虚拟置换后的膝关节力学分析

背景：仿真力学具有可重复性和对模型无损伤性的优势，加上个性化结构模型提高了有限元分析的可靠性，选择虚拟置换后对膝关节的力学分析不失为一种优化尝试。目的：通过膝关节置换虚拟手术，用有限元法全面分析术后的膝关节接触面的受力状况，为下一步“手术规划”实验提供客观资料。方法：CT/MR扫描患侧膝关节，激光扫描假体，经逆向软件数字化重建假体、膝关节及其韧带并测量下肢力线，根据膝关节置换标准，用Mimics中的Simulation性能模拟膝关节置换手术的截骨、置入假体之后，再将所得的模型导入ANSYS划分网格、材料赋值、施加载荷，以有限元法分析接触应力分布。结果与结论：获得最佳的全膝关节置换后3D膝关节有限元模型，测得的力学数据与前人在力学实验中对假体直接测试所获得的结果基本一致。以有限元方法分析出虚拟置换后膝关节的结构形变、应力分布、内部能量变化等情况，有利于寻找假体置入的最佳位置、优化截骨、预见手术结果，成为手术规划不可缺少的数据。

Mechanics analysis on knee joint after virtual replacement

BACKGROUND：Simulative dynamics provides advantages of repeatable and non-invasive to a model. Additional y, structural model of individualism improves the reliability of Finite Elemental Analysis. It is an optimal attempt to analyze mechanics of knee joint after virtual replacement surgery. OBJECTIVE：To achieve dynamic information of contact stress upon knee joint surface by finite element analysis surgery for total knee arthroplasty postoperatively, and to provide objective data for further“surgery plan”. METHODS：After scanning affected knee joint by CT/MR and scanning knee prosthesis by laser instrument, a model composed of prosthesis, knee joint as wel as its ligament was rebuilt computational y;dynamic lines were measured. After prosthesis instal ation＆osteotomy performed by facility of Simulation in Mimics according to knee joint replacement standard, this model was imported into ANSYS so as for Meshing, Material assignment, load applied. Stress distribution was analyzed by Finite Element Method. RESULTS AND CONCLUSION：The best finite element model of postoperative TKA 3D knee joint was obtained;dynamic data were tested to be approximately agreeable to those previous studies of direct measurement upon prosthesis. The experiment of analyzing structural deformation, stress distribution＆internal energy change benefits to search the best position for prosthesis instal ation, osteotomy and surgical result prediction. Thus, these are indispensable data in surgery plan.