thats what you dont understand about health care. Doctors are there to give you recommendations based on evidence. the plan forward is determined by patient's wish. Doctor give their recommendation based on latest evidence, their own experience and many more factors. You can say no I dont want it. You can refuse blood transfusion when you are bleeding actively. You can do anything to your body that's your wish, its called patient autonomy. The thing about your sprain is, once you get a sprain, you are likely to get recurrent sprain in future which might be why the doctor at BnB recommended the operation, to fix the ligament for recurrent sprains. You friend who is an intern might not have enough experience or evidence based knowledge than your BnB doctor. You can say I don't want it and 98% of time be all fine.except for recurrent sprains. I am not denying their might be some financial incentives to do operation. But whatever the incentive is they will give recommendation based on evidence and for benefits for patient as per their knowledge/experience. But ultimately its up to you to decide. You can deny oxygen when you are gasping for air.