Limited Return to Preinjury Performance in NCAA Division I American Football Players With Hamstring Injuries

Background

Hamstring strains are common among elite athletes, but their effect on return to the same level of play in American football has been incompletely characterized.

Purpose

Data on National Collegiate Athletics Association Division I college football players with acute hamstring strains were gathered to identify the effects these injuries have on both return to play and athletic performance regarding velocity, workload, and acceleration.

Study Design

Case Series; Level of evidence, 4.

Methods

Injury data for a single Division I football team were prospectively recorded over a 4-year period. Players wore global navigation satellite system and local positioning system (GNSS/LPS) devices to record movement data in practices and games. The practice and game data were cross-referenced to evaluate players with isolated acute hamstring strains. Comparisons were made regarding players' pre- and postinjury ability to maintain high velocity (>12 mph [19.3 kph]), maximal velocity, triaxial acceleration, and inertial movement analysis (IMA). There were 58 hamstring injuries in 44 players, of which 25 injuries from 20 players had GNSS/LPS data.

Results

Players were able to return to play from all 25 injury incidences at a mean of 9.2 days. At the final mean follow-up of 425 days, only 4 players had reached preinjury function in all measurements; 12 players were able to return in 2 of the 4 metrics; and only 8 players reached their preinjury ability to maintain high velocity. For those who did not achieve this metric, there was a significant difference between pre- and postinjury values (722 vs 442 m; P = .016). A total of 14 players were able to regain their IMA. Players who returned to prior velocity or acceleration metrics did so at a mean of 163 days across all metrics.

Conclusion

While players may be able to return to play after hamstring strain, many players do not reach preinjury levels of acceleration or velocity, even after 13.5 months. Further studies are needed to confirm these findings, assess clinical relevance on imaging performance, and improve hamstring injury prevention and rehabilitation.

Rotator Cuff Injuries in the Pediatric Population: A Retrospective Review of Patient Characteristics and Treatment at a Single Center

BACKGROUND

As youth participation in contact and overhead sports has increased in recent decades, so has the occurrence of injuries of the shoulder. Rotator cuff injury (RCI) is an infrequent shoulder pathology in pediatric patients and its description in the literature has been scarce. A greater understanding of RCI characteristics and treatment outcomes in children and adolescents would improve our understanding of this pathology and help to better guide clinical decision-making.

HYPOTHESIS

To identify pediatric patients with magnetic resonance imaging-confirmed RCI treated at a single center to summarize injury characteristics, treatment, and outcomes. It was hypothesized that injuries would occur predominantly in overhead throwing athletes and would demonstrate good outcomes among both operatively and nonoperatively treated patients.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A retrospective review of pediatric patients (<18 years old) diagnosed with and treated for an RCI between January 1, 2011 and January 31, 2021. Patient demographics, injury mechanism and type, treatment, and outcomes were collected. Descriptive statistics were performed. Bivariate testing was used to compare operatively and nonoperatively treated cohorts.

RESULTS

A total of 52 pediatric patients treated for a rotator cuff avulsion, partial tear, or complete tear were identified. Mean age was 15 years and 67% of patients were male. Injuries were related most commonly to participation in throwing sports. Operative management occurred in 23% of patients, while 77% were managed nonoperatively. Treatment cohorts differed based on tear type, with all complete tears being managed operatively (P < 0.01). Associated shoulder pathology was common, with the most frequent finding being anterior shoulder instability pathology. Return to play was longer for operatively managed patients (7.1 vs 4.5 months; P < 0.01).

CONCLUSION

The present study expands the limited data available regarding RCIs in pediatric patients. Most injuries are associated with sports and involve the supraspinatus tendon. RCIs were associated with good outcomes and low rates of reinjury in patients managed both nonoperative and operatively. RCI should be considered in throwing athletes with shoulder pain, even in skeletally immature patients.

CLINICAL RELEVANCE

This retrospective study fills the hole in the literature by detailing the patterns associated with RCI characteristics and treatment outcomes. In contrast to studies of adult RCIs, our results suggest that outcomes are good regardless of treatment type.

Concussion Rates in Youth Lacrosse Players and Comparison With Youth American Football

Background

There has been little focus on concussions in youth lacrosse players in the United States.

Purpose

To provide a descriptive analysis of the epidemiology and incidence of concussions in youth lacrosse and compare the results with well-documented analyses of concussions in youth American football.

Study Design

Descriptive epidemiology study.

Methods

Data on concussions in pediatric patients playing lacrosse from 2006 to 2019 were collected using the National Electronic Injury Surveillance System (NEISS). Weighted calculations and combined participation data obtained from membership in USA Lacrosse were used to estimate injury incidence. A comparison dataset was created using the NEISS data on youth football-related concussions. The cause of concussion was categorized into player-to-player, player-to-stick, player-to-ball, or player-to-ground contact.

Results

A total of 37,974 concussion injuries related to lacrosse were identified in players with a mean age of 14.5 ± 3.5 years; 70% of concussions occurred in boys. National participation in lacrosse increased from 2006 to 2011 by a mean of 10.3% annually, followed by a lower annual growth rate of 2.5% from 2012 to 2019. The overall incidence of concussion injuries increased over the study period (r = 0.314), with the incidence rate in boys being greater than that of girls from 2009 to 2013. The most common cause of concussion was player-to-ground contact for boys and player-to-ball or player-to-stick contact for girls. The mean annual concussion incidences in youth lacrosse and youth football were 443 and 355 per 100,000 participants, respectively.

Conclusion

Over the study period, 16% of lacrosse injuries were diagnosed as concussions, a higher mean annual incidence per 100,000 participants than that of youth football (443 vs 355). The cause of concussion was different based on sex, with higher rates of player-to-ball or player-to-stick contact in female players versus player-to-ground contact in male players.

Multiple Ankle Injuries Are Associated With an Increased Risk of Subsequent Concussion in National Football League Players

Background

There is a gap in the literature regarding musculoskeletal risk factors for concussion within the National Football League (NFL), which is an avenue that must be explored to promote player safety given the high incidence of both injury types. This study aims to observe if ankle injuries are associated with an increased risk of subsequent concussion in NFL players.

Methods

The public online database ProFootballReference.com was used to identify ankle injuries and concussions in NFL players from the 2009-2010 to 2019-2020 seasons. Multivariable logistic regression for subsequent concussion and ankle injury was performed, adjusting for body mass index (BMI), age, and player position. For descriptive statistics, unpaired t tests with unequal variance were performed for continuous variables, including BMI and age. χ2 testing was performed for categorical variables, including player position, and whether the position was offensive, defensive, or on special teams.

Results

Of the 5538 NFL players included in the study, 941 had an ankle injury, 633 had a concussion, and 240 had both an ankle injury and a subsequent concussion. The adjusted odds ratio (aOR) for concussion following a single ankle injury was 0.90 (95% CI 0.72-1.14, P = .387); however, the aOR for concussion following multiple ankle injuries was 2.87 (95% CI 1.23-6.75, P = .015). Special teams players had the lowest risk for concussion (aOR 0.17, 95% CI 0.069-0.36, P < .001) following ankle injury, and there was no significant difference in risk between offense and defense (aOR 0.91, 95% CI 0.77-1.08, P = .295).

Conclusion

Multiple ankle injuries were associated with an increased risk of a subsequent concussion after adjusting for BMI; player position; and offense, defense, or special teams designation. These findings can inform injury prevention practices in the National Football League.

Level of Evidence

Level III, retrospective comparative study.

Effect of the 2018 NCAA Kickoff Rule Change on Concussion Rates in Collegiate Football: Results From a Division 1 Conference

Background

Kickoff plays in American football are associated with an increased risk of concussion compared with other play types. In 2018, the National Collegiate Athletic Association (NCAA) Football Rules Committee altered the kickoff rules so a fair catch inside the 25-yard line results in a touchback, with the ensuing drive starting on the 25-yard line. The intention was to decrease the number of kickoff returns with a corresponding decrease in the rate of concussions on kickoff plays.

Purpose

To determine whether the 2018 rule changes had the intended effects in an NCAA Division 1 Conference.

Study Design

Cohort study; Level of evidence, 3.

