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5/2/09
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INNOVATION FOR INDEPENDENCE
ISSUE 65 February/March 09 £6.95
Stairclimbing puts most strain on hips By Dominic Musgrave
second time.
A TEAM of researchers in Portsmouth have found that walking up and down stairs puts the most strain on artificial hips compared with other routine activities such as walking.
“Our results are useful for orthopaedic surgeons and bone cement manufacturers, as both can now focus on improving the bonding between bone and cement, through improving surgical techniques and developing new formula for bone cements,” said Jie.
They also found that body weight is an important factor in determining the survival of cemented hip replacements. The findings could lead to improvements in the cemented hip replacements so that they last longer, and to new advice given to patients on how to reduce the strain on their new joint by lifestyle changes. The team at the University of Portsmouth, led by professor Jie Tong in the department of mechanical and design engineering, and Gavin Hussell, consultant surgeon at Queen Alexandra hospital in Cosham, were funded over two years by the Arthritis Research Campaign to find out why the artificial sockets used in cemented hip replacement operations came loose, leading to the need for the joint to be revised, that is replaced for a
“Overall improvements in cemented fixation will drive the revision rate down, which will benefit both the patients and the health service.” The team used a specially designed hip simulator to test the cemented implants under realistic loading conditions such as going up and down stairs, walking and a series of routine activities. They also used CT scanning and tested the outcomes on computer models in order to validate their findings. The team discovered that in hip joint replacements that come loose, there is a mechanical failure at the point where the bone and the cement connect, known as the bone-cement interface.
Jason Bradbury from Channel Five’s Gadget Show presented the creators of a prosthetic limb which fuses directly with a person’s own skin and bone with a top award. The ITAP (Intraosseous Transcutaneous Amputation Prosthesis), a British creation developed by the University College London and medical devices company Stanmore Implants, was named knowledge transfer champion at the inaugural London Knowledge Transfer Awards.