Life Estimation of Hip Joint Prosthesis

Abstract

Hip joint is one of the largest weight-bearing structures in the human body. In the event of a failure of the natural hip joint, it is replaced with an artificial hip joint, known as hip joint prosthesis. The design of hip joint prosthesis must be such so as to resist fatigue failure of hip joint stem as well as bone cement, and minimize wear caused by sliding present between its head and socket. In the present paper an attempt is made to consider both fatigue and wear effects simultaneously in estimating functional-life of the hip joint prosthesis. The finite element modeling of hip joint prosthesis using HyperMesh™ (version 9) has been reported. The static analysis (load due to the dead weight of the body) and dynamic analysis (load due to walking cycle) have been described. Fatigue life is estimated by using the S–N curve of individual materials. To account for progressive wear of hip joint prosthesis, Archard’s wear law, modifications in socket geometry and dynamic analysis have been used in a sequential manner. Using such sequential programming reduction in peak stress has been observed with increase in wear. Finally life is estimated on the basis of socket wear.