Methods

The study population included football athletes in the NCAA Pacific-12 (Pac-12) Conference. Data on the total number of plays, punts, kickoffs, touchbacks, and fair catches were obtained for all in-conference games from the 2016 to 2021 seasons. The number of game concussions and the play type were provided by each conference institution. Incidence of concussions occurring during kickoff plays before (2016-2017) and after (2018-2021) the rule change were compared with a difference-in-difference analysis using Poisson general linear models.

Results

There were 242 concussions in 108,774 total plays in the study period, with an overall concussion rate of 2.2 per 1000 plays. The percentage of touchbacks increased significantly from 45% to 51% (P < .001) and the percentage of fair catches increased from 1% to 7% (P < .001) from before to after the rule change. Kickoffs accounted for 6% of plays both before and after the rule change and 11% of concussions before and 14% after the change. The mean annual concussion rate (per 1000 plays) on kickoffs was 3.42 before and 5.31 after the rule change (rate difference: 1.89; 95% confidence interval, -1.22 to 5.01).

Conclusion

Touchbacks and fair catches increased after the kickoff rule change, but there was not a corresponding decrease in concussions during kickoff plays as anticipated. Concussions occurring during other football plays remained stable.

Prophylactic Knee Bracing in Offensive Linemen of the National Football League: A Retrospective Analysis of Usage Trends, Player Performance, and Major Knee Injury

Background

Offensive linemen in American football are prone to high-energy valgus forces to the knee, leading to associated injuries. Some offensive linemen in the National Football League (NFL) wear prophylactic knee braces (PKB) to prevent ligamentous injury.

Purpose/Hypothesis

This purpose of the study was to compare injury rates and performance between NFL offensive linemen who wear PKB and those who do not. It was hypothesized that brace wear would be associated with fewer major knee injuries and no difference in gameplay performance.

Study Design

Cohort study; Level of evidence, 3.

Methods

For the 2014 through 2020 NFL seasons, offensive linemen with at least 200 game snaps per regular season were identified. Players were grouped by PKB status (bracers vs nonbracers) based on visualization of bilateral, dual-hinged metal knee braces as part of gameday uniforms on publicly available imaging databases and/or game videos. Major knee injuries, defined as those requiring the missing of games, were identified using publicly available data. Performance was assessed with Pro Football Focus grades for each season. Rates of major knee injury were compared between groups with the 2-sample Z test for proportions, and performance grades were compared with the unpaired t test.

Results

For the cumulative study period, bracers demonstrated a significantly lower rate of major knee injuries than nonbracers (0.013 vs 0.049 injuries per player, respectively; P = .04). Isolated MCL injury was the most common injury for nonbracers. There was no group difference in performance for the cumulative study period or during most individual seasons. Yearly prevalence of PKB usage declined steadily from 16.3% in 2014 to 5.6% in 2020. A subgroup analysis of rookie players demonstrated an overall downtrend in usage during the study period as well.

Conclusion

Results indicated that knee brace prophylaxis by NFL offensive linemen was associated with a reduced risk of major knee injury without a significant difference in performance when compared with nonbracers. Despite this, the prevalence of PKB declined over the study period.

Factors Affecting Incidence Rate of Exertional Heat Illnesses: Analysis of 6 Years of High School Football Practices in North Central Florida

Background

Although experts have advocated for regionally specific heat safety guidelines for decades, guidelines have not been universally adopted.

Purpose

To describe the rate and risk factors associated with exertional heat illness (EHI).

Study Design

Descriptive epidemiology study.

Methods

For a 3-month period (August-October) over 6 years (2013-2018), athletic trainers at 13 high schools in North Central Florida recorded varsity football practice time and length, wet-bulb globe temperature (WBGT), and incidences of EHI, including heat stroke, heat exhaustion, and heat syncope.

Results

Athletes sustained 54 total EHIs during 163,254 athlete-exposures (AEs) for the 3-month data collection periods over 6 years (incidence rate [IR], 3.31 /10,000 AEs). Heat exhaustion accounted for 59.3% (32/54), heat syncope 38.9% (21/54), and heat stroke 1.9% (1/54) of all EHIs recorded. Of the EHIs, 94.4% (51/54) were experienced within the first 19 practices. The first 19 practices had an IR of 7.48 of 10,000 AEs, and the remaining 44 practices had an IR of 0.32 of 10,000 AEs, demonstrating that the risk of EHI for practices 1 to 19 was 23.7 times that of the remaining practices. When comparing morning to afternoon practices, 35.2% (19/54) EHI incidents occurred during morning practices. The risk of EHI during practices with WBGT >82°F (27.8°C) was 3.5 times that of practices with WBGT <82°F.

Conclusion

In the current study, the risk of EHI was greatest in the first 19 practices of the season and during practices with WBGT >82°F. As modifiable risk factors for EHI, increased vigilance and empowerment to adhere to acclimatization guidelines can mitigate EHI risk. Health care providers must continue to advocate for implementation of regulations and the authority to make decisions to ensure patient safety.

Pectoralis Major Ruptures in the National Football League: Incidence, RTP, and Performance Analysis

Background:

While pectoralis major (PM) tears are rare injuries in National Football League (NFL) athletes (previous study reported only 10 PM ruptures between 2000 and 2010), the incidence of these injuries has increased over the past decade. The impact these injuries have on a player’s performance after return has not been measured.

Purpose/Hypothesis:

To identify player characteristics that may predispose to PM tears and to determine the impact of this injury on return to play and performance. We hypothesized that there would be no difference in performance between the year before and after their injury.

Study Design:

Descriptive epidemiology study.

Methods:

NFL players who experienced PM tears between the years 2010 and 2018 were identified using publicly available reports. Several individual player characteristics were identified and recorded, and the return-to-play rates after injury were determined for each position. The pre- and postinjury Pro Football Focus grades of players who met inclusion criteria were compared. A paired t test analysis of the change in player performance was used for analysis.

Results:

In this study, 63 ruptures were identified between 2010 and 2018. Linebackers had the highest incidence of PM tear compared with any other position. Of all injuries, 79.3% were sustained by defensive players. The majority of PM tears occurred during games. Only 6.9% of players who sustained the injury were suspended for performance-enhancing drug use during their professional career. A total of 85.7% of players returned to play in the NFL after injury. Among those who returned to play there were no significant changes in player performance from pre- to post-injury.

Conclusion:

NFL players demonstrated 85.7% return-to-play rates and no significant drop-off in performance after PM ruptures. During the time period studied, there was an increase in incidence of PM ruptures compared with the previous decade. Further investigation is needed to determine potential causes for the increased incidence of PM ruptures in NFL players.

Epidemiology of American Football Injuries at Universities in the United Kingdom

Background:

College-level American football injury data are routinely collected; however, data relating to American football injuries at universities in the United Kingdom have never been reported.

Purpose:

To describe the epidemiology of UK university American football injuries.

Study Design:

Descriptive epidemiology study.

Methods:

An online survey tool was used to collect the injury data of 410 players from 56 UK university teams who participated in the 2014-2015 British Universities and College Sports American football season. Survey data were collected from January to February 2016 and were analyzed to determine the incidence and patterns of injury.

Results:

Overall, 710 injuries and 204 concussions were self-reported among the 410 participants, of which 334 (81.5%) were injured and 131 (32.0%) experienced concussion symptoms. The rate of injury per 100 athlete-seasons was greater in defensive players (195.3) than offensive players (155.1). The most common injuries were knee and ankle ligament injuries. Most injuries were classified as severe (time loss of >4 weeks).

Conclusion:

UK university American football injuries differ markedly from those reported for US colleges. UK university players appear to have less playing experience, greater concussion risks, more severe injuries, and a greater proportion of injuries in defensive players versus offensive players.

The Effect of Thursday Night Games on In-Game Injury Rates in the National Football League

BACKGROUND

Although claims of increased injury rates with Thursday night National Football League (NFL) games exist, a paucity of data exist substantiating these claims.

PURPOSE

To evaluate the effect of rest between games on in-game injury rates as it pertains to overall injury incidence, location, and player position.

STUDY DESIGN

Descriptive epidemiologic study.

