The surface topography of a metallic femoral head and its influence on the wear mechanism of a polymeric acetabulum

The wear mechanisms of friction components depend on conditions of articulation, material properties and surface topography of the co-acting parts. Therefore, it is important to examine these determinants in order to improve the durability of a friction pair. With the view of securing the longer life of articulating surfaces, a metallic femoral head used in conjunction with a polymeric acetabulum was subject to research. The components of the friction pair were prepared in accordance with the standard specification ASTM F2033-12. From the precision machining process of metallic femoral heads, two different kinds of surface topography (defined by Ra parameter: Ra(A) < Ra(B)) were obtained. The tribological research was performed with a testing machine simulating the kinematic movements and the working conditions of a natural joint (friction pair: ball-and-socket) in the Ringer's solution. The measurements of the surface topography (machined and worn surfaces) were conducted using the following measuring devices: coordinate measuring machine, white light interference microscopy and scanning electron microscopy. Based on the analysis results, the influence of the surface topography of the metallic ball upon tribological characteristics was determined. The wear mechanisms of the polymeric socket resulted from a number of phenomena, including plastic deformation, abrasive wear, fatigue and adhesion.