Recreational Injury Interventions

Snow Sports

Background

Covered in this section are skiing, snowboarding, and snowmobiling injuries. Most of the studies outlined in this review measure the effectiveness of interventions in adults or populations in general. However, data collected by Macnab & Cadman, 1996, from the Blackcomb ski patrol injury reports for 1991-1992 found that children age 7-12 and teens age 13-17 have a higher risk of skiing and snowboarding injury compared to people 18 and older. Head injuries constituted 17% (age 7-12) and 22% (age 13-17) of injuries in children and teens. Shorter et al, 1996, also reported head injuries, especially skull fractures, as the most common type of injury in children and adolescents who were hospitalized as a result of a skiing injury. Of the 38 patients (age 5-18) admitted to a pediatric trauma center after skiing related accidents 27 were head injuries, followed by 13 reported extremity injury fractures. The average cost per injury, in this study, was $22,000.

Rupture of the anterior cruciate ligament (ACL) has continued to be one of the most common serious medical problems associated with alpine skiing, Natri et al., 1999. Between, 1972 and 1994 knee sprains, usually involving the ACL, increased significantly by 228%. However, the incidence of injuries over time decreased from 3 to 4 injuries per1000 skier days in the early and mid 1980s to between 2 and 3 injuries per 1000 skier days in the late 1980s and early 1990s. This is generally attributed to advances in the ski/binding/boot system or through education programmes that have taught skiers to recognise and avoid high risk situations. Many of these developments in the ski/boot/binding system may have made skiing easier and perhaps safer when evaluating all ski-related injuries. But, Natri et al, concludes that these new ski/boot/binding systems produces an unique combination of forces and torques that frequently result in ACL injury, and might be the reason for the rise in such injuries. Two studies reviewed below focus on ski/boot/binding systems or equipment interventions and their impact on skiing-related lower extremity injuries.

Snowboarding has increased in popularity in recent years presenting its own unique set of injuries and injury prevention interventions. In 1998, in-area snowboarders number 3.6 million in the United States, Van Tilburg, 2000, 37.8% of these snowboarders were aged 12-17 years. This rise in snowboarding popularity amongst children is of particular interest to child injury; as snowboarders reported a 3 to 4 time higher incidence of injury compared to alpine and telemark skiers, Ronning et al, 2000. Regarding the type of injury experienced by young snowboarders head injuries appear to be common, Macnab & Cadman, 1996. This type of injury usually occurs when snowboarders jump, execute aerial maneuvers, or collide with trees, hard snow, of with other snowboarders. This study also reports an increase in the rate of ankle and wrist injuries in the 7-12 and 13-17 age groups, which may be related to increased snowboarding in these groups.

Van Tilburg, 2000 indicates that, while head injuries are a point of concern, snowboarders are more likely to experience upper and lower extremity injuries, with a slight favor of upper extremity injury, and most often a wrist sprain or fracture. One study below investigates injuries in snowboarders who wore protective wrist guards compared to those that did not. Regarding lower extremity injury, snowboarders primarily injure their ankle in contrast to knee injuries in skiers. One injury particular to the lower extremity of a snowboarders is fracture to the lateral process of the talus, called snowboarder's fracture. This type of injury can often mimic an ankle sprain and is often not seen on plain radiographs. Additionally, the lower frequency of knee injuries in snowboarders is most likely due to the minimization of torsional stretch to individal knees that is common in skiing. Stretch to the knees is reduced because of the following snowboard mechanics; relatively flexible snowboarding boots, fixed footing to a single board, and nonreleaseable bindings. Attempts to improve snowboarding performance by introducing stiffer boots could lead to more knee injuries and fewer ankle injuries. Equipment mechanics effect injury incidence.

Morbidity Mortality Weekly Report, 1997 (MMWR), findings indicate that most snowmobile incidents in Maine during 1991-1996 resulted from collisions caused by excessive speed and careless operation of the vehicle. Of the 903 reported injuries 31% were lower extremity, and 18% upper extremity. In thirteen percent of the incidents alcohol was determined to be a factor. MMWR further suggests that the majority of snowmobile-related deaths occur in males in their 20's. The fourth study included below assesses the role of a snowmobile surveillance program in the prevention of snowmobile-related deaths and injuries.


Review of snow sports studies:

Author

Finch and Kelsall, 1998

Study design and target population

Non-randomized controlled trial.

Critical review of anecdotal evidence, informed opinion, biomechanical studies, testing of equipment, epidemiological studies, and controlled field evaluations.

Population: 1150 skiers who responded to local press and radio releases during a 2-year period.

Intervention

Ski binding test and professional adjustment. (n=460) skiers in an experimental group had their bindings tested and adjusted professionally and (n=690) controls did not.

Outcomes

Injury events, specifically frequency of lower extremity equipment-related injuries.

Results

17.6% of skiers in the experimental group reported > 1 injury event compared to 24.5% of the control group.

Rate of lower extremity equipment related injuries in the experimental group was 3.5 times lower than control group.

Study quality and conclusions

Currently used bindings are insufficient for the multidirectional release required to reduce the risk of injury to the lower limb, especially the knee.

Further technical developments, innovations in binding-release function, case-control studies to evaluate binding adjustment, and skier education are needed.

Study utilized combination of epidemiological studies, biomechanical evidence, equipment-testing studies, and anecdotal evidence in review. Very little evidence is based on controlled trials or the actual evaluation of ski bindings and their adjustment.



Author

Goulet, et al.., 1999

Study design and target population

Case-control study, utilizing a questionnaire sent to parents of participants.

Population: 387skiers were recruited among skiers age 3-12 years at 1 major ski center in Quebec City, Canada during 1995-1996 ski season.

