The role of intra-articular hyaluronan (Sinovial^®) in the treatment of osteoarthritis

Osteoarthritis (OA) leads to significant pain and disability. For pain relief, a tailored approach using non-pharmacological and pharmacological therapies is recommended. If adequate symptom relief is not achieved with acetaminophen, other pharmacological options include non-steroidal anti-inflammatory drugs (NSAIDs), topical analgesics, intra-articular corticosteroids and intra-articular hyaluronic acid (HA) viscosupplementation. Most of these therapies generally do not improve functional ability or quality of life or are associated with tolerability concerns. In OA patients, concentration and molecular weight (MW) of HA are reduced, diminishing elastoviscosity of the synovial fluid, joint lubrication and shock absorbancy, and possibly anti-inflammatory, analgesic and chondroprotective effects. In knee OA, viscosupplementation with 3–5 weekly intra-articular HA injections diminishes pain and improves disability, generally within 1 week and for up to 3–6 months and is well tolerated. HAs have comparable efficacy as NSAIDs, with less gastrointestinal adverse events, and compared with intra-articular corticosteroids, benefits last generally longer. High MW hylans provide comparable benefits versus HA, albeit with an increased risk of immunogenic adverse events. In mild-to-moderate hip OA, intra-articular injection of HA moderately improved pain and function, generally for up to 3 months with no serious adverse events. Efficacy in other joints is being evaluated. Viscosupplementation with intra-articular Sinovial^® (other trade names: Yaral^®, Intragel^®) injections (an HA of low-medium MW) relieves pain and improves function in OA of the knee, and other joints including the carpometacarpal joint of the thumb and the shoulder. HA viscosupplementation, including use of Sinovial^®, is a valuable treatment approach for OA patients, if other therapies are contraindicated or have failed.