Direct Catastrophic Injury in Sports Abstract Catastrophic sports injuries are rare but tragic events. Direct (traumatic) catastrophic injury results from participating in the skills of a sport, such as a collision in football. Football is associated with the greatest number of direct catastrophic injuries for all major team sports in the United States. Pole vaulting, gymnastics, ice hockey, and football have the highest incidence of direct catastrophic injuries for sports in which males participate. In most sports, the rate of catastrophic injury is higher at the collegiate than at the high school level. Cheerleading is associated with the highest number of direct catastrophic injuries for all sports in which females participate. Indirect (nontraumatic) injury is caused by systemic failure as a result of exertion while participating in a sport. Cardiovascular conditions, heat illness, exertional hyponatremia, and dehydration can cause indirect catastrophic injury. Understanding the common mechanisms of injury and prevention strategies for direct catastrophic injuries is critical in caring for athletes. I n the United States, approximate- ly 10% of all brain injuries and 7% of all new cases of paraplegia and quadriplegia are related to athletic activity. 1 Information on catastroph- ic injuries in athletes is collected by the National Center for Catastroph- ic Sports Injury Research (NCCSIR), the United States Consumer Prod- uct Safety Commission (CPSC), and other organizations (Table 1). The NCCSIR defines catastrophic sports injury as “any severe spinal, spinal cord, or cerebral injury incurred dur- ing participation in a school/college sponsored sport.” 1 Injuries are classified by the NCCSIR as direct, resulting from participating in the skills of a sport (ie, trauma from a collision), or indi- rect, resulting from systemic failure caused by exertion while participat- ing in a sport. Direct and indirect in- juries are subdivided into three cat- egories: serious, nonfatal, and fatal. A serious injury is a severe injury with no permanent functional dis- ability (eg, a fractured cervical verte- bra without paralysis). 1 A nonfatal injury is any injury in which the ath- lete suffers a permanent, severe, functional disability. Indirect deaths in athletes are predominantly caused by cardiovascular conditions, such as hypertrophic cardiomyopathy and coronary artery disease. Concus- sions are not considered catastroph- ic injuries by the NCCSIR. However, their frequency and potential for long-term sequelae warrant discus- sion. The CPSC operates a statistically valid injury and review system known as the National Electronic In- Barry P. Boden, MD Dr. Boden is Adjunct Associate Professor of Surgery, Uniformed Services, University of the Health Sciences, Bethesda, MD, and Orthopaedic Surgeon, The Orthopaedic Center, Rockville, MD. Neither Dr. Boden nor the department with which he is affiliated has received anything of value from or owns stock in a commercial company or institution related directly or indirectly to the subject of this article. Reprint requests: Dr. Boden, The Orthopaedic Center, 9711 Medical Center Drive, #201, Rockville, MD 20850. JAmAcadOrthopSurg2005;13:445- 454 Copyright 2005 by the American Academy of Orthopaedic Surgeons. Volume 13, Number 7, November 2005 445 jury Surveillance System. Their esti- mates are calculated using data from a sample of hospitals that are repre- sentative of emergency departments in the United States. The CPSC does not provide data on injury specifics, nor does it include information on injuries that are initially presented to physicians. The National Collegiate Athletic Association (NCAA) and the National Federation of State High School Associations (NFSH) review injury epidemiology annually and publish a rules book for each sport with the intent of promoting safe play. Epidemiology For all sports followed by the NCCSIR, the total incidence of direct and indirect catastrophic injuries is 1 per 100,000 high school athletes and 4 per 100,000 college athletes. 2 The combined fatality rate for direct and indirect injuries is 0.40 per 100,000 high school athletes and 1.42 per 100,000 collegiate athletes. 2 Football is associated with the greatest num- ber of direct catastrophic injuries for all major team sports. Football, pole vaulting, gymnastics, and ice hockey have the highest incidence of direct catastrophic injuries per 100,000 male participants. 2 Cheerleading is associ- ated with the highest number of di- rect catastrophic injuries for all sports in which females participate. 2 Direct Injury Football Head Injury Football is associated with the highest number of severe head and neck injuries per year for all high school and college sports. 2 Head in- juries are the most common direct cause of death among football play- ers, accounting for 69% of all foot- ball fatalities (497/714) from 1945 through 1999. 