Intervention

Information regarding risk factors were collected for injured skiers (n=41) and a control group of uninjured skiers (n=346).

Injured skiers included skiers treated by a ski patroller for an injury suffered on the slopes.

Control group was selected at random and included skiers who had never suffered an injury resulting in a medical consultation or first-aid intervention.

Outcomes

Age, sex, skill level, binding adjustment, formal training, and ownership of equipment.

Trained ski patrol members measured release value of ski bindings for injured skiers.

Results

No significant group difference for mean age or sex distribution.

Adjusted odds ratio for injury were 7.54 (95% confidence interval [2.57, 22.15] for skiers in low level skill category relative to highly skilled skiers, 7.14 [2.59, 19.87] for skiers who rented their equipment compared with skiers who owned their equipment, and 2.11 [1.02, 4.33] for skiers with ill-adjusted bindings compared with skiers with better-adjusted bindings.

Study quality and conclusions

Incorrectly adjusted equipment is a significant risk factor for young skiers.

Prevention programs should include promotion of well-adjusted equipment, improvemnet of skill level, education of parents, application of recognized standards for adjusting rented equipment and use of binding testing devices in ski shops.

Study provides clear direct, simple steps to improve safety of young skiers.

Study may be limited by time constraints and the difficulty for parents to correctly assess hours of formal training and skill level of children.



Author

Idzikowski, et al., 2000

Study design and target population

Case-control study.

Population: 7430 snowboarding injuries over a 10 year period (1988-1998) in Colorado.

Intervention

Questionnaire completed by treating physician from 47 medical facilities located near ski resorts.

A control group of (n=3107) non-injured snowboarders.

Outcomes

Stance, equipment used, mechanism of injury, experience/skill level.

Age, sex, snowboard ability distributions, behaviors and attitudes of non-injured snowboarders.

Results

(N=377) or 5.6% of snowboarders in 6725 snowboarding injuries wore protective wrist guards.

Snowboarders who wore protective wrist guards were half, (11.8%) as likely to sustain wrist injuries compared to those who did not, (21.7%). (P=0.0001).

74% of injuries occured in men, 26% in women. 39% injured were beginners, 61% were intermediate or experts.

3645 (49.06% of total) were upper extremity injuries, 56.43% were fractures, 26.78% sprains, 9.66% dislocations. 21.6% were wrist injuries.

Average age of injured snowboarders 22.5 years (range 7-71). 19% of injuries occured in skeletally immature snowboarders.

Study quality and conclusions

Falling was the predominant mechanism for upper extremity injuries.

Skill level was self-reported.

Insignificant difference in use of wrist guards between control group and injured group.



Author

Rowe, et al., 1998

Study design and target population

Ecological time-trend study.

Population: snowmobile trauma within 1 region in Ontario, Canada- with population of 161,000.

Intervention

Community based STOP, Snowmobile Trail Officer Patrol program.

Voulnteers trained in police protocol policing 1,200km of groomed trails from 1993-1995.

Outcomes

Age, gender, event (riding status, say, time, location, mechanism, alcohol involvement, and acute care & in-patient costs estimated.

Survival, injury severity scoring ICD codes from ED physcian assessment, LOS for ICU & hospital, operative procedures mesarued.

Snowmobile-related injuries that result in hospital admissions or death measured in pre-STOP period (1990-1992) and post-STOP period (1993-1995).

Results

Pre-STOP 102 injuries, 87 admission, & 15 deaths compared to 57 injuries (p=0.0004), 53 admissions (p=0.00001), and 4 deaths (p=0.13) in post-STOP period.

39% reduction in snowmobile-related admissions (87 vs 53) and a 44% reduction in overall injuries and deaths (102 vs 57).

Acute care cost savings greater than $70,000/yr.

Study quality and conclusions

Interventions involving enforcement of snowmobile trails can reduce the incidence of injuries from snowmobile-related trauma.

Study reliability considered, a second reviewer examined a subset of outcomes.

Study results may have been influenced by behavior change due to public education & not survelliance, over 2 year post-STOP period, or by uncontrollable environmental factors. Recommend longer pre & post STOP periods.

Successful interventions require a coordinated and multi-level approach of surveillance and public education, centered on alcohol awareness and safety.

Summary of snow sports interventions

Poorly adjusted equipment is a significant risk factor for young skiers. Additionally, bindings currently used appear to be insufficient for the multidirectional release required to reduce the risk of injury to the lower limb, especially the knee for all skiers. Summary of skiing interventions suggests a standard of manufacture of ski boots and bindings is necessary. Snowboarders who wear protective wrist guards are less likely to sustain wrist injuries compared to those who do not. Interventions involving enforcement of snowmobile trails can reduce the incidence of injuries from snowmobile-related trauma.

Recommendations on snow sports programs

Prevention programs for skiing should include promotion of well-adjusted equipment, improvement of skill level, education of parents, application of recognized standards for adjusting rented equipment and use of ski binding testing devices in ski shops. Further technical developments and innovations in binding-release functions, and skier education are needed. Successful snowmobile interventions require a coordinated and multi-level approach of surveillance and public education, centered on alcohol awareness and safety.

Recommendations for future research

Because most of these studies measure the effectiveness of interventions in adults or populations in general there is a need for research focused on children participating in these sports. Randomized controlled trials are needed to control for all the individual and situational variations and study the contribution of conditioning to injury prevention in various snow sports. Considering the high incidence of head injury there is a need for studies evaluating the efficacy of helmet use and the role the helmet in both protection and possible causation of head injuries in skiing and snowboarding. Further case-control studies to evaluate ski binding adjustment and protective wrist guards for snowboarders are needed. Additionally, studies that assess new ski and snowboard designs will be needed as manufactures attempt to improve sport performance.