Analysis of squeaking frictional noise of hip endoprostheses

The ceramic-on-ceramic bearings are characterized by low wear rates and an excellent biocompatibility, motivating for the recent evolution of ceramic bearing surfaces for total hip arthroplasty and allowing the development of implants characterized by longer longevity. Nevertheless, recent worrisome rates of squeaking noise occurrence are reported for this kind of prosthesis. Although recent clinical literature focuses on this topic, the origin and factors leading to squeaking are not completely identified. The aim of this work is the development and validation of a numerical model able to predict the friction induced vibrations at the origin of the squeaking noise emission. A complex eigenvalue analysis of the hip prosthesis allowed for predicting the frictional instabilities recovered experimentally on a dedicated set-up. The model allowed as well for recovering the same in-vivo squeaking frequencies and for comparing squeaking propensity of different prosthesis designs.