3 Most of the fatalities were associated with subdural he- matomas (86%) and occurred in high school athletes (75%) during game situations (61%). 3 The greatest num- ber of brain injury–related fatalities occurred from 1965 through 1969. There has been a dramatic decrease in brain injury–related fatalities over the subsequent three decades. A ma- jor factor in the decline of head inju- ries since the 1960s is improved hel- met design and the establishment of safety standards by the National Op- erating Committee on Standards for Athletic Equipment. Improved med- ical care and technology also likely are responsible for the decline in fa- talities. Nonfatal head injuries are ex- tremely common in football; nearly 900 concussions were reported in the National Football League be- tween 1996 and 2001. 4 New data re- veal that the great majority of inju- ries occurred to the player being tackled. 4 Often the concussed player was hit from the side on the lower half of the face by the crown of an opponent’s helmet. New football helmets with better padding around the ear and jaw are currently being tested (Figure 1). Cervical Injury Although the incidence of head injury−related fatalities began to de- cline in the early 1970s, the number of cases of permanent cervical quad- riplegia continued to rise. This change likely is because of the im- proved helmets, which allowed tack- lers to strike an opponent using the crown of the head with less fear of self-induced injury. Torg et al 5 were instrumental in reducing the rate of quadriplegic events by demonstrating that spear-tackling a player with the top of the head is the major cause of permanent cervical quadriplegia (Fig- ure 2). When the neck is flexed 30°, the cervical spine becomes straight and the force of the impact is trans- mitted directly to the spinal struc- tures. After spearing was banned in 1976, the rate of catastrophic cervi- cal injuries declined dramatically, from 34 in 1976 to 3 in 1992 6,7 (Fig- ure 3). Cervical cord neurapraxia (CCN) is an acute, transient neurologic ep- isode associated with sensory chang- es with or without motor weakness Table 1 Sources of Information on Sport Safety American Association of Cheerleading Coaches and Advisors (AACCA) www.aacca.org U.S. Consumer Product Safety Commission (CPSC) www.cpsc.gov The National Collegiate Athletic Association (NCAA) www.ncaa.org National Center for Catastrophic Sport Injury Research (NCCSIR) www.unc.edu/depts/nccsi/ National Center for Injury Prevention and Control (NCIPC) www.cdc.gov/ncipc/ Centers for Disease Control and Prevention (CDC) www.cdc.gov/ National Federation of State High School Associations (NFHS) www.nfhs.org National Operating Committee on Standards for Athletic Equipment (NOCSAE) www.nocsae.org Pole Vault Safety Certification Board (PVSCB) www.pvscb.com USA Baseball www.usabaseball.com Direct Catastrophic Injury in Sports 446 Journal of the American Academy of Orthopaedic Surgeons or complete paralysis in at least two extremities. 8,9 The estimated preva- lence among football players is 7 per 10,000. 6 Complete recovery usually occurs within 10 to 15 minutes but may take longer. Cervical stenosis is believed to be the primary causative factor predisposing to CCN. The hy- pothesized mechanism of injury is either hyperflexion or hyperexten- sion of the neck causing a pincer- type compression injury to the spi- nal cord. An episode of CCN is not an ab- solute contraindication to return to football. Although published num- bers are too low to make any defin- itive statement, it is unlikely that an athlete who experiences CCN is at risk for permanent neurologic se- quelae with return to play. The over- all risk of a recurrent CCN episode with return to football is slightly more than 50% and is correlated with the canal diameter size. The smaller the canal diameter, the greater the risk of recurrence. 9 The athlete with ligamentous instability; neurologic symptoms lasting more than 36 hours; multiple episodes; or evidence of cord defect, cord edema, or minimal functional reserve on magnetic resonance imaging should not be allowed to return to contact sports. 6 Figure 2 Football player spear-tackling an opponent using the top of the head. (Reprinted with permission from Torg JS, Guille JT, Jaffe S: Injuries to the cervical spine in American football players. J Bone Joint Surg Am 2002;84:112-122.) Figure 3 The decline in cervical quadriplegic events after spear-tackling was banned in 1976. (Reprinted with permission from Torg JS, Guille JT, Jaffe S: Injuries to the cervical spine in American football players. J Bone Joint Surg Am 2002;84:112-122.) Figure 1 New football helmet design that provides more protection to the side of the face. (Reprinted courtesy of Riddell, Inc, Chicago, IL.) Barry P. Boden, MD Volume 13, Number 7, November 2005 447 The Torg-Pavlov ratio, which was developed as a method to assess cer- vical spinal stenosis, eliminates the need to correct for radiographic mag- nification. 