METHODS

Data were obtained from official NFL game books for regular season games from all 32 teams for the 2013-2016 seasons. All in-game injuries recorded in official game books were included. Rest periods between games were classified as short (4 days), regular (6-8 days), or long (≥10 days). Overall observed injury rates per team-game were analyzed in relation to different rest periods using negative binomial regression. For results with significant overall findings, pairwise comparisons were tested using the Wald chi-square test. Exploratory secondary analyses were performed in a similar fashion to assess differences in injury rates for the different rest periods when stratified by anatomic location and player position.

RESULTS

A total of 2846 injuries were identified throughout the 4 seasons. There was an overall significant difference in injuries per team-game between short, regular, and long rest (P = .01). With short rest, an observed mean of 1.26 injuries per game (95% CI, 1.06-1.49) was significantly different from the 1.53 observed injuries per game with regular rest (95% CI, 1.46-1.60; P = .03), but not compared with the 1.34 observed injuries per game with long rest (P = .56). For player position, only the tight end, linebacker, and fullback group demonstrated significant differences between the injury rates for different rest categories. Quarterback was the only position with more injuries during games played on Thursday compared with both regular and long rest. This specific analysis was underpowered and the difference was not significant (P = .08). No differences were found regarding injury rates in correlation with differences in rest periods with different injury locations.

CONCLUSION

A short rest period between games is not associated with increased rates of observed injuries reported in NFL game books; rather, our data suggest there are significantly fewer injuries for Thursday night games compared with games played on regular rest. Future research correlating rest and quarterback injury rates is warranted.

Using Variance to Explore the Diagnostic Utility of Baseline Concussion Testing

The Graded Symptom Checklist (GSC), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and King-Devick Test (KDT) are considered important components of concussion assessment. Whether baseline testing improves the diagnostic utility of these tests remains unclear. We performed an observational cohort study to investigate the within-subject and between-subjects variability of these tests over repeated assessments during two football seasons to examine whether baseline testing reduces variability in test performance. Thirty-five male collegiate football players completed weekly clinical concussion assessments over two seasons. Within-subject (week-to-week) and between-subjects (player-to-player) variability for each test were compared using a bootstrap analysis. Within-subject and between-subjects proportions of overall variance for each test score were calculated. Mixed-model analyses were used to quantify practice effects resulting from repeated testing. For the GSC and BESS, within-subject and between-subjects variability did not significantly differ. For the KDT, the proportion of within-subject variance (20.2%) was significantly less than the between-subjects variance (79.8%). For SAC, however, the proportion of within-subject variance (66.8%) was significantly greater than the between-subjects variance (33.8%). A small, but significant, practice effect was observed for the BESS and KDT tests. When athletes are evaluated during a football season for concussion using the GSC, SAC, and BESS, comparing their scores to baseline performance is likely no more beneficial than comparing them to normative population data for identifying neurological changes associated with concussion. For the KDT, comparison to baseline testing is likely beneficial because of significantly higher between-subjects variability.

Multiple Concussions Increase Odds and Rate of Lower Extremity Injury in National Collegiate Athletic Association Athletes After Return to Play

BACKGROUND

Concussion in collegiate athletics is one of the most prevalent sport-related injuries in the United States, with recent studies suggesting persistent deficits in neuromuscular control after a concussion and an associated increase in risk of lower extremity injury.

PURPOSE

To expand on the relationship between concussion and lower extremity injury by examining the effect of multiple concussions (MC) on rate and odds of future lower extremity injury in collegiate athletes after return to play (RTP) compared with matched controls.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

From 2001 to 2016, 48 National Collegiate Athletic Association Division I athletes sustaining multiple concussions at a single institution were identified. Athletes with multiple concussions (MC) were matched directly to athletes with a single concussion (SC) and to athletes with no concussion history (NC) by sex, sport, position, and games played. Incidence of, time to, and location of lower extremity injury were recorded for each group after RTP from their first reported concussion until completion of their collegiate career. Logistic regression was used to analyze odds ratios (ORs) for sustaining lower extremity injury, whereas time to injury was summarized by use of Kaplan-Meier curves and log rank test analysis.

RESULTS

The incidence of lower extremity injury after RTP was significantly greater (P = .049) in the MC cohort (36/48, 75%) than in SC athletes (25/48 = 52%) and NC athletes (27/48 = 56%). Similarly, odds of lower extremity injury were significantly greater in the MC cohort than in SC athletes (OR, 3.00; 95% CI, 1.26-7.12; P = .01) and NC athletes (OR, 1.66; 95% CI, 1.07-2.56; P = .02). Time to lower extremity injury was significantly shorter in the MC group compared with matched controls (P = .01). No difference was found in odds of lower extremity injury or time to lower extremity injury between SC and NC athletes.

CONCLUSION

Collegiate athletes with MC were more likely to sustain a lower extremity injury after RTP in a shorter time frame than were the matched SC and NC athletes. This may suggest the presence of a cohort more susceptible to neuromuscular deficits after concussion or more injury prone due to player behavior, and it may imply the need for more stringent RTP protocols for athletes experiencing MC.

Association of Adolescent Sport Participation With Cognition and Depressive Symptoms in Early Adulthood

Background:

Recent studies have associated sport-related concussion with depression and impaired cognitive ability later in life in former professional football players. However, population studies with two 1950s-era cohorts did not find an association between high school football participation and impaired cognition or depressive symptoms in late adulthood.

Purpose/Hypothesis:

This study assessed whether actual/intended participation in contact sports during adolescence had an adverse effect on participants’ cognition or depressive symptoms in early adulthood. We hypothesized that there would not be an association.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

This study used a subsample (n = 10,951) from the National Longitudinal Study of Adolescent to Adult Health (Add Health), a nationally (United States) representative prospective cohort study following participants through 4 waves of data collection from 1994 through 2008. Participants were categorized as actual/intended participation in no sports, noncontact sports only, and contact sports. We constructed 6 multivariate and logistic regression models predicting word recall, number recall, modified Center for Epidemiologic Studies Depression Scale, depression diagnosis, suicide ideation, and suicide attempts at wave IV as a function of sport participation during wave I. Sport participation was treated as a factor with the referent category noncontact sports. This analysis was repeated on a males-only sample (n = 5008). In the males-only analysis, participants were classified as actual/intended participation in no sports, noncontact sports, contact sports other than American football, and American football. The referent category remained noncontact sports.

Results:

Intention to participate in contact sports was not significantly associated with any of the outcomes in the full-sample analysis. Intention to participate in football was significantly associated with a reduced odds of depression diagnosis in adulthood (odds ratio, 0.70; P = .02) when compared with noncontact sports participation in the males-only sample. Football was not significantly associated with impaired cognitive ability, increased depressive symptoms, or increased suicide ideation.

Conclusion:

Actual/intended participation in contact sports during adolescence did not adversely affect Add Health participants’ cognition or depressive symptoms in young adulthood.

Medical Supervision of High School Athletics in Chicago: A Follow-up Study

Background:

High school sports participation in the United States has increased dramatically over the past 25 years. A corresponding increase in the number of injuries has been noted, particularly in contact sports such as football. This has led medical and sports organizations nationwide to advocate for proper medical supervision of athletes at games and practices.

Purpose:

To gather information from Chicago public high schools to gauge how medical supervision for high school sports has changed in 2017 compared with 2003.

Study Design:

Cross-sectional study.

Methods:

Survey questionnaires were sent to the athletic directors of all 99 Chicago public high schools to complete via email. The questionnaire survey contained the same questions as in a survey conducted in 2003 by Tonino and Bollier, with the addition of 4 novel questions relating to emergency action plans (EAPs), automated external defibrillators, concussion management policy, and tackling progression drills.

Results:

The response rate was 66.67% (66/99 schools). Of the 66 responding schools, all with football programs, no school had a physician on the sideline at home games (decrease from 10.6% in 2003), 37.9% had an athletic trainer present (increase from 8.5% in 2003), and 63.6% had a paramedic available (decrease from 89.4% in 2003). In 2017, 65.6% of responding schools had a coach certified in cardiopulmonary resuscitation (CPR) available at practice to handle medical problems, compared with 89.4% in 2003 (P < .001). Regarding the 4 novel questions, 93.9% of the responding schools had proper tackling progression drills in place, followed by 89.1% who had appropriate EAPs and 93.9% with concussion management protocols, including return-to-play and return-to-learn protocols.

