6.606 – Biological Effects of Wear Debris from Joint Arthroplasties

Wear of total joint replacements is inevitable with usage of the joint. Despite the potential alterations in the biological characteristics of the articulation, wear generates particulate debris. Upon generation, wear particles are normally processed by macrophages locally. Phagocytosis of particles activates macrophages and other cells to produce proinflammatory mediators. When the amount of wear debris generated is low, a state of homeostasis normally exists in the joint and surrounding tissues, and the localized biological reaction to wear debris is minimal. However, when the foreign body and chronic inflammatory reaction to wear debris and their byproducts is excessive and persistent, chronic inflammation can lead to periprosthetic bone loss (osteolysis). Osteolysis is a complex pathologic process with potentially significant adverse clinical implications. This chapter will review the basic science underlying the biological reactions to wear debris. The characteristics of wear particles and the cellular response to wear debris will be discussed.