应用三维有限元分析肱骨骨折后应力加载方向与加载力值(英文)

Three dimensional finite element analysis in the direction and amount of load applied on the fractured humerus

背景:肱骨骨折治疗中经常遇到的主要问题在于应力加载的方向与应力加载的力值。目的:探讨三维建模及有限元分析肱骨骨折治疗中轴向加载的力学理论依据。设计:构建肱骨骨折的三维有限元模型,进行不同方位的加载。单位:一所军医大学附属医院骨科和一所大学生命科学与生物工程学院。材料:实验于2002-04/2004-04在上海长海医院和上海同济大学生命科学实验室完成,选择肱骨标本行CT成像。方法:以肱骨横截面CT图像为基础,建立肱骨模型,利用ANSYS5.6软件进行计算,选取三维十结点四面体单元,共划分2729个结点、49041个单元,分析骨折断面与轴线成30°,45°,90°及X,Y,Z三方向固定时肱骨轴向受压的应力分布及大小。主要观察指标:对比不同方向肱骨骨折加载后的数值,寻求临床治疗的参考。结果:肱骨断面与非断面处应力差异较大,断面处应力较集中,且以断面为中心呈非严格对称分布,应力较大区域分布在距骨折部位10mm左右,是其他应力区的两三倍。结论:肱骨骨折治疗中应视不同情况估算所需载荷大小,选择合适内固定植入物以适应其功能活动的应力要求。

BACKGROUND:The most frequently encountered problem that an orthopedic doctor e ncounters in treating humerus fracture is how to choose the exact direction and amount of load applied on humerus. OBJECTIVE:To explore the clinical significance of establishing a three dimens ional model and finite element analysis in treating humerus fracture and to prov ide theoretical basis for applying appropriate axial stress. DESIGN:The three dimensional model of humerus was reconstructed,on which compr ession from different directions was applied. SETTING:Orthopedic department of an affiliated hospital and life science labor atory of a university. MATERIALS:A humerus specimen received CT scanning and the trial was conducted in Shanghai Changhai Hospital and Life Science Laboratory of Tongji University f rom April 2002 to April 2004. METHODS:The three dimensional model of humerus was established and relevant ca lculation was completed with ANSYS 5.6 software.The humerus model was divided in to 2 729 nodes and 49 041 units based on a three dimensional ten node tetrahed ron as one unit.The distribution and intensity of axial compression on the fract ure gap section were calculated and analyzed in the following conditions,i.e.whe n the humerus was fixed in X,Y and Z directions and the fracture gap section was 30°,45°,90°to Z axis. MAIN OUTCOME MEASURES:The axial pressure on the fracture gap section in differ ent conditions to provide evidence for clinical treatment. RESULTS:The stress applied on the fracture gap was relatively concentrated and was 2-3 times stronger than that in other areas,and it was generally symmetric ally distributed within 10 mm around the fracture gap. CONCLUSION:The required load on humerus fracture should be calculated before a suitable implant is applied to accommodate the movement of humerus without comp romising healing of the fracture.