Joint replacement implants, particularly knee and hip prostheses, are subject to a high degree of load and wear inducing movement that results in the release of abrasive particles. Wear and also the release of metal ions is caused by contact stress between the implant’s polyethylene bearing surfaces and the metallic components. Wear debris and metal ions have been shown to be the main cause of inflammation, premature loosening and allergic reactions associated with joint replacement implants.

In comparison to other joint prostheses, knee replacement implants, which are mainly manufactured from cobalt/ chromiumbased alloys, are required, for technical reasons to consist of up to 1 percent nickel traces. They also have a far larger bearing surface area than other joint prostheses. This can result in the continuous release of allergenic metal ions (nickel, chrome or cobalt) into the tissue surrounding the implant. Hence, the risk of post implantation adverse tissue reactions is particularly high in patients that are prone to allergy.

Additionally, one of the main development goals of modern manufacturing technologies, for new orthopaedic implants, is to improve their surfaces to avoid allergic reactions and wear debris caused by the articulating components.