Media Contact:

OSTEOARTHRITIS TREATMENT NO MORE EFFECTIVE THAN PLACEBO

Osteoarthritis (OA), the most common type of arthritis, is a major cause of disability in the elderly worldwide. One treatment for the disease involves using hyaluronic acid (HA), a substance found in normal joint fluid, to restore the elasticity of synovial fluid, which lubricates and protects joints. Injectable HA is approved by the FDA to treat knee OA, but its use remains controversial. There are few studies on the efficacy of HA for hip OA however, and so far there is little evidence to support its use, although some studies have suggested that a single injection of HA could be effective in treating hip OA. A new study found, however, that a single injection of HA is no more effective than a placebo in treating hip OA. The study was published in the March issue of Arthritis & Rheumatism (http://www3.interscience.wiley.com/journal/76509746/home).

Led by Xavier Chevalier of the Henri-Mondor Hospital in Paris, researchers conducted a randomized, placebo-controlled double-blind trial involving 85 patients with hip OA. Participants were assigned to receive either a single injection of IA or a placebo and were assessed for pain, stiffness and disability after three months.

The study, which was the first randomized controlled trial to evaluate a single injection of HA for treatment of hip OA, failed to demonstrate a significant difference between the HA and the placebo. The researchers chose to administer only one injection of HA because repeated injections might lead to an increased risk of side effects which could be difficult to manage in a deep joint such as the hip.

HA injections into the knee are commonly associated with a high placebo response that might limit the ability to detect benefits of the treatment, but the authors did not observe a high placebo response in the current study.

“The absence of any differences between treatment arms likely reflects the lack of clinical effect of one single intraarticular injection of HA for hip OA,” the authors state. They note that a recent review of seven other trials of HA injection in patients with hip OA showed results that were in the same range as the curresnt study.

The authors suggest that the results seen in this study could be due to the rapid clearance of HA from the synovial fluid compartment, which suggests that a single injection of HA might be insufficient to have an effect on OA symptoms. They conclude: “Future studies are warranted to confirm our results and to evaluate the effects of repeated HA injections in hip OA.”

Article:  “Effect of Hyaluronic Acid in Symptomatic Hip Osteoarthritis,” Pascal Richette, Philippe Ravaud, Thierry Conrozier, Liana Euller-Ziegler, Bernard Mazières, Yves Maugars, Denis Mulleman, Pierre Clerson, Xavier Chevalier, Arthritis & Rheumatism, March 2009.