Conclusion:

Although significant improvement was found in athletic trainer coverage, especially at games, physician coverage was lacking and fewer coaches were certified in CPR in 2017 compared with 2003. EAPs and concussion management protocols were present in most Chicago public high schools. Overall, greater medical supervision is needed, which we believe should come in the form of increased athletic training and physician involvement and coverage, given that expert, expedited medical care saves lives.

Multisystem afflictions in former National Football League players

Background

The long‐term health consequences of participation in American style football (ASF) are not well understood.

Methods

We conducted a retrospective cohort study of men who had played in the NFL after 1960. Participants were studied using a standardized self‐administered questionnaire designed to determine both the exposure history to ASF and the prevalence of chronic pain, sleep apnea, cardiometabolic disease, and neurocognitive impairment. Logistic regression and negative binomial regression models were used to assess associations between age, ethnicity, body‐mass index during professional football career, field position, and football career duration with individual and multiple afflictions.

Results

In this cohort of former NFL players (n = 3745), approximately one quarter of the eligible former players (27%) reported two or more medical afflictions (chronic pain, cardiometabolic disease, sleep apnea, or neurocognitive impairment). Career duration was significantly associated with an increase in the number of comorbidities. Age, race, and body‐mass index were associated with all affliction categories, other than neurocognitive impairment, which was similarly prevalent in middle‐aged players and older players. Earlier age when first playing the sport was protective against cardiometabolic affliction.

Conclusions

Former NFL players report significant combinations of cross‐system afflictions. Future work will be required to determine mechanistic underpinnings. However, attention to the whole player, rather than specific organ systems seems critical to improve long‐term health outcomes in former ASF professional athletes.

Lower Back Injuries in National Collegiate Athletic Association Football Players: A 5-Season Epidemiological Study

Background:

Low back injuries are common in collegiate football players and can frequently lead to persistent pain, reinjuries, and time lost from participation.

Purpose:

To describe the epidemiology of back injuries in National Collegiate Athletic Association (NCAA) football players during the 2009/2010 through 2013/2014 academic years utilizing the NCAA Injury Surveillance Program (ISP) database.

Study Design:

Descriptive epidemiology study.

Methods:

A convenience sample of NCAA varsity football teams was utilized to determine the rates and patterns of back injuries as well as to generate national injury estimates. The rates and distribution of back injuries were identified within the context of mechanism of injury, injury chronicity, and time lost from sport. Injury rates were calculated as the number of injuries divided by the total number of athlete-exposures (AEs). Incidence rate ratios were calculated to compare the rates of injury between season, event type, mechanism of injury, injury chronicity, and time lost from sport.

Results:

Nationally, there were 267 low back injuries reported in the database. These were used to estimate 7076 back injuries over the 5-year period, approximately 82% of which were new injuries. The injuries occurred at a rate of 2.70 per 10,000 AEs. Overall, injuries were 3.12 times more likely to occur in competitions than in practices. Athletes were 4.67 times more likely to sustain a back injury during the preseason compared with the postseason but were 1.41 times more likely to sustain a low back injury during the preseason compared with the regular season. Both contact and noncontact were reported equally as the mechanism of injury (37.8% and 38.3%, respectively), and unspecified low back pain was the most common injury (64.2%). Only 1.6% of patients required surgery for their injury, and the majority of athletes (59.6%) returned to play within 24 hours.

Conclusion:

There was a relatively high rate of lumbar back injuries at the collegiate level (2.70/10,000 AEs), the majority of which were new injuries. About 18% of reported injuries were reinjuries. Although very few required surgery, a careful examination and work-up should be conducted to evaluate each injury. Regimented physical therapy and reconditioning programs are recommended to avert reinjuries.

Incidence of Knee Injuries on Artificial Turf Versus Natural Grass in National Collegiate Athletic Association American Football: 2004-2005 Through 2013-2014 Seasons

BACKGROUND

The use of artificial turf in American football continues to grow in popularity, and the effect of these playing surfaces on athletic injuries remains controversial. Knee injuries account for a significant portion of injuries in the National Collegiate Athletic Association (NCAA) football league; however, the effect of artificial surfaces on knee injuries remains ill-defined.

HYPOTHESIS

There is no difference in the rate or mechanism of knee ligament and meniscal injuries during NCAA football events on natural grass and artificial turf playing surfaces.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

The NCAA Injury Surveillance System Men's Football Injury and Exposure Data Sets for the 2004-2005 through 2013-2014 seasons were analyzed to determine the incidence of anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), medial meniscus, and lateral meniscal tear injuries. Injury rates were calculated per 10,000 athlete exposures, and rate ratios (RRs) were used to compare injury rates during practices and competitions on natural grass and artificial turf in NCAA football as a whole and by competition level (Divisions I, Divisions II and III). Mechanisms of injury were calculated for each injury on natural grass and artificial turf surfaces.

RESULTS

A total of 3,009,205 athlete exposures and 2460 knee injuries were reported from 2004 to 2014: 1389 MCL, 522 ACL, 269 lateral meniscal, 164 medial meniscal, and 116 PCL. Athletes experienced all knee injuries at a significantly higher rate when participating in competitions as compared with practices. Athletes participating in competitions on artificial turf experienced PCL injuries at 2.94 times the rate as those playing on grass (RR = 2.94; 95% CI, 1.61-5.68). When stratified by competition level, Division I athletes participating in competitions on artificial turf experienced PCL injuries at 2.99 times the rate as those playing on grass (RR = 2.99; 95% CI, 1.39-6.99), and athletes in lower NCAA divisions (II and III) experienced ACL injuries at 1.63 times the rate (RR = 1.63; 95% CI, 1.10-2.45) and PCL injuries at 3.13 times the rate (RR = 3.13; 95% CI, 1.14-10.69) on artificial turf as compared with grass. There was no statistically significant difference in the rate of MCL, medial meniscal, or lateral meniscal injuries on artificial turf versus grass when stratified by event type or level of NCAA competition. No difference was found in the mechanisms of knee injuries on natural grass and artificial turf.

CONCLUSION

Artificial turf is an important risk factor for specific knee ligament injuries in NCAA football. Injury rates for PCL tears were significantly increased during competitions played on artificial turf as compared with natural grass. Lower NCAA divisions (II and III) also showed higher rates of ACL injuries during competitions on artificial turf versus natural grass.

Factors Affecting Return to Play After Primary Achilles Tendon Tear: A Cohort of NFL Players

Background:

Achilles tendon tears are potentially career-ending injuries for professional athletes. For players in the National Football League (NFL), return requires not only surgery and extensive rehabilitation but also the ability to compete in a market with limited positions that annually introduces new recruits.

Purpose/Hypothesis:

We authors sought to evaluate factors related to return to play (RTP) and changes in performance following a primary Achilles tear. Our hypothesis was that “skilled” position players and those drafted in later rounds would return at a lower rate as compared with “unskilled” position players and higher draft-round players.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

From a previously established database, 80 NFL players were identified as having primary Achilles tendon tears between the 2009 and 2014 seasons. RTP was defined as playing in a regular season or postseason game following injury. Probability of RTP was modeled as a function of time after injury in Kaplan-Meier analysis with demographic variables assessed via generalized linear models. Twelve players (15%) experienced a subsequent Achilles tendon tear during or after the study period and were included in the overall RTP rate but were excluded from performance analyses owing to the confounding effects of an ipsilateral retear or contralateral tear.

Results:

The overall RTP rate was 61.3%. Age, number of prior seasons, position type, or draft round status did not significantly affect RTP when evaluated with Kaplan-Meier analysis. In the season before their injury, players who did RTP played in a significantly greater number of regular season games (13.7) compared with players who did not RTP (8.71) (P = .011). Players who did not RTP exhibited a significant decrease in performance in the season preceding injury (12.7 regular season games played 2 seasons preinjury vs 8.71 regular season games played 1 season prior preinjury;, P = .019). Players who returned did not display a significant change in the number of games played or started in seasons following injury when >1 season after return was evaluated.

Conclusion:

Rate of RTP following primary Achilles tendon tears may be lower than previously published. However, for those able to return, performance only in the season immediately following injury appears to be affected; players return to preinjury levels if given the opportunity to play >1 season after injury.

