经Lister结节穿针多针阶梯形排列髓内弹性固定的3D有限元分析

目的：考察经Lister结节穿针多针阶梯形排列髓内弹性固定的力学效应。方法：采用CT扫描与计算机图象处理相结合的建模方法，进行尺桡骨受力的3D有限元分析，对比无克氏针固定、多针固定、传统针固定3种状态下，尺桡骨干在压缩和弯曲两种外载荷条件下的受力状态。结果：受压缩载荷作用时，桡骨在产生压缩变形的同时，横向（X轴方向）也产生一定的位移，且随着压缩载荷的增大，横向位移（绝对值）增加；尺骨压缩时横向位移很小。未植入克氏针与植入不同数量克氏针的尺桡骨压缩时，横向位移差异明显。传统针固定和多针固定时，受压缩载荷的尺骨受力较均匀，且等效应力低；而桡骨的等效应力分布不均匀，在桡曲的中间段内外侧应力明显集中；植入克氏针后骨干受力有所变化，尤其是尺骨的等效应力值明显下降。在受到横向的弯曲载荷时，尺桡骨同时产生横向弯曲，其中间部分的最大桡曲位移量随着弯曲载荷的增加而增大。在相同外载荷作用下，无克氏针固定和植入克氏针固定的尺桡骨的最大横向位移有一定差别，并且弯曲载荷越大，无克氏针固定、多针固定、传统针固定的差别越明显。克氏针固定后，其最大等效应力下降明显，尤以多针固定下降最明显。随着横向弯曲载荷的增加，尺桡骨横向弯曲变形越来越严重，外侧表现出纵向拉应力。植入克氏针尤其是多针后，桡骨内侧最大的压应力（绝对值）和外侧的最大拉应力值均明显降低，桡骨承载能力明显提高。结论：经Lister结节穿针多针阶梯形排列髓内弹性固定能有效分担外来载荷对尺桡骨的力学影响，提高固定的稳定性，维持桡骨的生理曲度，从而提高疗效。

3D finite element analysis on intramedullary elastic fixation with multi pin trapezoid arrangedly through the Lister tubercle

Objective：To explore the mechanical effects of intramedullary elastic fixation with multi-pin trapezoid-arrangedly through the Lister tubercle. Methods ：To make a 3D finite-element analysis of ulna and radius under stress through the modeling method in the adoption of CT scan and computer image processing,then compare the strained conditions of shaft of ulna and radius suffered from the external load of compression and bending on the states of non-fixation, fixation with multiple Kirschner wires and fixation with traditional Kirschner wire respectively. Results：Being suffered from compressive load, there happened a certain displacement horizontally（X-direction） for the radius at the same time of coming about compressive deformation ,and its horizontal displacement（ absolute value） increased following up with the en- largement of compressive load;while the horizontal displacement of ulna was much smaller than that of radius on the same conditions. There was a significant difference of horizontal displacements of the ulna and radius suffered from compressive load when they were unimplanted with Kirschner wire and implanted with different numbers of Kirschner wires. On the conditions of being fixed with traditional and multiple needles, the stress of ulna subject to compressive load was even,and its equivalent stress was weak;while equivalent stress of radius was uneven, and the stress concentrated on both medialis side and lateral side of middle section of radius. After being implanted with Kirschner wire, stress of bone shaft changed, and equivalent stress of ulna decreased evidently. Being suffered from bending load horizontally ,there happend horizontal bend on the ulna and radius at the same time, and the maximal extent of displacement on their middle section enlarged following up with the increase of bending load. Under the same external load, there was significant diference on the maximal horitzontal displacement of ulna-radius on the conditions of being fixed with or without Kirschner wires. Fu