From what I've seen in the US, it varies a lot from one facility to another. For surgery, most of what I've seen the consents address the expected operation "and all other indicated procedures" that give the surgeon the discretion to add something on intraoperatively if it's justified. That said, the facility I'm at now decidedly does NOT do that. They can add an operation on if it's an emergency, but something like a fibular nail would require specific consent. ...which they should have ahead of time, cuz imaging would make the need for one pretty obvious, but dumb shit happens and things get missed... So fast forward to the operation, patient is under, skin is cut, and circulator points out "uh, hey we only have consent for tibia..." If they have a family member available who can make decisions on the patient's behalf, that person could give consent, but if not they'd probably just skip it and schedule it as a later surgery.

...shit can get goofy.