Effect of surface modification of acetabular cup with embedded micro-pits on friction properties

Abstract

This study describes an investigation of the effect on friction when an acetabular cup surface is embedded with micro-pits. The micro-pit is potentially a suitable structure to act as a lubricant reservoir, in order to reduce the level of friction present between the surfaces of a hip prosthesis. The experiments were carried out using a modified four-ball tribometer. Refined, Bleached and Deodorised (RBD) palm olein and additive-free paraffinic mineral oil were selected to provide lubrication. When the palm olein was applied to the acetabular surface, friction in the hip implant decreased. Severe damage on the acetabular surface resulted in lubricant-free test conditions. Meanwhile, the results of tests on the acetabular cup, with 10 to 40 embedded micro-pits on the surface, indicated that friction had decreased. Based on the experiments, surface modification of the acetabular cup with embedded micro-pits, could prolong the biomechanics of hip prostheses.