Measurements of Local Strains Allows for Detection of Distinct Tribological Phenotypes of Arthritic Synovial Fluid and Efficacy of Viscosupplementation

INTRODUCTION: Patients with mild to moderate osteoarthritis have been treated with viscosupplementation using hyaluronic acid (HA) for decades as it functions to increase the viscosity of diseased synovial fluid and improve cartilage lubrication. Clinical efficacy of viscosupplementation has shown mixed results with some patients reporting reduced pain and function up to 6 months after injections and others reporting no change. It is unknown if there are different tribological phenotypes of arthritic synovial fluid, and if viscosupplementation may benefit specific disease states. Assessing friction coefficients of synovial fluid provides global measurements over the shear cycle, but does not account for temporal differences in static and kinetic friction. Few reports have investigated how static friction differs between pathologic human synovial fluid, and if temporal differences in static friction can explain observed strains through the tissue depth. The objective of this study was to investigate the effect of viscosupplementation on friction coefficients and shear strains in articular cartilage between inflammatory and non-inflammatory arthritic phenotypes of human synovial fluid, and identify any temporal differences in friction behavior.