Helmets, head injury and concussion in sport

Does Headgear Prevent Sport-Related Concussion? A Systematic Review and Meta-Analysis of Randomized Controlled Trials Including 6311 Players and 173,383 Exposure Hours

CONTEXT

A sport-related concussion (SRC) is a traumatic brain injury that is caused by biomechanical stresses and results in a complex pathophysiological process in the brain. Some in the sporting community believe that headgear (HG) can prevent SRC, and several professional Australian sports organizations, including rugby, football, and soccer clubs, recommend its use.

OBJECTIVE

The purpose of this study is to determine whether HG is effective in lowering the prevalence of SRC in sports.

DATA SOURCES

A systematic search for related studies published between 1985 and 2023 was conducted using the following databases: Cochrane Library, AMED, PubMed, Web of Science, and Physiotherapy Evidence Database (PEDro).

STUDY SELECTION

Only randomized controlled trials (RCTs) that investigated the effectiveness of HG in reducing SRC rate were included.

STUDY DESIGN

Systematic review and meta-analysis of RCTs.

LEVEL OF EVIDENCE

Level 1a.

DATA EXTRACTION

Two researchers independently completed the title and abstract search and performed full-text reviews. A third reviewer was consulted to reach a consensus if any discrepancies were noted. The PEDro scale was used to evaluate the quality of the included RCTs. Data recorded from each study included authors, year of publication, type and number of players, study design, duration of the study, injury rate, compliance (%), sports/level, and exposure hours.

RESULTS

The pooled results of 6311 players and 173,383 exposure hours showed 0% SRC reduction per 1000 hours of exposure in the experimental group compared with the control group, with an injury risk ratio of 1.03 (95% CI, 0.82-1.30; P = 0.79).

CONCLUSION

This systematic review and meta-analysis demonstrates that HG does not prevent SRC among soccer and rugby players, and therefore the findings from this meta-analysis do not currently support the use of HG to prevent SRC in soccer or rugby.

Epidemiology of Sports Injuries Among High School Athletes in the United States: Data From 2015 to 2019

Background

Nearly 8 million high school students in the United States participate in sports each year. With the lack of recent population data, an update to previous studies on US high school athletes is needed.

Purpose

To update the epidemiology of sports injuries in high school athletes in the United States.

Study Design

Descriptive epidemiology study.

Methods

The data from the National Health School Sports-Related Injury Surveillance Study, including 100 nationally representative high schools, were obtained for 9 high school sports (boys' football, soccer, basketball, wrestling, and baseball and girls' soccer, basketball, volleyball, and softball) between the 2015 and 2019 academic years. Injury rates were calculated as the ratio of injuries per 1000 athlete exposures (AEs), defined as 1 athlete participating in 1 practice or competition. Data on injured body area, injury type (sprains/strains, concussions, contusions, and fractures), time loss, and need for surgery were also obtained. Rate ratios (RRs) with 95% CIs and P values were calculated.

Results

Athletic trainers reported 15,531 injuries during 6,778,209 AEs, with an overall rate of 2.29 injuries per 1000 AEs. Injury rates were highest in football (3.96), girls' soccer (2.65), and boys' wrestling (2.36). The overall injury rate was lower in girls' sports (1.86) compared with boys' sports (2.52) (RR, 0.74 [95% CI, 0.71-0.76]; P < .001) and was higher in competition compared with practice (RR, 3.39 [95% CI, 3.28-3.49]; P < .001). The most commonly injured body areas were the head/face (24.2%), ankle (17.6%), and knee (14.1%). Sprains/strains (36.8%) and concussions (21.6%) were the most common diagnoses. Overall, 39.2% and 34% of injuries resulted in a time loss of <1 week and 1 to 3 weeks, respectively. Surgery was required in 6.3% of injuries, with wrestling (9.6%), girls' basketball (7.6%), and boys' baseball (7.4%) being the sports with the highest proportion of injuries needing surgery.

Conclusion

Study findings demonstrated that boys' football, girls' soccer, and boys' wrestling had the highest injury rates, with boys' sports overall having higher injury rates than girls' sports. Sprains/strains and concussions were the most common diagnoses. Few injuries required surgery.

