The Epidemiology of Hand-to-Elbow Injuries in United States Collegiate Sports Over 10 Academic Years

Methods

NCAA-ISP injury data across 10 academic years (July 1, 2004 to June 30, 2014) were used. These injury records contain voluntarily reported data from athletic trainers at participating NCAA programs.¹⁷ All athletic injuries reported in this dataset are a result of participation in athletic competitions or practices, required attention from a physician or athletic trainer, and resulted in the loss of 1 or more days of sports participation. Detailed information about the NCAA-ISP has been previously reported by Kerr et al.¹⁷ Beginning in the 2009–2010 academic year, injuries that did not result in a loss of 1 or more days of sports participation but met the other two criteria were also reported and included in that analysis. On a weekly basis, athletic trainers completed detailed event reports describing the injury and the exposure. Athletic trainers also reported the number of athletes participating in competitions and practices, which allows for the determination of athlete exposures. Data were de-identified by Datalys before being provided to researchers.¹⁷

Data from 16 collegiate sports were analyzed: men's baseball, men's basketball, men's football, men's ice hockey, men's lacrosse, men's soccer, men's tennis, men's wrestling, women's basketball, women's field hockey, women's ice hockey, women's lacrosse, women's soccer, women's softball, women's tennis, and women's volleyball. The database was queried for injuries to the fingers, hand, wrist, forearm, and elbow. Once identified, these injuries were categorized according to NCAA Division (I, II, or III), sport, academic year, time of season (pre-season, in-season, or post-season), competition versus practice, anatomic region, injury type, surgical versus non-surgical care, and time lost from sports participation. Injury data were weighted to provide national estimates. Rate ratios comparing the competition rate to the practice rate were computed by dividing the competition rate by the practice rate. Similarly, sport-specific rate ratios were calculated using women's ice hockey as the referent because it had a consistent intermediate injury rate and adequate athlete exposure, making it an appropriate referent with which to compare other sports.

Rates and relative risk ratios were calculated for hand-to-elbow injuries between sports. Injury and surgery rates per 1,000 athlete exposures, injury rate ratios relative to in-season practice rates, and 95% confidence interval (CI) limits were estimated using a general linear model with Poisson distribution. The estimates were calculated for each year and fit using linear regression analysis to reveal patterns over time. The changes in NCAA-ISP participation starting in 2009 were accounted for by the corresponding changes in athlete exposures and served as the denominator when calculating rates.

Results

Variation by Setting, Season, and Division

There were 6,663 injuries in the hand-to-elbow region during the study period, corresponding to a national estimate of 148,719 total injuries and 14,872 injuries per year. There was a competition injury rate of 1.56 per 1,000 athlete exposures (95% CI: 1.51 to 1.62) and a practice injury rate of 0.42 per 1,000 athlete exposures (95% CI: 0.41 to 0.44) (Table 1). Although there was no statistically significant difference in overall injury rates between Division I, II, and III athletes, there were significant differences in pre-season, in-season, and post-season injury rates between divisions. The highest injury rate seen was Division I pre-season competition: 2.53 injuries per 1,000 athlete exposures (95% CI: 2.35 to 2.72) (Table 1). The injury rate for pre-season competition was 8 times higher than in-season practice (95% CI: 7.40 to 8.72). Among practice injuries, post-season practice had the highest rate ratio relative to in-season practice (2.24 per 1,000 athlete exposures [95% CI: 2.03 to 2.47]) (Table 2).

Table 1: Hand-to-Elbow Injury Rates by Division and Season (2004–2005 to 2013–2014) for Participating ISPs

Table 2: Hand-to-Elbow Injury Rates and Rate Ratios by Sport from 2004–2005 to 2013–2014

Injury and Surgery Trends over Time

The total hand-to-elbow injury rates by year are represented as a general linear model in Figure 1 and listed in Table A (available in the online version of this article). A statistically significant average annual increase in the hand-to-elbow injury rate of 0.05 per 1,000 athlete exposures occurred between 2004–2005 and 2013–2014 (95% CI: 0.02 to 0.09; P = .016).

Figure 1. Hand-to-elbow injury rates by year and general linear model for injury rates by academic year. The 95% confidence interval of trend-line is depicted by shading. AE = athlete exposure

Table A: Competition, Practice, and Total Hand-to-Elbow Injury Rates by Academic Years

During the study period, 548 surgeries (0.05 surgeries per 1,000 athlete exposures) were performed for the reported hand-to-elbow injuries (Table 3). Linear modeling did not identify a significant annual change in the surgery rate (−0.001 surgeries per 1,000 athlete exposures [95% CI: −0.004 to 0.002]).

