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OBJECTIVE: To provide certified athletic trainers, team physicians, emergency responders, and other health care professionals with recommendations on how to best manage a catastrophic cervical spine injury in the athlete. BACKGROUND: The relative incidence of catastrophic cervical spine injury in sports is low compared with other injuries. However, cervical spine injuries necessitate delicate and precise management, often involving the combined efforts of a variety of health care providers. The outcome of a catastrophic cervical spine injury depends on the efficiency of this management process and the timeliness of transfer to a controlled environment for diagnosis and treatment. RECOMMENDATIONS: Recommendations are based on current evidence pertaining to prevention strategies to reduce the incidence of cervical spine injuries in sport; emergency planning and preparation to increase management efficiency; maintaining or creating neutral alignment in the cervical spine; accessing and maintaining the airway; stabilizing and transferring the athlete with a suspected cervical spine injury; managing the athlete participating in an equipment-laden sport, such as football, hockey, or lacrosse; and considerations in the emergency department. [ABSTRACT FROM AUTHOR]

BACKGROUND: Most anterior cruciate ligament research is limited to variables at the knee joint and is performed in the laboratory setting, often with subjects postinjury. There is a paucity of information on the position of the hip and ankle during noncontact anterior cruciate ligament injury. HYPOTHESIS: When landing after maneuvers, athletes with anterior cruciate ligament injury (subjects) show a more flatfooted profile and more hip flexion than uninjured athletes (controls). STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Data from 29 videos of subjects were compared with data from 27 videos of controls performing similar maneuvers. Joint angles were analyzed in 5 sequential frames in sagittal or coronal planes, starting with initial ground-foot contact. Hip, knee, and ankle joint angles were measured in each sequence in the sagittal plane and hip and knee angles in the coronal plane with computer software. The portion of the foot first touching the ground and the number of sequences required for complete foot-ground contact were assessed. Significance was set at P< .05. RESULTS: In sagittal views, controls first contacted the ground with the forefoot; subjects had first ground contact with the hind-foot or entirely flatfooted, attained the flatfoot position significantly sooner, had significantly less plantar-flexed ankle angles at initial contact, and had a significantly larger mean hip flexion angle at the first 3 frames. In coronal views, no significant differences in knee abduction (initial contact) or hip abduction angle were found between groups; knee abduction was relatively unchanged in controls but progressed in subjects. CONCLUSION: Initial ground contact flatfooted or with the hindfoot, knee abduction and increased hip flexion may be risk factors for anterior cruciate ligament injury. [ABSTRACT FROM AUTHOR]

BACKGROUND: Female college basketball and soccer athletes have higher rates of anterior cruciate ligament injury than do their male counterparts. Rates of anterior cruciate ligament injuries for women and men in collegiate lacrosse have not been examined. Understanding anterior cruciate ligament injury patterns in lacrosse, a full-contact sport for men and noncontact sport for women, could further injury prevention efforts. HYPOTHESES: Female anterior cruciate ligament injury rates will decrease over time owing to longer participation in sports. Lacrosse anterior cruciate ligament injury rates will be lower than rates in basketball and soccer possibly owing to beneficial biomechanics of carrying a lacrosse stick. STUDY DESIGN: Cohort study (Prevalence); Level of evidence, 2. METHODS: Data from the National Collegiate Athletic Association Injury Surveillance System were analyzed to compare men's and women's anterior cruciate ligament injuries in basketball, lacrosse, and soccer over 15 years. RESULTS: Anterior cruciate ligament injury rates in women's basketball and soccer were 0.28 and 0.32 injuries per 1000 athlete exposures, respectively, and did not decline over the study period. In men's basketball, injury rate fluctuated between 0.03 and 0.13 athlete exposures. Rates of anterior cruciate ligament injury did not significantly change in men's soccer over the study period. The rate of anterior cruciate ligament injury in men's lacrosse (0.17 athlete exposures, P < .05) was significantly higher than in men's basketball (0.08 athlete exposures) and soccer (0.12 athlete exposures). Injury rate in women's lacrosse (0.18 athlete exposures, P < .05) was significantly lower than in women's basketball and soccer. CONCLUSION: There was no discernable change in rate of anterior cruciate ligament injury in men or women during the study period. Men's lacrosse is a high-risk sport for anterior cruciate ligament injury. Unlike basketball and soccer, the rates of anterior cruciate ligament injury are essentially the same in men's and women's lacrosse. The level of allowed contact in pivoting sports may be a factor in determining sport-specific anterior cruciate ligament risk. [ABSTRACT FROM AUTHOR]

BACKGROUND: There are few epidemiologic studies of cheerleading injuries. PURPOSE: To develop a profile of catastrophic injuries in cheerleading and to describe relevant risk factors. STUDY DESIGN: Retrospective cohort study. METHODS: We reviewed 29 of 39 incidents of cheerleading injuries reported to the National Center for Catastrophic Sports Injury Research from 1982 to 2002. RESULTS: Twenty-seven of the injured cheerleaders were women. There were 1.95 direct catastrophic injuries per year or 0.6 injuries per 100,000 participants. The rate of injuries among college cheerleaders was five times that of high school participants. The most common stunts performed at the time of injury were a pyramid (9) or a basket toss (8). Catastrophic injuries included 17 severe head injuries, resulting in 13 skull fractures and 2 deaths; 8 cervical fractures or major ligament injuries; 3 spinal cord contusions; and 1 concomitant head injury and cervical fracture. CONCLUSIONS: Suggestions for reducing catastrophic injuries in cheerleaders include enhancing the number and training of spotters, mandating floor mats for complex stunts, restricting complex stunts when surfaces are wet, and encouraging safety certification of coaches. Pyramids and basket tosses should be limited to experienced cheerleaders who have mastered all other skills and should be performed with spotters and landing mats. [ABSTRACT FROM AUTHOR]

Supracondylar stress fractures are rare and can cause anterior knee pain. Persistent, intense pain occurs in the knee and distal thigh and may be mistaken for patellofemoral pain syndrome unless the fracture is identified by radiographic modalities (MRI or bone scan). Two cases of supracondylar femoral stress fractures in female runners highlight the need to seek proximal pathologies when patients report knee pain that cannot be explained by other conditions. [ABSTRACT FROM AUTHOR]

Stress fractures can occur in almost any bone in the body, with the lower extremity weightbearing bones, especially the tibia, tarsals, and metatarsals, being affected most frequently. Although the cause of these fractures is multifactoral, repetitive physical forces without adequate rest are the primary culprits. Stress fractures may be broadly classified as low-risk or high-risk injuries. Low-risk stress fractures, the topic of this review article, can be diagnosed through a thorough history, physical examination, and radiographs. Nuclear scintigraphy is occasionally necessary for confirmation, especially for fractures of the spine and pelvis. When diagnosed early and treated with restriction of activity, low-risk stress fractures have a favorable prognosis. [ABSTRACT FROM AUTHOR]

An understanding of the etiology and prevention of noncontact ACL injuries has lagged behind diagnosis and treatment. However, a growing research implicates hormonal, anatomic, environmental, and neuromuscular factors that may predispose athletes, particularly women, to these injuries. Specific factors may include estrogen levels, the shape of the intercondylar notch, playing style, and neuromuscular control of the quadriceps and hamstring muscles. Prevention programs that involve proprioception, plyometrics, strength training, and improved jumping, stopping, and turning techniques show promising results. [ABSTRACT FROM AUTHOR]

Context: Among American sports, football has the highest incidence of exertional heat stroke (EHS), despite decades of prevention strategies. Based on recent reports, 100% of high school and college EHS football fatalities occur during conditioning sessions. Linemen are the at-risk population, constituting 97% of football EHS deaths. Linemen heat up faster and cool down slower than other players., Evidence Acquisition: Case series were identified from organized, supervised football at the youth, high school, and collegiate levels and compiled in the National Registry of Catastrophic Sports Injuries. Sources for event occurrence were media reports and newspaper clippings, autopsy reports, certificates of death, school-sponsored investigations, and published medical literature. Articles were identified through PubMed with search terms "football," "exertional heat stroke," and "prevention.", Study Design: Clinical review., Level of Evidence: Level 5., Results: Football EHS is tied to (1) high-intensity drills and conditioning that is not specific to individual player positions, (2) physical exertion as punishment; (3) failure to modify physical activity for high heat and humidity, (4) failure to recognize early signs and symptoms of EHS, and (5) death when cooling is delayed., Conclusion: To prevent football EHS, (1) all training and conditioning should be position specific; (2) physical activity should be modified per the heat load; (3) understand that some players have a "do-or-die" mentality that supersedes their personal safety; (4) never use physical exertion as punishment; (5) eliminate conditioning tests, serial sprints, and any reckless drills that are inappropriate for linemen; and (6) consider air-conditioned venues for linemen during hot practices. To prevent EHS, train linemen based on game demands., Strength-Of-Recommendation Taxonomy: n/a., Competing Interests: The following authors declared potential conflicts of interest: J.K.D. is an employee of the Gatorade Sports Science Institute, a division of PepsiCo. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Inc. R.C. is on the medical advisory board for BOA. J.K.D. has stock options from PepsiCo.

