Fretting manifestations in total hip prosthesis

This paper analyses the fretting and fretting wear phenomena to the classical and modular hip prostheses. Theoretical and experimental manifestations are studied, at the interface of the femoral stem with the bone cement mantle, at the taper junction between the femoral stem and the femoral head of the prosthesis, as well as at the tapering of the femoral neck adapter’s connections with the stem and the femoral head. The aim of the paper is to highlight the modularization implications of the femoral component of the Total Hip Prosthesis, especially its tribological implications (fretting wear of modular junctions, fatigue and corrosion by fretting) which can contribute to wear and increasing ion concentrations of the metal in the blood, and the possibility of the femoral shaft fracture at the femoral head junction. Theoretical approach described, allows the “Archard” law implementation to predict the fretting wear. Experimental laboratory studies focused on the analysis of the tribological phenomena occurring at the taper junctions between the femoral head and neck, as well as the neck and femoral stem, highlighting the relevant qualitative tribological aspects. For this purpose, experimental junctions were fabricated and tested on a universal MTS mechanical machine, equipped with a fatigue testing device.