I am not a doctor nor did I stay at a Holiday Inn last night but I have some experience with this. My daughter tore her ACL in college basketball and in college lacrosse. There are 2 basic procedures. The first is an allograft in which tissue from a cadaver is used. it is a quicker recovery but perhaps not as durable. The second is an autograft from the opposite knee which is then put in as the ACL/MCL on the injured knee. Hence the scar on the opposite knee. It is a highly painful injury, surgery, and recovery and her mother was very rightly very proud of her comeback as I was for my daughter. This is a terrific kid who, with Paige, are going to be the role models, inspiration and gold standard for little and not so little girls all over the world for 20 years or more.