The influence of boundary conditions on finite element analysis

Implant modularity in stem and head-neck combinations allows greater flexibility during surgery. The Morse taper allows component modularity but is not impervious to biological fluids, and is susceptible to mechanically assisted fretting and corrosion. Contact mechanics of the taper and femoral head have been shown to play a role in in-vivo degradation of metal-alloy and ceramic-alloy implants. Ceramic heads have been limited to range from 28mm and upwards due to the stress that develops within the head from the contact conditions at the head-neck interface. The issue of using a smaller diameter head allows for a greater range of motion and less wear of the polyethylene liner. Some manufacturers of ceramic heads have used finite element analysis (FEA) to predict the stresses developed within the ceramic femoral head. This study examined the role of boundary conditions and their influence on the stresses developed within the ceramic femoral head.