'Smart' hip could treat itself

They are hopeful that such a device could cut number of joint replacements that fail due to persistent infections.

The joint would be able to tell an examining doctor whether it was under attack from bacteria, say researchers.

Work has already started in the US to incorporate nanotechnology into artificial hips or knees.

In the UK, thousands of these are implanted every year - but a few percent have to be removed because they become infected.

" There are technical hurdles that still need to be overcome, but I'm fairly confident that technology is evolving rapidly enough that we will be able to do this "
Dr Garth Ehrlich, Allegheny Singer Research Institute

Addressing the American Society for Microbiology meeting in New York, Dr Garth Ehrlich from the Center of Genomic Sciences at the Allegheny Singer Research Institute in Pittsburgh, said: "There are technical hurdles that still need to be overcome, but I'm fairly confident that technology is evolving rapidly enough that we will be able to do this."

Detection and cure

The implant would be covered with tiny sensors which, in theory, could both detect infection, and identify the type of bacteria involved.

Dr Ehrlich said that the correct drug could then be dispensed from an internal reservoir, while the implant monitored its progress and reported back to medical staff via a wireless link.

He said: "Two to three percent of total joint replacements fail due to chronic bacterial biofilm infections.

"The only recourse for such patients is the traumatic removal of the implant which results in additional bone loss, extensive soft tissue destruction, months of forced bed rest with intravenous antibiotics - and significant loss of quality of life."

Although this type of infection creates huge additional costs for the NHS, the cost of the "smart" hip has not yet been determined - and it is conceivable that it might be too steep for widespread use in the health service.

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