目的 建立正常与骨质疏松性肱骨的三维有限元模型,进行有限元分析,分析应力分布情况.方法 对一排除病变的志愿者右侧肱骨进行CT扫描,通过MIMICS软件进行三维重建、划分网格,按照灰度值分为密质骨与松质骨部分赋予材质,导入ANSYS软件,对肱骨近端进行约束限制,对远端按照肱骨小头40%、肱骨滑车60%的比例施加载荷,分析肱骨的应力分布状况.将该志愿者有限元模型中的弹性模量于密质骨部分减少33%、松质骨部分减少66%,泊松比不变,构建骨质疏松模型,按照与健康模型相同的约束与载荷施加条件,观察应力结果 ,进行比较.结果 健康模型与骨质疏松模型的应力基本集中于骨干中上部,肱骨近端和肱骨远端应力较小,整体受力趋势相似.提取髁上部位的节点,两种模型都是尺侧应力大于桡侧应力.随机选取肱骨头和大结节嵴下方的节点求应力均数,正常模型大于骨质疏松模型,推测是由于骨质疏松性骨骼骨密度减小、骨小梁变细、骨强度降低导致.结论 骨质疏松性肱骨与正常肱骨的整体受力趋势相似,表现为骨干部位受力大、两端受力小;正常肱骨的载荷强度更高.%Objective To establish a three-dimensional finite element model of normal and osteoporosis humerus and analyze the stress distribution. Methods A volunteer who was excluded from the lesion was selected to perform a CT scan on the right humerus. Three-dimensional reconstruction, grid partitioning and material assignment according to the grey value into compact bone and cancellous bone parts was conducted on the scanogram by MIMICS software. Then, the reconstructed scanogram was imported into the ANSYS software, and the restrictions were performed on the proximal humeral. Sixty percent of the loading was applied on the distal and forty percent was performed on the humeral capitellum pulley, the stress distribution condition of the humerus was then analyzed. A model of osteoporosis was constructed on the volunteer for the finite element model of the elastic modulus of in compact bone parts decreased by 33%, cancellous bone fell 66%, and poisson's ratio was in constant. The same constraints and loads as the health model was applied, the stress as a result was observed and the comparison was performed between them. Results Both of the stress of the health model and the osteoporosis model were almost focused on the backbone of the upper, the stress humerus of distal and proximal humerus was small, the overall stress trend was similar. As extracting the nodes on the upper part of the condyle, we found that both of the models measured by the ulnar stress was greater than the radial stress. Normal model was greater than the osteoporosis model when the mean value of stress was randomly selected from the humerus head and below the crest of the greater tuberosity node, presumably due to osteoporotic bone bone mineral density, bone trabeculae and bone strength decreased. Conclusion The overall force trend of the osteoporosis humerus is similar to that of the normal humerus, which is characterized by large force on the backbone area and small force on both ends of the bone. The normal humerus has a higher load intensity.
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