The Application Of Virtual Reality Interactive Technology In Computer Aided Design Of Cruciate Ligament Isometric Reconstruction

Knee joints are the most complex and easily damaged weight-loading joints. In many aspects, such as traffic accident, industrial and mining accidents, sports injury, et al, the probability of knee injury is comparatively large. Because of complexity of knees' structure and function, the research for knee joint was limited. This article used computer's technology, and set up motorial model which could simulate and reappearance the no-loading flectional processes of normal knee joint. Based on the model, we measured length changes of anterior cruciate ligaments, posterior cruciate ligaments during its flectional processes, and offered theoretical basises for clinical operation.Objeetive: Utilize computer's technology, we simulated movements of certain amount of normal knee joints, and got normal knee joint's computer motorial model. It could simulate and reappearance normal knee joint's movements in no-loading condition. Measure the length of cruciate ligament during flectional processes in each conditions, and validate the position of cruciate ligaments' attachment region in isometric reconstruction. It could provide theoretical bases for cruciate ligaments' isometric reconstruction. Methods: Six cases of fresh knee joints specimens of the human body would be given embedded ends, and used 3D scanning system to scan knee joints in each flexion angles, (or carried out CT scan with the objects embedded developer, and applied special software to mix together and registering.) then, gained scanning data. Imported them to "Geomagic Studio 8" software and mixed together the data of backbone and articular surface to showed intact knee joint's dynamic exercise phantom, which should be smoothed and glossied. The data from CT scan should be imported to "Materialise Mimics 10.01" software. After "Thresholding", "Region growing", "Editing", "Smoothing" and other operation, reconstructed femur and tibia s' models. Saved files as "STL" pattern. Reimported to "Geomagic Studio 8" software and mixed together with the data from 3D scanning system, then established computer models which could reflect femur and tibia s' relative position. Computer models were marked the position of cruciate ligament attachment region. All data were analyzed with the SPSS statistical software. Finally, we could definite the position of isometric point on femur and tibia separately.Results:1. It's femur that influences ACL and PCL s' isometric results.2. when reconstructed ACL, the best fixing of femur's tunnel should be behind-upper region on femur's ligament attachment, and anterior region on tibia's ligament attachment, its lenth is (31.90±0.65) mm.3. when reconstructed PCL, the best fixing of femur's tunnel should anteriomedialis region on femur's ligament attachment, and ahead-below region on tibia's ligament attachment, its lenth is (31.90±0.65) mm.Conclusions:1. Through computer technology, we could build computer models of knee joints for analyzing and measuring, and base on specimens anatomy, professional reference books to determine the location of the ligament attachment, then mark on the models, measure the distances between different marks on computer models of knee joint.2. Based on the data, we could analyze and definite suitable position of isometry point relatively.