Prosthesis work has good chemistry

Patients with hip implants will be less likely to need replacements with prosthesis design guidelines developed from research into the properties of ’synovial fluid’.

Researchers Dr Philippa Cann and Dr Janet Wong from Imperial College London’s mechanical engineering department are analysing the synovial fluid lubricating films formed on joints during rubbing.

The project will rely on in-contact fluorescence imaging and atomic force microscopy to study the fluid’s chemical composition, molecular structure and local physical properties such as rheology and friction.

The researchers hope their work will provide information on the fundamental lubrication mechanisms that occur in artificial hip joints. They believe this will have important implications for the development of new low-wear prosthesis designs.

The research could have benefits for the NHS, orthopaedic surgeons and patients as it is expected the outcome will improve joint life and reduce incidence of implant replacements.

In 2007, the UK performed 10,500 total hip replacement (THR) revision operations, each of which may cost up to £25,000, totalling £255m per year. THR revision operations are estimated to consume 10 per cent of the NHS joint-replacement budget.

The research programme, which has received £458,272 in EPSRC funding, will also deliver information on the effect of synovial fluid chemistry on joint wear. The researchers believe such knowledge will enable surgeons to make more informed choices on the most appropriate type of prosthesis for each patient depending on their synovial fluid chemistry.

The increased knowledge of synovial fluid tribology could even have implications after the prosthesis is implanted by helping doctors develop remedial strategies to improve joint lubrication.