Tribological behaviour of the 304L/HDPE contact: application for the knee prostheses

A specific wear and friction device was used in this work to analyse the tribological behaviour of the tibial insert used in total knee arthroplasty (TKA). This wear and friction device reproduced the movements of flexion extension (F/E) and anterior posterior translation (A/P). Two sinusoidal movements with frequency 1Hz and amplitudes 8.185° and 5 mm were imposed respectively on a metal cylinder and a flat polymer sample which were in contact under a constant normal load. Each one of these movements was simulated separately. The polymer used was the HDPE (high density polyethylene). Two values of the normal load (Fn=500N and Fn=1000N) were considered. For each one of these two values, tests with different numbers of cycles were carried out. The tribological response of the contact was analysed through the evolution with the number of cycles of the friction coefficient, the loss in mass of the samples and the wear zone with scanning electron micrograph observation. The results indicate that the tribological behaviour of the HDPE depends on the type of the imposed movement.