Government-approved treatments for knee arthritis, in which the joint is injected with fluid often made from rooster combs, offer little if any relief, researchers say.
Doctors should think twice about recommending hyaluronic acid treatments, which cost at least $100 per injection, said Dr. Grace Lo of Boston University, who led the analysis of 22 published studies.
The analysis found that the injections performed only slightly better than dummy treatments.
Lo said even those results may be overstated, since studies with positive results are more likely to be published than those with negative ones, and the researchers found at least two unpublished studies showing that hyaluronic acid performed no better than dummy treatments.
The analysis appears in Wednesday’s Journal of the American Medical Association.
Dr. Jack Klippel, president of the Arthritis Foundation, said that even if the treatments have only a slight effect on pain, that is beneficial since arthritis pain is so common and sometimes difficult to treat.
The foundation and the American College of Rheumatology have supported the use of such products for certain patients, and Klippel said the study does not change his opinion.
The treatment, sometimes called joint fluid therapy, generally involves three to five weekly injections in a doctor’s office. The injections are intended to replace the natural fluid that helps lubricate the knee joint.
The analysis included studies of three products approved for knee arthritis by the Food and Drug Administration: Hyalgan, Synvisc and Supartz. They are generally recommended for patients who have not responded well to aspirin or ibuprofen.
About 500,000 U.S. patients use such products annually, said Dr. Richard Polisson, senior vice president of clinical research at Genzyme Corp., which makes Synvisc.
Polisson said the researchers excluded some studies that showed Synvisc has significant benefits. And Michael Daley, U.S. medical director of Sanofi-Synthelabo Inc., which makes Hyalgan, complained the analysis included hyaluronic acid products not approved for use in this country.