基于全膝关节置换的三维术前规划实践

Practice of Preoperative Strategy Based on Total Knee Arthroplasty

目的:通过关节置换虚拟手术,以有限元法全面分析术后的膝关节接触面的受力状况,借此数据制订"三维手术规划"督导关节置换临床手术。方法:以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,以Mimics的Simulation性能模拟关节置换手术的截骨、假体植入术程,再将术后模型导入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。在这些力学数据所提炼成的"三维术前规划"的指导下施行20例(实验组)临床关节置换术,另外20例临床关节置换术作为对照组在无术前规划介导的情况下按传统术式施行。结果:筛选最佳的TKA模拟术后3D膝关节有限元模型,ANSYS分析数据与前人在力学实验中对假体直接测试所获得基本一致,其合理性由此确认。从这些基于TKA的虚拟资料所提炼出来的三维术前规划的指导下,实验组的临床手术精度(影像学测量及AKS评分)明显高于对照组。结论:以有限元方法分析出虚拟置换术后膝关节的结构形变、应力分布、内部能量变化等资料,提供了可靠的术前规划依据,有利于临床手术时寻找假体植入的最佳位置、优化截骨、预见手术结果,提高了关节置换的成功率。

Objective： Based on the information of Emulative surgeW of Joint rephcement as well as its postoperative dynamic data of Finite Element Analysis on Knee joint overall, a 3-dimension preoperative plan is designed to instruct Total Knee Arthroplasty. Methods：After scanning affected knee joint bv CT/MR and scanning knee prosthesis by Laser instrument, a model composed of prosthesis, knee joint as well as its ligament was rebuilt computationally, dynamic lines were measured. Processes of prosthesis installation ＆ osteotomy performed by facitity of Silnulation in Mimics according to the knee joint replacement standard, this postoperative model was imported into ANSYS so as for Meshing, Material assignment, load applied, then, stress distribution was analyzed by Finite Element Method. The 3-dimension preoperative plan was thus abstracted for these data so as to direct 20 cases of clinical joint replacement in Practical Group, another 20 cases of clinical joint replacement acted as Matched Group was undergone without 3-dimension preoperative plan traditionally. Results： The best finite element model of postoperative TKA 3D knee joint was obtained and selected, dynamic data is tested to be approximately agreeable to those previous studies of direct measurement upon prosthesis, and it＇s confirmed to be reasonable. Supervised by the 3-dimension preoperative plan concluded by those virtual data, the accuracy of Practical Group is much higher than the Matched Group. Conclusion： The information for this experiment of analyzing structural deformation, stress distribution ＆ internal energy change provides reliable base of preoperative planning, and it benefits to search the best position for prosthesis installation, osteotomy and surgical result prediction, consequently, the successful ratio of joint replacement is improved.