The Placebo Effect Doesn’t Apply Just to Pills
For a drug to be approved by the Food and Drug Administration, it must prove itself better than a placebo, or fake drug. This is because of the “placebo effect,” in which patients often improve just because they think they are being treated with something. If we can’t compare a new drug with a placebo, we can’t be sure that the benefit seen from it is anything more than wishful thinking.
But when it comes to medical devices and surgery, the requirements aren’t the same. Placebos aren’t required. That is probably a mistake.
At the turn of this century, arthroscopic surgery for osteoarthritis of the knee was common. Basically, surgeons would clean out the knee using arthroscopic devices. Another common procedure was lavage, in which a needle would inject saline into the knee to irrigate it. The thought was that these procedures would remove fragments of cartilage and calcium phosphate crystals that were causing inflammation. A number of studies had shown that people who had these procedures improved more than people who did not.
A total of 180 patients who had osteoarthritis of the knee were randomly assigned (with their consent) to one of three groups. The first had a standard arthroscopic procedure, and the second had lavage. The third, however, had sham surgery. They had an incision, and a procedure was faked so that they didn’t know that they actually had nothing done. Then the incision was closed.
The results were stunning. Those who had the actual procedures did no better than those who had the sham surgery. They all improved the same amount. The results were all in people’s heads.
Many who heard about the results were angry that this study occurred. They thought it was unethical that people received an incision, and most likely a scar, for no benefit. But, of course, the same was actually true for people who had arthroscopy or lavage: They received no benefit either. Moreover, the results did not make the procedure scarce. Years later, more than a half-million Americans still underwent arthroscopic surgery for osteoarthritis of the knee. They or their insurers spent about $3 billion that year on a procedure that was no better than a placebo.
Sham procedures for research aren’t new. As far back as 1959, the medical literature was reporting on small studies that showed that procedures like internal mammary artery ligation, a surgical procedure used to treat angina, were no better than a fake incision.
In 2005, a study was published in the Journal of the American College of Cardiology proving that percutaneous laser myocardial revascularization, in which a laser is threaded through blood vessels to cut tiny channels in the heart muscle, didn’t improve angina better than a placebo either. We continue to work backward and use placebo-controlled research to try to persuade people not to do procedures, rather than use it to prove conclusively that they work in the first place.