Investigating MoP bearing wear behavior in a hip simulator with muscular properties

Abstract

Metal-on-polyethylene (MoP) hip replacements with a CoCrMo alloy femoral head and an ultrahigh-molecular-weight polyethylene (UHMWPE) acetabular cup are strongly preferred due to their high clinical success. Despite this success, the wear of the bearing surfaces that causes a reduction in the prosthetic use of joint prostheses is still a baffling problem that cannot be solved. Although much research has been done on the tribological behavior of UHMWPE, there are a limited number of studies on the UHMWPE wear mechanism of all components in a hip prosthesis. This study aimed to determine the effect of all components of a total hip prosthesis on the wear behavior of UHMWPE according to three different gait cycles. The wear tests performed at the hip simulator were performed with reference to the hip joint movements and a maximum of 3000 N loads specified in ISO 14242-1. In addition to the abrasive and fatigue wear types of UHMWPE undercoat cups. It was observed that the third-body wear type, which was buried on the surface of polyethylene bearing Ti6Al4V alloy, occurred after 5 million cycles. As a result, according to wear test based on friction elements, it was determined that all hip prosthetic components play an active role in polyethylene wear due to repetitive movement and loading. Moreover, it was concluded that the wear model presented by finite-element analysis can predict the formation of wear in hip prostheses in a reasonable manner.