The author and Sulzer Medical Technology Ltd, Switzerland, have developed a new generation of metal on metal bearing total hip joints. The design is different than the McKee type prostheses in that the cobalt chrome alloy heads and cups (Metasul) are of the highest precision with controlled loose fitting. These allow low friction and low wear of approximately 5 micrometer per year. It is anticipated that debris related late loosening will be avoided by the use of this design. Approximately 30,000 Metasul bearings have been produced. The first 110 Weber metal on metal hip implants have been analyzed. No adverse effects from the wear of the new metal on metal components have been noted in this series.

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