Cobalt-Chromium Femoral Head

Stilling M, Nielsen KA, Soballe K, Rahbek O (2009), Clinical comparison of polyethylene wear with zirconia or cobalt-chromium femoral heads , Clin Orthop Relat Res, 467, 2644-2650, DOl 10.1007/sl 1999-009-0799-5. 

A healthy 46-year-old patient developed progressively worsening symptoms of cobalt toxicity following 6 months of synovectomy and replacement of ceramic-on-ceramic hip bearing to a metal-on-polyethylene bearing. Blood cobalt concentration peaked at 6521 p /L. The patient died from cobalt-induced cardiomyopathy. Implant retrieval analysis confirmed a loss qf28.3g mass cfthe cobalt-chromium femoral head as a result of severe abrasive wear by ceramic particles embedded in the revision polyethylene liner [83 ]. 

Tribological Response of Cobalt-Chromium Femoral Head under Lubrication of... 

Keywords— Atomic Force Microscopy (AFM), Tribological Property, Frictional Coefficient, Surface Roughness, Cobalt-Chromium Femoral Head. 

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). 

Smith SL, Unsworth A. A comparison between gravimetric and volumetric techniques of wear measurement of UHMWPE acetabular cups against zirconia and cobalt-chromium-molybdenum femoral heads in a hip simulator. Proc InstMech Eng 1999 213(6) 475-83. 

The head of the femoral component then articulates with an ion-bombarded, HDPE, high walled, acetabular liner which fits iato a screwed ia, machined, titanium, chromium—cobalt—molybdenum or vanadium—aluminum metallic alloy hydroxyapatite-coated acetabular shell/cup. Each of the separate parts of the modular system for total hip arthroplasty is manufactured ia several different sizes. 

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