I squatted and deadlifted heavy for over a year with no ACL in my right knee. I didn't wear anything on my knees and I had no problems at all. Now, the Olympic lifts are a different story. You probably won't be able to do them much, if at all, with no ACL. I would bite the bullet and get the surgery. If you want to do things like soccer and snowboarding, which are some of the top ACL tearing activities, be very careful doing them with no ACL, even if you're wearing a brace. I just got mine done four weeks ago and the recovery has been much quicker and stronger than I thought it would be. Good luck either way.