Towards wear testing of high demanding daily activities on total hip replacement: preliminary results

Abstract

A hip joint wear simulator is any device used to provide highly accurate predictions of the in vitro wear of a broad spectrum of bearing biomaterials. In recent years, more severe conditions have been successfully modeled and mechanical in vitro wear testing on total hip replacement is moving towards the simulation of the typical loads of high demanding daily activities including jogging, stair climbing, and other movements characteristic of daily life. In this work, we developed a flexible setup on a hip wear-testing machine capable of simulating various loading conditions simultaneously, with electrohydraulic valves capable to adapt rapidly to the input file changes. A high demanding activity protocol was developed to simulate the most important demanding activities that a prothesized patient could perform, analyzing also the amount of the various tasks accomplished in a day. The newly developed simulator showed to be highly flexible for each analysis purpose, allowing to simulate contemporaneously different loading conditions on different stations to analyze loads acting on the articular component and to precisely replicate the flexion extension condition thanks to the encoder feedback system installed.