Chapter 23 – Pathophysiologic Reactions to UHMWPE Wear Particles

Publisher Summary This chapter summarizes the current understanding of both the morphologic and inflammatory-related tissue changes that result from the generation of ultra-high molecular weight polyethylene (UHMWPE) wear debris. Implants for total joint replacement must contribute to a biologically favorable and mechanically stable environment to provide a satisfactory long-term outcome. One of the most important factors determining the success of a total joint replacement is implant wear and the associated adverse biologic reaction elicited by wear debris and one of the tissue responses to wear debris is both complex and patient specific. The most obvious gross, clinical manifestation associated with wear debris generation is bone loss, which is identified as a major reason for implant loosening and the need for revision surgery after total hip replacement. However, the limitations of earlier methods of tissue preservation and in vitro and in vivo model systems are being increasingly recognized. In addition, technological methods for tissue analysis are continually being updated, such as the use of protein microarrays to measure specific profiles of proteins and cell signaling factors. With new technological advances and increased implantation time comparisons for highly crosslinked UHMWPE components, an improved understanding of regional and systemic immune responses to UHMWPE wear debris continues to evolve. Ultimately, a better understanding of these processes will provide insights into the early diagnosis and treatment of inflammatory mechanisms involved in the loss of implant function.