6 The ratio is calculated by dividing the diameter of the spinal canal by the anteroposterior width of the vertebral body at the midpoint on the lateral radiograph. A ratio <0.8 was proposed as indicating signifi- cant spinal stenosis. The ratio has a high sensitivity for detecting signif- icant spinal stenosis but a poor pos- itive predictive value. In one study, 40 (32%) of 124 professional football players had a ratio <0.8. 10 Many foot- ball players have large vertebral bod- ies with normal canal dimensions, which may bring the ratio below 0.8. 11 Therefore, the ratio is a poor screening tool for athletic participa- tion. Functional spinal stenosis, de- fined as loss of cerebrospinal fluid around the spinal cord (documented by magnetic resonance imaging or computed tomography myelogra- phy), is a more accurate method of determining spinal stenosis. 12 There is currently no cost- effective tool to screen for athletes at risk for CCN; however, all athletes who experience an episode of CCN should undergo appropriate imaging studies to evaluate the risk of recur- rence. During the preparticipation physical examination, the physician should specifically ask whether an athlete has had a previous head or neck injury in order to provide ap- propriate counseling and return-to- play decisions. Pole Vaulting Pole vaulting is a unique sport in that athletes often land from heights ranging from 10 to 20 feet. Pole vaulting has one of the highest rates of direct, catastrophic injuries per 100,000 participants for all sports monitored by the NCCSIR. 13 The great majority of catastrophic pole vaulting injuries are head injuries occurring in male high school ath- letes. 13 The overall rate of cata- strophic pole vault injuries is ap- proximately 2.0 per year, with 1.0 fatality per year. 13 This is a high number, considering that there are only approximately 25,000 to 50,000 high school pole vaulters each year. Three common mechanisms of injury have been described. 13 The most typical occurs when the vault- er’s body lands on the edge of the landing pad and the head whips off the pad, striking a surrounding hard surface, such as concrete or asphalt. The second most common scenario occurs when the vaulter releases the pole prematurely or does not have enough momentum and lands in the vault or planting box. The third most common mechanism occurs when the vaulter completely misses the pad and lands directly on the sur- rounding hard surface. In response to the high cata- strophic injury rate, both the NCAA and National Federation of State High School Associations (NFHS) decided to increase the minimum pole vault landing pad size from 16' × 12' to 19'8″ × 16'5″ as of January 2003 (Figure 4). Because most inju- ries are caused by the athlete’s com- pletely or partially missing the land- ing pad, this rule change could significantly reduce the number of catastrophic injuries. The rules com- mittee also proposed enforcing a rule established in 1995 that any hard or unyielding surface (eg, concrete, metal, wood, asphalt) around the landing pad must be padded or cush- ioned. A new rule has been adopted placing the crossbar farther back over the landing pad to reduce the chance of an athlete’s landing in the vault or planting box. A painted square in the middle of the landing pad (coaching box) is also being pro- moted and should help train athletes to instinctively land near the center Figure 4 Footprint of high school landing pad after rule change requiring larger landing pad. Illustration also demonstrates recommended coaching box. (Adapted with permission from Boden BP, Mueller FO: Catastrophic injuries in pole-vaulters. Sports Medicine Update Jan-Feb 2003:4-7.) Direct Catastrophic Injury in Sports 448 Journal of the American Academy of Orthopaedic Surgeons of the landing pad. (The athlete’s head and shoulders should land in- side the painted box. Thus, the box allows the pole vaulter and coach to adjust performance variables for effi- ciency and safety.) Other safety mea- sures include marking the runway distances so athletes can better gauge their takeoff and prohibiting the practice of tapping or assisting the vaulter at takeoff. Pole vaulting is a complicated sport that requires extensive training and knowledge- able coaching; therefore, certifica- tion of coaches is encouraged. The value of helmets in reducing head in- juries in high school pole vaulters is controversial. Without conclusive data regarding their protective effect, the use of helmets is optional at this time. Cheerleading Over the past 20 years, cheerlead- ing has evolved into an activity de- manding high levels of skill, athlet- icism, and complex gymnastic maneuvers. In 2002, cheerleading was one of the most popular orga- nized sports activities for girls in high school. Compared with other sports, cheerleading has a low over- all incidence of injury, but there is a high risk of catastrophic injury. At the college and high school levels, cheerleading injuries account for more than half of the catastrophic injuries occurring in female ath- letes. 