Table 3: Surgery Rates for Competition and Practice by Academic Years

Sport-Specific Injury Rates

There were variable hand-to-elbow injury rates across sports (Figure 2, Table B, available in the online version of this article). The highest injury rates were found in men's ice hockey (1.04 injuries per 1,000 athlete exposures [95% CI: 0.95 to 1.12]), men's baseball (0.98 injuries per 1,000 athlete exposures [95% CI: 0.91 to 1.05]), and men's wrestling (0.84 injuries per 1,000 athlete exposures [95% CI: 0.74 to 0.96]). The lowest injury rates occurred in women's lacrosse (0.21 injuries per 1,000 athlete exposures [95% CI: 0.16 to 0.27]), women's soccer (0.26 injuries per 1,000 athlete exposures [95% CI: 0.23 to 0.30]), and men's soccer (0.27 injuries per 1,000 athlete exposures [95% CI: 0.23 to 0.31]).

Figure 2. Hand-to-elbow injury rates with 95% confidence intervals by sport per 1,000 athlete exposures (AE) for the combined study period.

Table B: Injury Rate Ratios for Hand-to-Elbow by Season and Setting

Types of Injuries

The most common injury was a contusion of the hand or finger (n = 620), accounting for 9% of the injuries and an estimated national incidence of 13,869 over the study period. Common and clinically relevant injuries included ulnar collateral ligament tears of the metacarpophalangeal joint of the thumb (n = 483) and ulnar collateral ligament tears of the elbow (n = 449), both accounting for approximately 7% of hand-to-elbow injuries with a national estimate of 10,000 cases each. Metacarpal fractures of the non-thumb digits (n = 405) comprised 6% of reported injuries, with a national estimated incidence of 7,250 cases. Scaphoid fractures (n = 114) comprised approximately 2% of all injuries, with a national estimate of 2,000 injuries during the study period (Table 4).

Table 4: Frequencies, Percentage of Total Injuries, and Rates for Commonly Occurring or Clinically Notable Hand-to-Elbow Injuries

Discussion

Across the 16 sports analyzed, an average yearly national estimate of approximately 15,000 hand-to-elbow injuries was found. Given the 291,506 current NCAA participants in these sports, approximately 1 in every 20 student-athletes would be expected to suffer such an injury during their season. Analysis by the NCAA Division shows a generally higher rate of injury in Division I competition relative to Division II or Division III, which is consistent with findings by Hootman et al.³ Because a large proportion of hand-to-elbow injuries sustained are contusions, fractures, dislocations, and other injuries caused by trauma, we suspect that the increased intensity and aggressive play at higher levels of competition may explain the increased rates of hand-to-elbow injury. There were significantly higher hand-to-elbow injury rates during competition compared to practice across all NCAA divisions at a nearly 4 times higher rate. This is consistent with findings by several authors at varying levels and sports who found a 2 to 40 times increased rate of general and specific injuries in competition.^18–20 Analysis by season reveals that the highest rates of competition injury are seen in the pre-season and the lowest rates are seen in the post-season. Pre-season competition injury rates are 2 to 8 times as high as in-season or post-season play. This may reflect the increased intensity of play during pre-season competition due to aggressive play and competition between players vying to earn a roster spot. This would be consistent with evidence of an increased injury rate at higher levels of competition.²¹ Additionally, athletes may be unprepared to resume high-intensity activity in the pre-season, a theory consistent with literature showing the efficacy of pre-season conditioning in preventing season injuries.²²

All of these findings are clinically relevant to athletic trainers and coaching staffs. Raising awareness of the return-to-participation timing and common injuries can help athletes prepare for their sports medical and upper extremity specialist coverage needs. Trainers and medical staff can also use this information to be mindful of how the time of season and practice versus play situations could influence return-to-participation decisions. Coaching staffs could also be prepared for different timing and rates of loss of athlete participation and plan their rosters accordingly. Eventually, there may be successful preventative measures or devices available to improve these injury rates.

The low rate of post-season competition injury is difficult to explain in light of the concept that higher intensity of play should logically lead to higher rates of injury. A possible explanation is that a lighter post-season schedule and athletes who are better conditioned at the end of the regular season may contribute to lower injury risk, again at least partially supported by the theories and literature cited above. A consideration noted by Hootman et al³ is that playing time is not included in the definition of an athlete exposure, so a single exposure can denote highly variable levels of actual exposure to game play. The differing injury rates observed suggested differences in intensity and nature of play between different seasons and levels of play. Further analysis of injury mechanism, such as whether the injury was sustained by player-to-player or player-to-ground contact, would help elucidate the nature of these differences and how they contribute to differing hand-to-elbow injury rates across different conditions of play. Such an analysis would help identify potential changes to practice regimens that may reduce the incidence of hand-to-elbow injury.

