Finite Element Modeling and Analysis of Prosthetic Knee Joint

Degenerative arthritis is a disease that affects the line cartilage of the knee joint. It causes severe pain in the joint and may require a replacement surgery of the affected knee with artificial components. Geometric complexity and non linearity of the materials of the knee make the analytical solutions of the mechanical behaviour of the knee joint difficult. The knee is the most complex joint within the human body. Proper motion of the joint relies significantly on the function of the soft tissue constituents including the four ligaments of the tibiofemoral joint. These ligaments allow primarily flexion/extension and rotation of the joint by enabling the bony constituents (femur and tibia) to translate and rotate relative to each other. In addition to the ligaments, soft cartilage in the joint space permits nearly frictionless contact between the bones. Computational modeling of the knee provides a way for better understanding the interplay between the hard and soft tissue constituents of the knee during normal and pathologic function. Additionally, properly validated models can be used in the design of knee implant systems by understanding the mechanics of the restored knee in order to more closely replicate the healthy knee. The objective of this paper was to design a model of prosthetic knee joint from the available literature and study the distribution of contact stresses in the same by assigning it the material properties of polyethylene chopped carbon fibre composite and conventional polyethylene for tibial component and alumina ceramic for femoral component. Commercially available software (ANSYS 11.0) was used for numerical estimation of contact stress. The effects of the sagittal radius, flexion angles on stresses in the joint were investigated. Keywords— Finite Element Analysis, Modeling, Prosthetic Knee Joint, Contact Stress, Flexion angle and Sagittal Radius