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Graphite Lubricant in Metal Hip Implants Paves Way for Better Hip Implant Design, Study Shows

Stryker hip replacements cause grief to hip injury victimsA lubricating layer made of graphitic carbon consequently forms in the joints of metal-on-metal hip implants, according to a study. This dense layer works more like an industrial lubricant than joint fluid. This discovery may aid researchers design longer-lasting metal-on-metal hips for osteoarthritis and other joint disorder therapy. Undertaking a hip replacement surgery is very risky. In fact, more and more patients have been distressed and endangered, leading to the filing of lawsuits. Although, the complainants worry that the court will dismiss their lawsuits.

Osteoarthritis is a painful condition frequently characterized by inflammation of the joints. It is usually the cause of disability in people as they grow older. The swelling of the joint may damage tissue and bone, in the end making the joint really painful. To pacify the condition, orthopedists resurface or change the joint with an implant.

Normally used hip implants are made of metal and polyethylene, a type of plastic. In the long run, metal and plastic joints wear down, and metal fragments may damage the remaining bone and tissue of the hip. In the last 10 years, all-metal joints have become progressively widespread, as they are mostly more firm and long-lasting. In some instances, though, metal-on-metal hip implants can still shed harmful metal debris over fretting and corrosion.

Metal-on-metal joints are not made with lubrication, but when used, a thin layer emerges in the joint between the ball and socket. This layer, which forms between the two rubbing metal faces, is called a tribological layer. Researchers originally thought that it was made of proteins and other biological material, similar to the lubrication in a normal joint.

The researchers studied the tribological layer on seven all-metal joints that had been detached from patients. They scraped off a bit of the layer and evaluated it by electron energy loss spectroscopy, a technique that exposes the type of atoms present in a material. The researchers did not see this coming. They learned that the layer was made up in large part of graphitic carbon, with slight or no traces of protein at all.

“Knowing that the structure is graphitic carbon really opens up the possibility that we may be able to manipulate the system,” states coauthor Dr. Alfons Fisher of the University of Duisburg-Essen, Germany. “We now have a target for how we can improve the performance of these devices.”

With this information, researchers will be able to produce safer, durable hip implants by making graphitic carbon to stick to the metal of the implant. This will lessen the cases associated with the recalled Stryker ABG II.

Sources:

northwestern.edu/newscenter/stories/2011/12/hip-replacements-metal.html

reuters.com/article/2011/12/22/us-hips-idUSTRE7BL1IB20111222

rsc.org/chemistryworld/2012/07/why-some-metal-hip-replacements-fail

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