Americans with osteoarthritis of the knee have 650,000 arthroscopies a year, at a cost of about $5,000 each. The operation has typically been recommended for people with more serious forms of the crippling joint ailment who don't respond to medication. However, there hasn't been much solid evidence the surgery was effective.
Texas researchers have now found two arthroscopic knee operations that remove scar tissue and other debris from the joint are no better than sham surgery at reducing arthritis pain or improving walking, stair climbing or other functions.In fact, patients did report some benefit from the treatment. However, that appears to be entirely the result of a psychological lift, or "placebo effect," says study author Dr. J. Bruce Moseley, an orthopedic surgeon at Baylor College of Medicine in Houston.
"This is a very expensive procedure that uses a lot of resources," says Moseley, who is also the team physician for the Houston Rockets and Houston Comets professional basketball clubs. "We believe you shouldn't have arthroscopic surgery for osteoarthritis of the knee."
A report on the findings appears in tomorrow's issue of the New England Journal of Medicine.
Nearly 21 million Americans suffer from osteoarthritis, according to the Arthritis Foundation. The bulk of patients are women over the age of 45.
Arthroscopy is a minimally invasive surgical technique in which doctors thread a narrow, pencil-like tube into joints and repair or remove damaged cartilage, ligaments or other tissues. The tubes are rigged with tiny cameras that let surgeons watch what they're doing on a monitor.
Previous, and largely anecdotal, reports suggested people with osteoarthritis of the knee who didn't respond to other treatments were often very happy with arthroscopy, at least for a short time. However, the trials that were conducted didn't include a sham surgery arm for comparison, an important pillar of scientific rigor.
Still, researchers have speculated that shredded cartilage and molecules in the joint fluid can exacerbate osteoarthritis. So, the notion that cleaning up the area might ease the pain associated with the deteriorating tissue, and even stall its progression, made some sense, says Dr. John Klippel, medical director of the Arthritis Foundation.
"I think the message [of the latest research] is clear," Klippel adds.
Moseley and his colleagues compared arthroscopic debridement and lavage -- two wound-cleaning techniques that cut or wash away aggravated cartilage -- with dummy surgery in 180 patients with arthritic knees. Moseley performed all of the procedures, which took about an hour each.
Over the next two years, pain and joint function scores in the three groups were essentially identical and remained steady over the period.
Dr. David Felson, a Boston University physician and co-author of an editorial accompanying the study, calls the size of the placebo effect in the study "surprisingly" small.
Felson believes arthroscopy is no longer a viable option for most people with knee osteoarthritis. However, he's open to the prospect that the treatment might work in a small group of patients. "Someone with something unusual in their knees or lots of crystals that are causing inflammation" may benefit from having the joint cleaned up, he says.
The patients in the study, who were seeking treatment at the Houston VA Medical Center, were mostly men with an average age near 50. They generally had moderate to severe joint symptoms, for which arthroscopy has typically been suggested.
Dr. Marc Hochberg, head of rheumatology at the University of Maryland School of Medicine in Baltimore, helped draft the American College of Rheumatology's 2000 guidelines for the treatment of knee osteoarthritis. At that time, the society said there wasn't enough evidence to recommend arthroscopic surgery for the condition.
"This study provides sufficient data not to recommend routinely the use of" the therapy in most people, Hochberg says. "I think it's likely that when the guidelines are updated [in a year or two], this study will be taken into consideration, and probably recommendations will be made," he adds.
Despite the setback, Klippel says there are ways people with advancing osteoarthritis can gain relief from the condition. Exercises that strengthen the quadriceps muscles of the leg help slow the disease, he says, as can biomechanical approaches such as special shoes. Certain dietary supplements, most notably glucosamine, have also shown promise.
"I think there's a lot on the horizon," Klippel says.
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