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Metal Ball and Polyethylene Liner
Metal Ball and Polyethylene Liner joints have been the leading replacement joints for 30 years. The ball is cobalt chrome molybdenum alloy and the liner is polyethylene. Metal-on-polyethylene hip joints wear about 0.1 mm per year. New wear-resistant "highly-cross-linked polyethylene" liners reduce average wear to 0.01 mm per year.
Ceramic Ball and Polyethylene Liner
Ceramic Ball and Polyethylene Liner joints are the most scratch-resistant replacement joints. Although previous ceramic ball and polyethylene liner joints were more prone to fracture than conventional metal on polyethylene joints, newer models have reduced the fracture rate to about one in ten thousand. Ceramic on polyethylene hip joints wear about 0.05 mm per year.
Metal Ball and Metal Liner
Metal Ball and Metal Liner joints reduce wear and bone loss considerably. The cobalt chrome alloy liner may be used alone, or inset into a conventional polyethylene liner. These replacement joints are available in a wider range of sizes than conventional joints. Metal-on-Metal replacement hip joints wear about 0.01 mm per year.
Ceramic Ball and Ceramic Liner
Ceramic Ball and Ceramic Liner joints are the hardest presently-available replacement joints. Although they have been used in Europe for almost 40 years, they first gained FDA approval for use in the United States in 2003. Ceramic-on-Ceramic implants wear about 0.0001 mm per year.
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