The deaths of Michael Kennedy and Sonny Bono prompted advocacy of mandatory helmet use; however, no mandate and universal recommendations on helmet use during winter sport participation are available. The American Medical Association found insufficient evidence to officially endorse helmet use in 1997; however, it did recommend voluntary use for children and adolescents while participating in winter sports. Hasler et al observed a large increase in helmet use in Switzerland, from 10% in the 2001 to 2002 season to 69.2% in the 2010 to 2011 season. In a recent study of skiing- and snowboarding-related injuries treated at a level I pediatric trauma center in Colorado from January 1999 through December 2014, it was discovered that 57% of children injured were helmeted. In patients who were admitted to the intensive care unit, the mean injury severity score and abbreviated injury severity score were considerably lower for those who were helmeted, compared with those who were not. Although the authors of the study demonstrated a trend of increased use, a substantial number of patients (40%) elected not to use a helmet. In a systematic review of the efficacy of helmets in reducing head injuries in snowboarders and skiers, Haider et al found overwhelming evidence that helmet use reduces the risk and severity of head injuries in these athletes. An increased risk of cervical spine injury or compensating "risky" behavior was not observed in those who were helmeted.
As the prevalence of upper extremity injuries has increased, especially in snowboarders, attention has turned to the possible protective effect of wrist guards. In a survey of snowboarding-related upper extremity injuries, Idzikowski et al determined that in 5.6% of injuries, the snowboarders had been wearing wrist guards. Women, older participants, and less experienced riders were more likely to wear wrist guards. Overall, wrist-guard wearers were approximately 50% as likely to sustain wrist injuries as those who did not wear wrist guards. The authors of the study were unable to correlate fracture severity with the use of guards; however, they concluded that wrist guards provided considerable protection against wrist injury. Russell et al also examined the effect of wrist guard use on wrist and arm injuries in snowboarders and found that the risk of wrist injury, sprain, and fracture was substantially reduced with the use of wrist guards. The authors of the study found that one wrist injury was prevented for every 50 snowboarders wearing wrist guards. Although these studies suggest that the use of wrist guards is beneficial, there is no consensus on which type of wrist guard design offers optimal protection against injury.
Knee Bracing and ACL Injury Prevention
A paucity of literature exists regarding knee braces and their ability to prevent skiing and snowboarding injuries in native knees; most of this research has focused on ACL-deficient or reconstructed knees.[6,43] Kocher et al studied a cohort of 180 professional alpine skiers with ACL deficiency and found that those who did not use braces were 6.4 times more likely to sustain an injury to the knee than those who did use braces. Injuries included meniscal tears and osteochondral and medial collateral ligament pathology. They concluded that, in the ACL-deficient knee, bracing can be beneficial. In a prospective cohort study by Sterett et al, the effect of bracing on ACL-reconstructed knees was evaluated. Similar to the study by Kocher et al, Sterett et al found that the risk for subsequent knee injuries was 2.7 times higher in recreational skiers who did not use braces than in those who used braces. Of 61 total injuries, 28 required surgery, 11 of which were revision ACL reconstructions. Overall, functional knee bracing seems to provide some degree of stability in the setting of rotational stress in skiers. Additional studies are needed to evaluate the effectiveness of bracing in preventing ACL injuries in native knees.
In addition to bracing, the focus of research has turned to other modifiable risk factors that may prevent initial knee injuries, especially in elite skiers. Raschner et al studied ACL injuries in relation to physical fitness over a 10-year period in skiers aged 14 to 19 years. The authors of the study found that decreased core strength strongly correlated with higher rates of ACL injury, especially in female skiers. In a study of elite Alpine skiers, Jordan et al compared the quadriceps and hamstring strength of ACL-reconstructed knees versus noninjured knees. They found substantial differences in quadriceps and hamstring maximal and explosive strength between ACL-reconstructed knees and both the contralateral extremities and the noninjured knees. Also of interest, uninjured male ski racers displayed bilateral deficits in hamstring maximal and late-phase explosive strength, demonstrating the need to focus on specific resistance training, not just when rehabilitating injured skiers, but also when training young elite skiers.
Improvements in ski bindings began in the 1970s, with no important advancements occurring after 1980. Modern ski boots are designed to provide excellent control and support, thereby restricting range of motion. Current ski bindings are adjusted based on weight, height, age, trail difficulty, and speed. Each season, bindings must be inspected and checked for proper calibration of the heel and toe pieces using the Deutsches Institut für Normung international standard to ensure disengagement. These design changes have improved the skiing experience; however, they simultaneously increase the number of situations that may place the ACL at risk for sprain or tear.
In a retrospective study of 498 recreational skiers who sustained an ACL injury, Ruedl et al reported that the bindings failed to release in 78% of cases, with a much higher incidence in female than male skiers. Falls at slow speed and falling backward resulted in a higher incidence of failed binding release than did falls at higher perceived speeds. Overall, failure of the binding to release was substantially associated with female sex, slow perceived speed, and complete rupture of the ACL.
Bindings and Boots
Snowboard bindings, unlike the typical recreational ski binding, are not releasable. An exception is the telemark ski, which lacks a heel binding, and is lighter and more flexible overall. Three different kinds of snowboard boots are available: soft, hybrid, and hard. Soft snowboarding boots are traditional and generally are constructed of leather or synthetic material that allows maneuvering and comfortable riding. Hybrid boots have gained popularity with new snowboarders. Typically, they are constructed of leather or an outer synthetic shell with a rigid inner boot. Hard snowboard boots, which are primarily worn by racers, provide increased ankle control and support. Each style of boot places different forces on the foot and the lower extremity.
Lower extremity snowboarding injury patterns have changed as the design of boots and bindings has evolved. Many studies have demonstrated that <50% of snowboarding injuries affect the lower extremity and are related to the type of boot used. Hard snowboard boots place snowboarders at risk for fracture of the fibula and tibia at the top of the boot, known as boot top fracture (Figure 4). Telemark ski boots, which contain an open heel, effectively can prevent these fractures in a forward fall. Hard snowboard boots have been shown to place snowboarders at approximately two times the risk of knee injury compared with soft boots; however, soft snowboard boots place these athletes at approximately two times the risk of ankle injuries compared with hard snowboard boots.
Illustration demonstrating the mechanism of injury for a tibia and fibula fracture (ie, boot top fracture), which is the result of a bending moment secondary to the more rigid boot.
Although releasable ski bindings are thought to prevent lower extremity injuries, the bindings often do not actually release under applied stress and falls. In a review of telemark skiing injuries, the type of bindings and boots and the skier's experience level were the most important risk factors for injuries. The authors noted a reduced injury rate overall for telemark skiing compared with alpine skiing. They attributed this finding partly to the increased stability provided by telemark boots. Increased stability can reduce falls caused by a ski edge catching the snow during a turn, which is a common mechanism of injury. Additional improvements in binding technology and release mechanisms is a possible area of future focus to further reduce injury rates.
J Am Acad Orthop Surg. 2018;26(1):e1-e10. © 2018 American Academy of Orthopaedic Surgeons