Soft-shell headgear in rugby union: a systematic review of published studies

Objectives

To review the rate of soft-shell headgear use in rugby union, consumer knowledge of the protection potential of soft-shell headgear, incidence of concussion reported in rugby headgear studies, and the capacity of soft-shell headgear to reduce acceleration impact forces.

Design

A systematic search was conducted in July and August 2021 using the databases SPORT Discus, PubMed, MEDLINE, CINAHL (EBSCO), Scopus, and Science Direct. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The protocol for this systematic review was registered on PROSPERO (registration number: CRD42021239595).

Outcome measures

Rates of headgear use, reports of estimated protection of headgear against head injury, incidence of concussion and magnitude of impact collisions with vs. without headgear, impact attenuation of headgear in lab studies.

Results

Eighteen studies were identified as eligible: qualitative (N = 4), field (N = 7), and lab (N = 7). Qualitative studies showed low rates of headgear use and varying understanding of the protection afforded by headgear. Field studies showed negligible association of headgear use with reduced impact magnitude in headgear vs. non-headgear cohorts. Lab studies showed increased energy attenuation for thicker headgear material, poorer performance of headgear after repetitive impacts and increased drop heights, and promising recent results with headgear composed of viscoelastic polymers.

Conclusions

Rates of adoption of soft-shell headgear remain low in rugby and any association between its use and reduction in acceleration impact forces remains unclear. Lab results indicating improved impact attenuation need to be validated in the field. Further headgear-related research is needed with youth and female rugby players.

Incidence of concussions and helmet use in equestrians

OBJECTIVES

Equestrians have a high risk of concussions per hospital records. However, most concussions occur in private settings where concussions are not tracked. We determined concussion incidence by self-report, expressed per 1000 h of exposure, and determined helmet usage and concussion knowledge.

DESIGN

Descriptive epidemiological study.

METHODS

Equestrians were recruited using a snowball method of sampling in which enrolled participants recruited more equestrians. Participants completed a survey of equestrian experience and history of concussion, symptoms and provided estimates of hours spent in various equestrian activities. From these data, incidences of concussions were calculated. In addition, they answered questions regarding helmet usage and willingness to take risks when concussed.

RESULTS

210 participants (203 women) reported 27 ± 14 years of equine experience and 728 concussions, 3.47 ± 5.34 per person (0-55). Incidence while riding was 0.19/1000 h which was greater than the incidence while driving (0.02/1000 h) or handling horses (0.03/1000 h). Riders were helmeted at the time of injury 85% of the time. While concussion knowledge was high, most reported willingness to risk permanent injury by continuing to work with horses while injured.

CONCLUSIONS

To our knowledge this is the first study to document incidence of concussions in equestrians: incidence is higher while riding than during football or rugby training. Helmets were far more commonly worn at the time of concussion than reported in hospital data, suggesting that helmets effectively reduce concussions severe enough to warrant urgent medical care.

International perspectives on trends in paediatric sports-related concussion: knowledge, management, unanswered questions

Purpose

In the last 20 years, concussion has received increased attention in the media, with distinct recognition of sports-related concussion (SRC). Much of this attention has centred on the paediatric population, due to concerns over adolescent brain development and the high numbers of teenagers playing contact sport. This qualitative study explored (1) what experts in the field of concussion perceive regarding trends in paediatric concussion awareness and management, and (2) how responses to these questions differ by country (US vs. NZ) and by discipline (research vs. sports coaching vs. sports medicine).

Methods

After the development of a semi-structured interview template, questions were coded for interviews of six (N = 6) experts in academia, medicine, and coaching: three in the United States (N = 3) and three in New Zealand (N = 3). Interviews were then transcribed and qualitatively analysed using a thematic narrative analysis. Emergent themes included concussion knowledge, management, and unanswered questions.

Results

Findings showed general commonalities on the importance of concussion education, the improvement of concussion awareness, compliance to concussion protocols, and the need to research long-term outcomes. Fewer commonalities were found regarding the level of concussion reporting, the impact of multiple concussions, whether paediatric and adult concussion should be treated similarly, and the utility of concussion tests.

Conclusions

Concussion experts agree on many areas; however, divergent opinions were apparent. Further original research is required within the paediatric population to analyse the efficacy of current concussion guidelines.

