1.1 Total Hip Replacement (THR) with metal on metal articulations have been used clinically for more than 50 years. Early designs had mixed clinical results. Eventually they were eclipsed by THR systems using metal on polyethylene articulations. In the 1990s the metal on metal articulation again became popular with more modern designs, including surface replacement. In the 1970s the first ceramic on ceramic THR articulations were used. In general, the early results were not satisfactory. Improvement in alumina, and new designs in the 1990s improved the results for ceramic on ceramic articulations. An argument has been made that the hard on hard THR articulation may be better for younger more active patients. These younger patients may be more physically fit and expect to be able to perform more energetic activities. Consequently, new designs of hard on hard THR articulations may have some implantations subjected to more demanding and longer wear performance requirements .
Currently, there is no test method to test metal-on-metal hip articulations in regimes beyond a simple walking cycle. Work needs to start on developing a standard. This guide will promote standardization while it helps to guide the development of appropriate methods. Eventually, it should be adopted by the US FDA.
high demand wear; metal on metal; hip simulator testing third-body wear; insert/shell angle
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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