Defining Exposures in Professional Football: Professional American-Style Football Players as an Occupational Cohort

Studies of professional American football players have shown that football-related activities lead to acute injuries and may have long-term adverse health outcomes including osteoarthritis, neurocognitive impairment, and cardiovascular disease. However, the full complement of what constitutes professional football exposure has yet to be effectively articulated. Most likely, professional football exposure encompasses a multifaceted array of experiences including head impacts and joint stresses, long-term pain medication use, dietary restrictions, and strenuous training regimens. To study the health of professional American football players, characterizing the group as an occupational cohort and taking advantage of methods established within the discipline of occupational epidemiology may be beneficial. We conducted a narrative review of existing football research, occupational epidemiological methods papers, and occupational medicine studies. Here we describe the traditional occupational epidemiological approach to assessing exposure in a novel cohort and show how this framework could be implemented in studies of professional football players. In addition, we identify the specific challenges associated with studying an elite athletic occupational group, including the healthy worker effect and other types of selection and information biases, and explore these in the context of existing studies of football-related health. The application of well-established occupational epidemiological methods to professional football players may yield new insights into the effects of playing exposure and may provide opportunities for interventions to reduce harm.

Effect of Playing and Training at Altitude on Concussion Incidence in Professional Football

Background:

Despite the increased attention to sports-related concussion, the literature lacks information about the environmental factors that contribute to concussion incidence. Previous investigators have noted a decreased rate of concussion in football games played at higher altitude.

Purpose/Hypothesis:

The purpose of this study was to investigate whether the protective effects of altitude on concussion rate, as described by previous investigators, were due to acute effects of altitude exposure or chronic adaptations to training at altitude. Our hypothesis was that these protective effects are not attributable to relative cerebral edema that occurs in conditions of altitude-associated hypobaric hypoxia, known as the “slosh effect,” but rather result from long-term adaptations to training at altitude.

Study Design:

Descriptive epidemiology study.

Methods:

Athletes from the 2012, 2013, 2014, and 2015 National Football League (NFL) seasons were included in this analysis of publicly available data. Concussion rates were subdivided into 4 groups: (1) low-altitude teams playing below 644 feet (low-low), (2) low-altitude teams playing above 644 feet (low-high), (3) high-altitude teams playing below 644 feet (high-low), and (4) high-altitude teams playing above 644 feet (high-high).

Results:

Away teams had a significantly higher rate of concussion (0.32 concussions per exposure) compared with their home team counterparts (0.27 concussions per exposure; P = .03). Teams training and playing at high altitude had a 28% decreased concussion rate, which was significantly lower compared with concussion incidence rates for overall, low-low, and high-low groups (P < .05). In comparison, teams that trained at altitude but played below 644 feet had the highest rate of concussion, at 0.36 concussions per exposure (P < .05).

Conclusion:

These data indicate that living and training at altitude may have a protective effect on concussion rate, as evidenced by the significant reduction in the high-high group and the lack of an effect in the low-high group. However, teams from low altitude playing at high altitude did not have a statistically significant reduction in concussion rate. These results show that the slosh theory does not completely explain the effects of altitude on concussion incidence rate in the NFL. Further analyses are needed to investigate the true cause of altitude-induced protection in the NFL.

Previous foot injuries associated with a greater likelihood of Achilles tendon ruptures in professional American football players

OBJECTIVES

The purpose of this study was to build on current understanding of Achilles tendon (AT) ruptures in football through the examination of lower extremity injury rates (IR) in the season prior to AT rupture.

METHODS

An online review was conducted to document AT ruptures in the National Football League (NFL) from the 2010-11 through 2016-17 seasons. Player-specific information was gathered through the online search, injury reports, or video analysis. Injury incidence was recorded for each season. Descriptive statistics were calculated for all variables. IRs per 1000 athlete-exposures with 95% confidence intervals (CI) were established. Injury rate ratios (IRR) with 95% CI were calculated to evaluate differences in IR with statistical significance established at p < 0.05.

RESULTS

From the 2010-11 to 2016-17 NFL seasons, 109 AT ruptures were identified. 36 athletes participated in the NFL the season prior and sustained a total of 40 injuries. Thirty-two (32/40, 80%) of the injuries involved the lower extremity. The most frequent body parts injured in the NFL season prior to AT rupture were the knee (n = 8, 22.5%), upper leg and thigh (n = 7, 17.5%), lower leg and shin (n = 5, 12.5%), and ankle (n = 5, 12.5%). The overall IR for the AT rupture group was not significantly different than the NFL group (IRR: 0.94, 0.68-1.31 95% CI, p = 0.73). The AT rupture group demonstrated a significantly increased rate of foot injuries compared to the NFL cohort (IRR: 2.58, 1.16-5.77 95% CI, p = 0.02).

CONCLUSION

There was an increased identified incidence of AT ruptures in the NFL from 2010 to 2017 compared to AT ruptures reported from 1997 to 2002. There was no significant difference in lower extremity IR the season prior to AT rupture. Only foot injuries demonstrated an increased IR the season prior to AT rupture compared to an NFL cohort. Eleven athletes sustained 2 AT ruptures and all 11 players sustained the subsequent AT rupture to the contralateral limb.

Effect of Concussions on Lower Extremity Injury Rates at a Division I Collegiate Football Program

Background:

Football has one of the highest injury rates (IRs) in sports, ranging from 4.1 to 8.6 per 1000 athlete-exposures (AEs). Previous research has reported that athletes may be at an increased risk of suffering lower extremity (LE) injuries after a concussion.

Purpose/Hypothesis:

The purpose of this study was to evaluate the rate of LE injuries in collegiate football athletes after a concussion. We predicted that the overall LE IR would increase after a concussion and that each position group would also demonstrate a similar increase in LE injuries after a concussion.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Daily attendance and injury records were prospectively collected by licensed team medical providers for the 2012 through 2016 college football regular seasons. Each injury report included the date of injury, position group, body part injured, and type of injury. IRs per 1000 AEs with 95% CIs were calculated to evaluate LE injuries at different time points after a concussion (remainder of season, next season, any additional seasons) and by months (<6 months, 6-12 months, >12 months). Mid-P exact tests were utilized to establish injury rate ratios (IRRs) to compare the IR between variables.

Results:

There was no significant difference in LE IRRs between the athletes post- versus preconcussion (P = .20) or between the postconcussion and no concussion (control) athletes (P = .08). There was an increased LE IR beyond 12 months in the postconcussion group (IR, 9.08 [95% CI, 3.68-18.89]) compared with the no concussion group (IR, 2.88 [95% CI, 2.04-3.96]) (IRR, 3.16 [95% CI, 1.21-7.15]; P = .02). Line position players had an increase in LE injuries after a concussion (IRR, 6.22 [95% CI, 1.31-23.68]; P = .03) compared with linemen with no concussion.

Conclusion:

There was no initial increase in LE IRs immediately after a concussion; however, there was an increased LE IR more than 12 months after a concussion. There was no increase in LE IRs demonstrated by skill and other position groups. Line position players experienced an increased LE IR the next season after a concussion or greater than 12 months after the injury.

Jones Fractures Identified at the National Football League Scouting Combine: Assessment of Prognostic Factors, Computed Tomography Findings, and Initial Career Performance

Background:

Jones fractures result in subsequent dysfunction and remain an issue for athletes.

Purpose:

To (1) describe the epidemiology, treatment, and impact of Jones fractures identified at the National Football League (NFL) Scouting Combine on players’ early careers and (2) establish the value of computed tomography (CT) to determine bony healing after a fracture in prospective players.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

All players who attended the combine between 2009 and 2015 were retrospectively reviewed to identify their history of Jones fractures. The playing position, treatment method, and number of missed collegiate games were recorded. The mean overall draft pick number, number of games started and played, snap percentage, and position-specific performance scores (fantasy score) over the first 2 years in the NFL were compared between players with fractures and controls. An imaging classification system was applied based on grading of each quadrant of the fifth metatarsal (plantar, dorsal, medial, lateral), with a score of 0 for not healed or 1 for healed.

