Effect of contact stress on friction and wear of ultra-high molecular weight polyethylene in total hip replacement

This paper studies the effect of contact stress on friction and wear of ult ra-high molecular weight polyethylene (UHMWPE) acetabular cups by means of friction and wear joint simulator testing under serum lubrication. For a gi ven applied load, increasing the contact stress by increasing the ball/sock et radial clearance decreased both the coefficient of friction and the wear rate. Friction and wear were highly correlated. The dependence of friction on contact stress for the UHMWPE socket under serum lubrication was simila r to that of semi-crystalline polymers under dry sliding. This finding indi cates: the occurrence of partial dry contact at asperity levels for the met al polyethylene ball-in-socket joint under serum lubrication.