Knee injuries make up one-third of the total injuries that occur during ski season. Overall, ski injury rates have decreased over the years, but knee injuries have stuck around.  With enhanced designs of modern ski boots, we’ve been able to better protect bodies from ankle and tibia (shin) injuries, but these modifications have not significantly reduced knee injuries. We’re going to take a look at the most common knee injuries, incidents that cause them, and a few basic prevention steps you can take to keep your knees safe this winter! 

The Most Common Ski Knee Injuries

The two most common knee injuries that occur among skiers are MCL and ACL injuries. These knee ligaments are most at-risk when skiing. 

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  1. Medial Collateral Ligament (MCL) Injuries

The medial collateral ligament (MCL) runs along the inside of your knee from your upper shin bone (fibula) to your lower thigh bone (femur). MCL injuries are the most common injuries in skiing, accounting for 15-20% of all injuries and 60% of all knee injuries in skiers! In most ski injury cases, these tears are usually isolated without additional injuries to other parts of the body or knee. 

When you angle the tips of your skis towards each other in the “pizza” or “snowplow” position, and you fall, this puts pressure on the outside of your knee, which can cause an MCL injury. This may seem counter to what you’d think since the MCL runs along the inside of your knee, but stress on the outside of your knee can leverage the force and impact. If you fall during skiing and feel pain on the inside of your knee, it’s possible that you could have injured your MCL. 

*The best way to prevent MCL injuries while skiing is to stick to terrain that is a comfortable challenge. This can help decrease your risk of falling and increase your sense of control in a situation where you fall. When you’re in the “pizza” or “snowplow” position, make sure to balance your weight as evenly as possible to prevent falling. Learning how to properly be in this position could also help reduce your risk for injury. 

  1. Anterior Cruciate Ligament (ACL) Injuries

The anterior cruciate ligament is a small ligament in the center of your knee. It helps stabilize the knee during running, jumping, cutting, and pivoting. The ACL is commonly torn during skiing with hyperextension or abruptly falling backward. ACL injuries are the second-highest knee injuries seen among skiers. 

ACL injuries are commonly caused by landing a jump with poor form or while hyper-flexing the knee. *Knowing how to properly land a jump is one of the best ways to prevent ACL injuries in skiing. 

Incidents That Cause the Most Common Ski Knee Injuries

Multiple ski incidents lead to MCL and ACL injuries. The six-year study “Knee Injuries in Downhill Skiers”  assessed over 540 skiers with acute knee injuries in six ski seasons. Dr. Nathan L. Grimm is a contributing author of this article who is also on staff at ISMI. The phantom foot, valgus-external rotation, hyperextension, and boot-induced incidents were all outlined in this study as common knee injury contributors. 

1. Valgus External Rotation

Unless you’re an anatomy wiz, you probably won’t be able to visualize this incident by the name alone. This skiing crash occurs when the skier loses their balance with their center of gravity moving forward beyond the knees. Imagine the inside edge of their ski tip catching on the ground- propelling them forward while their knee moves towards the center line of their body while their shin bone is externally rotated. This force of the knee can cause MCL injuries and sometimes ACL injuries. 

2. Hyperextension

It’s a heavy snow day with tons of fresh powder, and you’re moving through it on your run. Suddenly you start to feel resistance from the loose snow, and your legs start to slow down a lot faster than your upper body! To keep from falling, most skiers instinctually cross the ski tips unexpectedly. While this is what you similarly do in the “pizza” or “snowplow” motion when slowing down, the lack of control and sheer force can cause strong forces on the knee. An ACL injury could be the result. 


3. Boot-Induced Incident

When a skier jumps and lands, the ski tails (back of the skis) are usually the first to touch the ground. This motion causes the skier’s body weight to move backward while their lower legs are bound to the skis. Once they’ve made contact with the ground, the ski tips are forced down too. By stabilizing the body, the ACL can be isolated and prone to injury. 

4. Phantom Foot Incident

The phantom foot incident is the most common cause of injury among recreational skiers. It happens when the skier loses their balance backward, causing them to sit back on the rear portion of the skis with the hips below the knees. In an attempt to balance, the skier shifts their weight off the uphill ski and onto the downhill ski. This causes hyperflexion on the knee bound to the downhill ski. If the bindings don’t release, the knee experiences much more force. This can result in both ACL and MCL injuries. 

Out of these four incidents, this study showed that adults most commonly experience injuries caused by valgus external rotation (35%)  and phantom foot incidents (25%).

If you have received a knee injury while skiing, it’s extremely important to seek out proper medical attention. After you receive a diagnosis, surgery and/or physical therapy can help you to heal and recover.

Contact us today to see how we can help you with knee injury recovery.


Merkur WK, Kuah E, Choo P. The effect of ski shape on injury occurrence in downhill skiing In: RJ Johnson, MK Lamont, JE Shealy, eds. Skiing Trauma and Safety: Fourteenth Volume (ASTM STP 1440). West Conshohocken, PA: ASTM International; 2003:129–139.

Paletta GA, Warren RF. Knee injuries and Alpine skiing. Treatment and rehabilitation. Sports Med. 1994 Jun;17(6):411-23. doi: 10.2165/00007256-199417060-00006. PMID: 8091049.


*Please always consult your physician before beginning any exercise program. This general information is not intended to diagnose any medical condition or to replace your healthcare professional. Consult with your healthcare professional to design an appropriate exercise prescription. If you experience any pain or difficulty with these exercises, stop and consult your healthcare provider.