Results:

Overall, the number of Jones fractures identified was 72 in 2285 athletes (3.2%), with all treated via intramedullary screw fixation. The mean overall draft pick number for players with fractures was 111.2 ± 67.9 compared with 99.0 ± 65.9 for controls (P = .12). Performance scores for players with fractures were lower than those for controls across all positions, with a significant difference in running backs (2.6 vs 4.0, respectively; P < .001) and defensive linemen (1.4 vs 2.3, respectively; P = .02). The mean CT score was 2.5 ± 1.3. Of the 32 athletes who underwent imaging, 16 Jones fractures (50.0%) were healed or nearly healed, 12 (37.5%) were partially healed, and 4 (12.5%) showed little or no healing. The plantar cortex demonstrated the least healing (18/32; 56.3%), followed by the lateral cortex (15/32; 46.9%). Players with a mean score <1 were found to have fewer games started (2.7 ± 2.5) than those with 1 to 3 cortices healed (17.4 ± 10.4) or all cortices healed (8.7 ± 11.2).

Conclusion:

Based on CT, 50% of all players with a previous Jones fracture demonstrated incomplete healing. Moreover, position-specific performance scores over the first 2 years of a player’s career were lower across all positions for those with fractures compared with controls. Players with CT scores <1 were found to start fewer games and were drafted later than controls.

Management of Elbow Dislocations in the National Football League

Background

Although much literature exists regarding the treatment and management of elbow dislocations in the general population, little information is available regarding management in the athletic population. Furthermore, no literature is available regarding the postinjury treatment and timing of return to play in the contact or professional athlete.

Purpose

To review the clinical course of elbow dislocations in professional football players and determine the timing of return to full participation.

Study Design

Case series; Level of evidence, 4.

Methods

All National Football League (NFL) athletes with elbow dislocations from 2000 through 2011 who returned to play during the season were identified from the NFL Injury Surveillance System (NFL ISS). Roster position, player activity, use of external bracing, and clinical course were reviewed. Mean number of days lost until full return to play was determined for players with elbow dislocations who returned in the same season.

Results

From 2000 to 2011, a total of 62 elbow dislocations out of 35,324 injuries were recorded (0.17%); 40 (64.5%) dislocations occurred in defensive players, 12 (19.4%) were in offensive players; and 10 (16.1%) were during special teams play. Over half of the injuries (33/62, 53.2%) were sustained while tackling, and 4 (6.5%) patients required surgery. A total of 47 (75.8%) players who sustained this injury were able to return in the same season. For this group, the mean number of days lost in players treated conservatively (45/47) was 25.1 days (median, 23.0 days; range, 0.0-118 days), while that for players treated operatively (2/47) was 46.5 days (median, 46.5 days; range, 29-64 days). Mean return to play based on player position was 25.8 days for defensive players (n = 28; median, 21.5 days; range, 3.0-118 days), 24.1 days for offensive players (n = 11; median, 19 days; range, 2.0-59 days), and 25.6 days for special teams players (n = 8; median, 25.5 days; range, 0-44 days).

Conclusion

Elbow dislocations comprise less than a half of a percent of all injuries sustained in the NFL. Most injuries occur during the act of tackling, with the majority of injured athletes playing a defensive position. Players treated nonoperatively missed a mean of 25.1 days, whereas those managed operatively missed a mean of 46.5 days.

National Football League Skilled and Unskilled Positions Vary in Opportunity and Yield in Return to Play After an Anterior Cruciate Ligament Injury

BACKGROUND

Anterior cruciate ligament (ACL) injuries pose a significant risk to the careers of players in the National Football League (NFL). The relationships between draft round and position on return to play (RTP) among NFL players are not well understood, and the ability to return to preinjury performance levels remains unknown for most positions.

PURPOSE

To test for differences in RTP rates and changes in performance after an ACL injury by position and draft round. We hypothesized that skilled positions would return at a lower rate compared to unskilled positions. We further hypothesized that early draft-round status would relate to a greater rate of RTP and that skilled positions and a lower draft round would correlate with decreased performance for players who return to sport.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Utilizing a previously established database of publicly available information regarding ACL tears among NFL players, athletes with ACL tears occurring between the 2010 and 2013 seasons were identified. Generalized linear models and Kaplan-Meier time-to-event models were used to test the study hypotheses.

RESULTS

The overall RTP rate was 61.7%, with skilled players and unskilled players returning at rates of 64.1% and 60.4%, respectively (P = .74). Early draft-round players and unskilled late draft-round players had greater rates of RTP compared to skilled late draft-round players and both unskilled and skilled undrafted free agents (UDFAs). Skilled early draft-round players constituted the only cohort that played significantly fewer games after an injury. Unskilled UDFAs constituted the only cohort to show a significant increase in the number of games started and ratio of games started to games played, starting more games in which they played, after an injury.

CONCLUSION

Early draft-round and unskilled players were more likely to return compared to their later draft-round and skilled peers. Skilled early draft-round players, who displayed relatively high rates of RTP, constituted the only cohort to show a decline in performance. Unskilled UDFAs, who exhibited relatively low rates of RTP, constituted the only cohort to show an increase in performance. The significant effect of draft round and position type on RTP may be caused by a combination of differences in talent levels and in opportunities given to returning to play.

The Latarjet Procedure at the National Football League Scouting Combine: An Imaging and Performance Analysis

Background:

The Latarjet procedure is commonly performed in the setting of glenoid bone loss for treatment of recurrent anterior shoulder instability; however, little is known regarding the outcomes of this procedure in elite American football players.

Purpose:

(1) Determine the prevalence, clinical features, and imaging findings of elite college football athletes who present to the National Football League (NFL) Combine with a previous Latarjet procedure and (2) describe these athletes’ performance in the NFL in terms of draft status and initial playing time.

Study Design:

Case series; Level of evidence, 4.

Methods:

After review of all football players who participated in the NFL Combine from 2009 to 2016, any player with a previous Latarjet procedure was included in this study. Medical records, position on the field, and draft position were recorded for each player. In addition, imaging studies were reviewed to determine fixation type, hardware complications, and status of the bone block. For those players who were ultimately drafted, performance was assessed based on games played and started, total snaps, and percentage of eligible snaps in which the player participated during his rookie season.

Results:

Overall, 13 of 2617 (<1%) players at the combine were identified with a previous Latarjet procedure. Radiographically, 8 of 13 (61%) showed 2-screw fixation, while 5 of 13 (39%) had 1 screw. Of the 13 players, 6 (46%) players demonstrated hardware complications. All players had evidence of degenerative changes on plain radiographs, with 10 (77%) graded as mild, 1 (8%) as moderate, and 2 (15%) as severe according to the Samilson Prieto classification. Six of the 13 (46%) players went undrafted, while the remaining 7 (54%) were drafted; however, no player participated in more than half of the plays for which he was eligible during his rookie season.

Conclusion:

Only a small percentage of players at the NFL Combine (<1%) had undergone a Latarjet procedure. High rates of postoperative complications and radiographically confirmed degenerative change were observed. Athletes who had undergone a Latarjet procedure demonstrated a variable amount of playing time, but none participated in more than half of their eligible plays during their rookie season.

Epidemiology of Navicular Injury at the NFL Combine and Their Impact on an Athlete's Prospective NFL Career

Background:

Navicular injuries can result in persistent pain, posttraumatic osteoarthritis, and diminished performance and function.

Purpose:

To determine the epidemiology of navicular fracture in players participating in the National Football League (NFL) Scouting Combine and evaluate the impact of a navicular injury on the NFL draft position and NFL game play compared with matched controls.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Data were collected on players who previously sustained a navicular injury and participated in the NFL Combine between 2009 and 2015. The epidemiology of navicular injury was determined through an evaluation of the number of injuries, surgeries, and collegiate games missed as well as the position played, a physical examination, the surgical technique, and imaging findings. Players with a previous navicular injury (2009-2013) were compared with a set of matched controls. NFL performance outcomes included the draft position, career length ≥2 years, and number of games played and started within the first 2 years.

Results:

Between 2009 and 2015, 14 of 2285 (0.6%) players were identified as having sustained a navicular injury. A total of 11 of 14 (79%) athletes had sustained an overt navicular fracture, while 3 of 14 (21%) were diagnosed with stress reactions on magnetic resonance imaging. Eight patients who sustained a navicular fracture underwent surgery. There was evidence of ipsilateral talonavicular arthritis in 75% of players with a navicular fracture versus only 60% in the uninjured foot (odds ratio, 1.3; P = .04). Fifty-seven percent of players with navicular injury (72.7% of fractures) were undrafted versus 30.9% in the control group (P = .001). Overall, 28.6% of players with navicular fracture played ≥2 years in the NFL compared with 69.6% in the control group (P = .02).

