Lead scientist Professor Nicholas Spencer suspected that this property could neutralise the effectiveness of the synovial fluid as a lubricant - increasing friction and wear in the hip implant.

BBC: Longer-lasting hip-joint hope

Overall, investigators found wear from friction and vibration in 15, 000 places, in varying degrees, in 3, 401 tubes inside the four generators.

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He found there was less friction, which would translate to less wear, than when the polyethylene was untreated.

BBC: Longer-lasting hip-joint hope

Also friction from eating and other jaw movement can cause the bone around the implant to wear away.

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