What is the mechanism of action of intra-articular hyaluronic acid in osteoarthritis?

• A. Provides joint lubrication, promotes cartilage matrix synthesis, reduces matric degradation
• B. Inhibits bone mineralization
• C. Increases inflammatory cytokines
• D. Enhances cartilage breakdown

Answer: (A)

The main effect of intra-articular hyaluronic acid is to restore the joint’s lubrication and mechanical properties while supporting the cartilage matrix. By replenishing the viscoelastic component of synovial fluid, it improves lubrication and shock absorption, which reduces friction and pain during movement. It also appears to promote cartilage matrix production by chondrocytes (proteoglycans and collagen type II) and to dampen matrix degradation by decreasing degradative enzymes and inflammatory mediators. This combination helps protect the cartilage and improve joint function. It does not inhibit bone mineralization, increase inflammatory cytokines, or promote cartilage breakdown.