Wear mechanisms and surface topography of artificial hip joint components at the subsequent stages of tribological tests

It is virtually impossible to follow through changes in surface topography and analyse wear mechanisms of the friction components of a hip joint prosthesis under in vivo conditions. Only under laboratory conditions can analysis of operation process of friction pairs be undertaken. Research on wear mechanisms and formation of surface topography at the subsequent stages of operation process (during in vitro testing) analyzed in this work is a new approach to the current problem concerning investigation and analysis of the lifespan of an artificial hip joint. The paper presents issues of artificial hip joint wear mechanisms and methods for studying changes in the surface topography of a ball-and-socket friction pair at the subsequent stages of tribological research. The subjects of research were co-acting components of an artificial hip joint: a metallic ball and a polymeric socket. Tribological tests were performed with a hip joint simulator replicating the physiological movements and working conditions of the natural hip joint. After each stage of tribological tests, the surface texture of friction pair components was measured using a white light interference microscopy. In addition, the surface topography was examined before and after the operation process, using a coordinate measuring machine as well as an optical microscope. Based on the results, changes in surface topography (its functional properties) occurring at the subsequent stages of tribological tests were assessed. The wear mechanisms of the interacting components, i.e. abrasion, fatigue and adhesion, were identified. (C) 2017 Elsevier Ltd. All rights reserved.