£1M Cambridge project to improve hip & knee implants

BERTI, a new collaborative research project, is developing new methods of extending the life of knee and hip implants by using advanced innovative coatings which reduce implant wear and combat infection by releasing anti-microbial agents.

Project BERTI; (Biomedical implant with Exceptional Resistance to Tribo-bio-corrosion and with Inherent antimicrobial properties) is expected to lead to new designs of knee and hip implants and substantially reduce the number of costly revision surgeries faced by patients undergoing hip and knee replacements; 163,940 primary hip and knee replacement procedures were carried out in England and Wales alone in 2010. Partners in the project include Corin Plc, Tecvac Ltd, Imperial College London, Charing Cross Hospitals, Queen Mary, University of London and the University of Sheffield. The project, valued at £1.1 million over 3 years is co-funded with £577,000 by the government-backed Technology Strategy Board.

“This project has the potential to make a major contribution to improving patient outcomes and reducing cost” commented Dr David Simpson, BERTI project leader & research manager at Corin, and Jonathan Housden, research manager at Tecvac, “Obviously both patients and medical teams want to experience a hip or knee implant operation once only. But despite the best surgeons and procedures these are still complex operations with attendant risks of infection and adverse patient reactions, Of course any implant must wear eventually so this work to extend implant lifetimes and reduce infections will produce a major resource and cost benefit by reducing the number of revision surgeries.”

Revision surgery* is especially costly, reaching maybe £25,000 or more for each patient. It often requires a lengthy stay in hospital and may affect one in 75 or more of primary procedures in the following three years.

The number of primary hip & knee procedures is predicted to increase by 673% and 173% for knee and hip replacements respectively by 2030, due to the increasing population and life expectancy. The growth in these procedures is placing a huge burden on the NHS and health services worldwide, as are the relatively small proportion of revision surgeries which are more complex and frequently involve longer stays in hospital.

Around 50% of all revision surgeries result from direct wear of the implant components, and sometimes immune reactions, to wear particles or infections. One of the key BERTI objectives is to develop an innovative joint replacement with a coating that minimises polyethylene and metal wear debris, prevents metal ion release (and related patient reactions) and releases antimicrobial agents to prevent infection.

The BERTI project will also determine a method that establishes drivers for the detrimental responses to wear debris observed in patients. This information will be used to optimise a recently developed PVD coating that minimises wear and tribo-bio-corrosion while delivering an antimicrobial agent. In addition, the project will establish a test for patient susceptibility to metal ions released from implants. The project will utilise translational research methods to identify the best method of improving patient outcomes. This will improve patient selection and help identify patient cohorts who would benefit most from the novel coated implants, and will deliver to them, and the wider population, a world-leading joint replacement with exceptional biocompatibility, longevity and antimicrobial properties. Project BERTI will ultimately increase the longevity of orthopaedic implants, and reduce the number of revision surgeries, benefiting the patients, the UK and wider economy, and implant teams worldwide.