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Last Updated: Friday, 13 June, 2003, 17:10 GMT 18:10 UK
Longer-lasting knee joints hailed
Mr Timothy Wilton (left) with David Whitehurst holding the joint
The material in the joint is used in racing car engines
A hard-wearing material used in jet engines is providing a new source of long-lasting knee replacements.

Younger people are often not given knee surgery because the joints can wear out and patients require subsequent operations which are less successful.

But surgeons say ceramic knee joints last longer than standard implants, which often need replacing after 10 to 15 years.

They claim they offer up to 85% improvement in wear and tear over standard knee implants, which are made out of cobalt chrome.

This new knee works better than my healthy normal knee
David Whitehurst
The Oxinium joints, manufactured by the British company Smith & Nephew, are made of zirconium metal, which is heated, converting the surface to a ceramic.

This means it is more "slippery", reducing the friction with the other part of the replaced joint, which is made of plastic, but still has a strong core.

Pressure

David Whitehurst from Derby was one of the first UK patients to receive an Oxinium joint.

He damaged his knees in a car accident in the 1960s.

He said: "As an engineer I know the importance of maintaining smooth, long-wearing moving parts, and for this reason use the same ceramic component that is in my knee replacement in the engines of racing cars.

"It is interesting that this ceramic is also used in jet engines because it is an excellent heat conductor, and can withstand huge amounts of pressure and friction.

"It doesn't surprise me that the Oxinium knee made it possible for me to have surgery at a younger age than a traditional implant would allow because it is so hard wearing."

He added: "I'm doing really well and have been able to get on with my life, enjoying working again, driving and walking around with no pain at all since the surgery.

"In fact this new knee works better than my healthy normal knee."

Brittleness

Mr Timothy Wilton, an orthopaedic surgeon at Nuffield Hospital Derby and the Derby Royal Infirmary performed Mr Whitehurst's operation.

He said: "This knee replacement addresses one of the most critical issues in orthopaedics today, namely that the lower the amount of wear, the longer the implant will last.

"The second issue is the brittle nature of standard ceramic components which can occasionally break, but with Oxinium there is no brittleness.

He added: "We now have a superior implant that is expected to last longer and will allow active, younger patients to benefit much earlier from a replacement knee.

"This in turn will reduce the amount of suffering a patient often experiences due to a painful knee."

More than 30,000 knee replacement operations are carried out every year in the UK.

Mr Roger Smith, secretary of the British Orthopaedic Association said the joint was a recent addition to what was available to UK surgeons.

He told BBC News Online: "It may well last longer because they don't wear at the same rate.

"They need to be shown to be effective in reducing the wear and they last and don't crack and have a low rate of failure "

But Mr Smith warned: "We can't make any judgement on a joint until its been in use for a good five years."


SEE ALSO:
Pig gut helps knees heal
31 Mar 02  |  Health
'Grow your own knee'
29 Jun 00  |  Health


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