点接触锁定接骨板固定股骨干骨折的三维有限元分析

Finite element analysis on point contact locking plate fixating femoral shaft fractures

目的探讨点接触锁定接骨板固定股骨干横行骨折的生物力学性能。方法通过CT扫描和软件建立股骨三维模型，采用计算机辅助技术设计出点接触锁定接骨板的三维模型。模型装配后，采用ANSYS软件分析在四点前后弯曲、轴向压缩和扭转三种不同受力情况下，股骨和点接触锁定接骨板的应力分布情况。结果（1）系统在四点前后弯曲条件下，股骨各个螺孔处无明显应力集中现象，接骨板应力集中于边缘。（2）系统在轴向压力作用下，股骨螺孔处的最大应力集中于最远端螺孔处，接骨板应力集中于中间两个螺孔处。（3）系统在扭转载荷下，股骨干两端螺孔处受力较大，接骨板应力集中于中部及中间两个螺孔处。结论在四点前后弯曲、轴向压缩和扭转三种载荷下，接骨板上应力集中于板边缘或者中间，而股骨的应力都集中在骨折位点最近的两个螺孔或最远的两个螺孔处。

Objective To set up a three-dimensional finite element model （FEM） to investigate biomechanics of point contact locking plate （PC-LP） fixating femoral shaft fractures. Methods One intact fresh adult cadaveric femur was scanned by CT at 1 mm interval. Then, the data of CT were utilized to establish three-dimensional FEM by using software Mimics and PRO/E and simulate the different clinical loading conditions. The changes of theoretical stress of femur and PC-LP were analyzed under flexion, axial compression and torsion loads. Results （ 1 ） Under four-point bending load, the distribution of femur stress was in uniformity, with the largest stress of the PC-LP focused on the edge. （2） Under axial compression load of 250 N, the largest stress of the femur was focused on the screw holes on both distal ends, with the largest stress of the PC-LP focused on the middle screw holes. （ 3 ） Under the torsion load of 15 N · m, the distribution of femur stress was in uniformity, with the largest stress of the PC-LP focused on the middlepart and the middle screw holes. Conclusions Under the four-point bending, axial compression and torsion loads, the distribution of femur stress is in uniformity, when the largest stress of the PC-LP focuses on edge or the middle screw holes, while that of the PC-LP on two screw holes of proximal or distal ends.