Nanocrystalline layer on the bearing surfaces of artificial hip implants induced by biotribocorrosion processes

Orthopedic prostheses are lubricated by a pseudosynovial fluid that contains proteins. Under regular movements, bearing surfaces would suffer wear and corrosion. More importantly, their interaction controls the material degradation process. Nanocrystalline layer was found on the surface of CoCrMo alloy surface after tribocorrosion tests. Tribocorrosion tests were taken in 0.9% NaCl and 0.9% NaCl with 1% bovine serum albumin (BSA) solution. Small angle X-ray Scattering was applied to measure the size distribution of the nano-crystals. As a general conclusion, proteins can absorb on prosthesis materials and act as a lubricant during sliding. The negative charge distribution on the material surface can promote the adsorption of protein. The average size of the nano-crystals on the bearing surface was 5 nm.