Background: Research on the cause of lateral patellar dislocation (LPD) has focused on trochlear morphologic parameters, joint alignment, and patellofemoral soft tissue forces. A paucity of information is available regarding how patellar morphologic parameters influence the risk for LPD., Purpose/hypothesis: The purpose was to assess whether patellar morphology is a risk factor for recurrent LPD. It was hypothesized that (1) patients with recurrent LPD would have decreased patellar width and volume and (2) patellar morphologic parameters would accurately discriminate patients with recurrent LPD from controls., Study Design: Cohort study (diagnosis); Level of evidence, 3., Methods: A total of 21 adults with recurrent LPD (age, 29.7 ± 11.1 years; height, 170.8 ± 9.9 cm; weight, 76.1 ± 17.5 kg; 57% female) were compared with 21 sex- and height-matched controls (age, 27.2 ± 6.7 years; height, 172.0 ± 10.6 cm; weight, 71.1 ± 12.8 kg; 57% female). Three-dimensional axial fat-saturated magnetic resonance imaging scans were used to measure patellar medial, lateral, and total width; patellar volume; patellar medial and lateral facet length; the Wiberg index; and previously validated knee joint alignment and femoral shape measurements (eg, tibial tuberosity to trochlear groove distance, trochlear dysplasia)., Results: The LPD group demonstrated reduced medial patellar width (Δ = -3.6 mm; P < .001) and medial facet length (Δ = -3.7 mm; P < .001) but no change in lateral width or facet length. This resulted in decreased total patellar width (Δ = -3.2 mm; P = .009), decreased patellar volume (Δ = -0.3 cm 3 ; P = .025), and an increased Wiberg index (Δ = 0.05; P < .001). No significant differences were found for all other patellar shape measures between cohorts. Medial patellar width was the strongest single discriminator (83.3% accuracy) for recurrent LPD. Combining medial patellar width, patellofemoral tilt, and trochlear groove length increased the discrimination to 92.9%., Conclusion: The medial patellar width was significantly smaller in patients with recurrent LPD and was the single most accurate discriminator for recurrent LPD, even compared with traditional trochlear shape and joint alignment measures (eg, trochlear dysplasia, patella alta). Therefore, medial patellar morphology should be assessed in patients with LPD as a risk factor for recurrence and a potential means to improve treatment., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This work was funded by the Intramural Research Program of the National Institutes of Health Clinical Center, Bethesda, Maryland, and the Medical Research Scholars Program (https://fnih.org/what-we-do/current-education-and-training-programs/mrsp). AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Objective: To describe the epidemiology, mechanisms, treatment, and disability for facial injuries in National Basketball Association (NBA) athletes., Methods: This was a retrospective descriptive epidemiological chart review using NBA Electronic Medical Record (EMR) system. Responses to injuries reported in games, practices, and other activities were used for all data analysis, except for game incidence rates. Incidence rates were calculated by the game-related facial injury incidence per total athlete exposure (player-games)., Results: There were 440 facial injuries among 263 athletes during the 5 NBA seasons with an overall single-season risk of 12.6% and a game incidence of 2.4 per 1000 athlete-exposures (95% CI: 2.18-2.68). The majority of injuries were lacerations ( n  = 159, 36.1%), contusions ( n  = 99, 22.5%), or fractures ( n  = 67, 15.2%), with ocular ( n  = 163, 37.0%) being the most commonly injured location. Sixty (13.6%) injuries resulted in at least one NBA game missed (224 cumulative player-games) with ocular injuries resulting in the most cumulative games missed ( n  = 167, 74.6%). Nasal fractures ( n  = 39, 58.2%) were the most common fracture location followed by ocular fractures ( n  = 12, 17.9%) but were less likely to lead to games missed (median = 1, IRQ: 1-3) than ocular (median = 7, IQR: 2-10) fractures., Conclusions: An average of one in eight NBA players sustained a facial injury each season with ocular injuries being the most common location. While most facial injuries are minor, serious injuries, especially ocular fractures, can result in games missed.

➤ Catastrophic injuries in U.S. high school and college athletes are rare but devastating injuries.➤ Catastrophic sports injuries are classified as either traumatic, caused by direct contact during sports participation, or nontraumatic, associated with exertion while participating in a sport.➤ Football is associated with the greatest number of traumatic and nontraumatic catastrophic injuries for male athletes, whereas cheerleading has the highest number of traumatic catastrophic injuries and basketball has the highest number of nontraumatic catastrophic injuries for female athletes.➤ The incidence of traumatic catastrophic injuries for all sports has declined over the past 40 years, due to effective rule changes, especially in football, pole-vaulting, cheerleading, ice hockey, and rugby. Further research is necessary to reduce the incidence of structural brain injury in contact sports such as football.➤ The incidence of nontraumatic catastrophic injuries has increased over the last 40 years and requires additional research and preventive measures. Avoiding overexertion during training, confirming sickle cell trait status in high school athletes during the preparticipation physical examination, and developing cost-effective screening tools for cardiac abnormalities are critical next steps., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H773 )., (Copyright © 2023 Written work prepared by employees of the Federal Government as part of their official duties is, under the United States Copyright Act, a ‘work of the United States Government’ for which copyright protection under that Act is not available. As such, copyright protection does not extend to the contributions of employees of the Federal Government prepared as part of their employment.)

Background: A previous report revealed an average of 7.2 (0.67 per 100,000 participants) sport-related structural brain injuries (SRSBIs) with macroscopic lesions per year in high school (HS) and college football players. The Lystedt law and other rule changes have been implemented with intent to reduce the risk of brain injury in football., Hypothesis: To update the profile of SRSBIs in HS and college football players and evaluate the efficacy of legislation intended to reduce brain injuries., Study Design: Descriptive epidemiology study., Level of Evidence: Level 4., Methods: We retrospectively reviewed 18 academic years (July 2002 through June 2020) of SRSBIs catalogued by the National Registry of Catastrophic Sports Injuries. The incidence of SRSBIs was assessed at the HS level during the pre (July 2002 through June 2009), transitional (July 2009 through June 2014), and post (July 2014 through June 2020) universal adoption time periods of the Lystedt law. In addition, the incidence of SRSBIs during the second half of the study (2011-2012 through 2019-2020) was compared with the first half of the study (2002-2003 through 2010-2011)., Results: During the study period, there was a total of 228 SRSBIs (12.7 per year, 1.01 per 100,000 participants): 212 (93%, 11.8 per year, 1.00 per 100,000) in HS athletes and 16 (7%, 0.89 per year, 1.17 per 100,000) in college athletes. There were 52 fatalities (2.9 per year, 0.22 per 100,000 participants) with 46 (2.56 per year, 0.22 per 100,000) in HS athletes and 6 (0.33 per year, 0.43/100,000) in college athletes. There was no significant difference in risk of HS total SRSBIs or fatalities during the 3 Lystedt periods. The risk of combined SRSBI cases [relative risk (RR) = 1.22, P = 0.13] and fatalities (RR = 1.20, P = 0.52) was similar in the second half of the study compared with the first half of the study., Conclusion: Despite implementation of rule changes intended to reduce head injury, in particular the Lystedt law, the incidence of SRSBIs has remained unchanged. Further research is necessary to develop effective prevention programs for SRSBIs., Clinical Relevance: SRSBIs remain a persistent problem in HS and college American football. The recent head injury rule changes have not been effective at reducing SRSBIs.

