When a skier falls and one of the knee (or both) twists while the foot remains planted on the ski, the skier will most likely suffer an ACL rupture.
The ACL or anterior cruciate ligament is one of the four important ligaments holding the knee joint together. The ACL can tear when a skier lands on a bent knee then twisting it or landing on an overextended knee. A popping sound can be heard and the skier will have the sensation that the knee gave out. This sensation is caused by the knee joint becoming lax after the ACL quits its job of holding it together and assuring its stability.
An ACL tear is a serious skiing ailment, and one of the most widespread among skiers. Because the feet are bound to long thin boards and are independent from each other, as opposed to skiboarding or snowboarding, the risk of one ski getting caught while the other continues its course is very high. Other ligament sprains often occur as well, but the ACl rupture is the most common and the most severe.
Instability from such an occurrence happens often, and the duration is usually determined by the severity of the tear. It is just about impossible to prevent yourself from falling when on the slopes, and every time you fall you run the risk of injuring your ACL. There is something you can do…to avoid ACL injuries while skiing, wear a knee brace that offers extra support to your ACL. This will ensure you sufficiently protect your knees while skiing and allow you to stabilize them if they do become injured.