yep, this is how I tore mine, no rearward fall, just a severe forward fall where I collapsed the ankle over the outside of my foot, essentially creating enough forward energy of the Femur over the tibia, when there is a an abrupt stop there was enough to force to pop the ACL (and ankle/tibia parts too).....
I injured by knee on February 18, 2012, I completely tore the ACL and the tibia has internal fractures and many micro fractures close to the knee. The Dr. does not want to work on the ACL until the bone has healed so my recuperation will be prolonged for a while.
In an attempt to anylize the incident I wonder how much my choice of boot could have affected the outcome. I have two pairs of Nordicas, one pair is a size 28.5 with an adjustable stiffness of 70 to 90. The other pair is a size 27.5 with an adjustable stiffness of 110 to 120. I was using the softer boots at the softer setting, mostly because they let me stand upright when I am at rest. The stiffer boot has an increased ramp angle and tend to tire me out more. Walking in them is also more difficult because the size makes for a tighter fit, it's OK for skiing but walking tends to duff my big toe into the shell of the boot, the last is also somewhat thinner.
What I'm getting at is could the reduced precision from the softer boot have attributed to the incident that led to the injury?
All I really did was catch an edge at speed. It happened very quickly, I don't recall having gotten rearward although it may be that the ski was pulled to the side and forward by the caught edge which would cause the same result. Catching an edge is nothing unusual but this time the outcome was different. I have caught edges using the stiffer boot too so that may not have had anything to do with it but I do see some logic in the idea that sloppier control could constribute to causing a fall, especially if the skiing style (speed, agressiveness, etc.) exceeds the intended design of the equipment.