The sham surgeries aren't done by fraudulent physicians. There have been studies done for knee pain, where patients are randomly selected for traditional arthroscopy versus a sham surgery, where arthroscopy style skin incisions are created, and then sewn shut. When the patient awakens, they don't know if they had actual surgery or not. This is the study's design, and all patients in the study agree to the randomization process. This is quite different that a surgeon "pretending" to do surgery to bill patient. That, of course, would be fraudulent, unethical, and illegal.
(Can't make a link!! My coding-fu is weak this morning)