2 College athletes are more likely to sustain a catastrophic inju- ry than their high school counter- parts, probably because of the in- creased complexity of stunts at the college level. 14 The NCCSIR reports approximately two direct cata- strophic cheerleading injuries per year (0.6 per 100,000 cheerlead- ers). 14 In 2000, the CPSC estimated that there were 1,258 head injuries and 1,814 neck injuries in cheerlead- ers of all ages; 6 were skull fractures and 76, cervical fractures. The most common stunts result- ing in catastrophic injury are the basket toss and the pyramid; the cheerleader at the top of the pyramid is most frequently injured. 14 In the basket toss, the cheerleader is thrown into the air, often between 6 and 20 feet, by three or four tossers (Figure 5). Less common mecha- nisms include advanced floor tum- bling routines, performing on a wet surface, or performing a mount. Most injuries occur when an athlete lands on a hard indoor gym sur- face. 14 The NFHS and NCAA have at- tempted to reduce pyramid injuries by limiting the height and complex- ity of a pyramid and by specifying positions for spotters. (The spotter is the individual who remains on the ground to assist and catch the top person in the pyramid.) Height re- strictions on pyramids are limited to two levels in high school and to 2.5 body lengths in college. The top cheerleaders are required to be sup- ported by one or more individuals (base) who are in direct weight- bearing contact with the performing surface. Spotters must be present for each person extended above shoul- der level. The suspended person is not allowed to be inverted (head be- low horizontal) or to rotate on the dismount. Limiting the number of cheerleaders in a pyramid and taking care during the quick transition be- tween pyramids and other complex stunts also may help reduce injuries. Safety measures have been insti- tuted for the basket toss as well, such as limiting the basket toss to four throwers, starting the toss from the ground level (no flips), and hav- ing one of the throwers positioned behind the top person (flyer) during the toss. The flyer is trained to main- tain a vertical position and to not al- low the head to drop backward out of alignment with the torso or below a horizontal plane with the body. Other preventive measures that may reduce the incidence of basket toss injuries include evaluating the height thrown, using mandatory landing mats for complex stunts, and improving the skills of the spot- ters. Several injuries have been re- ported during rainy weather; thus, all stunts should be restricted in the presence of wet conditions. Injury during floor tumbling routines can be prevented by proper supervision, by progression to complex tumbling only when simple maneuvers are mastered, and by using spotters as necessary. Mini trampolines, spring- boards, or any other apparatus used to propel a participant have been prohibited since the late 1980s. During practice, cheerleading coaches need to devote as much time and attention on the technique Figure 5 Basket toss in cheerleading. (Adapted with permission from Boden BP, Tacchetti R, Mueller FO: Catastrophic cheerleading injuries. Am J Sports Med 2003;31:881-888.) Barry P. Boden, MD Volume 13, Number 7, November 2005 449 and attentiveness of the spotters as on the athletes performing the stunts. Coaches are encouraged to complete a safety certification, espe- cially for any teams that perform pyramids, basket tosses, and/or tum- bling. Pyramids and basket tosses should be limited to experienced cheerleaders who have mastered all other skills. They should not be per- formed without qualified spotters or landing mats. Baseball Similar to cheerleading, baseball has a low rate of noncatastrophic in- juries, but it has a relatively high in- cidence of catastrophic injuries. Head injuries constitute the majori- ty of catastrophic injuries. Approxi- mately two direct catastrophic inju- ries are reported to the NCCSIR each year (0.5 injuries per 100,000 participants). 2,15 The most common mechanism of catastrophic injury in baseball is a collision, either between fielders or between a base runner and a fielder. 15 Proper training is the easiest way to prevent collisions between fielders. When an outfielder and infielder are racing for a ball, the outfielder should call off the infielder. When two infielders are running for a pop- up, the pitcher should determine who catches the ball. Players should be drilled on these techniques in practice sessions so that they be- come instinctual in game situations. Collisions between base runners and fielders often involve the catch- er. A typical scenario is a base run- ner who dives headfirst into a catch- er and sustains an axial compression cervical injury. 