You can do a lot to reduce the risk of ACL tears. The unfortunate fact is that many people have a short IT band, and compromised hip range of motion, resulting in their feet naturally pointing out (duck footed) and their knees rolling to the inside when they squat. This puts a lot of tension on the ACL and compromises it. boots like Fischer's SOMA tech and Nordica's whatever they call it, exacerbate this problem.
Focusing on proper stance, lengthening and softening your IT band, improving hip range of motion will help reduce your likely hood of an ACL tear.