锁骨中段骨折三种固定的有限元分析

A finite element analysis on three types of internal fixation for middle clavicle fracture

[目的]通过有限元分析的方法,比较锁骨中段骨折三种固定的生物力学特点。[方法]64排螺旋CT扫描青年志愿者锁骨图像数据,经Mimics 14.0、Geomagic Studio10.0和Creo4.0软件处理,建立锁骨中段骨折锁定钢板(locking plate,LP)、弹性髓内钉(elastic stable intramedullary nail,ESIN)和螺纹弹性髓内钉(threaded intramedullary nail,TIN)内固定模型,导人Hypermesh 13.0划分单兀网格,在Abaqus 6.14软件中添加250 N轴向载荷及250 N垂直载荷,分析骨折端位移量及内固定应力分布。[结果]轴向和垂直载荷下骨折端位移和锁骨骨远端位移量由高至低均依次为:ESIN>TIN>LP,差异有统计学意义(P<0.05)。骨折端应力由高至低均依次为:ESIN>TIN>LP,差异有统计学意义(P<0.05)。三种固定下斜形骨折的骨折端位移和应力均大于横形骨折(P<0.05)。垂直载荷下,各模型的位移量和内固定应力均显著大于轴向载荷,差异有统计学意义(P<0.05)。[结论]TIN固定锁骨中段骨折的力学特性优于ESIN,但两种髓内钉对锁骨远端的控制均弱于LP,提示临床术后应注意避免上肢过早负重。

[Objective]To compare the biomechanical characteristics of three types of internal fixation for middle clavicle fracture by a finite element analysis.[Methods]The data of 64-slice spiral CT thin-layer scan of the clavicle in a young volunteer were processed by using Mimics 14.0,Geomagic Studio 10.0 and Creo 4.0 software to establish digital 3-dimensional models of middle clavicle fracture with internal fixation of locking plate(LP),elastic stable intramedullary nail(ESIN)and threaded intramedullary nail(TIN).The models were pro-cessed further by Hypermesh 13.0 software to mesh,added 250 N axial load and 250 N vertical load by Abaqus 6.14 to analyze fracture end displacement and stress distribution.[Results]The displacements of the fracture ends and the distal clavicle under axial and vertical loads were ranked up-down in order of ESIN>TIN>LP,which was statistically significant(P<0.05).In addition,the stress on the fracture ends were ranked up-down in order of ESIN>TIN>LP,with statistically significant differences(P<0.05).The displacement and stress on the fracture ends in the three types of fixation proved significantly greater in oblique fractures than transverse fractures(P<0.05).Under vertical load the displacement and stress in each model were significantly greater than those under axial load(P<0.05).[Conclusion]The TIN has better mechanical properties than ESIN for fixation of the middle clavicle fracture,however,both abovesaid intramedullary nails has weaker capacity to control the distal clavicle than LP,suggesting that care should be taken to avoid early weight bearing of upper limb in clinical setting.