Conclusion:

A previous navicular fracture results in a greater risk of developing posttraumatic osteoarthritis. Although only a low prevalence of navicular injury in prospective NFL players was noted, players with these injuries had a greater probability of not being drafted and not competing in at least 2 NFL seasons when compared with matched controls without an injury history to the NFL Combine.

Epidemiology of Injuries Identified at the NFL Scouting Combine and Their Impact on Performance in the National Football League: Evaluation of 2203 Athletes From 2009 to 2015

Background:

At the annual National Football League (NFL) Scouting Combine, the medical staff of each NFL franchise performs a comprehensive medical evaluation of all athletes potentially entering the NFL. Currently, little is known regarding the overall epidemiology of injuries identified at the combine and their impact on NFL performance.

Purpose:

To determine the epidemiology of injuries identified at the combine and their impact on initial NFL performance.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

All previous musculoskeletal injuries identified at the NFL Combine from 2009 to 2015 were retrospectively reviewed. Medical records and imaging reports were examined. Game statistics for the first 2 seasons of NFL play were obtained for all players from 2009 to 2013. Analysis of injury prevalence and overall impact on the draft status and position-specific performance metrics of each injury was performed and compared with a position-matched control group with no history of injury or surgery.

Results:

A total of 2203 athletes over 7 years were evaluated, including 1490 (67.6%) drafted athletes and 1040 (47.2%) who ultimately played at least 2 years in the NFL. The most common sites of injury were the ankle (1160, 52.7%), shoulder (1143, 51.9%), knee (1128, 51.2%), spine (785, 35.6%), and hand (739, 33.5%). Odds ratios (ORs) demonstrated that quarterbacks were most at risk of shoulder injury (OR, 2.78; P = .001), while running backs most commonly sustained ankle (OR, 1.39; P = .040) and shoulder injuries (OR, 1.55; P = .020) when compared with all other players. Ultimately, defensive players demonstrated a greater negative impact due to injury than offensive players, with multiple performance metrics significantly affected for each defensive position analyzed, whereas skilled offensive players (eg, quarterbacks, running backs) demonstrated only 1 metric significantly affected at each position.

Conclusion:

The most common sites of injury identified at the combine were (1) ankle, (2) shoulder, (3) knee, (4) spine, and (5) hand. Overall, performance in the NFL tended to worsen with injury history, with a direct correlation found between injury at a certain anatomic location and position of play. Defensive players tended to perform worse compared with offensive players if injury history was present.

Epidemiological Patterns of Initial and Subsequent Injuries in Collegiate Football Athletes

BACKGROUND

A body of epidemiological studies has examined football injuries and associated risk factors among collegiate athletes. However, few existing studies specifically analyzed injury risk in terms of initial or subsequent injuries.

PURPOSE

To determine athlete-exposures (AEs) and rates of initial and subsequent injury among collegiate football athletes.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

Injury and exposure data collected from collegiate football players from two Division I universities (2007-2011) were analyzed. Rate of initial injury was calculated as the number of initial injuries divided by the total number of AEs for initial injuries, while the rate for subsequent injury was calculated as the number of subsequent injuries divided by the total number of AEs for subsequent injury. Poisson regression was used to determine injury rate ratio (subsequent vs initial injury), with adjustment for other covariates.

RESULTS

The total AEs during the study period were 67,564, resulting in an overall injury rate of 35.2 per 10,000 AEs. Rates for initial and subsequent injuries were 31.7 and 45.3 per 10,000 AEs, respectively, with a rate ratio (RR) of 1.4 for rate of subsequent injury vs rate of initial injury (95% CI, 1.1-1.9). Rate of injury appeared to increase with each successive injury. RR during games was 1.8 (95% CI, 1.1-3.0). The rate of subsequent injuries to the head, neck, and face was 10.9 per 10,000 AEs, nearly double the rate of initial injuries to the same sites (RR = 2.0; 95% CI, 1.1-3.5). For wide receivers, the rate of subsequent injuries was 2.2 times the rate of initial injuries (95% CI, 1.3-3.8), and for defensive linemen, the rate of subsequent injuries was 2.1 times the rate of initial injuries (95% CI, 1.1-3.9).

CONCLUSION

The method used in this study allows for a more accurate determination of injury risk among football players who have already been injured at least once. Further research is warranted to better identify which specific factors contribute to this increased risk for subsequent injury.

Superior Labrum Anterior-Posterior Tears in the National Football League

BACKGROUND

Shoulder disorders are common in football players, with up to 50% of National Football League (NFL) recruits reporting a history of shoulder injuries. Superior labrum anterior-posterior (SLAP) tears are an entity with well-described detrimental effects on return to play in overhead-throwing athletes but with minimal data in contact athletes.

PURPOSE

To identify the incidence, predisposing factors, and effect of SLAP tears in NFL athletes and prospects as well as the treatment patterns of NFL team physicians.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

This study was a comprehensive analysis of SLAP tears in elite football players using a dual approach: (1) SLAP injuries recorded in the NFL Injury Surveillance System from 2000 to 2014 were evaluated by player position, type of play, days/games lost, and surgical intervention; (2) NFL Scouting Combine athletes from 2003 to 2011 with prior SLAP repair were evaluated for draft success, and drafted athletes were compared with matched controls for career length and performance scores.

RESULTS

SLAP tears represented a small portion (3.1%) of shoulder injuries in NFL athletes from 2000 to 2014, occurring most commonly in offensive linemen (28%). Surgically treated SLAP tears (42%) resulted in more days missed than did nonoperatively managed tears (140.2 vs 21.5 days; P < .001) and more games missed (8.4 vs 2.6 games; P = .003). SLAP repairs were also rare in NFL Combine athletes (n = 25 of 2965 athletes), with most having been performed in offensive linemen (32%). As compared with control NFL Combine athletes without SLAP tears, those drafted into the NFL with prior SLAP repair played significantly fewer games (33.7 vs 48.3; P = .049) and had fewer game starts (19.6 vs 35.4; P = .036).

CONCLUSION

In this comprehensive analysis of SLAP tears in elite football players, it is clear that these injuries have the potential to cause significant detriment to an athlete's career.

Anterior Cruciate Ligament Injuries in National Football League Athletes From 2010 to 2013: A Descriptive Epidemiology Study

BACKGROUND

There is a high incidence of anterior cruciate ligament (ACL) injuries among National Football League (NFL) athletes; however, the incidence of reinjury in this population is unknown.

PURPOSE

This retrospective epidemiological study analyzed all publicly disclosed ACL tears occurring in NFL players between 2010 and 2013 to characterize injury trends and determine the incidence of reinjury.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

A comprehensive online search identified any NFL player who had suffered an ACL injury from 2010 to 2013. Position, playing surface, activity, and date were recorded. Each player was researched for any history of previous ACL injury. The NFL games database from USA Today was used to determine the incidence of ACL injuries on artificial turf and grass fields. Databases from Pro Football Focus and Pro Football Reference were used to determine the injury rate for each position.

RESULTS

NFL players suffered 219 ACL injuries between 2010 and 2013. Forty players (18.3%) had a history of previous ACL injury, with 27 (12.3%) retears and 16 (7.3%) tears contralateral to a previous ACL injury. Five players (2.28%) suffered their third ACL tear. Receivers (wide receivers and tight ends) and backs (linebackers, fullbacks, and halfbacks) had significantly greater injury risk than the rest of the NFL players, while perimeter linemen (defensive ends and offensive tackles) had significantly lower injury risk than the rest of the players. Interior linemen (offensive guards, centers, and defensive tackles) had significantly greater injury risk compared with perimeter linemen. ACL injury rates per team games played were 0.050 for grass and 0.053 for turf fields (P > .05).

CONCLUSION

In this retrospective epidemiological study of ACL tears in NFL players, retears and ACL tears contralateral to a previously torn ACL constituted a substantial portion (18.3%) of total ACL injuries. The significant majority of ACL injuries in players with a history of previous ACL injury were retears. Skilled offensive players and linebackers had the greatest injury risk, and significantly more ACL tears occurred among interior linemen than perimeter linemen. The month of August had the highest incidence of ACL injuries, probably because of expanded roster sizes at that point in the NFL season.

