A comparison of head injuries in male and female lacrosse participants seen in US emergency departments from 2005 to 2016

a b s t r a c t

Introduction: In the United States there has been a large increase in participation in lacrosse for both Males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.

Methods: We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.

Results: A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R² = 0.823; p = 0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R² = 0.800; p = 0.007), but again, there was no significance for female injury count (R² = 0.417; p = 0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the Type of injury recorded.

Conclusion: The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport con- tinues to grow there will likely be more total head injuries and visits to the emergency department.

Introduction

Recently, sports have been under much scrutiny due to the fre- quency of head injuries and their lasting effects. According to the Centers for Disease Control and Prevention (CDC), a concussion is de- fined as a blow to the head that causes the head and brain to move back and forth rapidly. Individuals who get concussions can display many different symptoms including amnesia, loss of consciousness, confusion, nausea and vomiting, headache, Blurred vision, difficulty concentrating, balance issues and many other non-specific symptoms [1]. These concussions also may lead to the accumulation of neurode- generative proteins that permanently alter the composition of the brain and lead chronic traumatic encephalopathy [2].

? This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

* Corresponding author.

E-mail address: [email protected] (A.O. Esquivel).

Much of the research emphasis has been on collegiate athletes and boys’ football; however, head injuries occur in many other sports, in- cluding boys’ and girls’ lacrosse. Lacrosse is a sport played between two teams using a small, dense rubber ball and a long-handled stick. The rules for lacrosse differ for male and female athletes. For male par- ticipants, the sport is considered full contact where body and stick checks are allowed. Male athletes are required to wear helmets with facemasks, mouth guards, shoulder pads, arm pads and gloves. Lacrosse is considered a “non-contact” sport for female participants and female athletes are only required to wear mouth guards and eye protection. The effects of requiring eye protection for female lacrosse athletes have been previously examined [3,4]. One study collected injury data from 25 schools in Virginia and compared the rates and types of injuries that occurred before and after the implementation of eye protection [3]. They found that there was a statistically significant decrease in eye injuries following the implementation of protective eye equipment. An- other study conducted by Webster et al. showed a significant decrease in facial injuries especially to the ocular and forehead region with ath- letes wearing eye protection [4].

https://doi.org/10.1016/j.ajem.2018.05.011

Despite women’s lacrosse being labeled non-contact, incidental con- tact does occur. A 2000 study conducted by Diamond et al. examined head injuries in men’s and women’s lacrosse over a ten year time period and found that women were at risk of serious injury to the head and face region even though they are not required to wear a helmet or face pro- tection [5]. The head and face region was the most common area injured (20.4%). Injuries to the head and face were significantly more prevalent among females than males in their study [5]. Closed head injuries repre- sented 5.6% of all lacrosse-related injuries and were slightly more prev- alent among females according to the study [5]. A recent national study examined concussions to high school athletes in the US [6]. In this study, the authors collected data on sport-related concussion (SRC) for 20 sports over three years, including the number of SRCs and athletic expo- sures (AE) [6]. During games, girls’ lacrosse had the second highest con- cussion rate for all girls’ sports (8.6 SRC per 10,000 AEs). However, when competition and practice were combined, girls’ lacrosse had the highest SRC rate. These injuries were most often caused by contact between the player and equipment (player/stick, player/ball). However, player-to- player contact was the cause of 28% of the SRCs, despite the non-contact rules. They also found that there was no statistical difference in concus- sion rates between boys and girls [6]. A 2014 study by Vincent et al. found that women experienced fewer concussions but more facial frac- tures when compared to men. The study also found that injuries to women involving foot/ankle, head, face, wrist and hand more often re- quire surgery [7]. A 2007 study by Lincoln et al. analyzed over one mil- lion athletic exposures in men’s and women’s lacrosse at the high school and college level and found that the incidence of injury to the head, face and eyes were significantly higher in the women’s game than in the men’s game [8].

In response to these injuries, the Florida High School Athletic Associ- ation began the process of implementing a new requirement that fe- male participants wear helmets in high school competition. However, US Lacrosse (the leading governing body of the sport in the United States) strongly disagreed with this new mandate. They believed that the state of Florida was requiring women to wear helmets without any evidence to justify the need. Despite their position, the mandate of hard headgear will go into be implemented in the 2018 season and is the first state in the country to do so [9].