Adult sports-related traumatic spinal injuries: do different activities predispose to certain injuries?

OBJECTIVE

Sports injuries are known to present a high risk of spinal trauma. The authors hypothesized that different sports predispose participants to different injuries and injury severities.

METHODS

The authors conducted a retrospective cohort analysis of adult patients who experienced a sports-related traumatic spinal injury (TSI), including spinal fractures and spinal cord injuries (SCIs), encoded within the National Trauma Data Bank from 2011 through 2014. Multiple imputation was used for missing data, and multivariable linear and logistic regression models were estimated.

RESULTS

The authors included 12,031 cases of TSI, which represented 15% of all sports-related trauma. The majority of patients with TSI were male (82%), and the median age was 48 years (interquartile range 32-57 years). The most frequent mechanisms of injury in this database were cycling injuries (81%), skiing and snowboarding accidents (12%), aquatic sports injuries (3%), and contact sports (3%). Spinal surgery was required during initial hospitalization for 9.1% of patients with TSI. Compared to non-TSI sports-related trauma, TSIs were associated with an average 2.3-day increase in length of stay (95% CI 2.1-2.4; p < 0.001) and discharge to or with rehabilitative services (adjusted OR 2.6, 95% CI 2.4-2.7; p < 0.001). Among sports injuries, TSIs were the cause of discharge to or with rehabilitative services in 32% of cases. SCI was present in 15% of cases with TSI. Within sports-related TSIs, the rate of SCI was 13% for cycling injuries compared to 41% and 49% for contact sports and aquatic sports injuries, respectively. Patients experiencing SCI had a longer length of stay (7.0 days longer; 95% CI 6.7-7.3) and a higher likelihood of adverse discharge disposition (adjusted OR 9.69, 95% CI 8.72-10.77) compared to patients with TSI but without SCI.

CONCLUSIONS

Of patients with sports-related trauma discharged to rehabilitation, one-third had TSIs. Cycling injuries were the most common cause, suggesting that policies to make cycling safer may reduce TSI.

Soft-shell headgear, concussion and injury prevention in youth team collision sports: a systematic review

OBJECTIVES

To assess the association between soft-shell headgear (HG) use and sports-related concussion (SRC). Secondary objectives were to assess the association between HG and superficial head injury and investigate potential increase in injury risk among HG users.

DESIGN

A systematic search in Ovid MEDLINE, Cochrane Library, Scopus, PsycINFO and SPORTDiscus was conducted in April 2020. Inclusion criteria were youth <18, English language, in vivo studies published after 1980 that evaluated SRC and other injury incidence in HG users compared with non-users.

OUTCOME MEASURES

Incidence rates of SRC, superficial head injury or other injuries.

RESULTS

Eight studies were eligible. The majority (n=5) reported no difference in the rate of SRC among HG users versus non-users. One rugby study identified significantly lower risk of SRC for non-HG users (risk ratio (RR) 0.63; 95% CI 0.41 to 0.98) compared with HG users, whereas a cross-sectional survey of soccer players indicated higher risk of SRC for non-HG users (RR 2.65; 95% CI 1.23 to 3.12) compared with HG users. Three of the four studies investigating superficial head injury found no significant differences with HG use, though the soccer survey reported reduced risk among HG users (RR 1.86; 95% CI 0.09 to 0.11). Increased incidence of injuries to all body regions for rugby HG users was reported in two studies with adjusted RRs of 1.16 (95% CI 1.04 to 1.29) and 1.23 (95% CI 1.00 to 1.50).

CONCLUSIONS

HG use was not associated with reduced rates of SRC or superficial head injury in youth soccer and rugby. The possibility of increased injury risk to all body regions for rugby HG users was raised. The need for research specific to youth and female athletes was highlighted.

PROSPERO REGISTRATION NUMBER

CRD42018115310.

Cerebral Salt Wasting in Traumatic Brain Injury Is Associated with Increased Morbidity and Mortality

INTRODUCTION

In the setting of cerebral injury, cerebral salt wasting (CSW) is a potential cause of hyponatremia, which contributes to adverse effects and mortality.

