A unique study at five orthopedic clinics in Finland compared APM with "sham surgery." That is, surgeons took patients with knee pain to operating rooms, made incisions, faked surgeries, and then sewed them back up. Neither the patients nor the doctors evaluating them knew who had received real surgeries and who was sporting a souvenir scar. A year later, there was nothing to tell them apart. The sham surgery performed just as well as real surgery. Except that, in the long run, the real surgery may increase the risk of knee osteoarthritis. Also, it's expensive, and, while APM is exceedingly safe, surgery plus physical therapy has a greater risk of side effects than just physical therapy.
At least one-third of adults over 50 will show meniscal tears if they get an MRI. But two-thirds of those will have no symptoms whatsoever. (For those who do have pain, it may be from osteoarthritis, not the meniscus tear.) They would never know they had a tear if not for medical imaging, but once they have the imaging, they may well end up having surgery that doesn't work for a problem they don't have.
For obvious reasons, placebo-controlled trials of surgeries are difficult to execute. The most important question then is: Why, when the highest level of evidence available contradicts a common practice, does little change?
For one, the results of these studies do not prove that the surgery is useless, but rather that it is performed on a huge number of people who are unlikely to get any benefit. Meniscal tears are as diverse as the human beings they belong to, and even large studies will never capture all the variation that surgeons see; there are compelling real-world results that show the surgery helps certain patients. "I think it's an extremely helpful intervention in cases where a patient does not suffer from the constant ache of arthritis, but has sharp, intermittent pain and a blockage of motion," says John Christoforetti, a prominent orthopedic surgeon in Pittsburgh. "But when you're talking about the average inactive American, who suffers gradual onset knee pain and has full motion, many of them have a meniscal tear on MRI and they should not have surgery as initial treatment."
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