How should the doctor treat my mcl knee sprain?

MCL sprain: It depends upon the severity and other associated injuries, such as meniscal tear, acl and PCL and lcl tear. A mild sprain (grade ! mcl) just requires rest/possible short term bracing. Isolated mcls usually don't require surgery. If surgery is being done for other reasons and the mcl is grade 3 (complete), then surgery can be entertained.