15 Baseball rules state that the runner should avoid the fielder because the latter has the right to the base path. Unfortunate- ly, this rule is not always enforced when a base runner is racing toward home plate. Because the speed of headfirst sliding has been shown not to be statistically different from feet- first sliding, the rule allowing head- first sliding should be reassessed at the high school and college levels. 16 In Little League baseball, headfirst sliding is not allowed at any base. The next most common injury mechanism after collisions is a pitcher hit by a batted ball. The pitcher is vulnerable to injury be- cause of the proximity to the batter and from being propelled forward, of- ten off balance, toward the batted ball. Many coaches and concerned parents perceive a problem from non-wood (eg, aluminum) bats and have demanded that regulations be placed on non-wood bats. Their lighter weight allows aluminum bats to be swung faster than wood bats, resulting in a higher ball exit velocity. 17 In response to the poten- tial problem, the NCAA and NFHS now require all high school and col- lege bats to be labeled with a perma- nent certification mark indicating that the ball exit speed ratio cannot exceed 97 miles per hour, as set by the Baum Hitting Machine (Baum- Bat, Traverse City, MI). Other impor- tant new regulations relate to bat thickness and weight: the thickest diameter of the bat (barrel diameter) is restricted to 2.625 in, and the weight of the bat in ounces shall not be less than the length of the bat in inches minus three (ie, a 34-in–long bat cannot weigh less than 31 oz). 18,19 Although these regulations show promise for reducing the num- ber of injuries, no clinical studies to date confirm their effectiveness. In addition to regulating the bat, several other measures are available to protect pitchers. Protective screens (L-screens) are recommend- ed at all times during practice ses- sions. Unfortunately, screens are not practical during game situations. Players and coaches also should be educated about the risk to pitchers, who should have the option of wear- ing protective equipment. Finally, it has been hypothesized that decreas- es in ball hardness and weight may significantly reduce injury severity to players hit by a batted ball. 20 The coefficient of restitution, which is the measure of rebound that a ball has off a hard surface, has been adopted as the testing standard for baseballs. At the high school and collegiate levels, the coefficient of restitution of a baseball cannot ex- ceed 0.555. Another concern in baseball is commotio cordis or arrhythmia, which is often associated with sud- den death from low-impact blunt trauma to the chest in subjects with no preexisting cardiac disease. 21 These incidents occur most com- monly in baseball, but they have been reported to occur in hockey, softball, lacrosse, and other sports. The proposed mechanism of injury is impact just before the peak of the T wave, which induces ventricular fibrillation. Although the rate of res- cue from commotio cordis was ini- tially documented to be extremely low, more recent reports indicate that survival is possible with imme- diate resuscitative measures, such as a precordial thump or use of an auto- matic external defibrillator. 22,23 The pediatric population may be more susceptible to commotio cordis be- cause of the thinner layer of soft tis- sue to the chest wall, increased com- pliance of the immature rib cage, and slower protective reflexes. Preventive measures for commo- tio cordis have focused on chest pro- tectors and soft-core baseballs. 24,25 Unfortunately, neither has been shown to reduce the risk of arrhyth- mia and may in fact exacerbate the force to the chest. Preventive strate- gies are currently limited to teaching youth baseball players to turn the chest away from a wild pitch, a bat- ted ball, or a thrown ball. Further analysis is required of the biome- chanics of commotio cordis and the effectiveness of resuscitative mea- sures, especially with automatic ex- ternal defibrillators. Soccer Injuries to the head, neck, and face account for between 5% and 15% of all injuries in soccer players. Direct Catastrophic Injury in Sports 450 Journal of the American Academy of Orthopaedic Surgeons Most head and neck injuries occur when two players collide, especially when jumping to head the ball. Fa- talities are usually associated with either a movable goalpost falling onto a player or player impact with the goalpost. 