Cellular Responses to Orthopaedic Wear Debris Are Influenced by Particle Morphology

Introduction Total joint arthroplasty (TJA) is commonly used to alleviate the debilitating effects of arthritis. Nevertheless, up to 25% of TJA cases will require surgical revision due to implant failure. The generation of wear debris through articulation of the artificial joint is considered one of the prime factors promoting the chronic inflammation that leads to implant failure. Previous studies using uniformly shaped debris have identified that the particulate size, debris concentration, and material composition of the wear debris are factors that influence the degree of the inflammatory reaction that subsequently leads to the aseptic loosening of the prosthesis. However, scanning electron microscopy (SEM) of debris isolated from periprosthetic tissue shows that wear particulates have neither a consistent shape nor texture. We have previously demonstrated that any deviation from a smooth round wear debris morphology results in a pronounced cellular activation and inflammatory cytokine production in a murine model of inflammation. To extend these findings to arthroplasty patients, we have developed a proliferation assay to examine the human cellular response to variations in wear debris morphology.