三维有限元分析外固定支架与掌骨板治疗Rolando骨折的力学稳定性

Mechanical stability of external fixator versus metacarpal plate for Rolando fracture by three-dimensional finite element analysis

背景:Rolando骨折发病率较高,治疗上对于外固定支架与掌骨板的选择目前尚无统一定论。目的:建立三维有限元模型,比较外固定支架与掌骨板在力学稳定性方面的差异,为临床治疗Rolando骨折提供理论依据。方法:随机选取1名健康志愿者,拍摄手腕关节的三维CT及MRI图像。将数据导入Mimics 10.0软件中,分别对第1、2掌腕关节骨组织及软组织进行三维建模,并将数据导入至Geomogic Studio 10软件中进行精细化处理。最后将所有数据以IGES格式输出至ANSYS 12.0软件中,利用软件的分割功能建立Rolando骨折模型,并使用建模功能建立掌骨板及外固定支架的实体模型。按照临床治疗方式将其固定,对各模型的材料属性进行赋值、划分网格,建立三维有限元模型。在第1掌骨头施加100 N的纵向负荷进行非线性分析,测定骨折面的最大位移。结果与结论:(1)外固定支架组掌尺侧骨折块的相对位移与总位移最大、最小值依次为2.033,0.201,5.674,0.548 mm,背外侧骨折块为2.537,0.405,4.479,0.127 mm;掌骨板组掌尺侧骨折块的相对位移与总位移最大、最小值依次为0.385,0.133,0.595,0.163 mm,背外侧骨折块为0.278,0.164,0.501,0.142 mm。经统计学分析,掌骨板组显著优于外固定支架组(P<0.05);(2)结果提示,掌骨板是治疗Rolando骨折的理想方法。

BACKGROUND： The incidence of Rolando fracture is high, and there is no unified theory for the selection of external fixation and internal fixation plate. OBJECTIVE： To compare the mechanical stability of the external fixator and metacarpal plate by establishing the three-dimensional （3D） finite element models, so as to provide a theoretical basis for the clinical treatment of Rolando fracture. METHODS： One healthy adult volunteer was selected, and the wrist joint was scanned by CT and MRI. The data were imported into Mmics 10.0, and the 3D model of the first and the second metacarpal and trapezium was established. All data were imported into Geomagic studio 10 for editing, and then transferred into ANSYS 12.0. Micro external fixator, the micro metacarpal bone plate model and Rolando fracture type in the clinical treatment principle of the two kinds of fixation methods were constructed. Each model was built following appropriate unit type, and then given 100 N of vertical load in the first metacarpal fracture distal, and the maximum displacement was detected. RESULTS AND CONCLUSION： （1） In the external fixation group, the relative displacement and total displacement of the maximum and minimum values of palm ulnar fracture end were 2.033, 0.201, 5.674, and 0.548 mm, were 2.537, 0.405, 4.479, 0.127 mm on the dorsolateral fracture end, respectively. In the plate group, the relative displacement and total displacement of the maximum and minimum values of palm ulnar fracture end were 0.385, 0.133, 0.595, 0.163 mm, were 0.278, 0.164, 0.501, 0.142 mm on the dorsal lateral fracture end, respectively. The differences were significant between two groups （P 〈 0.05）. （2） To conclude, metacarpal plate is an ideal method for Rolando fracture.