In the United States there has been a large increase in participation

in lacrosse for both males and females. According to US Lacrosse, it is the fastest growing sport in the United States. US Lacrosse estimates that there were 253,931 people playing organized lacrosse at the end of 2001. Since then the number has grown 325% to 826,033 participants in 2016 [10]. As the number of participants increases, the number of in- juries may also increase. The purpose of this study was to analyze the number of head injuries, Injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States. We compared injuries be- tween male and female lacrosse participants.

Methods

This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission. The data- base, National Electronic Injury surveillance System (NEISS) is a na- tional probability sample of hospitals in the United States [11]. Each NEISS hospital Emergency Department reports patient injury informa- tion involving an injury associated with specific products. From this data, the total number of product-related injuries nationwide can be es- timated. The NEISS database uses information obtained from approxi- mately 100 hospitals across the United States. Inclusion criteria are: hospitals with 6+ beds and an emergency department while psychiat- ric and penal institutions are excluded. The hospitals are broken down further into five strata (four strata based on size and one consisting of children’s hospital). Data is then collected from these hospitals and given a specific weight based on strata. Adjustments are made to these weights due to non-response and hospital mergers [11].

To quantify the number of injuries, we queried the NEISS database

from January 2002 to December 2016 for lacrosse related injuries (prod- uct code 1215) and looked at all diagnoses that involved the head re- gion. The comments section of each case was examined and cases were excluded if the comments indicated that the patient was not playing lacrosse at the time of injury. Some examples of exclusions were fans getting hit with lacrosse balls not participating in the game and individuals getting injured with lacrosse equipment while not playing or practicing.

We used the US Lacrosse Participation Census data from 2006 to 2016 to gauge the number of active participants in the US. US Lacrosse was founded in 1998 and is consider the national governing body of men’s and women’s lacrosse in the US. US Lacrosse publishes a partici- pation survey yearly to monitor participation in the sport throughout the country. The survey only includes participation on organized la- crosse teams collected from regional chapters. Each chapter reports par- ticipation at the youth, high school, collegiate and post-collegiate levels. According to US Lacrosse the data is also obtained from US Lacrosse membership records, the National Collegiate Athletic Association and the National Federation of State High School [10].

Combining both the NEISS and US Lacrosse data we were able to compile injury rates. Data reported include the number of head injuries to males and females from 2002 to 2016 and the injury rate for males and females from 2006 to 2016 per 10,000 participants. We also exam- ined the mechanism of injury by examining the comments section. In- jury mechanisms were categorized as ground-to-head, stick-to-head, ball-to-head, head-to-head, player collision/body-to-head and other. Examples of “other” included collision with the goal post, cleats to the head and player’s own gear cutting him/herself.

A simple linear regression was calculated to predict number of inju- ries and injury rate based on year for males and females. This analysis was completed for two data ranges - up to 2010 and from 2010 to

Fig. 1. Total number of lacrosse related head injuries from 2002 to 2010 and 2010 to 2016. For males from 2002 to 2010, R² = 0.823, p = 0.001; for females over the same period, R² = 0.375, p = 0.08. For males from 2010 to 2016, R² = 0.800, p = 0.007; for females over the same period, R² = 0.417, p = 0.117. Results considered significant if p b 0.05.

Fig. 2. Lacrosse related head injury rates per 10,000 participants from 2002 to 2010 and 2010 to 2016. For males from 2006 to 2010, R² = 0.712, p = 0.072; for females over the same period, R² = 0.00, p = 0.991. For males from 2010 to 2016, R² = 0.854, p = 0.003; for females over the same period R² = 0.606, p = 0.039. Results considered significant if p b 0.05.

2016. Data were also stratified by diagnosis and descriptive information is reported for concussion, laceration and closed head injury numbers. A chi-square analysis was conducted to examine the frequency of these injuries for males and females. Additional descriptive information re- ported includes disposition and cause of injury (stick, ground, collision, etc.). All statistics were computed using SPSS 24.0. Data were consid- ered significant if p b 0.05.

