Finite element analysis of hip stem designs

A finite element analysis (FEA) was performed on six hip stem designs. The hip implant designs were then analyzed at forces ranging from 2.5 to 7 kN. These forces were selected because a typical gait cycle generates forces up to 6-7 times the body weight in the hip joint. The FEA results were compared for various stem designs assuming a rectangular cross-section. The design objective for a hip stem is to have a low stress, displacement, and wear at a very high fatigue life. The analysis performed in this paper may aid also in the fatigue testing of implants and/or base the designs for tested materials at a suitable fatigue life. Subsequently, the stems that had the highest stress and displacement models were then optimized for a lower stress and displacement combination. The cross-section that comprised a circle in the medial end and a square at the lateral end was found to provide suitable design characteristics. Fatigue and wear analyses were performed assuming that the implants were made of metal and polyethylene liner. (C) 2007 Published by Elsevier Ltd.