Sports participation is a leading cause of catastrophic cervical spine injury (CSI) in the United States. Appropriate prehospital care for athletes with suspected CSIs should be available at all levels of sport. Planning the process of transport for home venues before the start of the season and ensuring that a medical time out occurs at home and away games can reduce complications of transport decisions on the field of play and expedite transport of the spine-injured athlete., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: There have been numerous case series of exertional rhabdomyolysis (ER) but no comprehensive studies investigating the incidence of ER in the civilian athletic population in the United States (US)., Methods: A retrospective review of patients with ER presenting to emergency departments in the US over a 20-year period between 2000 and 2019 was performed using the National Electronic Injury Surveillance System (NEISS) database., Results: The national estimate of hospital visits in the US for ER during the 20-year period was 40,654 (0.66 per 100,000 population). There was a 10-fold increase in the incidence of ER from the first to the second decade. The odds of ER were 3.77 (95% CI 3.67-3.86, P < .0001) times higher for males (31,921, 78.5%, 1.06 per 100,000) than females (8,733, 21.5%, 0.28 per 100,000) and 3.82 (95% CI 3.71-3.93, P < .0001) higher in African Americans (33.6, 0.93 per 100,000) than white patients (53%, 0.24 per 100,000). American football (3,064, 7.5%) was responsible for 43.9% of the sports-induced ER cases. The majority (67.3%) of ER cases occurred between the ages of 16 and 35 years old. The majority of patients required hospitalization (26,550, 65.3%)., Conclusions: The number of ER cases presenting to emergency departments in the US increased from 2000-2009 to 2010-2019. Young males and African Americans are at highest risk of ER. There was a high rate of hospitalization.

Background: Nontraumatic fatalities occur on a regular basis in high school (HS) and college football athletes, primarily in obese linemen performing high-intensity exercise. One contributing factor to these deaths may be a mismatch between baseline aerobic (cardiorespiratory) fitness and exercise regimens., Hypothesis: There is a wide range of aerobic fitness in HS and college football players. Body mass index (BMI) is a safe and simple method for estimating baseline aerobic fitness., Study Design: Retrospective cohort study., Level of Evidence: Level 3., Methods: A retrospective review was performed on 79 HS football athletes who had VO 2Peak (mL·kg -1 ·min -1 ) measured during the offseason. Multivariate regression analysis was used to determine if BMI (obese, overweight, and normal; kg/m 2 ), position played (linemen vs other), year in school (freshmen vs other), and/or race (African American vs White) were risk factors for poor aerobic fitness. A separate cohort of 135 (48 HS; 87 college) football athletes performed a 6-minute run test to determine speed (miles/min), extrapolate VO 2Max , and calculate reference values for suggested upper threshold safe starting speeds (85% of maximum) for aerobic training based on BMI. The relationship between BMI and VO 2Peak was assessed. The exercise regimens (speeds) of 2 collegiate football fatalities from the public domain were used to predict their VO 2Max values., Results: Mean VO 2Peak (mL·kg -1 ·min -1 ) was 38.5 ± 8.6 (range 19.1-60.6); when grouped by BMI, low scores (<40) were found in 87.5% of obese (32.4 ± 7.7), 47.8% of overweight (40.8 ± 7.6), and 45.2% of normal (41.4 ± 7.8) athletes. VO 2Peak was significantly lower in linemen (32.8 ± 6.4; P = 0.007) compared with nonlineman (41.8 ± 7.9), and in obese players (by BMI; 32.4; P = 0.019) compared with nonobese players (41.4 ± 7.6), but did not differ by age, year in school, or race. Means for speed (min/mile) and extrapolated VO 2Max (mL·kg -1 ·min -1 ) for the 6-minute run test by BMI groups were both significantly different ( P = 0.001) for normal (7.0 ± 0.6; 51.1 ± 2.6), overweight (7.6 ± 0.8; 46.5 ± 3.2), and obese (8.9 ± 1.5; 36.8 ± 5.9) athletes. There was a significant negative correlation ( r = -0.551; P = 0.001; R 2 = 0.304) between VO 2Peak and BMI. Safe starting speed recommendations for running 1 mile range from 7.3 to 12.1 min/mile for BMIs 20 to 40 kg/m 2 for HS and college athletes. For the 2 fatalities (mean, BMI of 36.5 kg/m 2 ) repetitive sprint speeds were 49 and 89% higher than our safe starting speeds for their BMI., Conclusion: A large spectrum of baseline aerobic fitness was noted in HS and college football players. Obese players and linemen had statistically lower baseline aerobic fitness, a major risk factor for possible heat illness. BMI is an acceptable surrogate for VO 2Peak and can be employed to develop safe training regimens without the need for a maximum fitness test, which can place the athlete at risk for a medical event., Clinical Relevance: Knowledge of BMI provides an estimate of baseline aerobic fitness and a foundation for prescribing safe, individualized exercise regimens.

Anterior cruciate ligament (ACL) ruptures significantly impact athletes in terms of return to play and loss of long-term quality of life. Before the onset of this study, understanding the mechanism of ACL injury was limited. Thus, the primary focus of this manuscript is to describe our multi-faceted approach to uncovering the mechanism of noncontact ACL injury (NC-ACLI) with the goal of developing preventive strategies. The initial qualitative analysis of ACL injury events revealed most (70%) injuries involve minimal to no contact and occurr during landing or deceleration maneuvers in team sports with a minor perturbation before the injury that may disrupt the neuromuscular system leading to poor body dynamics. A series of quantitative videotape studies demonstrated differences in leg and trunk positions at the time of NC-ACLI in comparison to control subjects. Analysis of the faulty dynamics provoking NC-ACLI, especially the flat-footed landing component, supports the theory that an axial compressive force is the critical factor responsible for NC-ACLI. Our magnetic resonance imaging study demonstrated the NC-ACLI position was associated with a higher tibial slope, and joint contact occurring on the flat, anterior portion of the lateral femoral condyle versus the round, posterior aspect. Both anatomic conditions favor sliding (pivot shift) over rolling in the presence of an axial compressive force. Subsequent cadaveric studies supported axial compressive forces as the primary component of NC-ACLI. Both a strong eccentric quadriceps contraction and knee abduction moments may increase the compressive force at the joint thereby lowering the axial threshold to injury. This manuscript summarizes the NC-ACLI mechanism portion of the 2021 OREF Clinical Research Award., (© 2021 Orthopaedic Research Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

Background: Chronic idiopathic patellofemoral pain is associated with patellar maltracking in both adolescents and adults. To accurately target the underlying, patient-specific etiology, it is crucial we understand if age-of-pain-onset influences maltracking., Methods: Twenty adolescents (13.9 ± 1.4 years) and 20 adults (28.1 ± 4.9 years) female patients with idiopathic patellofemoral pain (age-of-pain-onset: < 14 and > 18 years of age, respectively) formed the patient cohort. Twenty adolescents and 20 adults (matched for gender, age, and body mass index) formed the control cohort. We captured three-dimensional patellofemoral kinematics during knee flexion-extension using dynamic MRI. Patellar maltracking (deviation in patient-specific patellofemoral kinematics, relative to their respective age-controlled mean values) was the primary outcome measure, which was compared between individuals with adolescent-onset and adult-onset patellofemoral pain using ANOVA and discriminant analysis., Findings: The female adolescent-onset patellofemoral pain cohort demonstrated increased lateral (P = 0.032), superior (P = 0.007), and posterior (P < 0.001) maltracking, with increased patellar flexion (P < 0.001) and medial spin (P = 0.002), relative to the adult-onset patellofemoral pain cohort. Post-hoc analyses revealed increased lateral shift [mean difference ± 95% confidence interval = -2.9 ± 2.1 mm at 10° knee angle], posterior shift [-2.8 ± 2.1 mm, -3.3 ± 2.3 mm & -3.1 ± 2.4 mm at 10°, 20°& 30°], with greater patellar flexion [3.8 ± 2.6 mm & 5.0 ± 2.8 mm, at 20°& 30°] and medial spin [-2.2 ± 1.7 mm & -3.4 ± 2.3 mm at 20°& 30°]. Axial-plane maltracking accurately differentiated the patient age-of-pain-onset (60-75%, P < 0.001)., Interpretation: Age-of-pain-onset influences the maltracking patterns seen in patients with patellofemoral pain; with all, but 1, degree of freedom being unique in the adolescent-onset-patellofemoral pain cohort. Clinical awareness of this distinction is crucial for correctly diagnosing a patient's pain etiology and optimizing interventional strategies., (Copyright © 2021. Published by Elsevier Ltd.)

Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: K.M.F. has received honoraria and consulting fees from Flexion Therapeutics and education payments from Supreme Orthopedic Systems. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: A novel algorithm and clinical prediction rule (CPR), with 18 variables, was created in 2014. The CPR generated a bone stress injury (BSI) score, which was used to determine the necessity of imaging in suspected BSI. To date, there are no validated algorithms for imaging selection in patients with suspected BSI., Hypothesis: A simplified CPR will assist clinicians with diagnosis and decision making in patients with suspected BSI., Study Design: Prospective cohort study., Level of Evidence: Level 3., Methods: A total of 778 military trainees with lower extremity pain were enrolled. All trainees were evaluated for 18 clinical variables suggesting BSI. Participants were monitored via electronic medical record review. Then, a prediction model was developed using logistic regression to identify clinical variables with the greatest predictive value and assigned appropriate weight. Test characteristics for various BSI score thresholds were calculated., Results: Of the enrolled trainees, 204 had imaging-confirmed BSI in or distal to the femoral condyles. The optimized CPR selected 4 clinical variables (weighted score): bony tenderness (3), prior history of BSI (2), pes cavus (2), and increased walking/running volume (1). The optimized CPR with a score ≥3 yielded 97.5% sensitivity, 54.2% specificity, and 98.2% negative predictive value. An isolated measure, bony tenderness, demonstrated similar statistical performance., Conclusion: The optimized CPR, which uses bony tenderness, prior history of BSI, pes cavus, and increased walking/running volume, is valid for detecting BSI in or distal to the femoral condyles. However, bony tenderness alone provides a simpler criterion with an equally strong negative predictive value for BSI decision making., Clinical Relevance: For suspected BSI in or distal to the femoral condyles, imaging can be deferred when there is no bony tenderness. When bony tenderness is present in the setting of 1 or more proven risk factors and no clinical evidence of high-risk bone involvement, presumptive treatment for BSI and serial radiographs may be appropriate.

Background: The incidence of nontraumatic fatalities in high school (HS) and National Collegiate Athletic Association (NCAA) football players has continued at a constant rate since the 1960s., Purpose: To describe the causes of nontraumatic fatalities in HS and NCAA football players and provide prevention strategies., Study Design: Descriptive epidemiology study., Methods: We reviewed 187 fatalities in HS and NCAA nontraumatic football players catalogued by the National Registry of Catastrophic Sports Injuries during a 20-year period between July 1998 and June 2018., Results: The majority (n = 162; 86.6%) of fatalities occurred during a practice or conditioning session. Most fatalities, when timing was known, (n = 126; 70.6%) occurred outside of the regular playing season, with the highest incidence in the August preseason (n = 64; 34.2%). All documented conditioning sessions were supervised by a coach (n = 92) or strength and conditioning coach (n = 40). The exercise regimen at the time of the fatality involved high-intensity aerobic training in 94.7%. Punishment was identified as the intent in 36 fatalities. The average body mass index of the athletes was 32.6 kg/m 2 . For athletes who died due to exertional heat stroke, the average body mass index was 36.4 kg/m 2 , and 97.1% were linemen., Conclusion: Most nontraumatic fatalities in HS and NCAA football players occurred during coach-supervised conditioning sessions. The primary cause of exertion-related fatalities was high-intensity aerobic workouts that might have been intended as punishment and/or excess repetitions. Exertion-related fatalities are potentially preventable by applying standards in workout design, holding coaches accountable, and ensuring compliance with the athlete's health and current welfare policies., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: K.M.F. has received consulting fees from Flexion Therapeutics. AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2020.)

Background: Football has the highest number of nontraumatic fatalities of any sport in the United States., Purpose: To compare the incidence of nontraumatic fatalities with that of traumatic fatalities, describe the epidemiology of nontraumatic fatalities in high school (HS) and college football players, and determine the effectiveness of National Collegiate Athletic Association (NCAA) policies to reduce exertional heat stroke (EHS) and exertional sickling (ES) with sickle cell trait (SCT) fatalities in athletes., Study Design: Descriptive epidemiology study., Methods: We retrospectively reviewed 20 academic years (1998-2018) of HS and college nontraumatic fatalities in football players using the National Registry of Catastrophic Sports Injuries (NRCSI). EHS and ES with SCT fatality rates were compared before and after the implementation of the NCAA football out-of-season model (bylaw 17.10.2.4 [2003]) and NCAA Division I SCT screening (bylaw 17.1.5.1 [2010]), respectively. Additionally, we compiled incidence trends for HS and college traumatic and nontraumatic fatalities in football players for the years 1960 through 2018 based on NRCSI data and previously published reports., Results: The risk (odds ratio) of traumatic fatalities in football players in the 2010s was 0.19 (95% CI, 0.13-0.26; P < .0001) lower in HS and 0.29 (95% CI, 0.29-0.72; P = .0078) lower in college compared with that in the 1960s. In contrast, the risk of nontraumatic fatalities in football players in the 2010s was 0.7 (95% CI, 0.50-0.98; P = .0353) in HS and 0.9 (95% CI, 0.46-1.72; P = .7413) in college compared with that in the 1960s. Since 2000, the risk of nontraumatic fatalities has been 1.89 (95% CI, 1.42-2.51; P < .001) and 4.22 (95% CI, 2.04-8.73; P < .001) higher than the risk of traumatic fatalities at the HS and college levels, respectively. During the 20 years studied, there were 187 nontraumatic fatalities (average, 9.4 per year). The causes of death were sudden cardiac arrest (57.7%), EHS (23.6%), ES with SCT (12.1%), asthma (4.9%), and hyponatremia (1.6%). The risk of a nontraumatic fatality was 4.1 (95% CI, 2.8-5.9; P < .0001) higher in NCAA compared with HS athletes. There was no difference in the risk of an EHS fatality in NCAA athletes (0.86 [95% CI, 0.17-4.25]; P = .85) after implementation in 2003 of the NCAA football out-of-season model. The risk of an ES with SCT fatality in Division I athletes was significantly lower after the 2010 NCAA SCT screening bylaw was implemented (0.12 [95% CI, 0.02-0.95]; P = .04)., Conclusion: Since the 1960s, the risk of nontraumatic fatalities has declined minimally compared with the reduction in the risk of traumatic fatalities. Current HS and college nontraumatic fatality rates are significantly higher than rates of traumatic fatalities. The 2003 NCAA out-of-season model has failed to significantly reduce EHS fatalities. The 2010 NCAA SCT screening bylaw has effectively prevented ES with SCT fatalities in NCAA Division I football., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: K.M.F. has received consulting fees from Flexion Therapeutics. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2020.)

Introduction: Sports participation is among the leading causes of catastrophic cervical spine injury (CSI) in the United States. Appropriate prehospital care for athletes with suspected CSIs should be available at all levels of sport. The goal of this project was to develop a set of best-practice recommendations appropriate for athletic trainers, emergency responders, sports medicine and emergency physicians, and others engaged in caring for athletes with suspected CSIs., Methods: A consensus-driven approach (RAND/UCLA method) in combination with a systematic review of the available literature was used to identify key research questions and develop conclusions and recommendations on the prehospital care of the spine-injured athlete. A diverse panel of experts, including members of the National Athletic Trainers' Association, the National Collegiate Athletic Association, and the Sports Institute at UW Medicine participated in 4 Delphi rounds and a 2-day nominal group technique (NGT) meeting. The systematic review involved 2 independent reviewers and 4 rounds of blinded review., Results: The Delphi process identified 8 key questions to be answered by the systematic review. The systematic review comprised 1544 studies, 49 of which were included in the final full-text review. Using the results of the systematic review as a shared evidence base, the NGT meeting created and refined conclusions and recommendations until consensus was achieved., Conclusions: These conclusions and recommendations represent a pragmatic approach, balancing expert experiences and the available scientific evidence.

Sport-related spine injury can be devastating and have long-lasting effects on athletes and their families. Providing evidence-based care for patients with spine injury is essential for optimizing postinjury outcomes. When caring for an injured athlete in American tackle football, clinicians must make decisions that involve unique challenges related to protective equipment (eg, helmet and shoulder pads). The Spine Injury in Sport Group (SISG) met in Atlanta, Georgia, March 2-3, 2019, and involved 25 health care professionals with expertise in emergency medicine, sports medicine, neurologic surgery, orthopaedic surgery, neurology, physiatry, athletic training, and research to review the current literature and discuss evidence-based medicine, best practices, and care options available for the prehospital treatment of athletes with suspected cervical spine injuries.1,2 That meeting and the subsequent Mills et al publication delineate the quality and quantity of published evidence regarding many aspects of prehospital care for the athlete with a suspected cervical spine injury. This paper offers a practical treatment guide based on the experience of those who attended the Atlanta meeting as well as the evidence presented in the Mills et al article. Ongoing research will help to further advance clinical treatment recommendations., (© by the National Athletic Trainers' Association, Inc.)