Results

Between 2006 and 2016 there were a total of 7,178,136 lacrosse participants of which 4,448,512 were male and 2,729,636 female. From 2006 to 2016 there were an estimated total of 50,743 lacrosse related head injuries reported to US emergency departments. Head related injuries consisted of concussion, closed head injury, and facial/ head lacerations. Of the 50,743 head injuries, 36,534 were to males and 14,208 were to females. The age range of the injured patients was 6-55 years.

There was a significant positive correlation between the number of head injuries to males and time from 2002 to 2010 (R² = 0.823; p = 0.001). While the number of injuries to the head in female la- crosse participants fluctuated from year to year and was not signifi- cant during the same time period (R² = 0.375; p = 0.08) (Fig. 1). For injury rates per 10,000 participants during the same time period, there was no significance between year and injury rate for males (R² = 0.712; p = 0.072) or females (R² = 0.00; p = 0.991) (Fig. 2). There was a significant negative correlation (R² = 0.800; p = 0.007) for the number of male injuries from 2010 to 2016, but again, there was no significance for female injury count (R² = 0.417; p = 0.117) (Fig. 1). However, a significant negative correlation was found for both males (R² = 0.854; p = 0.003) and females (R² = 0.606; p = 0.039) when examining injury rate during that same time period (Fig. 2).

A chi-square test of independence was calculated for all head inju- ries comparing the frequency of concussion, closed head injury, concus- sion plus closed head injury and lacerations in male and female lacrosse participants from 2006 to 2016. A significant interaction was found in all four cases (p b 0.004). Males were more likely to have a concussion or laceration than females. Females were more likely to have a closed head injury than males (Table 1). Females were more likely to sustain head injury with ball to head (28.9%) and stick to head (28.2%) mecha- nisms. In contrast to males, ball to head (16.3%) and stick to head (21.7%) mechanisms were less (Fig. 3). Compared to females, males were more likely to sustain head injuries via head to head contact (10.1%) and body to head contact (12.4%), while female athletes sustained injuries due to these mechanisms 6.3% and 5.1%, respectively (Fig. 3).

Discussion

In general, the number of head injuries and injury rates increased from 2002 to 2010 and then decreased from 2010 to 2016. Although there were no changes in equipment for either sex in these time periods, there were significant rule changes in the high school game. The NFHS (National Federation of State High School Associations) made it illegal to body check a defenseless player and has continued to emphasize the enforcement of penalties for contact to the head and neck [12]. Crisco et al. recommended that strict enforcement of rules and imple- mentation of rules to protect players’ heads would likely decrease head injuries. The authors noted that the National Football League, Na- tional Hockey League and NCAA Football have implemented significant fines and suspensions on players for direct hits to the head which ulti- mately decreased head injuries in the game without significantly alter- ing the competitive nature of the game [13].

When comparing rates of head injuries to other sports, many of our results were similar. We found that approximately 72% of injuries oc- curred in males and 28% in women. A retrospective NEISS study from 2007 to 2011 looked at all causes of non-fatal head traumas [14]. The au- thors examined athletics, motor vehicle accidents, work related injuries and other incidents of head injuries. Their results for sports related inju- ries mirrored ours. They showed that 69% of their sport-related head in- juries occurred in males compared to 31% in women [14]. The highest incidence of head injuries for male athletes occurred in football and bas- ketball and for female athletes, basketball and soccer [14].

Previous studies have shown that the implementation of eye protec- tion has decreased the number of ocular injuries to female participants. Our data showed that the mechanism of head injury to female lacrosse athletes seen in the emergency department is most commonly caused by ball to head and stick to head which mirrors previous research [15,16]. Caswell et al. examined the mechanism of head injuries in ju- nior varsity and varsity high school girls [15]. They found that stick to head contact was the most frequent cause of injury followed by body to head contact [15]. They also showed that the majority of injuries

Table 1

Chi square test of independence comparing the frequency of concussions, closed head inju- ries, concussions plus closed head injuries, and lacerations from 2006 to 2016 for participants who sustained head injuries. Frequency of concussion and laceration were higher with men; frequency of CHI and concussion + CHI were higher with women. p b 0.004 for all cases.

