Intra-articular Hyaluronic Acid Injections

Intra-articular hyaluronic acid (HA) viscosupplementation has been a mainstay of osteoarthritis treatment for many decades. Viscosupplementation as the name suggests involves the restoration of the viscosity and the lubricating ability of injured or inflamed synovial fluid. While the lubricating ability of HA injections has been well characterized, recent studies have demonstrated that the anti-inflammatory, anti-catabolic, and chondroprotective actions of HA reduce pain and improve patient function. This chapter details some of these biologic effects of intra-articular HA. The key mechanical properties that contribute to joint lubrication and can predict clinical outcomes in patients have also been described. Additionally, future directions for the characterization and application of synthetic HA-derived viscosupplements are discussed.