Background:: Cheerleading is a specialized athletic activity that can lead to catastrophic injuries. Cheerleading rules are in place to maximize safety of participants. The purpose of this study was to describe catastrophic cheerleading injuries among high school and collegiate-level participants in the United States and to explore whether the 2006-2007 basket toss rule change was effective at reducing the number of catastrophic injuries., Hypothesis:: The 2006-2007 basket toss rule change contributed to a reduction in the number of catastrophic injuries among high school and collegiate cheerleaders., Study Design:: Case series., Level of Evidence:: Level 4., Methods:: Data on catastrophic cheerleading injuries were collected by the National Center for Catastrophic Sport Injury Research from July 2002 to June 2017. Information collected included cheerleader, event, and injury characteristics. The impact of the 2006-2007 rule change banning the basket toss on any hard surfaces was assessed by comparing injury rates and 95% CIs before and after the rule change., Results:: There were 54 catastrophic cheerleading injuries, or 3.6 injuries per year. From July 2002 through June 2017, the injury rate was 2.12 per 1,000,000 cheerleaders (95% CI, 1.56-2.69). Most cheerleaders sustained serious injuries (n = 27; 50%) during practice (n = 37; 69%) to the head (n = 28; 52%) and cervical spine (n = 17; 32%). From July 2002 through June 2017, basket tosses were the stunt that accounted for the highest proportion of injuries (n = 19; 35%). The basket toss injury rate decreased from 1.55 to 0.40 per 1,000,000 cheerleaders among both high school and collegiate cheerleaders after the rule change., Conclusion:: Catastrophic injury rates in cheerleading decreased dramatically after the 2006-2007 rule change banning basket tosses from being performed on any hard surfaces. In particular, there was a nearly 4-fold reduction in the rate of catastrophic basket toss injuries.

Background: Patellofemoral pain is one of the most common forms of knee arthralgia in adolescent females. Unlike in adults, in whom the etiology of patellofemoral pain is considered to be multifactorial (eg, altered bone shape and musculoskeletal dynamics), the etiology of adolescent patellofemoral pain has been historically attributed to overuse. Although it is highly plausible that adolescent patellofemoral pain results from excessive maltracking, as suggested by recent research, an increase in patellar, relative to femoral, size could also contribute to patellofemoral pain through altered cartilage stresses/strains, resulting in overloading of the subchondral bone. Because the role of bone morphology in the genesis of patellofemoral pain in adolescent females remains largely unknown, research is needed in this area to improve our understanding of patellofemoral pain and advance diagnosis/treatment., Questions/purposes: (1) Are patellar volume and width increased, and femoral trochlear width decreased, in female adolescents with patellofemoral pain compared with asymptomatic females? (2) Are measures of patellofemoral size correlated with patellofemoral tracking?, Methods: Twenty adolescent females with patellofemoral pain (age, 13.7 ± 1.3 years) and 20 asymptomatic female control participants (age, 13.6 ± 1.3 years) were enrolled in this case-control institutional review board-approved study. This study focused on a strict definition of patellofemoral pain, peripatellar pain in the absence of other structural pathologic conditions (eg, tendinitis, ligament injury, Osgood-Schlatter disease) or a history of dislocations/trauma. Control participants with no history of patellofemoral pain or other lower extremity pathology were matched for age (within 6 months) and body mass index (within 5 kg/m). Participants self-referred and were recruited through clinicaltrails.gov, printed advertisements, and word of mouth. Three-dimensional (3-D), static, T1-weighted, gradient recalled echo MR images were acquired, from which 3-D patellofemoral models were created. Patellar volume and width, patellar-to-femoral volume and width ratios, and femoral trochlear width were compared across cohorts. In addition, 3-D patellofemoral tracking was quantified from dynamic MR images captured during cyclical flexion-extension volitional movements of the lower extremity. The size measures and ratios were correlated to patellofemoral tracking., Results: Compared with control participants, the cohort with patellofemoral pain had greater patellar volume (13,792 ± 2256 versus 11,930 ± 1902 mm; 95% confidence interval [CI], 1336 mm; p = 0.004; d = 0.89) and width (38.4 ± 3.0 versus 36.5 ± 2.7 mm; 95% CI, 1.8 mm; p = 0.021; d = 0.67). The femoral trochlear width was smaller (32.0 ± 1.8 versus 32.9 ± 1.8 mm; p = 0.043, d = 0.54). The patellar-to-femoral volume ratio and the patellar-to-trochlear width ratio were greater in adolescents with patellofemoral pain (0.15 ± 0.02 versus 0.13 ± 0.01, p = 0.006, d = 0.83 and 1.20 ± 0.09 versus 1.11 ± 0.09, p = 0.001, d = 1.02). No correlations were found between patellar size and patellofemoral tracking (r < 0.375, p > 0.103)., Conclusions: In adolescent females with patellofemoral pain, the increased patellar volume/width and patellar-to-trochlear width ratio, along with the decreased femoral trochlear width, may initiate a pathway to pain through improper engagement of the patella within the femoral trochlea. Specifically, the mean differences between cohorts in patellar and femoral trochlear width (1.9 mm and 0.9 mm) are 58% and 37% of the mean patellar and femoral cartilage thickness in females, respectively, as reported in the literature. Further studies are needed to fully elucidate the mechanism of pain., Level of Evidence: Level III, prognostic study.

Background: Although eye injuries constitute a small percentage of high school and college sports injuries, they have the potential to be permanently debilitating., Hypothesis: Eye injury rates will vary by sport, sex, and between the high school and college age groups., Study Design: Descriptive epidemiology study., Level of Evidence: Level 3., Methods: Data from eye injury reports in high school and college athletes were obtained from the National High School Sports-Related Injury Surveillance System, High School Reporting Information Online (HS RIO) database over a 10-year span (2005-2006 through 2014-2015 school years) and the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) over an 11-year span (2004-2005 through 2014-2015 school years). Injury rates per 100,000 athlete-exposures (AEs), injury rate ratios (RRs), and 95% CIs were calculated. Distributions of eye injuries by diagnosis, mechanism, time loss, and surgery needs were also examined., Results: A total of 237 and 273 eye injuries were reported in the HS RIO and the NCAA ISP databases, respectively. The sports with the highest eye injury rates (per 100,000 AEs) for combined high school and college athletes were women's basketball (2.36), women's field hockey (2.35), men's basketball (2.31), and men's wrestling (2.07). Overall eye injury rates at the high school and college levels were 0.68 and 1.84 per 100,000 AEs, respectively. Eye injury rates were higher in competition than practice in high school (RR, 3.47; 95% CI, 2.69-4.48) and college (RR, 3.13; 95% CI, 2.45-3.99). Most injuries were contusions (high school, 35.9%; college, 33.3%) and due to contact (high school, 89.9%; college, 86.4%). Only a small percentage of injuries resulted in time loss over 21 days (high school, 4.2%; college, 3.0%)., Conclusion: Eye injury rates and patterns vary by sport, sex, and between the high school and college age groups. Although severe injuries do occur, most eye injuries sustained by high school and college athletes are minor, with limited time loss and full recovery., Clinical Relevance: Additional focus needs to be placed on preventing eye injuries at the collegiate level in women's and men's basketball, women's field hockey, and men's wrestling.