26 The CPSC identified at least 21 deaths associated with movable goalposts over a 16-year pe- riod. Goalpost injuries can be pre- vented by never allowing children to climb on the net or the goal frame- work. Soccer goalposts should be se- cured at all times. During the off- season, goals should be either disassembled or placed in a safe stor- age area. Goals should be moved only by trained personnel and should be used only on flat fields. The use of padded goalposts also may reduce the incidence of impact injuries with the posts. 26 Although catastrophic head inju- ries are rare in soccer, the incidence of concussions is relatively high at the elite college level, with approxi- mately one per team per season. 27 Barnes et al 28 reported that male pro- fessional soccer players have a 50% risk of sustaining a concussion over a 10-year span. Most concussions oc- cur as a result of contact with an op- posing player—especially head-to- head collisions—rather than with the soccer ball. 27 No evidence sug- gests that an isolated episode of heading a soccer ball causes head in- jury; however, there is controversy as to whether repetitive heading over a prolonged soccer career can lead to neuropsychological deficits. Until conclusive data show that repetitive heading of a soccer ball causes no long-term damage, it is recommended that children use smaller soccer balls to reduce head impact. Leather or water-soaked soc- cer balls should never be used be- cause of their heavier weight. Prop- er heading techniques also should be taught: contact should be made with the forehead, with the neck muscles contracted. Soccer players should be trained to hit the ball, not to be hit by the ball. A long-term prospective study on the cumulative effects of heading a soccer ball is underway. Wrestling Approximately two direct cata- strophic wrestling injuries occur per year at the high school and college levels (1 per 100,000 participants). 29 There is a trend toward more direct injuries in the lightweight and mid- dleweight classes. The majority of direct catastrophic wrestling injuries are cervical fractures or major cervi- cal ligament injuries. 29 Most injuries occur in match competitions, in which intense, competitive situa- tions place wrestlers at higher risk. 29 The position most frequently as- sociated with injury is the defensive posture during the takedown ma- neuver, followed by the down position (kneeling), and the lying position. 29 There is no clear pre- dominance of any one type of take- down hold that contributes to wrestling injuries. The athlete is typically injured by one of three sce- narios. (1) The wrestler’s arms are in a hold such that he or she is unable to prevent himself or herself from landing on his or her head when thrown to the mat. (2) The wrestler attempts a roll but is landed on by the full weight of the opponent, causing a twisting (usually hyper- flexion) neck injury. (3) The wrestler lands on the top of his or her head, sustaining an axial compression force to the cervical spine. Referees and coaches are critical- ly important in preventing direct catastrophic wrestling injuries. Ref- erees should strictly enforce penal- ties for slams and should gain more awareness of dangerous holds. 29 Stringent penalties for intentional slams or throws are encouraged. The referee should have a low threshold of tolerance for stopping the match during potentially dangerous situa- tions. Coaches can prevent serious injury by emphasizing safe, legal wrestling techniques, such as teach- ing wrestlers to keep the head up during any takedown maneuver to prevent axial compression injury to the cervical spine. 29 Proper rolling techniques, which include avoiding landing on the head, need to be em- phasized in practice sessions. Ice Hockey Although the number of cata- strophic injuries in ice hockey is low compared with other sports, the in- cidence per 100,000 participants is high. 2 Catastrophic accidents from collisions with goal cages were com- mon before the advent of displace- able goal cages. Most recent cata- strophic injuries have been reported to occur in the cervical spine, espe- cially between levels C5 and C7. 30 The most common mechanism of injury is checking from behind and being hurled horizontally into the boards (Figure 6). Contact with the boards typically occurs to the crown of the player’s head, subjecting the neck to an axial load. 30 Head and fa- cial injuries, which are caused by collisions, fighting, and being hit by the puck or stick, also are common. The frequency and severity of head and neck injuries may be re- duced by enforcing current rules against pushing or checking from be- hind, padding the boards, and encour- aging the use of helmets and face masks. In a prospective analysis of fa- cial protection in elite amateur ice hockey players, players wearing no protection were injured twice as of- ten as players wearing partial protec- tion, and nearly seven times more of- ten than those wearing full protection. 