OBJECTIVE

The primary objective of this study was to evaluate the clinical outcomes of severe traumatic brain injury (TBI) patients complicated by CSW.

METHODS

A retrospective data analysis was performed on data collected from patients with TBI with an abbreviated injury scale (AIS) greater than 3. Data was divided into 2 groups of patients with CSW and those without. The primary endpoint was incidence of adverse effects of CSW in regard to injury severity score (ISS), hospital length of stay (HLOS), ventilator days, ICU length of stay (ICU LOS) and survival to discharge. Data was analyzed using a one-way analysis of variance (ANOVA).

RESULTS

A total of 310 consecutive patients with severe head injury (anatomic injury score 3 or greater) were evaluated over a 3-year period. A total of 125 of the 310 patients (40%) were diagnosed with cerebral salt wasting as defined by hyponatremia with appropriate urinary output and salt replacement. Patients with CSW had poorer outcomes in regard to ISS (21.8 vs 14.2, p<0.0001), HLOS (14.1 vs 3.5, p<0.0001), ventilator days (5.0 vs 0.45, p<0.0001), ICU LOS (8.5 vs 1.6, p<0.0001), and survival to discharge (88% vs 99%, p<0.0001).

DISCUSSION

Common adverse effects of CSW were noted in this study. Patients with TBI have a predilection towards development of CSW and consequently have poorer outcomes including increased morbidity and mortality. Data is sparse on the duration of CSW and degree of hyponatremia over time. Larger, comparative studies need to be performed to investigate the hyponatremic patient population and the clinical outcomes of those who present with CSW.

Prevention of Concussion

Concussion is a common pediatric problem, and the best point of intervention would be to prevent a concussion from occurring. Unfortunately, information in this area has inconsistent support for the various methods that have been attempted. In infants, concussions are typically related to safety hazards in the environment and attempts to make the environment safer have resulted in decreased injuries over time. Toddlers also face environmental hazards that are slightly different in light of their increased mobility. School-aged children and adolescents primarily sustain concussions in the course of participation in organized contact sports. Although much research has been devoted to protective equipment, there is not a clearly effective piece of equipment that prevents concussions. Some effect has been demonstrated with changes in rules and policy that limit or eliminate certain kinds of dangerous contact. Research is still being performed to adequately evaluate methods that are already being used, as well as to find new methods in the future that may help protect today's children from concussions.

A review of impact testing methods for headgear in sports: Considerations for improved prevention of head injury through research and standards

Standards for sports headgear were introduced as far back as the 1960s and many have remained substantially unchanged to present day. Since this time, headgear has virtually eliminated catastrophic head injuries such as skull fractures and changed the landscape of head injuries in sports. Mild traumatic brain injury (mTBI) is now a prevalent concern and the effectiveness of headgear in mitigating mTBI is inconclusive for most sports. Given that most current headgear standards are confined to attenuating linear head mechanics and recent brain injury studies have underscored the importance of angular mechanics in the genesis of mTBI, new or expanded standards are needed to foster headgear development and assess headgear performance that addresses all types of sport-related head and brain injuries. The aim of this review is to provide a basis for developing new sports headgear impact tests for standards by summarizing and critiquing: 1) impact testing procedures currently codified in published headgear standards for sports and 2) new or proposed headgear impact test procedures in published literature and/or relevant conferences. Research areas identified as needing further knowledge to support standards test development include defining sports-specific head impact conditions, establishing injury and age appropriate headgear assessment criteria, and the development of headgear specific head and neck surrogates for at-risk populations.

Comparison of Concussion Rates Between NCAA Division I and Division III Men's and Women's Ice Hockey Players

BACKGROUND

Examinations related to divisional differences in the incidence of sports-related concussions (SRC) in collegiate ice hockey are limited.

PURPOSE

To compare the epidemiologic patterns of concussion in National Collegiate Athletic Association (NCAA) ice hockey by sex and division.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

A convenience sample of men's and women's ice hockey teams in Divisions I and III provided SRC data via the NCAA Injury Surveillance Program during the 2009-2010 to 2014-2015 academic years. Concussion counts, rates, and distributions were examined by factors including injury activity and position. Injury rate ratios (IRRs) and injury proportion ratios (IPRs) with 95% confidence intervals (CIs) were used to compare concussion rates and distributions, respectively.

