The Establishment Of Finite Element Model For Knee Joint And Research On Stress Distribution Of Cruciate Ligaments

Objective:A three-dimensional solid model and a finite element model of the human knee joint were established, applying MRI technology, MIMICS and ANSYS software. At the same time, stress distribution of cruciate ligaments in different injury mechanism was analyzed.Methods:The knee joint of healthy male was scanned in stretched position using MRI, and a continuous image sequence was obtained, of which layer thickness is 0.8mm. Saving the image data as DICOM format in personal computers, and a three-dimensional solid model of knee joint was built using MIMICS software, including distal femur, proximal tibia, ACL, PCL and intra-articular liners. Then a three-dimensional finite element model was generated, after the above-built solid model was meshed by ANSYS software, and different material properties were assigned to each component of joints. The stress distribution and variation of cruciate ligaments was analyzed, under the conditions of variety motion for knee flexion, rotation, posterior drawer, and so on.Results:1. A three-dimensional solid model of the human knee joint was constructed, successfully using the MRI collected data and the MIMICS software. And the model can be viewed in arbitrary angles and arbitrary cross-sections in the computer.2. A three-dimensional finite element model of the knee joint was established using ANSYS software, and the material properties and boundary conditions were assigned for the model.3. The displacement load was loaded in order to simulate injury mechanism of knee joint, and the stress and the spatial stress distribution cloud of cruciate ligament was obtained by computation during the activities of in the knee joint.Conclusion:1. A more real and authentic three-dimensional solid model can be built by knee image data of the human body obtained through MRI scanning, and its anatomical locations and shape of the ligaments are generally consistent with the real situations.2. This model can be used to make further finite element analysis, and through the simulation of its various working conditions, it is proved that the accident injury mechanism is the joint oversize activities, especially in the large compound activity and which can easily cause ligament injury or fracture. 3. The stress on femoral attachment point of cruciate ligament is larger than other section, which is the most likely the damaged or fractured site of cruciate ligament.