Each year, an estimated 17,500 skiers tear an anterior cruciate ligament (ACL), accounting for about a third of all skiing injuries, according to researchers at the University of Vermont School of Medicine.
Each year, an estimated 17,500 skiers tear an anterior cruciate ligament (ACL), accounting for about a third of all skiing injuries, according to researchers at the University of Vermont School of Medicine. (EyesWideOpen / Getty Images)

Ask downhill skiers why they spend huge amounts of time and money to feed their habit and they might describe the feeling of speeding down a groomed trail early in the morning, carving turns across icy mountain pitches or slicing through powder with a bunch of friends.

With the fun comes risk. While your next ski trip probably will not leave you with a broken leg or a head injury, the risk of knee injury remains, despite decades of improvements in skis, bindings and lessons.


Each year, an estimated 17,500 skiers tear an anterior cruciate ligament (ACL), accounting for about a third of all skiing injuries, according to researchers at the University of Vermont School of Medicine. This figure has remained steady for the past decade, while the number of skier and snowboarder visits to slopes has stayed at about 55 million per year, according to industry estimates. (As for fatalities, running into other skiers, trees or ski lifts accounts for about 38 deaths a year, according to the National Ski Areas Association.)

"Skiing has never been safer," said David Byrd, director of safety and regulatory affairs at the association, a trade group whose members own and operate ski slopes. He notes that nearly 7 of 10 skiers and snowboarders now strap on a helmet before hitting the slopes, compared with fewer than 1 in 4 just a decade ago. The death rate (fatalities per overall skier visits) has declined 25 percent from 1992-1993 to 2013-2014, according to the University of Vermont studies, a trend the researchers associate with greater use of helmets.

Helmets are the low-hanging fruit of ski safety, Byrd said. As instructors pushed for kids to use them during ski lessons, more parents and young adults began wearing them as well.

Still, orthopedic surgeons get a mini-boom every winter in sprained and torn ligaments.

"We see a lot of knee injuries," said Robert LaPrade, chief medical officer at the Steadman Philippon Research Institute in Vail, Colo., a nonprofit that studies sports injuries. He is also an orthopedic surgeon, treating hundreds of ski-related injuries each winter.

In the past 15 to 20 years, the ski industry has developed hourglass-shaped skis that make it easier for beginner and intermediate skiers to make a carved turn on the snow. There have also been unintended consequences, LaPrade said.

"With the improved ski design, skiers can go faster," he said. "The problem is, when people go faster, they fall harder."

As a result, ski manufacturers are working on bindings that sense a fall before it happens — just as crash-avoidance sensors do on automobiles. These sensors would pick up forces that are leading to a bad fall, then trigger the ski to release from the boot, preventing the twisting forces on the knee that result in an ACL tear.

To address the problem of ACL injuries, Irv Scher, a Seattle-based ski industry consultant, says he's betting on a technological fix.

Scher, a biomechanical research engineer and scientific chairman of the International Society for Ski Safety, said "electro-mechanical" bindings are being tested by ski manufacturers but are still several years away from widespread use.

ACL injuries strike weekend warriors, longtime instructors and elite athletes. American downhiller Lindsey Vonn tore her right knee ACL twice, in 2013. She returned this season after surgery and has won several World Cup races. NotNot everyone is able to make such a comeback.

ACL injuries cost skiers and resorts money and time, according to Robert Johnson, a retired orthopedic surgeon at the University of Vermont School of Medicine who has compiled data on ski injuries for more than 40 years.

"Yes, it's a big problem, a big expense, and not all those knees get back," Johnson said.

One company that has taken up the quest to reduce the risk of those injuries, Vermont-based KneeBinding, says its binding releases the ski boot's heel before too much force has built up from the side during a fall.


Scher, the ski industry consultant, says there isn't firm evidence yet whether KneeBinding works. It could be that the skiers who use them ski less aggressively, reducing their risk of falling and tearing an ACL, for example.

The popularity of what are often called "fat skis" — they have a wider platform designed to help skiers stay above soft snow and deep powder — has also caused problems for skiers' knees. While an extra inch in width may not seem like much, it creates significantly greater twisting force on a skier's knee, according to John Seifert, a professor of sports physiology at Montana State University.

A Czech study of downhill skiers published last year in the Journal of Sports Science Medicine found that the increased torque connected with fat skis could result in more degenerative knee injuries over time.

Some experts say prevention is a better approach than switching skis. They are working on strengthening the muscles around the knee, reducing fatigue that occurs during skiing. Less fatigue means less risk of a fall, especially the kind of fall that can produce a torn ACL, according to Michael Decker, a biomechanical engineer at the University of Denver.

"What we are finding is the non-dominant leg has been injured, especially the ACL, much more than the dominant," Decker said. "Females have two times the rate as males of the non-dominant leg."

Spending more time in the gym could be the key for many.

"Most people are physically not as equipped as they probably should be," said Roy Pumphrey, a certified strength and conditioning specialist in Baltimore who trains many skiers.

Pumphrey agrees that the key to protecting the knee from injury is keeping the gluteus muscles tight while skiing, strengthening the muscles around the knee beforehand and learning how to increase your body's mobility, no matter how old you are.