Improving the metal-on-metal hip prosthesis

Project leader

Dr Tom Joyce

Dates

October 2009 to September 2012

Project staff

Mr James Lord

Sponsors

EPSRC

Partners

University Hospital of North Tees

Description

Metal-on-metal hip arthroplasty had, until very recently, been undergoing a renaissance. But high profile failures such as that of the DePuy Articular Surface Replacement (ASR) metal-on-metal hip resurfacing have led to a backlash against all metal-on-metal hip prostheses.

But is this fair, or are younger, more active patients denied the opportunities of a low wear metal-on-metal couple?

The project teamed up with orthopaedic surgeons at the University Hospital of North Tees. They supplied failed and explanted metal-on-metal hip prostheses for a full engineering analysis.

We measured wear using a state-of-the-art co-ordinate measuring machine. We measured s urface roughness, which can inform the lubrication regime occurring in vivo. We used a non-contact profilometer with nanometre resolution.

Overall, the project aimed to evaluate and minimise the volumetric wear of metal-on-metal hip replacements. They are in use worldwide.

The project also aimed to minimise variability across patients by reducing prosthesis sensitivity to surgical and patient related factors. And increase the longevity of devices for the long-term benefit of patients.