Finite element modelling and analysis of a new cemented hip prosthesis

Abstract

In this study, four different stem shapes for hip prosthesis have been designed to investigate an optimum stem shape. The stem shapes have geometries of varying curvatures. The first stem has standard straight geometry. The other two have notched geometries and the last one has curved geometry. The notched and curved types have been intended to reduce sliding of the implant in the bone–cement. They have been also aimed the implant to stick to the bone–cement securely. The static and dynamic FE analyses of the stems have been conducted using implicit commercial finite element code. The static analyses have been conducted using a load of an average body weight. The dynamic analyses are performed using a load of walking condition of a human. Based on static and dynamic FE analysis results, safety factors for fatigue life of the hip prosthesis have been calculated. Fatigue calculations have been carried out for Ti–6Al–4V, cobalt–chromium alloy materials and bone cement based on Goodman, Soderberg, and Gerber fatigue theories. All calculations have been performed according to the infinite fatigue life criteria. The results obtained have been compared and concluded to the results found by Charnley.