虚拟现实互动技术在交叉韧带等长重建计算机辅助设计中的应用

目的 利用虚拟现实技术还原膝关节骨性结构在屈伸运动过程中的三维空间形态，为观测膝关节面交叉韧带附丽区的相对位置变化和进一步研究前、后交叉韧带等长重建最佳等长点提供计算机辅助设计新方法。方法 采用实验与计算机仿真相结合的方法，对新鲜人体膝关节标本进行屈伸运动实验，并通过激光三维扫描方法记录、计算膝关节的空间活动指标，然后重建膝关节计算机三维模型。通过实验中的空间活动指标控制此模型虚拟运动，再现膝关节各屈伸角度下股骨、胫骨和腓骨的空间位置。结果 计算机还原出各运动角度下膝关节骨性结构（股骨、胫骨及关节面）的空间形态，利用软件Geomagic的几何计算功能可分别测量模型中各个运动状态交叉韧带附丽区两点间的三维空间距离。讨论本研究方法可以真实地记录和再现膝关节三维运动过程，从空间结构上更精确、合理地寻找重建等长点，对膝关节交叉韧带手术重建有重要临床意义。

Application of virtual reality interactive technology in computer aided design of cruciate ligament isometric reconstruction

Objective To provide a new method of computer-aided virtual reconstruction of the knee joint bone structure which can be used for determination of the best isometric points of ACL and PCL under clear observation of variable attachment sites of erueiate ligaments in flexion and extension in the three-dimensional reconstruction. Methods Computer simulations and biomechanical experiments were used in this study. Experiments on flexion and extension movements of the knee joint were performed on specimens of fresh human knee joint. Laser Three Dimensional Scanning was used to record and calculate the indexes of movements. Three-dimensional models of knee joint bone structure were then reconstructed on computer with the experimental data. Simulations of flexion and extension movements were carried out on the models to show the spatial positions of femur, tibia and fibula and label the attachment sites of cruciate ligaments. Results The three-dimensional models could demonstrate the spatial positions of the bone structure of the knee in different flexions and extensions. The models could be used to measure the spatial distance between 2 points on the femoral and tibial planes and determine the best isometric points of ACL and PCL. Conclusions The computer-aided virtual reconstruction of the knee joint bone structure can be used for precise determination of the best isometric points of ACL and PCL under clear observation of variable attachment sites of cruciate ligaments in different flexion and extension movements. It is clinically significant for reconstruction of cruciate ligaments of the knee joint.