Wrist Injuries in Winter Alpine Sports: An Assessment of Epidemiological Factors. Student: Noah Quinlan. Faculty Mentor: Dr.

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1 Wrist Injuries in Winter Alpine Sports: An Assessment of Epidemiological Factors Student: Noah Quinlan Faculty Mentor: Dr. Adam Shafritz

2 GOAL Injuries are common in winter alpine sports. Approximately half of these injuries are of the upper extremities, with a majority being wrist fractures or sprains 1-3. Wrist fractures can result in significant consequences including impaired function, arthritis, nerve damage, and tendon rupture. Treatment may include extended immobilization, or surgery 4. Therefore, understanding risk factors for injury are of great importance. Last year, the National Sporting Goods Association reported that 5.1 million people participated in snowboarding 6. Previous studies have shown that snowboarders are more prone to injury than skiers and are more likely to sustain injuries requiring immediate medical attention 3,5. While these studies provide data suggesting differences in wrist injury between skiers and snowboarders, they lack proper controls to effectively evaluate risk factors. The objective of this study was to assess the difference in frequency and facture pattern between snowboarders and skiers, as well as identify risk factors for wrist injury. Our hypothesis was that the overall incidence of wrist fractures in winter sports is rising, and there is an increase in both frequency and severity of wrist fractures in snowboarders as compared to skiers. APPROACH Data was collected from injured and uninjured winter sports participants at a large ski resort starting in the winter of 1972, continuing through today. Much of the data has already been analyzed, and this project only looked at the past six years. Wrist injuries during this time period were assessed through radiographs with the aid of Dr. Shafritz. Distal ulna and distal radius injuries were defined as those occurring between the diaphyseal-metaphyseal junction and the radiocarpal joint. The AO classification system of distal radial fractures was used to evaluate injuries and place cases into three distinct categories: simple/extra-articular patterns AO 23-A1 and 23-A2; comminuted/intra-articular fractures AO 23-A3, 23-B, and 23-C; and buckle fractures. These categories each contain multiple types of fractures, but group patients based on the likely intensity of treatment required. This provides an assessment of severity. Patient surveys provided demographic information, experience level, hours of instruction, conditions, location on the mountain, circumstances surrounding the injury, use of protective equipment, etc. This data set was analyzed to identify risk factors for wrist fracture. Results from the past six years were compared to results observed in the first thirty-four years of the study. RESULTS From the 2006/2007 ski season through the 2011/2012 ski season, there were 4,034 injuries with 165 (4.1%) fractures of the distal radius or ulna. The proportion of wrist injuries has increased as wrist fractures constituted only 2.4% of all injuries in the first thirty-four seasons. A majority of wrist fractures in the last six years were sustained by snowboarders (82.4%), whereas snowboarders accounted for 66.5% of wrist fractures in the first 34 years (Table 1). Over the past six years, the overall number of wrist fractures per year demonstrated little change (27.5 fractures/year, SD = 6.6) and snowboarders consistently represented a majority of

3 these injuries. The number of wrist fractures per year in skiers has not changed dramatically. Snowboard injuries steadily rose after the sport was allowed at the resort in 1978, but has plateaued since the 1987/1988 season (Figure 1). Buckle fractures were the most common wrist injury observed in skiers (10 fractures, 34.5%) and snowboarders (63 fractures, 46.3%). Of AO classified fractures, A3 fractures were the most prevalent in skiers (9 fractures, 31.0%) and A2 fractures predominated in snowboarders (30 fractures, 22.1%). Interestingly, 41.3% of skier fractures fell into the category of comminuted/intra-articular fractures, while only 31.6% of snowboarder fractures met these criteria (Table 1). This indicates that while skiers are less likely to sustain a fracture, they have a greater risk of a higher severity fracture. Sex did not appear to be a risk factor when comparing the proportion of males with wrist fractures skiing (17 fractures, 58.6%) to snowboarding (84 fractures, 61.8%). Skiers with wrist fractures tended to be slightly older (24.7 years old, SD = 17) than snowboarders (18.1 years old, SD = 9.5). Experience was assessed by the number of days skiing the previous season. Of skiers with wrist fractures, the average experience time was 25.6 days (SD = 24.7), but only 11.3 days (SD = 15.3) for snowboarders. Analyzing laterality, 86.2% of injured skiers were right hand dominant and 62.1% fractured their left wrist. In snowboarders, 86.8% were right hand dominant and only 54.5% fractured there left wrist. Since snowboarders have a leading and a trailing hand, side of injury may be more associated with falling forward or backward than hand dominance. In conclusion, these preliminary results suggest that snowboarders are at a greater risk for wrist fracture, however skiers may sustain more severe fractures. Snowboarders with wrist fractures tend to be younger and have less experience than skiers. Skiers appear to have a higher risk of injuring their dominant hand, however snowboard injury is more likely associated with their leading/trailing hand. Data from the last six years supports the trends that were observed in the first thirty-four years of the study. OBSTACLES Surveys and information on uninjured control subjects could not be obtained at this time. Therefore, incidence as a proportion and odds ratios could not be calculated. Results are preliminary and need statistical analysis by chi square tests to determine statistical significance. PROJECTION/BENEFIT These results require control data and statistical testing to assess validity. Once analysis of the past six years is complete, it will be combined with the previous thirty-four year project. The duration of this study, as well as its use of a large control population, will ultimately give it significant power to accurately identify risk factors, incidence, and severity of wrist fractures. Assessing how to use this knowledge to prevent injury could be the focus of future work. Potential recommendations for winter sports participants may include safety precautions, instructional advice, and protective equipment use.

4 Table 1. Incidence of wrist fractures arranged by fracture classification, sport, and time point in the study. SNB = Snowboard. AO Classification Total Total Ski Ski SNB SNB Extra-articular Fractures A1 - ulna fracture, radius intact A2 - radius fracture, simple, impacted A3 - radius fracture, multifragmentary Partial-articular Fractures B1 - radius fracture, sagital B2 - radius fracture, frontal, dorsal rim B3 - radius fracture, frontal, volar rim Complete-articular Fractures C1 - articular simple, metaphyseal simple C2 - articular simple, metaphyseal multifragmentary C3 - multifragmentary Buckle Fractures Total Figure 1. Incidence of ski and snowboard wrist fractures per year. FxSKI = skier wrist fracture, FxSNB = snowboarder wrist fracture.

5 REFERENCES 1. Abu-Laban, RB. Snowboarding injuries: an analysis and comparison with alpine skiing injuries. Can Med Assoc J. 1991; 145: Idzikowski JR, Janes PC, Abbott PJ. Upper extremity snowboarding injuries: ten-year results from the Colorado Snowboard Injury Survey. Am J Sports Med. 2000; 28(6): O Neill DF, McGlone MR. Injury risk in first-time snowboarders versus first-time skiers. Am J Sports Med. 1999; 27(1): Ilyas AM, Jupiter JB. Distal radius fractures classification of treatment and indications for surgery. Orthop Clin North Am. 2007; 38(2): Dohjima T, Sumi Y, Ohno T, Sumi H, Shimizu K. The dangers of snowboarding: a 9- year prospective comparison of snowboarding and skiing injuries. Acta Orthop Scand. 2001; 72(6): Hawks, T. Facts About Skiing/Snowboarding Safety. National Ski Areas Association, 2012 October 1. Accessed March 10, Facts-About-Skiing-Snowboarding-Safety pdf.