Friction between a polyethylene pin and a microtextured CoCrMo disc, and its correlation to polyethylene wear, as a function of sliding velocity and contact pressure, in the context of metal-on-polyethylene prosthetic hip implants.

The longevity of metal-on-polyethylene prosthetic hip implant bearings, in which a polished CoCrMo femoral head articulates with a polyethylene liner, is limited by mechanical instability or inflammation resulting from osteolysis caused by polyethylene wear debris. We use pin-on-disc experiments to measure friction and wear of a polyethylene pin that articulates with different microtextured CoCrMo surfaces, covering a wide range of operating conditions including sliding velocity and contact pressure. We determine how the lubrication regime changes as a function of operating conditions, and show that the microtexture accelerates the transition from boundary to elastohydrodynamic lubrication. Additionally, we illustrate that the microtexture could enable tailoring the hip implant to the specific patient needs based on activity level, gender, and age.