Tribological analysis of failed resurfacing hip prostheses and comparison with clinical data

Abstract

Abstract

Metal-on-metal resurfacing hip prostheses offer potential benefits over total hip replacement for younger and more active patients. Although some reported clinical results of resurfacing hip prostheses are excellent, other outcomes are less positive. To aid with understanding the balance of benefits related to these devices, analysis of failed resurfacing prostheses can contribute critical insights. However, because these implants are so new there are relatively few such prostheses available for independent ex vivo analysis. From a single-surgeon clinical cohort, a number of failed resurfacing hip prostheses were obtained and studied. It was found that roughness values of the articulating surfaces had increased so that the theoretical lubrication regime would shift from the fluid film to the boundary. In turn, this would likely result in increased wear from the articulating surfaces. High ion levels were seen in the patients from whom the explants were obtained, thus supporting the hypothesis that wear was linked with failure of the explanted hip resurfacing prostheses.