Treating knee osteoarthritis with intra-articular hyaluronans

Objective: Intra-articular hyaluronan (HA) or hylan is approved for the treatment of osteoarthritis (OA) knee pain. The authors review here published evidence of efficacy and safety of intra-articular HA for the treatment of knee pain. Since the systemic safety of nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclo-oxygenase (COX-2) inhibitors for OA knee treatment are a current concern, the authors also offer recommendations for repositioning HA in the OA treatment paradigm. Methods: Relevant HA literature was identified by searching MEDLINE and EMBASE from their inception to April 2008 using the search words hyaluronan, hyaluronic acid, sodium hyaluronate, and hylan G-F 20, with knee and OA. Data from randomized, placebo-controlled trials were reviewed and summarized in this article. While not a systematic review, this article reviews the best available evidence for the use of HA to treat knee OA. Results: For the most part, patients in the reviewed studies were adults over the age of 40 with mild to severe symptomatic OA of the knee. Reviewed studies demonstrated significant improvements in pain and physical function with HA or sodium hyaluronate and hylan G-F 20. HA or hylan products were most effective between 5 and 13 weeks after injection with improvements also observed at 14-26 weeks or sometimes longer, and were well tolerated with a low incidence of adverse events. HA also provides beneficial treatment effects when administered in conjunction with other therapies. Conclusions: Intra-articular HA or hylan has proven to be an effective, safe, and tolerable treatment for symptomatic knee OA. In an effort to limit cardiovascular, gastrointestinal, and renal safety concerns with COX-2 selective and nonselective NSAIDs and maximize HA efficacy, the authors proposed using HA earlier in the treatment paradigm for knee OA and also as part of a comprehensive treatment strategy.