2～5掌指关节屈伸活动中关节面应力分布的有限元分析

Finite element analysis of the stress distribution in articular surface during flexion and extension of 2～5 metacarpophalangeal joint

目的建立掌指关节三维有限元模型,分析掌指关节屈伸活动中掌指关节面应力分布情况。方法健康男性志愿者1名,对其右手掌指关节分别于0°、30°、60°、90°屈曲位进行CT扫描,利用扫描数据建立掌指关节三维有限元模型;于4个角度沿指骨径向分别施以10、20、30、40、50 N荷载,观察掌指关节应力分布,并对结果进行分析。结果 4组不同弯曲角度的掌指关节网格模型节点数量、单元数量基本相同,每组模型约40070个节点,178903个四面体单元。相同载荷作用下,弯曲的角度越大,各掌指关节面的应力越大。在实现0°、30°、60°、90°屈曲过程中,2~5掌指关节掌骨头应力峰值变化范围分别为0.20~2.46、0.22~1.58、0.22~1.69、0.22~2.25 Mpa。结论掌指关节屈伸过程中,弯曲的角度越大,掌指关节面的接触应力越大,其应力分布范围亦增大。

Objective To establish a three-dimensional finite element model of the metacarpophalangeal joint(MPJ),and analyze the stress distribution of the MPJ surface in the flexion and extension of the MPJ.Methods The hands of one healthy volunteer were examined.Three-dimensional CT scanning was performed at 30°intervals during passive flexion from 0°to 90°with use of a CT scanner.The CT scan data were used to establish the three-dimensional finite element model of the MPJ.The load distribution of the MPJ was observed by applying 10,20,30,40 and 50 N loading along the radial direction of the phalanx at four angles,and the results were analyzed.Results The number of nodes and the number of units of the four sets of MPJ mesh models with different bending angles were basically the same.Each group of models has about a total of 40070 nodes and 178903 tetrahedral units.Under the same load,the greater the angle of bending,the greater the stress on the MPJ surface.During the angles of 0°,30°,60°and 90°,the peak stress range of the metacarpal head of 2~5 MPJs was respectively,0.20~2.46,0.22~1.58,0.22~1.69,0.22~2.25 MPa.Conclusion During the flexion and extension of the MPJ,the greater the angle of bending,the greater the contact stress of the MPJ surface,and the wider the range of stress distribution.