Male Female

Concussion 26.86% 24.22%

Closed head injury 27.91% 31.89%

Concussion + CHI	54.78%	56.11%
Laceration	24.61%	14.10%

Fig. 3. Mechanism of head injury for males and females.

occurred in close proximity to the goal [15]. A similar study, by Lincoln et al. analyzed the mechanisms of injury in the high school men’s game [17]. They found that the most common mechanism of injury was player to player contact on unanticipated contact or a defenseless player which occurred when athletes were attempting to recover loose balls [17]. If the addition of eye protection decreased the number of eye injuries, this raises the question that if female lacrosse players were to wear head protection, would the rates of these injuries decrease.

According to a laboratory study conducted by Clark et al., there were three incidents in women’s lacrosse (when played within the rules of the game) that could produce enough linear and angular acceleration to cause concussions. The three mechanisms were falls, high velocity ball impacts and high velocity stick impacts [16]. We showed that women are at a significantly higher risk than their male counterparts of receiving head injuries due to the ball hitting the head (28.9%) and stick impacts to the head (28.2%). A study by Crisco et al. analyzed com- mercially available protective helmets to determine whether they would provide any reduction in linear and angular head acceleration. They found that 3 out of 4 commercially available men’s helmets signif- icantly reduced the peak linear and angular acceleration and could lead to a reduction in concussions However, soft headgear is currently the only head protection available to female lacrosse athletes [16]. A labora- tory study by Rodowicz et al. showed that soft headgear did not offer the same reduction in head acceleration as helmets for male athletes. While soft headgear provided protection against low velocity ball impacts, it did not provide protection against high velocity ball impacts where con- cussions typically occur [18]. Indicating that mandated soft headgear use may function differently than mandated eye protection use.

A concerning cohort study by Sandel et al. looked at 112 male and 112 female athletes ages 13-17 that were diagnosed with concussions. It showed that the after effects of an acute concussion on female athletes were significantly worse than males when comparing neurocognitive test results. Female athletes also had a greater number of symptoms when compared to males [19]. This indicates that concussion preven- tion in this population is an important goal.

Opponents to helmet use in girls’ lacrosse state that they will alter the mindset of players and increase injury rates [20]. They believe that players may believe they are protected more and therefore play more aggressively [20], which is referred to as the “gladiator effect” [21]. In our literature search we found no peer-reviewed studies that state that this “gladiator effect” exists and that personal protective equip- ment would lead to more aggressive play. However, it is possible that in some circumstances, this could be the case.

There were several limitations to our study. First, this study only ex- amined head injuries due to lacrosse seen in emergency departments. It is likely that additional head injuries occurred in this time period that were seen by an athletic trainer, family physician or pediatrician. Addi- tionally, some athletes could have been injured multiple times in one year. Another limitation was our use of the US Lacrosse data as our

denominator. Many research studies that report injury rates, report their results as number of injuries per 10,000 athletic exposures (de- fined as games and practices played). However, these studies often ex- amined several specific high schools or universities [6]. We used the number of people reportedly playing organized lacrosse. By using this number as our denominator, we were able to examine all ages of partic- ipants in the United States.

Conclusion

Our study showed that females were likely to sustain a closed head injury that were caused by ball to head or stick to head contact. Males in contrast were more likely to sustain concussions and lacerations by head to head and body to head contact. The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency depart- ment. Future studies should examine whether or not the addition of protective headgear could decrease the number of head injuries in fe- male athletes. Previous research has shown that when personal protec- tive equipment such as googles were mandated, the number of ocular injuries decreased. While male and female lacrosse athletes play the sport with different rule sets, there is still an opportunity to further de- crease head injury in women’s lacrosse. It is not uncommon to see some of these head injured players for initial evaluation and multiple subse- quent follow up visits in the ED for management of post-concussive symptoms and/or suture removal. Reducing these visits to already overburdened US emergency departments are imperative.

Conflict of interest

The authors have no conflicts of interest to declare.

References

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