Portsmouth researchers aim for longer-lasting hip replacements
A team of researchers in Portsmouth are to carry out important research which they hope will lengthen the lifespan of hip replacements.
Dr Jie Tong, Reader in Mechanical Engineering at the University of Portsmouth, and Gavin Hussell, consultant orthopaedic surgeon at Queen Alexandra Hospital in Cosham, have been awarded funding of more than £84,000 over two years by medical research charity the Arthritis Research Campaign.
The Portsmouth team aim to find out why the artificial sockets used in cemented hip replacement operations come loose, leading to the need for the joint to be revised, that is, replaced for a second time. Their work could be of major significance in reducing the revision rate.
Despite a variety of different types of hip replacement and fixation techniques now available, in particular hip resurfacing for younger patients, cemented total hip replacement remains one of the most successful forms of surgery for older patients with severe forms of osteoarthritis. More than 40,000 hip replacement operations are performed in the UK each year, but most fail between 10 and 20 years later.
The main reason why hip replacements fail in the long-term is because the artificial socket (known as the acetabular cup), usually secured with bone cement, becomes loose.
"The long term stability of total hip replacement critically depends on the lasting integrity of the bond between the implant and the bone, " explained Dr Tong. "Loosening of the acetabular cup may happen because the hip is subjected to high forces up to three times of body weight during routine activities, and fatigue cracks can develop at the point where the implant and the bone meet. There is clearly a need to study these failure mechanisms. "
The team also draw on their expertise in aerospace research by developing a detailed 3D computer model to simulate implanted pelvic bones and to study the failure of fixation caused by cement fractures using a CT scanner.
"We believe our project offers a unique promise in understanding the long-term fixation rate in cemented acetabular cups," added Dr Tong. "Real improvements in cemented fixation will significantly reduce the revision rate, which will be of considerable benefit to both the patients and the health service."
For more information email info@arc.org.uk.
