Optimization of fretting resistance of modular stem

The modular neck hip prostheses mechanical failure can have several causes, separated or combined such as fretting, corrosion, wear and fatigue. Corrosion mechanism is overcome by specific heat treatment. The fatigue mechanism occurrence is delayed by forging process coupled with finishing process such as shot penning. The breakage of the modular neck becomes mainly related to fretting issues. This is firstly due to the amplitudes of micro-movements of a mismatched geometric tolerance. The effect of contact condition on the fretting behaviour should also be put in relationship with to the used material performances. This study aims to highlight the effect of design parameters on the modular stem fretting resistance. The overall analysis of the results from the design of experiments carried out have shown that a trade-off should to be found between parameters since their variation could be beneficial for fretting wear resistance while becoming unfavorable for fretting fatigue, according to the evaluation criteria.