锁骨骨折复位拉伸力优化加载方案的模拟分析

Simulation analysis on optimial loading scheme of resetting tensile stress for clavicular fracture

目的探讨锁骨骨折复位拉伸力的外部加载最优方案,为锁骨骨折外固定器的优化设计提供力学参考。方法利用志愿者肩部CT扫描数据通过Mimics软件建立人体左侧肩部的三维模型。为了更好地模拟实际人体肩部,在模型中添加韧带组织并考虑肌肉组织的约束,建立复位拉伸力模拟分析的实验模型。通过3组仿真实验,分别模拟分析复位拉伸力方向、作用点位置的影响及取值范围,采用正交试验法综合模拟多种外部载荷情况下人体肩部模型锁骨部位获得的复位拉伸力。结果当外固定器加载在肩部合力方向在水平面的投影与冠状轴的夹角θ>45°时,锁骨获得复位拉伸力,且随着夹角越大拉伸力越大。外固定器加载在肩部合力方向在矢状面的投影与矢状轴的夹角η=30°~45°时,锁骨复位拉伸力最大。外固定器在肩部作用的位置离锁骨水平位置越远,锁骨复位拉伸力就越大。结论正交试验结果表明,产生最佳复位拉伸力的参数组合为θ=65°,η=50°,施加在人体肩部肱骨头中心。

Objective To investigate the optimal scheme about the external loading of resetting tensile stress for clavicular fracture, so as to provide some mechanical references for optimal design of external fixators for clavicu- lar fracture. Methods The shoulder CT scanning data from a volunteer were used to establish the three-dimen- sional model of human left shoulder by Mimics software. In order to better simulate the actual human shoulder, the ligament tissues were added in the model and the constraints of muscles were considered, and the experi- mental model for simulation analysis on resetting tensile stress was established. By 3 simulation experiments, the impacts from directions of resetting tensile stress, positions of action points and value ranges were simulated and analyzed, respectively. The resetting tensile stresses obtained from clavicle of the shoulder model under various external loading cases were simulated by orthogona~ test methods. Results When the 0 （ angle between the hori- zontal plane projection of shoulder force which was loaded by external fixator and the coronal axis） was greater than 45°, clavicle could obtain the resetting tensile stress, which became greater with the angle 0 increasing. When rl （angle between the sagittal plane projection of shoulder force which was loaded by external fixator and the sagittal axis） was 30°-45°, the resetting tensile stress of clavicle was the maximum. The farther the position on which the loads from external fixator was exerted from the horizontal position of clavicle, the larger the reset- ting tensile stress of clavicle was. Conclusions The results of orthogonal test show that the optimal resetting ten- sile stress is produced with parameter combination of θ = 65°, η =50°, acting on the center of humerus head of the shoulder.