Metal Alternative Hip Bearings

Although a variety of metallic biomaterials have been employed in joint arthroplasty, alloys of cobalt, 28% chromium, and 6% molybdenum (CoCr) are viewed as the gold standard for use in MOM bearings. CoCr alloy is also considered the gold standard as a femoral head material for articulations against conventional as well as highly crosslinked UHMWPE (Muratoglu and Kurtz 2002, Sauer and Anthony 1998). CoCr alloys (e.g., Vitallium ) have been used for hip replacements since 1938, when the biomaterial was employed in the Smith-Petersen mold arthroplasty (Smith-Petersen 1948). 

Interestingly, earlier (imsuccessful) iterations of the mold arthroplasty, dating from 1923 to 1937, employed glass, Pyrex, viscaloid, and bakelite (Smith-Petersen 

An example of a metallic Smith-Petersen mold arthroplasty (with its original packaging). 

Minimum American Society for Testing and Materials Specifications for Mechanical Properties of Cast, Forged, and Wrought CoCr Alloys for Use in Implants 

Condition ASTM standard Yield strength (MPa) Ultimate tensile strength (MPa) Ultimate elongation (%) Hardness, HRC, typical 

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