Carbon layer may aid hip replacements
Friday December 23rd, 2011
A carbon layer on metal hip replacement parts could help to improve the longevity and comfort, researchers reported last night.
Scientists
in the USA and Germany have found that the carbon layer reduces friction
as well as wear and corrosion, and does not contain any significant amount
of protein. The results offer a new route for improving the design of
these types of implants.
Writing in the 23 December edition of Science, Yifeng Liao and colleagues say the layer lubricates the device in a manner similar to the way oil lubricates a car engine.
The discovery opens the door to new ways of improving metal hip implants.
Although a hip implant would ideally function throughout a lifetime, metal-polymer implants material degradation tends to cause wear debris, leading to inflammation and potential failure of the implant.
Protein in the surrounding joint fluid is believed to provide lubrication similar to what occurs in natural hip joints, but very little is known about the region where the sliding between the two metal surfaces takes place.
By analysing samples from patients, Yifeng Liao and colleagues used electron microscopy to reveal a graphitic layer at the metal surfaces of the implants.
Researcher Professor Joshua Jacobs, of Rush University Medical Center, Chicago, USA, said: "By the time patients get to me, most of them are disabled. Life is unpleasant. They have trouble working, playing with their grandchildren or walking down the street.
"Our findings will help push the field forward by providing a target to improve the performance of hip replacements. That's very exciting to me."
Graphitic Tribological Layers in Metal-on-Metal Hip Replacements. Y. Liao; J.J. Jacobs; L.D. Marks at Northwestern University in Evanston, IL; R. Pourzal; A. Fischer at University of Duisburg-Essen in Duisburg-Essen, Germany; M.A. Wimmer; J.J. Jacobs; A. Fischer at Rush University Medical Center in Chicago, IL. 23 December Science and 22 December Science Express
Tags: Europe | Orthopaedics | North America
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