RESULTS

Overall, 415 concussions were reported for men's and women's ice hockey combined. The highest concussion rate was found in Division I men (0.83 per 1000 athlete-exposures [AEs]), followed by Division III women (0.78/1000 AEs), Division I women (0.65/1000 AEs), and Division III men (0.64/1000 AEs). However, the only significant IRR was that the concussion rate was higher in Division I men than Division III men (IRR = 1.29; 95% CI, 1.02-1.65). The proportion of concussions from checking was higher in men than women (28.5% vs 9.4%; IPR = 3.02; 95% CI, 1.63-5.59); however, this proportion was higher in Division I women than Division III women (18.4% vs 1.8%; IPR = 10.47; 95% CI, 1.37-79.75). The proportion of concussions sustained by goalkeepers was higher in women than men (14.2% vs 2.9%; IPR = 4.86; 95% CI, 2.19-10.77), with findings consistent within each division.

CONCLUSION

Concussion rates did not vary by sex but differed by division among men. Checking-related concussions were less common in women than men overall but more common in Division I women than Division III women. Findings highlight the need to better understand the reasons underlying divisional differences within men's and women's ice hockey and the need to develop concussion prevention strategies specific to each athlete population.

Head impact velocities in FIS World Cup snowboarders and freestyle skiers: Do real-life impacts exceed helmet testing standards?

Introduction

Prior to the 2013–2014 season, the International Ski Federation (FIS) increased the helmet testing speed from a minimum requirement of 5.4 to 6.8 m/s for alpine downhill, super-G and giant slalom and for freestyle ski cross, but not for the other freestyle disciplines or snowboarding. Whether this increased testing speed reflects impact velocities in real head injury situations on snow is unclear. We therefore investigated the injury mechanisms and gross head impact biomechanics in four real head injury situations among World Cup (WC) snowboard and freestyle athletes and compared these with helmet homologation laboratory test requirements. The helmets in the four cases complied with at least European Standards (EN) 1077 (Class B) or American Society for Testing and Materials (ASTM) F2040.

Methods

We analysed four head injury videos from the FIS Injury Surveillance System throughout eight WC seasons (2006–2014) in detail. We used motion analysis software to digitize the helmet’s trajectory and estimated the head’s kinematics in two dimensions, including directly preimpact and postimpact.

Results

All four impacts were to the occiput. In the four cases, the normal-to-slope preimpact velocity ranged from 7.0(±SD 0.2) m/s to 10.5±0.5 m/s and the normal-to-slope velocity change ranged from 8.4±0.6 m/s to 11.7±0.7 m/s. The sagittal plane helmet angular velocity estimates indicated a large change in angular velocity (25.0±2.9 rad/s to 49.1±0.3 rad/s).

Conclusion

The estimated normal-to-slope preimpact velocity was higher than the current strictest helmet testing rule of 6.8 m/s in all four cases.

Helmet efficacy against concussion and traumatic brain injury: a review

Helmets are one of the earliest and most enduring methods of personal protection in human civilization. Although primarily developed for combat purposes in ancient times, modern helmets have become highly diversified to sports, recreation, and transportation. History and the scientific literature exhibit that helmets continue to be the primary and most effective prevention method against traumatic brain injury (TBI), which presents high mortality and morbidity rates in the US. The neurosurgical and neurotrauma literature on helmets and TBI indicate that helmets provide effectual protection against moderate to severe head trauma resulting in severe disability or death. However, there is a dearth of scientific data on helmet efficacy against concussion in both civilian and military aspects. The objective of this literature review was to explore the historical evolution of helmets, consider the effectiveness of helmets in protecting against severe intracranial injuries, and examine recent evidence on helmet efficacy against concussion. It was also the goal of this report to emphasize the need for more research on helmet efficacy with improved experimental design and quantitative standardization of assessments for concussion and TBI, and to promote expanded involvement of neurosurgery in studying the quantitative diagnostics of concussion and TBI. Recent evidence summarized by this literature review suggests that helmeted patients do not have better relative clinical outcome and protection against concussion than unhelmeted patients.