Bait and switch is illegal everywhere, right? If the surgeon stated that they were the one that would be doing the job, they are guilty of this.
The nominal surgeon usually does the “heart” of the procedure: replacing your ACL, removing a tumor, etc. Their assistants just get you into/out of the state where that happens.
Surely you don’t expect the surgeon to personally do everything related to the case, right? Wash the drapes, prep the instruments?
Or maybe something more important came up just prior. Ultimately people have the learn and have a go at some point - with your attitude they would be no more doctors.