Background: The tibial tubercle to trochlear groove (TT-TG) distance is used for screening patients with a variety of patellofemoral joint disorders to determine who may benefit from patellar medialization using a tibial tubercle osteotomy. Clinically, the TT-TG distance is predominately based on static imaging with the knee in full extension; however, the predictive ability of this measure for dynamic patellar tracking patterns is unknown., Purpose: To determine whether the static TT-TG distance can predict dynamic lateral displacement of the patella., Study Design: Cohort study (Diagnosis); Level of evidence, 2., Methods: The static TT-TG distance was measured at full extension for 70 skeletally mature subjects with (n = 32) and without (n = 38) patellofemoral pain. The dynamic patellar tracking patterns were assessed from approximately 45° to 0° of knee flexion by use of dynamic cine-phase contrast magnetic resonance imaging. For each subject, the value of dynamic lateral tracking corresponding to the exact knee angle measured in the static images for that subject was identified. Linear regression analysis determined the predictive ability of static TT-TG distance for dynamic patellar lateral displacement for each cohort., Results: The static TT-TG distance measured with the knee in full extension cannot accurately predict dynamic lateral displacement of the patella. There was weak predictive ability among subjects with patellofemoral pain ( r 2 = 0.18, P = .02) and no predictive capability among controls. Among subjects with patellofemoral pain and static TT-TG distances 15 mm or more, 8 of 13 subjects (62%) demonstrated neutral or medial patellar tracking patterns., Conclusion: The static TT-TG distance cannot accurately predict dynamic lateral displacement of the patella. A large percentage of patients with patellofemoral pain and pathologically large TT-TG distances may have neutral to medial maltracking patterns.

Background: Patellofemoral pain (PFP) is a prevalent disorder among female adolescents. Overuse is frequently cited as the cause of pain for this population. What is currently unclear, however, is if the patella demonstrates abnormal tracking patterns relative to the femoral trochlear groove in female adolescents with PFP., Purpose: The aim of this case-control study was to determine if abnormal patellar tracking patterns are present in female adolescents with PFP. The secondary aim was to identify if an increased tibial tuberosity-trochlear groove (TT-TG) distance is associated with the observed kinematic patterns., Study Design: Controlled laboratory study., Methods: Twenty female adolescent knees from 12 patients with PFP and 20 age-matched female knees from 13 healthy controls were recruited for this study. Patellofemoral kinematics (eg, lateral patellar displacement) during a repetitive knee extension-flexion maneuver was quantified by dynamic cine phase-contrast magnetic resonance imaging (MRI). Static MRI scans were used to determine the TT-TG distance., Results: Relative to the control cohort, female adolescents with PFP demonstrated significantly greater lateral displacement at 10° (3.2 mm; P < .001), 20° (2.3 mm; P < .001), and 30° (1.7 mm; P = .014) of knee flexion. A subgroup within this cohort (7 knees from 5 patients) demonstrated extreme lateral maltracking >2 SDs of the mean of the control cohort. This subgroup also demonstrated a greater TT-TG distance relative to the controls (Δ = 4.2 mm; P = .001)., Conclusion: This study demonstrates abnormal lateral patellar displacement in the absence of patellar tilt in female adolescents with PFP. Because all adolescents from both cohorts participated in impact sports, it appears that rigorous athletic training alone is inadequate to produce symptoms in this population. Rather, PFP may derive from a combination of physical activity in the context of pathological kinematics., Clinical Relevance: Abnormal patellar tracking patterns and abnormal static alignment have been shown to contribute to the etiology of patellofemoral pain in adults. This study demonstrates that pathologic patellar tracking patterns are present in adolescent females with patellofemoral pain.

Background: The distance between the tibial tubercle (TT) and trochlear groove (TT-TG distance) is known to be greater in patients with patellar instability. However, the potential role and prevalence of pathological TT-TG distances in a large cohort of skeletally mature patients with isolated patellofemoral pain (PFP) are not clear., Purpose: To determine if the mean TT-TG distance is greater in patients with PFP, who lack a history of patellar dislocations, knee trauma, or osteoarthritis, relative to healthy controls., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A total of 50 knees (38 patients) with PFP and 60 knees (56 controls) without PFP formed the basis of this study. Magnetic resonance imaging was used to determine the TT-TG distance from 3-dimensional static scans., Results: The cohort with PFP demonstrated a significantly greater mean TT-TG distance relative to asymptomatic controls (13.0 vs 10.8 mm, respectively; P = .001). Among the cohort with PFP, 15 knees (30%) demonstrated TT-TG distances ≥15 mm, and 3 knees (6%) demonstrated TT-TG distances ≥20 mm., Conclusion: Most adult patients with isolated PFP have elevated TT-TG distances compared with controls, which likely contributes to the force imbalance surrounding the knee.

Background: Patellofemoral pain is one of the most common conditions seen in sports medicine practices, particularly among adolescent females. However, the natural history of the underlying pathology in patellofemoral pain during puberty remains poorly understood., Purpose: The purpose of this longitudinal study is to assess changes in patellar maltracking patterns in subjects with patellofemoral pain as they mature from mid- to late adolescence., Study Design: Cohort study; Level of evidence, 3., Methods: Three-dimensional patellofemoral kinematic data were acquired during active knee extension-flexion using dynamic magnetic resonance imaging in 6 girls (10 knees; mean age, 14.0 years) with clinically diagnosed patellofemoral pain. The subjects then returned as late adolescents (mean age, 18.5 years) for follow-up scanning. Three-dimensional patellofemoral kinematic parameters were evaluated across the range of motion, but comparison between time points was restricted to 10° of flexion. Participation in impact and nonimpact physical activities, pain score based on the visual analog scale, and the anterior knee pain score were also compared across initial and follow-up visits., Results: All subjects reported improved patellofemoral pain symptoms at follow-up, and one subject reported complete resolution. However, relative to the initial visit, no differences were found in patellar maltracking. There was a decrease in hours engaged in impact physical activities for all subjects at follow-up., Conclusion: This study provides insight into the natural history of patellofemoral pain in adolescent females. The relatively unchanged patellofemoral maltracking across subjects suggests that potential anatomic and kinematic abnormalities contributing to patellofemoral pain during mid-adolescence persist during skeletal maturation. Symptom improvement for these subjects did not result from a change in patellofemoral tracking, but rather from other causes., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This research was supported by the Intramural Research Program of the National Institutes of Health (NIH), Clinical Center, Functional and Applied Biomechanics Section.

Background: As the most viable method for investigating in vivo anterior cruciate ligament (ACL) rupture, video analysis is critical for understanding ACL injury mechanisms and advancing preventative training programs. Despite the limited number of published studies involving video analysis, much has been gained through evaluating actual injury scenarios., Methods: Studies meeting criteria for this systematic review were collected by performing a broad search of the ACL literature with use of variations and combinations of video recordings and ACL injuries. Both descriptive and analytical studies were included., Results: Descriptive studies have identified specific conditions that increase the likelihood of an ACL injury. These conditions include close proximity to opposing players or other perturbations, high shoe-surface friction, and landing on the heel or the flat portion of the foot. Analytical studies have identified high-risk joint angles on landing, such as a combination of decreased ankle plantar flexion, decreased knee flexion, and increased hip flexion., Conclusions: The high-risk landing position appears to influence the likelihood of ACL injury to a much greater extent than inherent risk factors. As such, on the basis of the results of video analysis, preventative training should be applied broadly. Kinematic data from video analysis have provided insights into the dominant forces that are responsible for the injury (i.e., axial compression with potential contributions from quadriceps contraction and valgus loading). With the advances in video technology currently underway, video analysis will likely lead to enhanced understanding of non-contact ACL injury.

Background: There is limited information on the relationship between football helmet fit and concussion severity., Hypothesis: Poor helmet fit may predispose football players to a more severe concussion., Study Design: Descriptive epidemiology study., Level of Evidence: Level 3., Methods: Data from concussion injury reports were obtained from the National High School Sports-Related Injury Surveillance System over a 9-year period. Symptoms, duration, and helmet parameters (fit, interior padding) were analyzed for all first-time concussions., Results: Data from 4580 concussions were analyzed. Patients who suffered concussions with a helmet that did not fit properly (3.22%), as determined by an athletic trainer, had higher rates of drowsiness (RR, 1.46; P = 0.005), hyperexcitability (RR, 2.38; P = 0.047), and sensitivity to noise (RR, 1.88; P < 0.001); had more symptoms (5.34 vs 4.54, P = 0.004); and had longer symptom duration (P = 0.04). Athletes with helmets lined with an air bladder had greater rates of sensitivity to light (RR, 1.13; P = 0.02), sensitivity to noise (RR, 1.25; P = 0.009), and longer symptom duration (P = 0.004) compared with foam or gel liners., Conclusion: An improperly fitted football helmet is a risk factor for a concussion with more symptoms and of longer duration. Concussions of longer duration are also more common in players with an air bladder-lined helmet. Current high school football rules should mandate supervision and maintenance of helmet fit throughout the season, prior to impact., Clinical Relevance: Team physicians, athletic trainers, coaches, and high school officials should ensure proper oversight of helmet fit in high school athletes to decrease concussion severity and duration., (© 2016 The Author(s).)

