Example: Before any elective surgery, the patient is always told: Stop aspirin and ibuprofen products, nothing to eat or drink after midnight, etc, etc.
If you dont follow the orders, you dont get your surgery. Why? Because you could bleed out or aspirate on your vomit and the docs arent going to risk that happening. They want your surgery to be as safe and successful as possible.
It's good doctoring.
If he looked hard enough, Mr. Ankle guy might be able to find a surgeon who will do his procedure. One who isnt concerned with liability. Because you can bet if there is a poor outcome, this guy will turn around and sue.
....And it already standard medical practice to have overweight patients lose weight prior to joint replacement. Extra weight puts a lot of stress on the joints.