Exertional Heat Illnesses and Environmental Conditions During High School Football Practices

BACKGROUND

Guidelines for preventing exertional heat illnesses (EHIs) during extreme heat stress should be specific to regional environments, age, and sport and should be based on evidence of reducing the risk. Each year in the United States, over 1 million high school football players practice in the August heat; however, no published data describe the incidence of EHIs in these athletes.

PURPOSE

To describe the environmental conditions and incidence of EHIs during high school football practices over a 3-month period.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

For a 3-month period (August-October), athletic trainers at 12 high schools in North Central Florida recorded the practice time and length, environmental conditions (wet-bulb globe temperature), and incidences of EHIs in varsity football athletes.

RESULTS

Athletes suffered 57 total EHIs during 29,759 athlete-exposures (AEs) for the 3-month data collection period (rate = 1.92/1000 AEs). August accounted for the majority of all EHIs, with 82.5% (47/57) and the highest rate (4.35/1000 AEs). Of total heat illnesses, heat cramps accounted for 70.2% (40/57), heat exhaustion 22.8% (13/57), and heat syncope 7.0% (4/57). The odds ratio indicated that athletes in August practices that lasted longer than the recommended 3 hours were 9.84 times more likely to suffer a heat illness than those in practices lasting ≤3 hours.

CONCLUSION

The highest rate of EHIs was during August. Practices in August that exceeded the recommended 3 hours were associated with a greater risk of heat illnesses. The overall rate of EHIs was lower for the high school football athletes observed in the study compared with that reported for collegiate football athletes in the region. The low rates of EHIs recorded suggest that the prevention guidelines employed by sports medicine teams are appropriate for the region and population.

CLINICAL RELEVANCE

Team physicians and athletic trainers should employ evidence-based, region- and population-specific EHI prevention guidelines. Sports medicine teams, coaches, and athletes should be aware of the increased risk of EHIs during August practices and the risk of prolonged practices during August.

Acromioclavicular joint injuries in the National Football League: epidemiology and management

BACKGROUND

Previous studies investigating acromioclavicular (AC) joint injuries in professional American football players have only been reported on quarterbacks during the 1980s and 1990s. These injuries have not been evaluated across all position players in the National Football League (NFL).

PURPOSE

The purpose of this study was 4-fold: (1) to determine the incidence of AC joint injuries among all NFL position players; (2) to investigate whether player position, competition setting, type of play, and playing surface put an athlete at an increased risk for this type of injury; (3) to determine the incidence of operative and nonoperative management of these injuries; and (4) to compare the time missed for injuries treated nonoperatively to the time missed for injuries requiring surgical intervention.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

All documented injuries of the AC joint were retrospectively analyzed using the NFL Injury Surveillance System (NFLISS) over a 12-season period from 2000 through 2011. The data were analyzed by the anatomic location, player position, field conditions, type of play, requirement of surgical management, days missed per injury, and injury incidence.

RESULTS

Over 12 NFL seasons, there were a total of 2486 shoulder injuries, with 727 (29.2%) of these injuries involving the AC joint. The overall rate of AC joint injuries in these athletes was 26.1 injuries per 10,000 athlete exposures, with the majority of these injuries occurring during game activity on natural grass surfaces (incidence density ratio, 0.79) and most often during passing plays. These injuries occurred most frequently in defensive backs, wide receivers, and special teams players; however, the incidence of these injuries was greatest in quarterbacks (20.9 injuries per 100 players), followed by special teams players (20.7/100) and wide receivers (16.5/100). Overall, these athletes lost a mean of 9.8 days per injury, with quarterbacks losing the most time to injury (mean, 17.3 days). The majority of these injuries were low-grade AC joint sprains that were treated with nonoperative measures; only 13 (1.7%) required surgical management. Players who underwent surgical management lost a mean of 56.2 days.

CONCLUSION

Shoulder injuries, particularly those of the AC joint, occur frequently in the NFL. These injuries can result in time lost but rarely require operative management. Quarterbacks had the highest incidence of injury; however, this incidence is lower than in previous investigations that evaluated these injuries during the 1980s and 1990s.

Estimation of head impact exposure in high school football: implications for regulating contact practices

BACKGROUND

Increased attention is being placed on the role of subconcussive impacts to the head during football participation and long-term cognitive health. Some have suggested that mitigating impacts to the head can be achieved by reducing or eliminating contact football practices. The effect that this might have on the number and magnitude of impacts is unknown.

PURPOSE

To estimate the effect of limiting contact practices on the frequency and magnitude of head impacts through the retrospective assessment of in vivo head impact data.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Data on impact magnitude and frequency were collected with the Head Impact Telemetry System during the 2009 football season among 42 varsity high school football athletes (mean age, 16.2 ± 0.6 years; mean height, 180.9 ± 7.2 cm; mean weight, 89.8 ± 20.1 kg). Head impacts were compared between player positions and session types (noncontact practice, contact practice, and game). These results were used to estimate the frequency and magnitude of head impacts when contact sessions were restricted.

RESULTS

The participants collectively sustained 32,510 impacts over the 15-week season. The typical athlete sustained a mean of 774 ± 502 impacts during the season, with linemen (center, guard, and offensive or defensive tackle positions) sustaining the highest number of impacts per athlete (1076 ± 541), followed by tight ends, running backs, and linebackers (779 ± 286); wide receivers, cornerbacks, and safeties (417 ± 266); and quarterbacks (356 ± 433). When viewed by session type, noncontact practices (n = 21) accounted for 1998 total impacts (2.4 ± 1.4 per athlete per session), contact practices (n = 36) accounted for 16,346 impacts (10.5 ± 7.7 per athlete per session), and games (n = 14) accounted for 14,166 impacts (24.1 ± 19.1 per athlete per session). Significantly more impacts occurred during games when compared with contact (P = .02) and noncontact practices (P < .001), and contact practices yielded significantly more impacts than noncontact practices (P = .02). Limiting contact practices to once per week would result in a 18% reduction in impacts for the duration of a season, while eliminating all contact practices would further reduce seasonal impacts by 39% across all players. Impact magnitudes were significantly highest during game sessions compared with contact and noncontact practices.

CONCLUSION

Our findings suggest that limiting or eliminating contact football practices may reduce the number of head impacts sustained by athletes over the course of a season, although the effect that such rule changes may have on the magnitude of head impacts during practice sessions is less clear. As such, the potential effect of reductions in contact practices on athletes' long-term cerebral health remains unknown.

Return to athletic activity after plate fixation of displaced midshaft clavicle fractures

BACKGROUND

Recent data support primary plate fixation of displaced midshaft clavicle fractures. The safety and efficacy of this practice have not been well documented in athletes.

HYPOTHESIS

Plate fixation of clavicle fractures in athletes is a safe and effective procedure, resulting in a reliable and timely return to play.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 29 patients with displaced midshaft clavicle fractures from athletic activity were treated with plate fixation between January 1, 2003 and December 31, 2008, including 1 patient treated for each clavicle for separate injuries. All 29 patients were contacted for follow-up. At a mean follow-up of 21 months, patients completed a questionnaire focused on the time to return to athletics and treatment course. Patients also completed the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire. Radiographs were reviewed to identify fracture comminution, displacement, shortening, and angulation; radiographic union time; and malunion.

RESULTS

All of the patients (30/30 cases) returned to sports after open reduction internal fixation of their fracture. The mean time to return to play was 83 days with a range of 13 to 277 days. Seven (23%) of the cases returned to athletics at ≤6 weeks after surgery, and a total of 20 patients (67%) returned at ≤12 weeks after surgery. All patients (100%) were satisfied with their treatment. The QuickDASH scores revealed almost perfect recovery (mean score, 0.8 of 100). Four minor complications were identified. No patient had a refracture, plate fracture, loss of fixation, nonunion, malunion, or deep wound infection.

CONCLUSION

Plate fixation of displaced clavicle fractures in athletes is a safe procedure, resulting in a high satisfaction rating and minimal disability to the upper extremity. An early return (<6 weeks) to sports is possible after this treatment; however, the time to return is highly variable.