Contact Analysis of Prosthetic Knee Joint Using ANSYS

Abstract

The objective of this study is to determine the best materials for the tibia/femoral combination of the prosthetic knee joint using commercial available FEM software. Insertion of these joints in human should not result in too much of discomfort and postoperative treatment. Further, the life and performance of the artificial joints is of prime concern. During activation, contact is established between tibia and femoral components leading to stresses at the interface, which in turn dictates the performance of these joints. The intensity of the developed stresses at the interface depends on several important factors such as the materials used for tibia/femoral components and the load acting on the bearing surfaces of the joint. To ensure reduction in the stress intensity, it is of utmost importance to select the best materials for tibia/femoral combination. In this regard, FEM the most powerful and widely accepted numerical tool to predict the state of stress is currently gaining importance in optimization of design of knee joint. In the light of the above, this paper discusses the modeling and finite element analysis of prosthetic tibia/femoral joint with different material combinations. The materials like stainless steel, titanium alloy and alumina ceramic are considered for the femoral component. Polyethylene and polyethylene chopped carbon fiber composite are considered for the tibial insert. The three dimensional model was developed using PRO E software for sagittal radius of 40 mm and 0 degree flexion angle, while load was varied from 500-2667N. An explicit finite element was generated using hyper mesh software and was solved by ANSYS. For a given load, a considerable reduction in the stress intensity at the interface of femur made of alumina ceramic and tibia made of polyethylene chopped carbon fiber composite have been observed when compared with other combinations of materials investigated.