Arthroscopic knee surgery, the most commonly performed orthopaedic procedure in the United States, may be no better than medical or physical therapy for relieving chronic pain, according to the results of two studies published in the New England Journal of Medicine

Researchers at the University of Western Ontario randomly assigned 178 people with moderate to severe osteoarthritis of the knee to either arthroscopic surgery, where the inside of the joint is cleaned and smoothed with the aid of a pencil-sized camera, or to a combination of medications, supplements and physical therapy. After two years, both groups reported nearly the same levels of pain, stiffness and disability.

In addition to cleaning and smoothing the inside of the knee, arthroscopic knee surgery is commonly performed to repair tears to a wedge of cartilage in the joint called the meniscus. 

“What typically happens is that a doctor will get a patient with knee pain and give them an MRI [magnetic resonance imaging] scan, and they’ll find a meniscal tear,” said David T. Felson, MD, MPH, a rheumatologist with the Boston University School of Medicine.

But in a separate study in the same issue, Dr. Felson and his colleagues performed MRI scans on 991 people living in Framingham, Mass. They found that meniscal tears were common and often did not correspond to a patient’s pain.  In fact, 61 percent of people who had meniscal tears in their knees reported that they had no pain, aching or stiffness during the previous month.

"I think this shows pretty persuasively that arthroscopy does not benefit osteoarthritis of the knee," Dr. Felson said.

According to the National Center for Health Statistics, more than 650,000 arthroscopic lavage and debridement (cleaning and smoothing) procedures are performed for knee pain each year in the United States, at an average cost of $5,000 each.

"The joint becomes full of all kinds of junk – cartilage, degrading materials and little strands of stuff and tiny tears in the meniscus and shards of things that are sometimes attached to the tissue," Dr. Felson said. "And the thinking was that if you cleaned that up, it would help the pain," he added.

These studies were not the first to question knee surgery, arthritis and pain relief.