My ACL was repaired with a cadaver graft. I was cleared for skiing in about 10 months after the repair, but prescribed a brace to wear for the first year or two because it would take a while for the graft to be fully healed. After that I could wear it or not depending on how I felt about it. There is a psychological factor involved (particularly after being taken out from behind by a snow boarder and feeling the brace take the hit)!