Case Study

A promising new material for knee joint replacements is being put through its paces in Leeds’ world class joint replacement simulation facility in a project developed in partnership with biomedical materials specialist, Invibio.

New materials for bone implant surgery are continually under investigation. As people’s life expectancy increases, there is an ongoing need to find materials that are resistant to wear and that will not need to be replaced during the patients’ lifetime.

Through the IKC, researchers in Leeds Institute of Medical and Biological Engineering have been working with Invibio, to test the function of a material called polyetheretherketone, or PEEK. Invibio currently use PEEK in spinal implants, but the company had identified a market need to develop the material for other implants. The company approached Leeds to set up a co-development project that would accelerate their PEEK-based knee implants towards clinical trials.

PEEK has properties that are similar to natural bone, but it is lighter and cheaper than cobalt chrome, currently the preferred material for knee replacement surgery. It also doesn’t feel cold to patients, which is another disadvantage of cobalt chrome devices.

Invibio worked with Leeds researchers to study wear in its first prototype implant. Alongside this, researchers at the University of Southampton have been looking at fatigue in the implant, and a team in the Netherlands has been using computer simulation techniques to test overall performance.

“In the simulation laboratory we are able to look at a whole range of variables, including surgical variables, and patient factors such as weight and lifestyle, to understand the effects of wear on these joints,” explains Dr Louise Jennings, Associate Professor in Leeds Institute of Medical and Biological Engineering.

“Our results so far have shown that the wear in PEEK implants is actually very similar to that in cobalt chrome devices. Given that PEEK has a number of other advantages over cobalt chrome, that means it’s a very promising material and our research could well lead to Invibio being able take these implants forward into clinical trials and ultimately market them as a new product.”