In the 1950s, many physicians treated angina with ligation of the internal mammary artery. Despite claims of up to a 91% success rate, in the late 1950s, two skeptics conducted separate double-blind tests in which half the patients received skin incision, but not artery ligation12-13. In both studies, the placebo surgery proved equally effective as the ligation. And the overall rate of improvement with the placebo was 37%.
A 2002 study of arthroscopic knee surgery found that the outcomes for a placebo procedure were as good as those of the “real” surgery14.
Link -Thanks, Karen!
(image credit: Flickr user Akácio S. [ /photographyk ])