DEVELOPMENT AND VALIDATION OF 3D FINITE ELEMENT MODEL OF THE HUMAN KNEE JOINT FOR TIBIO-FEMORAL CONTACT ANALYSIS
Shriram Duraisamy, Subburaj Karupppasamy
Singapore University of Technology and Design, Singapore
A three-dimensional (3D) finite element (FE) model of the human knee joint was developed and validated to study the biomechanical behavior of tibio-femoral contact forces and pressures in different loading conditions. Knee sub-structures including distal portion of femur, proximal tibia, lateral and medial meniscus, articular cartilage of both femoral condyles and tibial plateau, the anterior and posterior cruciate ligaments, and the lateral and medial collateral ligaments were semi-automatically segmented from the MR Images (Open Knee project) using an in-house developed medical modeling software program. 3D geometries of those sub-structures were reconstructed from the segmented data to build a 3D FE model. In the computational model, bones (femur and tibia) were modeled as rigid bodies, cartilage and menisci were modeled as elastic materials, and ligaments were modeled as isotropic and hyperelastic materials represented by an incompressible Neo-Hookean behavior. For all analyses, bones were meshed with tetrahedral elements, while the soft tissues were meshed with 8-noded hexahedral elements. For all the kinematic simulations, the femur component was not constrained in all degrees of freedom (three translations and rotations) except flexion, while the tibia was fixed. Contact forces and pressures in the tibio-femoral joint obtained from the developed computational model were validated with experimental measurements in the literature. At 1000 N load at 0° flexion and 15° flexion, the maximum contact pressures predicted on the tibial cartilages were 6.209 MPa (3.5% deviation from the experimental value) and 5.895 MPa (0.5% deviation from the experimental value). Such a validated model will facilitate in depth understanding of various joint injury mechanisms and their impact of knee sub-structures.
Keywords: biomechanics, finite element, human knee joint, contact pressure