[Intra-articular injection of hyaluronan for the treatment of knee osteoarthritis].

Osteoarthritis, involves mainly in the knees, is a disease characterized by a mixture of degradative and reparative processes in the articular cartilage. Many compounds have been used intra-articularly. Of those, corticosteroids are very potent anti-inflammatory agents. Although intra-articular injections have been used for the symptomatic treatment of osteoarthritis, corticosteroids injections may suppress cartilage proteoglycan synthesis, worsen cartilage lesion, or even cause degenerative lesions in normal cartilage. Viscosupplementation is a novel, safe, and possibly effective form of local treatment for osteoarthritis. It aims at supplying replacement hyaluronic acid into the joint space to return the elasticity and viscosity of the synovial fluid to normal. Hyaluronic acid, a polysaccharide, is a natural component of cartilage and plays an essential part in the viscoelastic properties of the synovial fluid. Although there is still insufficient information to permit a conclusion concerning the effect of this treatment, if any, on the progression of osteoarthritis in humans, considerable evidence supports the positive effects of hyaluronic acid on joint cellular and immunological function.