Sport-by-sport analysis shows variable rates of hand-to-elbow injury. This is not surprising given the varying levels of physical activity and the differences of each sport. It is logical that contact-heavy sports should have higher rates of injury, and this was evident for football and wrestling. It is also expected that higher hand-to-elbow injury rates would occur in stick-handling sports. Men's ice hockey, a sport involving both contact and stick-handling, had the highest overall rates of hand-to-elbow injury. Men's baseball and women's softball showed relatively high rates of injury consistent with upper extremity use when handling the ball and bat and the vulnerability of the upper extremity when sliding. Despite being a stick-handling sport, women's lacrosse had the lowest rate of hand-to-elbow injury. Bowers et al¹⁴ analyzed hand and finger injuries in sports and, similarly, found lower rates of injury in women's lacrosse compared to other stick-handling sports. They reported a rate of 0.05% for injuries to the hand in women's lacrosse and our study found a rate of 0.21% for hand and forearm injuries. This may be due to less physical contact, including the illegality of cross-checking. Men's and women's tennis showed relatively low hand-to-elbow injury rates, although this is not surprising given the non-contact nature, the softer and lighter ball, and the relatively low risk of direct trauma from the ball or racquet. Typically, racquet-and-ball sports are seen as less injurious to the hand than stick-and-ball sports, at least when considering possible acute traumatic events. Knowing these results can inform coaching and training staffs on having adequate hand and upper extremity medical coverage for their respective sports.

During the 10-year study period, we identified a small but significant increase in the rate of hand-to-elbow injuries. This may reflect the increasing media exposure, public awareness and interest, and competitiveness of NCAA athletics, particularly at the Division I level. Examining the surgery rate revealed that approximately 1 in every 12 hand-to-elbow injuries were treated operatively and there were no significant changes in surgical management rates during the study period. The inclusion of non–time-loss and, presumably, less severe injuries starting in 2009 may explain the increased injury rate without a corresponding change in surgery rate. Additionally, it may be a result of athletes or practitioners being increasingly reluctant to opt for surgical treatment. Morgan and Slowman²³ suggested that pressures on athletes to return to play and perform may lead to players, coaches, and physicians having inadequate concern for upper extremity injuries, leading to undertreatment and the potential detriment of long-term outcome. Additional studies are needed to investigate the time lost for hand-to-elbow injuries and the relationship between the time lost and operative versus non-operative injury management for specific injuries and sports.

One limitation of our study is the potential reporting bias associated with low program participation. Given the variability in the level of play within the divisions, a lack of injury reporting from certain programs may lead to an inaccurate assessment of injury rates. Additionally, the subjective nature of whether to report an injury is another limitation. Although data from 16 NCAA sports were included, the results are likely not generalizable to sports not included, such as swimming or golf. Another limitation is the use of athlete exposures instead of athlete minutes or another time-based measure of exposure. In the current study, an athlete exposure indicates an athlete participating in a NCAA-sanctioned practice or competition without regard to the length of time of participation. Given the varying lengths of practices and competitions, as well as varying time of participation for each athlete at different levels and seasons of play, this is a potentially important factor for which we could not account.

Also, the NCAA-ISP has undergone changes in reporting and operations since its inception in 1982. The change most relevant to this study was the 2009 transition from electronic software provided by the NCAA to software provided by the Datalys Center. Following this conversion, athletic program participation in the NCAA-ISP dropped. For example, men's football program participation dropped from approximately 10% in the 2004 to 2009 period to approximately 4% in the 2009 to 2014 period. Similar reductions in participation occurred across all sports.¹⁷ This level of participation allows for the collection of hundreds of thousands of collegiate athlete exposures and represents a large enough sample to generalize across all collegiate athletics.⁴ However, the exclusion of non–time-loss injuries prior to 2009 likely underestimates the total number of injuries reported to the NCAA ISP.

Implications for Clinical Practice

The current study has important practice implications. Trainers, medical staff, and coaches will now be aware of significantly higher risks of upper extremity injuries during pre-season competition, with rates 2 to 8 times higher than other periods during the season. Knowing this information will allow sports organizations to establish appropriate medical staff personnel and team participant rosters throughout the season.

Conclusions

Hand-to-elbow injuries are increasing among collegiate athletes and men's ice hockey and baseball have the highest injury rates. Pre-season competition injury rates are 2 to 8 times higher than those during the regular or post-season. These results can help training and coaching staffs be prepared for these injuries throughout the course of their season. Further analysis of high-risk sports and injury types may identify opportunities for prevention through program changes or equipment design.