The effect of a novel CoCr electropolishing technique on CoCr-UHMWPE bearing frictional performance for total joint replacements

This study quantified the effect of a novel electropolishing treatment (Ultra Polish™) on CoCr surface morphology and coefficients of friction (CoF) when slid against UHMWPE pins. Standard and Ultra Polish CoCr samples were characterized using non-contact surface profilometry and SEM. The Ultra Polish process showed aggressive surface carbide removal, leaving behind large randomized pitted areas on CoCr. The trading of carbide peaks for pitted valleys, resulted no statistical change in surface roughness average (Ra) or dynamic CoF between Standard and Ultra Polish Treated groups. Mean Valley Roughness (Rvm) was better able to quantify changes in surface morphology seen in this study.