Mechanisms of anterior cruciate ligament injury in world cup alpine skiing: a systematic video analysis of 20 cases
- T Bere1,
- T W Flørenes1,
- T Krosshaug1,
- H Koga1,2,
- L Nordsletten1,3,4,
- C Irving5,
- E Muller6,
- R C Reid7,
- V Senner8,
- R Bahr1
- 1Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway
- 2Section of Cartilage Regeneration, Tokyo Medical and Dental University, Tokyo, Japan
- 3Orthopaedic Department, Oslo University hospital, Oslo, Norway
- 4University of Oslo, Oslo, Norway
- 5Canadian Sport Centre Calgary, Calgary, Canada
- 6Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria
- 7Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
- 8Department of Sport Equipment and Materials, Technical University of Munich, Munich, Germany
Background We have limited insight into the mechanisms of anterior cruciate ligament (ACL) injuries in alpine skiing, particularly among professional ski racers.
Objective To describe the mechanisms of ACL injury in World Cup alpine skiing.
Design Descriptive video analysis.
Setting World Cup alpine skiing.
Methods 20 cases of ACL injuries reported through the International Ski Federation Injury Surveillance System for three consecutive World Cup seasons (2006–2009) were obtained on video. Seven international experts performed visual analyses of each case to describe the injury mechanisms in detail (skiing situation, skier behaviour, biomechanical characteristics).
Results Three main categories of injury mechanisms were identified: the slip-catch, landing back-weighted and the dynamic snowplow. The slip-catch mechanism accounted for half of the cases (n=10), and all these injuries occurred during turning, without or before falling. The skier lost pressure on the outer ski, and while extending the outer knee to regain grip, the inside edge of the outer ski abruptly caught in the snow, forcing the knee into internal rotation and valgus. The same loading pattern was observed for the dynamic snowplow (n=3). The landing back-weighted category included cases (n=4) where the skier was out of balance backwards in-flight after a jump and landed on the ski tails with nearly extended knees. The suggested loading mechanism was a combination of tibiofemoral compression, boot induced anterior drawer and quadriceps anterior drawer.
Conclusion A consistent pattern was observed where the main mechanism of ACL injury in World Cup alpine skiing appeared to be a slip-catch situation where the outer ski suddenly catches the inside edge, abruptly forcing the outer knee into internal rotation and valgus. A similar loading pattern was observed for the dynamic snowplow. Injury prevention efforts should focus on the slip-catch mechanism and the dynamic snowplow.