Background: Fatalities in football are rare but tragic events., Purpose: The purpose was to describe the causes of fatalities in high school and college football players and potentially provide preventive strategies., Study Design: Descriptive epidemiology study., Methods: We reviewed the 243 football fatalities reported to the National Center for Catastrophic Sports Injury Research from July 1990 through June 2010., Results: Football fatalities averaged 12.2 per year, or 1 per 100,000 participants. There were 164 indirect (systemic) fatalities (average, 8.2 annually [or 0.7 per 100,000 participants]) and 79 direct (traumatic) fatalities (average, 4.0 annually [or 0.3 per 100,000 participants]). Indirect fatalities were 2.1 times more common than direct fatalities. The risk of a fatality in college compared with high school football players was 2.8 (95% CI, 0.7-8.2) times higher for all fatalities, 3.6 (95% CI, 2.5-5.3) times higher for indirect events, 1.4 (95% CI, 0.6-3.0) times higher for direct injuries, 3.8 (95% CI, 1.8-8.3) times higher for heat illness, and 66 (95% CI, 14.4-308) times higher for sickle cell trait (SCT) fatalities. Most indirect events occurred in practice sessions; preseason practices and intense conditioning sessions were vulnerable periods for athletes to develop heat illness or SCT fatalities, respectively. In contrast, most brain fatalities occurred during games. The odds of a fatality during the second decade, compared with the first decade of the study, were 9.7 (95% CI, 1.2-75.9) for SCT, 1.5 (95% CI, 0.8-2.9) for heat illness, 1.1 (95% CI, 0.8-1.7) for cardiac fatalities, and 0.7 (95% CI, 0.4-1.2) for brain fatalities. The most common causes of fatalities were cardiac failure (n = 100, 41.2%), brain injury (n = 62, 25.5%), heat illness (n = 38, 15.6%), SCT (n = 11, 4.5%), asthma and commotio cordis (n = 7 each, 2.9% each), embolism/blood clot (n = 5, 2.1%), cervical fracture (n = 4, 1.7%), and intra-abdominal injury, infection, and lightning (n = 3, 1.2% each)., Conclusion: High school and college football have approximately 12 fatalities annually with indirect systemic causes being twice as common as direct blunt trauma. The most common causes are cardiac failure, brain injury, and heat illness. The incidence of fatalities is much higher at the college level for most injuries other than brain injuries, which were only slightly more common at the college level. The risk of SCT, heat-related, and cardiac deaths increased during the second decade of the study, indicating these conditions require a greater emphasis on diagnosis, treatment, and prevention.

Background: A prior review of catastrophic pole vaulting injuries from 1982 through 1998 revealed an average of 2.0 injuries per year, with 69% (1.38 per year) of the injuries secondary to athletes landing off the sides or back of the landing pad and 25% (0.5 per year) from athletes landing in the vault box. In 2003, several rule changes for the sport of pole vaulting were mandated, including enlarging the minimum dimensions of the landing pad., Hypothesis/purpose: Our goals were to (1) identify the post-2003 rule change incidence and profile of catastrophic pole vaulting injuries through 2011 and compare them, where possible, with the prior incidence and profile and (2) determine, via a questionnaire, the frequency with which pole vaulters land in the vault box. We hypothesized that the new, larger landing pads would reduce the number of catastrophic injuries., Study Design: Descriptive epidemiology study., Methods: We prospectively reviewed all catastrophic pole vaulting injuries (ie, brain hemorrhage; skull, spine, or pelvic fracture; substantial pulmonary or intra-abdominal injury) in the United States from 2003 through 2011, surveyed 3335 pole vaulters to determine the frequency of landing in the vault box, and compared results with those in the literature., Results: From 2003 to 2011, 19 catastrophic injuries occurred (average of 2.1 per year), with the majority (n = 14, 74%, 1.55 per year) landing in or around the vault box. Four (21%, 0.44 per year) injuries occurred when an athlete landed off the sides or back of the landing pad and 1 (5%) when the pole broke. There were 11 (58%) major head injuries (1 fatality), 4 (21%) spine fractures (1 with paraplegia), 2 (11%) pelvic fractures (both with intra-abdominal injuries), 1 (5%) brain stem injury (fatal), and 1 (5%) thoracic injury (rib fractures and pneumothorax). The annual fatality rate fell from 1.0 in the prior study to 0.22 in the current study. According to the pole vaulters survey, during their careers, 77.12% (n = 2572) landed in the vault box 1 to 3 times, 15.92% (n = 531) never landed in the vault box, 6.12% (n = 204) landed in the vault box 4 to 6 times, and 0.84% (n = 28) landed in the vault box 7 or more times., Conclusion: The 2003 rule changes have markedly reduced the number of catastrophic injuries, especially fatalities, from pole vaulters missing the back or sides of the landing pads; however, the average annual rate of catastrophic injuries from pole vaulters landing in the vault box has more than tripled over the past decade and remains a major problem.

Background: Recent studies have demonstrated that trunk control likely plays a role in anterior cruciate ligament (ACL) injury. Yet, the majority of ACL research remains focused on the lower limb, with limited information on the trunk position at the time of injury., Hypotheses: Athletes experiencing a noncontact ACL injury after a 1-legged landing position their center of mass (COM) more posterior from the base of support (BOS) at initial ground contact in comparison with uninjured athletes. The distance from the COM to the BOS (COM&#95;BOS) is larger in female, as compared with male, athletes during 1-legged landing., Study Design: Case control study; Level of evidence, 3., Methods: Movie captures of 20 athletes performing a 1-legged landing maneuver resulting in a torn ACL were compared with matched (for gender, sport, and activity just before landing) movie captures of 20 athletes performing a similar maneuver that did not result in an ACL disruption (controls). The COM&#95;BOS, trunk(G) angle, and limb(G) angle (both relative to the gravity vector) were measured in the sagittal plane at initial ground-foot contact. A 2-way ANOVA (injury status × gender) was used to examine the hypotheses., Results: There was a significant difference in all 3 measures based on injury status but not on gender. The COM&#95;BOS, normalized by femur length, and limb(G) angle were greater (Δ = 0.9, P < .001 and Δ = 16°, P = .004, respectively), and the trunk(G) angle was smaller (Δ = 12°, P = .016) in the participants who sustained an ACL injury as compared with controls. The average COM was calculated as 38 cm more posterior relative to the BOS in the participants who sustained an ACL injury as compared with controls., Conclusion: Landing with the COM far posterior to the BOS may be a risk factor for noncontact ACL injury and potentially can be addressed in prevention programs.

Background: Compressive and quadriceps forces have been associated with noncontact anterior cruciate ligament (ACL) injury. The purpose of this study was to quantify the relative importance of each load component during noncontact ACL injury., Hypothesis: We hypothesized that the introduction of a quadriceps force lowers the axial compressive force threshold to produce ACL injury., Study Design: Controlled laboratory study., Methods: Six pairs of fresh-frozen cadaveric knees, flexed to 15°, were loaded with axial compression (group A) or compression with a quadriceps force (group B) until failure. All specimens underwent axial compressive loading under displacement control with a time to peak load of 50 msec. The initial displacement of the MTS actuator was 8 mm and was increased in 2-mm increments with successive tests until catastrophic damage of the joint occurred. Failure was determined by a combination of clinical specimen examination and force-displacement data analysis and by dissection and direct visualization after failure was recognized. Differences in failure load between groups were examined using a paired t test (significance, P ≤ .05)., Results: In group A, there were 2 isolated ACL injuries, 2 ACL ruptures combined with a tibial plateau fracture, and 2 isolated tibial plateau fractures. In group B, there were 5 isolated ACL ruptures and 1 tibial plateau fracture. There was a significant difference in the average failure load between groups A and B: 10 832 N (95% confidence interval [CI], 9743-11,604 N) and 6119 N (95% CI, 4335-7903 N), respectively., Conclusion: Isolated compressive forces displayed an ability to produce an ACL injury in this cadaveric model, but the addition of a quadriceps load significantly reduced the compressive force required for ACL injury., Clinical Relevance: Compressive and quadriceps forces contribute to noncontact ACL injury and should be taken into account when developing ACL injury prevention programs and rehabilitation after ACL reconstruction.

