This paper on "Finite Element Analysis and Bone Remodelling After Total Hip Replacement" was presented at the NAFEMS World Congress on The Evolution of Product Simulation From Established Methods to Virtual Testing & Prototyping - 24-28 April 2001, The Grand Hotel, Lake Como, Italy.

Abstract

Total hip replacement has become an increasingly standard and successful surgical procedure, with roughly 800'000 operations per year in Europe and North America. The revision rate of total hip replacement after 12 years is 5%, 79% of which are due to implant loosening. The reasons are multifactorial, including implant design, patient-related factors, and operation technique. A possible cause of implant loosening is a negative bone remodelling response due to poor implant design or operation technique. Finite element analysis combined with bone remodelling algorithms offers an opportunity to simulate the bone response to a total joint replacement. Normally, such information is only available through long-term clinical results. The goal of this study was to gain a better understanding of how bone remodels to an implant so as to be able to apply this knowledge to the development of total joint replacements. In this study, the two clinically observed patterns of bone remodelling have been compared with computer based predictions for one particular design of prosthesis, the Thrust Plate Prosthesis (Sulzer Medica AG, Baar, Switzerland). Three-dimensional finite element models were created using geometric and bone density data obtained from computed tomography scanning. The methods used to create accurate FE models and perform numerical bone remodelling are presented.