【作者】 谢强；

【导师】 雷光华；

【作者基本信息】 中南大学 ， 临床医学， 2013， 硕士

【摘要】 目的：收集正常人膝关节CT及MRI扫描图像,利用三维重建及ANSYS等三维有限元软件,建立正常人膝关节三维有限元模型。在此基础上,模拟后交叉韧带(posterior cruciate ligament, PCL)完全断裂(Ⅲ损伤)的三维有限元模型,计算并分析正常膝关节模型和PCL完全断裂模型中内侧副韧带(Medial collateral ligament, MCL)、外侧副韧带(lateral collateral ligament, LCL)和前交叉韧带(Anterior cruciate ligament, ACL)的应力分布及变化情况,从而全面了解PCL断裂后对其他韧带产生的影响,为PCL断裂后恢复膝关节动态稳定的重要性进一步提供理论依据。方法：1.利用螺旋CT机及Siemensl.5T超导磁共振仪对正常男性志愿者的膝关节分别采集经SCT扫描获取的计算机断层扫描图像及膝关节的横断面、冠状面及矢状面质子密度加权(PDWI)图像及脂肪抑制的T2加权(T2WI)图像,并将其以Dicom格式保存到工作电脑中,再导入E-feature Biomedical Modeler软件中获取骨骼、韧带、半月板、关节软骨层的边界。将取得数据转换为DIP文件,从而获得每个层面边界的三维空间坐标,再对该模型进行有限元网格划分,定义材料属性,最终生成膝关节三维有限元模型,再将其导入ANSYS有限元分析软件中,对模型进行生物力学分析。2.在已建立的正常人膝关节三维有限元模型上模拟正常膝关节屈曲0°、30°、60°时施加内外翻及内外旋力矩,计算并记录四条主要韧带(PCL、LCL、ACL、MCL)的平均应力值及等效应力分布图。3.将已建立的正常人膝关节三维有限元模型去除PCL,模拟PCL完全断裂(Ⅲ度损伤),对PCL完全断裂有限元模型按上述步骤进行力学分析,计算并记录三条主要韧带(LCL、ACL、 MCL)的平均应力值及等效应力分布图,再将其与正常人膝关节模型进行比较。结果：成功建立正常人膝关节三维有限元模型及PCL完全断裂膝关节有限元模型并进行了生物力学分析,结果显示：1.在20N·m的内翻力矩作用下,PCL完全断裂模型LCL在不同屈曲角度时的等效应力值平均值(3.39MPa、12.41MPa、14.56MPa)较正常组(2.30MPa、11.22MPa.12.84MPa)明显增大；2.在8N·m外旋力矩作用下,PCL完全断裂模型中LCL在不同屈曲角度时的等效应力值平均值(1.34MPa、12.24Mpa、12.56MPa)较正常组(0.22MPa、10.1OMPa、10.42MPa)明显增大；3.在20N·m的内外翻力矩和8N·m内外旋力矩作用下,PCL断裂模型中ACL及MCL的等效应力平均值与正常膝关节模型比较,差别很小。结论：1.根据正常膝关节CT及MRI的图像,运用E-feature Biomedical Modeler等三维有限元软件成功建立了正常人膝关节三维有限元模型及PCL完全断裂膝关节三维有限元模型,并进行膝关节主要韧带的生物力学分析。2.三维有限元生物力学分析数据显示PCL断裂后LCL在膝关节内翻及外旋运动时应力明显增大,ACL及MCL在膝关节运动时应力变化较小,进一步提示PCL断裂后应尽早重建,以免造成LCL的慢性损伤。更多还原

【Abstract】 Objective:Collect the normal image of CT and MRI scans of the knee, take advantage of the three-dimensional reconstruction and ANSYS three-dimensional finite element softwares to the establishment of dimensional finite element model of the normal human knee. On this basis, the simulation of three-dimensional finite element model of the posterior cruciate ligament (PCL) complete rupture (Ⅲ injury), calculate and analyze the normal knee model and the PCL complete rupture model of the stress distribution and changes of the medial collateral ligament (MCL), the lateral collateral ligament (LCL and the anterior cruciate ligament (ACL) to a comprehensive understanding of the PCL rupture it would affect the surrounding ligaments,which provides a theoretical basis for testing the importance of restoring the stability of the knee after PCL rupture.Methods:1. CT images and knee sagittal proton density-weighted (PDWI) images and cross-sectional, coronal and sagittal fat-suppressed T2-weighted images (T2WI) were obtained by using Spiral CT machine and Siemens1.5T superconducting magnetic resonance instrument,which were saved Dicom format to a working computer for bone, ligament, meniscus and articular cartilage layer boundary, in the period of import E-feature Biomedical Modeler software. Data obtained from the E-feature Biomedical Modeler software was digitized to DIP file, to obtain a three-dimensional spatial coordinates of the boundary of each level, and then finite element mesh, the definition of material properties, the model and the resulting knee dimensional finite element model, and then import it into the ANSYS finite element analysis software, the model for biomechanical analysis.2. A flexion moment at0°,30°,60°, varus/valgus and internal/external rotation torque were applied on the established three-dimensional finite element model of the normal knee, calculate and record the average stress and the equivalent stress distribution of PCL, LCL, ACL, MCL.3. In the established three-dimensional finite element model of the knee,the PCL was removed to analog PCL complete rupture (Ⅲ degree injury). The same mechanical analysis of the PCL complete rupture of the finite element model, the same calculate and record the average stress and the equivalent stress distribution of LCL,ACL, MCL, then compared with normal knee model and the statistical analysis.Results:The purpose of this study is to establish the three-dimensional finite element model of normal human knee and the model of the PCL complete rupture, the biomechanical analysis of the models. The results showed that:1. with the20N· m varus PCL complete rupture of the model LCL equivalent stress at different flexion average value (3.39MPa,12.41MPa,14.56MPa) than the normal group (2.30MPa,11.22MPa,12.84MPa) significantly increased;2. With8N· m external rotation torque PCL complete rupture model LCL equivalent stress at different flexion average value(1.34MPa,12.24MPa,12.56MPa) than the normal group (0.22MPa,10.10MPa,10.42MPa) significantly increased;3. with20N· m varus/valgus moment or8N· m internal/external rotation torque PCL rupture model of ACL and MCL of average equivalent stress compared with the normal group, the change of the stress is very small.Conclusion:1. A three-dimensional finite element model of normal human knee and the PCL complete rupture ware established. On this basis, biomechanical analysis of ligaments of human knee joint can put into practice. 2. Through the data comparison, it shows that LCL in the knee of PCL rupture varus and external rotation exercise stress increased significantly, ACL and MCL in knee of PCL rupture varus-valgus and internal and external rotation exercise stress change is small,For further validation PCL rupture should be reconstructed early to avoid LCL chronic injury.更多还原