的有效性。 结果 站立位时，应力与位移分布左右对称，应力主要集中在弓状线起点处、耻骨支以及髋臼后上方。骨盆位移分布类似于以骶骨为中心向外传导并逐渐减弱的波浪形，骶骨背侧的骶正中嵴位移最大，髂骨窝、股骨位移较小，并逐渐减小直至股骨，同时发现3种内固定都可增加骨折稳定性。 结论 利用六面体网格建立的三维有限元模型，能够准确模拟站立位时骨盆力学特性，为临床研究提供直观准确的依据。

Stability analysis of the pelvis and fracture fixation in standing position

Objective To develop the three-dimensional (3D) finite element (FE) models of pelvis and fracture fixation, and test their validity. Methods Based on CT scan images, the 3D FE model of the pelvis was built by software of Mimics, ANSYS ICEM, Hypermesh and ABAQUS. A uniformly distributed load of 600 N was applied in vertical direction on the upper lamina of S1 vertebrae to simulate the stresses on the pelvis in standing position and to verify the validity of the pelvis model. T-shaped acetabular fracture models with 3 types of fixation were also established to verify the validity of internal fixation. ResultsBoth the stress and displacement distributions were found to be bilaterally symmetrical on the pelvis in standing position, with the Von Mises stresses mainly distributed in the beginning of arcuate line, pubic branch and posterior-superior area of acetabulum. The largest displacement occurred in the center of the sacral crest, and became relatively smaller in iliac fossa and femur, which was reduced gradually to the femur. Each of the three fixation types in acetabulum showed good biomechanical stability. Conclusions The established hexahedral grid-3D FE model can accurately simulate mechanical properties of the femur in standing position, which would provide an intuitive basis for clinical study.