Hotline Archive - Hyaluronic Acid Treatment for Osteoarthritis
July 1997
Several new products were recently approved by the Food and Drug Administration for the treatment of symptomatic osteoarthritis (OA), particularly disease in the knee. The therapy on which these products are based is referred to as "viscosupplementation."
Intact articular cartilage is needed to provide a cushion and very smooth surface for proper joint function. Normal hyaluronic acid lubricates articular cartilage within the joint. The small degree of inflammation found in some patients with OA metabolizes normal hyaluronic acid so that adequate lubrication is lost. The new therapy purports to replace or "supplement" this abnormal hyaluronic acid.
This supplemental hyaluronic acid is isolated from the combs of roosters and is purified. It is a highly viscous substance that is injected into the joint either three or five times in consecutive weeks depending on the product used. Side effects noted in clinical studies include local irritation due to the injection. A significant allergic reaction was noted in a few patients. Clinical studies show these drugs were equally as effective as acetaminophen for pain relief. Specifically five injections (thus only five weeks of consecutive therapy) provided similar pain relief as did 26 weeks of continuous acetaminophen therapy at an adequate dose.
As with analgesic therapy, there was only evidence of pain relief. There was no evidence that this new therapy altered the biology of the joint (at least in animals who were tested), nor was there alteration of the natural history of OA. Although significant amounts of the drug have been used in other countries, the long-term effects of repeated cycles of injections are unknown. However, this therapy may be useful in some patients with OA who cannot take typical pharmacologic interventions such as analgesic therapy and/or NSAIDs and/or who are not yet ready to undergo a surgical procedure. The cost of therapy has yet to be determined.
July 21, 1997
Robert Thoburn, MD
William Ginsburg, MD
Co-editors,
ACR Hotline
Lee Simon, MD
Contributor
Hotline is provided by the ACR Communications and Marketing Committee as a service to members. This Hotline reflects the views of the author(s) and does not represent a position statement of the College.
