A preliminary experimental investigation on the biotribocorrosion of a metal-on-polyethylene hip prosthesis in a hip simulator

Abstract

Corrosion at the taper/trunnion interface of total hip replacement (THR) often results in severe complications. However, the underlying mechanisms of biotribocorrosion at the taper/trunnion interface during the long-term walking gait cycles remain to be fully understood. In this study, a hip joint simulator was therefore instrumented with an electrochemical cell for in-situ monitoring of the tribocorrosion evolution in a metal-on-polyethylene (MoP) THR during a typical long-term walking gait. In addition, the biotribocorrosion mechanism was investigated via surface and chemical characterizations. The experimental results confirmed that the taper/trunnion interface dominated the contemporary MoP hip joint corrosion. Three cyclic variations in the open circuit potential (OCP) were observed throughout the long-term electrochemical measurements, attributed to the formation and disruption of the adsorbed protein layer. The corrosion exhibited an initial increase at each period, peaking at approximately 0.125 million cycles, followed by a subsequent gradual reduction. Surface and chemical analyses revealed the formation of a tribochemical reaction layer (tribolayer) on the worn surface of the taper/trunnion interface. The surface/chemical characterizations and the electrochemical measurements indicated that the adhesion force of the adsorbed protein layer was weaker than that of the tribolayer. In contrast, the opposite was true for the corrosion resistance. Based on the observations from this study, the tribocorrosion mechanism of the taper/trunnion interface under the long-term walking gait cycles is deduced.

Influence of Proteins and Building Direction on the Corrosion and Tribocorrosion of CoCrMo Fabricated by Laser Powder Bed Fusion

“…In the presence of the proteins, especially with the larger protein Fbn present, the COF and wear track width decreased significantly. The lubricating action of the proteins dominated the tribocorrosion process during the 60 min period tested, which is similar to other studies. − Also, as visible from no significant Mo oxide buildup in the wear track (XPS), the protein layer might have had a local pH buffer effect and hindered or reduced the anodic/cathodic cell separation during tribocorrosion . This is a very interesting finding, and the presented method to combine tribocorrosion and spot size XPS analysis might be an interesting path for future studies of tribocorrosion mechanisms in other systems, which should include other proteins and more complex solutions.…”