Knee Surgery No Better Than Placebo

July 10 -- On a scale of zero to 10, Eutimo Perez Jr. says the pain in his knee that was once "worse than 10" is no more.

Perez, who suffers from the degenerative joint disease osteoarthritis, took part in a clinical trial designed to test the efficacy of arthroscopic surgery on osteoarthritic knees, and has been pain-free for more than two years since.

The interesting thing, though, is that Perez was in the "sham surgery" group of the study and the researchers did almost nothing to him.

Osteoarthritis, which afflicts more than 20 million Americans, is characterized by the breakdown of cartilage in the joints. Oral medications as well as lifestyle changes can treat the disease, but for some patients, arthroscopic surgery — in which damaged cartilage is scraped or flushed out with the aid of a thin viewing scope — is also an option.

Perez was assigned to the placebo group of the trial: He was given anesthesia and doctors made incisions in his knee so that it looked as though he had an arthroscope inserted. This sham surgery group was compared to other patients who underwent an actual arthroscopic procedure.

The study, published this week in the New England Journal of Medicine, found some surprising results.

"The groups were all reporting improvement; it's just there was no greater benefit in any of the groups compared to the placebo," Dr. Bruce Moseley, lead author of the study and clinical associate professor of orthopedic surgery at Baylor College of Medicine in Houston, told ABCNEWS' Jackie Judd.

This experience has left Perez with a strong understanding of the placebo effect and of how belief that a surgery can relieve pain may actually do just that. "It's a mental thing," he said. "I think that if you believe in something, you can get well."

And for the medical community, it has led to the understanding that arthroscopic surgery, as performed an estimated 200,000 times a year for the treatment of osteoarthritic knees, may be useless. "My opinion is we probably shouldn't be doing it," said Moseley.