Researchers at the Houston Veterans Affairs Medical Center reported the results of a dramatic study, in which 180 patients with osteoarthritis were randomly assigned to one of three groups: treatment with arthroscopic surgery with lavage; treatment with arthroscopic debridement; or to placebo surgery, where doctors cut into the skin but perform a fake procedure.

The VA team found no difference in pain or function between the study participants who had arthroscopic procedures and those that had the sham surgery. Their study was published in the July 11, 2002, issue of the New England Journal of Medicine.

Another review published earlier this year by the Cochran Collaboration, a group of scientists based in the U.K. that reviews the evidence behind medical treatments, found that arthroscopic debridement was not an effective remedy for osteoarthritis of the knee.

"They all show the same thing," said Claude T. Moorman III, MD, an orthopedic surgeon and director of sports medicine at the Duke University Medical Center in Durham, NC. "If your outcomes measure is whether you cure arthritis or help pain, arthroscopy is not going to be your tool."

But in cases where people with osteoarthritis experience certain functional problems, like a knee that suddenly locks up, or a joint that clicks and pops when they try to play sports – "not  he grinding and crunching of chronic arthritis" – Dr. Moorman said, then arthroscopic knee surgery may be indicated to repair injured tissue.

"There's no such thing as never or always in medicine," Dr. Moorman said. "That's the danger with this type of study, making absolute conclusions from a limited amount of data."

But Dr. Moorman was quick to add that people with arthritis and their doctors should think very carefully about arthroscopic procedures because there is emerging evidence that they may make the condition worse.

"If you're really scoping a knee in a patient with significant arthritis," Dr. Mooman said," I think you have a 1 in 20 chance of making them worse."