NEW YORK, July 10 (Reuters Medical News) – Minimally invasive operations typically used to treat knee osteoarthritis do not really improve pain and joint motion for patients, according to a new study. Researchers found that applying arthroscopy for debridement and irrigation to relieve symptoms of knee osteoarthritis was no better than sham surgery in 180 patients. Dr. Nelda P. Wray of Baylor College of Medicine in Houston, Texas, told Reuters Medical News that it’s not that patients didn’t feel better after the arthroscopic procedure, it’s just that they didn’t feel better than patients who underwent the so-called placebo procedure. Patients did feel better, but it was just a placebo effect. D., and colleagues write in the July 11 issue of the New England Journal of Medicine that the question is whether the operation should make sense based on the magnitude of the risk and the cost. Osteoarthritis occurs when cartilage in the joints is damaged, which often leads to pain, swelling, and impaired mobility. about 12% of Americans over the age of 65 have knee osteoarthritis. When medications and other methods (such as exercise) fail to provide relief, patients often turn to arthroscopy for debridement or lavage. Approximately 650,000 such procedures are performed in the United States each year, costing about $5,000 per procedure. The procedure removes loose cartilage and other debris located in the inflamed joint, thus improving the patient’s pain and function. Irrigation involves flushing the knee joint with fluid, and additional debridement can be performed in conjunction with irrigation to repair damaged tissue fragments and smooth the surface. Both operations use optical fibers to help the surgeon see the inside of the joint through small incisions. It’s unclear whether such debris removal actually helps patients, and Wray says experts don’t know the source of arthritis pain. She notes that some patients have severe joint damage but no severe pain, while others have mild joint damage but worsening disease. Therefore, the team concluded that patients who felt improvement after knee lavage or debridement were likely to have a placebo effect, a psychological effect that made patients feel physically better. The patients in the study were treated with one of lavage, debridement, or placebo surgery. One of the placebo surgeries was where the surgeon made tiny superficial incisions around the knee joint, but did not do anything inside the joint. Wray noted that there are ethical issues with the use of sham surgery, centering on whether patients are adequately informed that they will undergo a comfort procedure and whether the risks of this operation are low, both of which were assured in the study. In addition, the investigators claim that arthroscopic irrigation and debridement itself now seems to have become a comfort procedure. The medical community is advised to reconsider whether the risks of this procedure are meaningful (including the associated infections or clots) and whether the billions of dollars spent annually on it in the United States are worth it. In a related review, David T. Felson, MD, of Boston University, and Joseph Buckwalter, MD, of the University of Iowa, also questioned the value of lavage and debridement. They argue that debris removal from an inflamed knee sounds appealing, but more important are muscle weakness, joint instability and obesity in patients with knee osteoarthritis. and Buckwalter noted that in past studies without sham treatment, patients who had lavage or debridement reported improved knee pain compared with untreated patients. But a sham-operated control is still needed to accurately evaluate both operations.