股骨转子间骨折外侧壁重建PFNA固定的有限元分析△

A finite element analysis on lateral wall reconstruction of femoral intertrochanteric fracture with proximal femoral nail anti-rotation fixation

摘要:

[目的] 构建3 种不稳定转子间骨折模型并进行三维有限元分析，探讨外侧壁对股骨转子间骨折术后稳定性影响。[方法] 选取老年女性志愿者1 名，获取股骨CT 数据，经医学三维软件构建外侧壁完整的股骨粗隆间骨折股骨近端防旋髓内钉（proximal femoral nail anti-rotation, PFNA） 固定模型（完整组）、外侧壁缺损的骨折PFNA 固定模型模型（缺损组） 以及外侧壁钢板重建的骨折PFNA 固定模型（重建组）。设定边界条件、约束条件，于股骨头施加不同载荷，分析股骨-PFNA 系统的VonMises 应力、位移以及应变。[结果] 股骨-PFNA 系统位移研究结果显示，完整组和缺损组较重建组的位移稍大，但三组差异无统计学意义（P＞0.05）。Von Mises 应力研究结果显示：在不同应力加载下，三个模型组间平均最大应力差异无统计学意义（P＞0.05）。最大主应变依次为重建组＞完整组＞缺损组。股骨模型中重建组平均最大主应变显著大于缺损组[(30.3±15.1)×10-3 vs(22.5±12.1)×10-3, P＜0.001]，而PFNA 模型中重建组和缺损组差异无统计学意义（P＞0.05）。[结论] 外侧壁重建可提升股骨-PF-NA 系统整体稳定性，降低股骨-PFNA 系统应力分布，增加股骨近端应变分布。

Abstract:

[Objective] To investigate the effect of lateral wall reconstruction on postoperative stability of femoral intertrochanteric frac-tures. [Methods] One elderly female volunteer was selected to obtain the femoral CT data. Medical 3D software was used to construct themodel of intertrochanteric fracture and proximal femoral nail anti-rotation (PFNA) with intact lateral wall (the intact group), lateral wall de-fect (defect group), and lateral wall reconstructed by plate (reconstruction group). Boundary conditions and constraint conditions were set,and different loads were applied to the femoral head to analyze Von Mises stress, displacement and strain of the femor-PFNA system. [Results] The displacement femor-PFNA system was slightly larger in the intact group and defect group than that of reconstruction group,whereas which were not statistically significant between any two of the three groups (P＞0.05). The Von Mises stress was not significantly dif-ferent in the mean maximum stress between any two of the three model groups under different stress loads (P＞0.05). The maximum mainstrain was ranked in the order of reconstruction group ＞ intact group ＞ defect group, which in the reconstructed group was significantly high-er than that of the defect group [(30.3±15.1)×10-3 vs (22.5±12.1)×10-3, P＜0.001], while there was no significant difference between the re-constructed group and the defect group in the mean maximum PFNA strain (P＞0.05). [Conclusion] Lateral wall reconstruction can improvethe overall stability of the femor-PFNA system, reduce the stress distribution of the femor-PFNA system, and increase the strain distribu-tion of the proximal femur.