Moseley and coworkers studied the effect of arthroscopic surgery for osteoarthritis of the knee establishing two treatment groups and a sham-operated control group. They found that patients in the treatment group did no better than those in the control group. The fact that all three groups improved equally points to the placebo effect in surgical interventions. In a 2016 study it was found that arthroscopic partial meniscectomy does not offer any benefit over sham surgery in relieving symptoms of knee locking or catching in patients with degenerative meniscal tears. A randomised controlled trial was carried out to investigate the effectiveness of shoulder surgery to remove an acromial spur (bony protuberance on x-ray) in patients with shoulder pain. This found that improvement after sham surgery was as great as with real surgery. A systematic review has identified a number of studies comparing orthopedic surgery to sham surgery. This demonstrates that it is possible to undertake such studies and that the findings are important. Animal research Sham surgery has been widely used in surgical animal models. Historically, studies in animals also allowed the removal or alteration of an organ; using sham-operated animals as control, deductions could be made about the function of the organ. Sham interventions can also be performed as controls when new surgical procedures are developed. See also Royal Commission on Animal Magnetism References Human subject research Deception Clinical research Ethically disputed medical practices Medical terminology Surgery