Implant–bone interface healing and adaptation in resurfacing hip replacement

Abstract

Hip resurfacing demonstrates good survivorship as a treatment for young patients with osteoarthritis, but occasional implant loosening failures occur. On the femoral side there is radiographic evidence suggesting that the implant stem bears load, which is thought to lead to proximal stress shielding and adaptive bone remodelling. Previous attempts aimed at reproducing clinically observed bone adaptations in response to the implant have not recreated the full set of common radiographic changes, so a modified bone adaptation algorithm was developed in an attempt to replicate more closely the effects of the prosthesis on the host bone. The algorithm features combined implant–bone interface healing and continuum bone remodelling. It was observed that remodelling simulations that accounted for progressive gap filling at the implant–bone interface predicted the closest periprosthetic bone density changes to clinical X-rays and DEXA data. This model may contribute to improved understanding of clinical failure mechanisms with traditional hip resurfacing designs and enable more detailed pre-clinical analysis of new designs.

Keywords:

• hip resurfacing
• finite element analysis
• remodelling
• mechanobiology

Acknowledgements

The authors would like to acknowledge funding from the EPSRC and the European Union Seventh Framework Programme. None of the authors has any conflict of interest arising from the research presented in this article.