ORTHOVISC® is indicated in the United States for the treatment of pain in osteoarthritis (OA) of the knee in patients who have failed to respond adequately to conservative non-pharmacologic therapy and to simple analgesics, such as acetaminophen. It is a sterile, clear, viscoelastic solution of ultra-pure high molecular weight hyaluronic acid (HA) contained in a single-use syringe that is injected into the joint in a series of intra-articular injections spaced one week apart.