Stress fractures of the tarsal navicular, first described in 1970, were initially thought to be rare injuries. Heightened awareness and increased participation in athletics has resulted in more frequent diagnosis and more aggressive treatment. The vascular supply of the tarsal navicular results in a relatively avascular zone in the central one-third, which experiences severe compressive forces during explosive manoeuvers such as jumping and sprinting. Repetitive activities can result in stress reactions or even fracture. Patients often initially complain of vague midfoot pain localized to the medial border of the foot. The pain is usually exacerbated by activity and relieved with rest. The diagnosis of tarsal navicular stress fracture is challenging because of the high false negative rate of plain radiographs. Additional diagnostic testing with bone scan, CT and MRI are often required for diagnosis. The proper treatment of tarsal navicular stress fractures has become a topic of debate as surgical intervention for these injuries has increased. In a recent meta-analysis, Torg et al. found that 96% of tarsal navicular stress fractures treated with non-weight-bearing (NWB) conservative treatment for 5 weeks went on to successful outcomes. However, only 44% of patients treated with weight-bearing (WB) conservative treatment had successful outcomes. Surgical treatment resulted in successful outcome in 82% of patients. Interestingly, the meta-analysis also found that fracture type did not correlate with outcomes, regardless of treatment. The meta-analysis also found no difference in time to return to activity between patients treated surgically and those who underwent NWB conservative treatment. The recent literature indicates that patients are undergoing surgery or are receiving WB conservative management as a first-line treatment option with the expectation that they will return to their activity more quickly. Although surgical treatment seems increasingly common, the results statistically demonstrate an inferior trend to conservative NWB management. Conservative NWB management is the standard of care for initial treatment of both partial and complete stress fractures of the tarsal navicular. WB conservative treatment and surgical intervention are not recommended.

Significant advances have recently been made in understanding the mechanisms involved in noncontact anterior cruciate ligament (ACL) injury. Most ACL injuries involve minimal to no contact. Female athletes sustain a two- to eightfold greater rate of injury than do their male counterparts. Recent videotape analyses demonstrate significant differences in average leg and trunk positions during injury compared with control subjects. These findings as well as those of cadaveric and MRI studies indicate that axial compressive forces are a critical component in noncontact ACL injury. A complete understanding of the forces and risk factors associated with noncontact ACL injury should lead to the development of improved preventive strategies for this devastating injury.

The incidence of catastrophic cervical spine injury in sports is low compared with other injuries. However, cervical spine injuries necessitate delicate and precise management, often involving the combined efforts of a variety of health care providers. The outcome of a catastrophic cervical spine injury depends on the efficiency of this management process and timeliness of transfer to a controlled environment for diagnosis and treatment. The objective of the National Athletic Trainers' Association (NATA) position statement on the acute care of the cervical spine-injured athlete is to provide the certified athletic trainer, team physician, emergency responder, and other health care professionals with recommendations on how to best manage a catastrophic cervical spine injury in an athlete. Recommendations are based on current evidence pertaining to prevention strategies to reduce the incidence of cervical spine injuries in sport; emergency planning and preparation to increase management efficiency; maintaining or creating neutral alignment in the cervical spine; accessing and maintaining the airway; stabilizing and transferring the athlete with a suspected cervical spine injury; managing the athlete participating in an equipment-laden sport such as football, hockey, or lacrosse; and imaging considerations in the emergency department.

Background: The mechanisms of noncontact anterior cruciate ligament injury remain undefined. The purpose of this study was to identify the tibiofemoral alignment in the lateral compartment of the knee for three variations of a one-limb landing in noncontact sports activities: the safe, provocative, and exaggerated provocative positions. These positions were chosen on the basis of a previous study that measured the average joint angles of the limb at the point of ground contact for athletes who landed without injury (safe) and those who sustained an anterior cruciate ligament injury (provocative). It was hypothesized that, in the provocative positions, altered tibiofemoral alignment predisposes the knee to possible subluxation, potentially leading to an anterior cruciate ligament injury., Methods: Magnetic resonance images were acquired for a single knee in twenty-five noninjured athletes for the three landing positions. The angle between the posterior tibial slope and the femur along with three distances (from the tibiofemoral point of contact to [1] the femoral sulcus point, [2] the posterior tibial point, and [3] the most anterior point of the circular posterior aspect of the condyle) were measured for each acquisition., Results: The tibial slope relative to the femur was directed significantly more inferior to superior in the provocative and exaggerated positions than in the safe landing position. Similarly, as the limb transitioned from the safe to the provocative positions, the tibiofemoral joint contact point was significantly closer to the femoral sulcus point and to the most anterior point of the circular posterior portion of the lateral femoral condyle., Conclusions: As the limb moves toward the provocative landing position, the anatomical alignment based on slope and contact characteristics places the knee at possible risk for noncontact anterior cruciate ligament injury. An enhanced understanding of the mechanism of anterior cruciate ligament injury may lead to improved preventative strategies.

Background: The combined positioning of the trunk and knee in the coronal and sagittal planes during non-contact anterior cruciate ligament (ACL) injury has not been previously reported., Hypothesis: During ACL injury female athletes demonstrate greater lateral trunk and knee abduction angles than ACL-injured male athletes and uninjured female athletes., Design: Cross-section control-cohort design., Methods: Analyses of still captures from 23 coronal (10 female and 7 male ACL-injured players and 6 female controls) or 28 sagittal plane videos performing similar landing and cutting tasks. Significance was set at p < or = 0.05., Results: Lateral trunk and knee abduction angles were higher in female compared to male athletes during ACL injury (p < or = 0.05) and trended toward being greater than female controls (p = 0.16, 0.13, respectively). Female ACL-injured athletes showed less forward trunk lean than female controls (mean (SD) initial contact (IC): 1.6 (9.3) degrees vs 14.0 (7.3) degrees, p < or = 0.01)., Conclusion: Female athletes landed with greater lateral trunk motion and knee abduction during ACL injury than did male athletes or control females during similar landing and cutting tasks., Clinical Relevance: Lateral trunk and knee abduction motion are important components of the ACL injury mechanism in female athletes as observed from video evidence of ACL injury.

Athletic competition has long been a known source of spinal injuries. Approximately 8.7% of all new cases of spinal cord injuries in the United States are related to sports activities. The sports activities that have the highest risk of catastrophic spinal injuries are football, ice hockey, wrestling, diving, skiing, snowboarding, rugby, and cheerleading. Axial compression forces to the top of the head can lead to cervical fracture and quadriplegia in any sport. It is critical for any medical personnel responsible for athletes in team sports to have a plan for stabilization and transfer of an athlete who sustains a cervical spine injury.

Recent studies have focused on gender differences in movement patterns as risk factors for ACL injury. Understanding intrinsic and extrinsic factors which contribute to movement patterns is critical to ACL injury prevention efforts. Isometric lower-extremity muscular strength, anthropometrics, and jump-landing technique were analyzed for 2,753 cadets (1,046 female, 1,707 male) from the U.S. Air Force, Military and Naval Academies. Jump-landings were evaluated using the Landing Error Scoring System (LESS), a valid qualitative movement screening tool. We hypothesized that distinct anthropometric factors (Q-angle, navicular drop, bodyweight) and muscle strength would predict poor jump-landing technique in males versus females, and that female cadets would have higher scores (more errors) on a qualitative movement screen (LESS) than males. Mean LESS scores were significantly higher in female (5.34 ± 1.51) versus male (4.65 ± 1.69) cadets (P<.001). Qualitative movement scores were analyzed using factor analyses, yielding five factors, or "patterns", contributing to poor landing technique. Females were significantly more likely to have poor technique due to landing with less hip and knee flexion at initial contact (P<.001), more knee valgus with wider landing stance (P<.001), and less flexion displacement over the entire landing (P<.001). Males were more likely to have poor technique due to landing toe-out (P<.001), with heels first, and with an asymmetric foot landing (P<.001). Many of the identified factor patterns have been previously proposed to contribute to ACL injury risk. However, univariate and multivariate analyses of muscular strength and anthropometric factors did not strongly predict LESS scores for either gender, suggesting that changing an athlete's alignment, BMI, or muscle strength may not directly improve his or her movement patterns.

Athletic events have long been identified as a source of catastrophic spinal injuries. One of the most notorious sports has been American football. At both the amateur and professional level, this collision sport is associated with the highest number of direct catastrophic injuries including cervical spine trauma and quadriplegia. Although modifications in the rules of play and education of players and coaches have significantly diminished the rate of quadriplegia, there remains a need to decrease the number of catastrophic spine injuries in football. Further research related to the prevention and management of athletic cervical spine trauma is necessary.