有限接触动力加压接骨板固定股骨干骨折的三维有限元分析

Finite element analysis of femoral shaft fracture fixed by limited contact dynamical compression plate

目的探讨有限接触动力加压接骨板固定股骨干横行骨折的生物力学性能,为将来的临床应用提供科学依据。方法通过CT扫描获取股骨的空间结构信息,利用软件建立其三维实体模型,采用三维反求技术获得有限接触动力加压接骨板的三维模型。模型装配后,采用ANSYS软件模拟在"四点"前后弯曲、轴向压缩和扭转3种不同受力情况下,股骨和有限接触动力加压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,股骨螺孔处的最大应力集中于最远端螺孔处;而接骨板应力集中于边缘。(2)系统受到15Nm的扭转载荷时,股骨干骨折线两端螺孔应力分布较均匀,无明显应力集中现象;而接骨板应力集中于靠近骨折线的中间两个螺孔处。结论在"四点"前后弯曲、轴向压缩和扭转3种载荷下,接骨板上应力集中的区域位于板边缘或者中间,而股骨的应力都集中在骨折位点中间的螺孔或最远的两个螺孔处。

Objective To set up a three dimensional finite element model（FEM） and investigate biomeehanies of transverse fracture of femoral shaft fixed by the limited contact dynamical compression plate. Methods One intact fresh adult eadaverie femur was scanned by CT with 1 mm interval. Then the data of CT were utilized to establish the three dimensional FEM by using software and simulate the different clinical loading conditions. Relying on the software analysis, the changes of theoretical stress in different positions of femur and the limited contact dynamical compression plate （ PC-LP） were analyzed, when the femur was in flexion, axially compression and torsion. Resuits （ 1） Under the four point bending load,the largest stress of the femur focused on the screw hole at the distal end,while the largest stress of the PC-LP focused on the edge. （2） Under the torsion load of 15Nm, femur stress was well-distributed,while the largest stress of the PC-LP focused on the middle screw holes. Conclusion Under the four point bending, axially compression and torsion load, the femur stress is well-distributed. The largest stress of the femur focuses on the distal or the middle screw holes, while the largest stress of the PC-LP focuses on the middle screw holes or the edges of the plate.