31 Eye injuries were nearly five times greater for players with no facial protection compared with those wearing partial protection. Al- though it has been suggested that wearing head and facial protection leads to an increased risk of cata- strophic spinal injury, this has not been substantiated. 31 Aggressive play and fighting also should be discour- aged and penalized appropriately. The “heads up, don’t duck” program teaches players to avoid contact with Barry P. Boden, MD Volume 13, Number 7, November 2005 451 the top of the head when taking a check, giving a check, or sliding on the ice. In the Safety Toward Other Players (STOP) program, a STOP patch is affixed to the back of the jer- sey of amateur athletes as a visual re- minder not to hit an opponent from behind. Swimming Most catastrophic swimming in- juries are related to the racing dive into the shallow end of the pool. 2 The NFHS and NCAA have implemented rules to prevent injury during the rac- ing dive. At the high school level, swimmers must start the race in the water when the depth at the starting end of the pool is <3.5 ft. When the water depth is 3.5 ft to <4 ft at the starting end, the swimmer may start in the water or from the deck. When the water depth at the starting end is ≥4 ft, the swimmer may start from a platform up to 30 in above the water surface. The NCAA requires a min- imum water depth of 4 ft at the start- ing end of the pool. During practice sessions in which platforms may not be available, swimmers are advised to dive into only the deep end of the Figure 6 A and B, An ice hockey player (no. 8) sustaining an axial cervical injury against the boards. (Courtesy of J. S. Torg, MD, Philadelphia, PA.) Table 2 Guidelines on Exercise Restriction for Athletes With Cardiovascular Disease Contraindications to vigorous exercise Hypertrophic cardiomyopathy Idiopathic concentric left ventricular hypertrophy Marfan syndrome Coronary heart disease Uncontrolled ventricular arrhythmia Severe valvular heart disease (especially aortic stenosis and pulmonic stenosis) Coarctation of the aorta Acute myocarditis Dilated cardiomyopathy Congestive heart failure Congenital anomaly of the coronary arteries Cyanotic congenital heart disease Pulmonary hypertension Right ventricular cardiomyopathy Ebstein’s anomaly of the tricuspid valve Idiopathic long QT syndrome Conditions requiring close monitoring and possible restriction Uncontrolled hypertension Uncontrolled atrial arrhythmia Hemodynamic significant valvular heart disease (eg, aortic insufficiency, mitral stenosis, mitral regurgitation) Adapted with permission from 26th Bethesda Conference: Recommendations for determining eligibility for competition in athletes with cardiovascular abnormalities. January 6-7, 1994. J Am Coll Cardiol 1994;24:845-899. Direct Catastrophic Injury in Sports 452 Journal of the American Academy of Orthopaedic Surgeons pool or to jump into the water feet first. Indirect Injury Indirect (nontraumatic) catastrophic injury and death in athletes are pre- dominantly caused by cardiovascu- lar conditions, such as hypertrophic cardiomyopathy, coronary artery anomaly, arrhythmogenic right ven- tricular dysplasia, myocarditis, and dysrhythmia. 32 Noncardiac condi- tions that cause catastrophic indi- rect injuries are heat illness, dehy- dration, exertional hyponatremia, rhabdomyolysis, status asthmaticus, and electrocution caused by light- ning. A complete personal and fam- ily history as well as a physical ex- amination are recommended for all athletes before participating in sports. Participation guidelines for athletes with cardiovascular condi- tions are summarized in Table 2. 33 At the preparticipation physical, the physician should specifically ask whether an athlete has had a previ- ous head or neck injury in order to determine appropriate counseling and make decisions about return to play. Summary Physical activity has numerous health-related benefits. Nonetheless, there is a risk of catastrophic injury in certain organized sports, particu- larly football, pole vaulting, cheer- leading, and ice hockey. The cost to the injured athlete and to society can be great. In addition to the decreased quality of life for the patient, the life- time cost of caring for a complete quadriplegic individual can easily exceed $2 million. 34 It has been esti- mated that the annual aggregate cost of treating patients with sports- related spinal cord injury in the United States in 1995 was close to $700 million. 34 Prevention is the most effective means of reducing the incidence and costs associated with catastrophic head and neck injury in sports. Continued research of the ep- idemiology and mechanisms of cat- astrophic injury is critical to pre- venting these injuries. Acknowledgment The author wishes to thank Freder- ick Mueller, PhD, for sharing data from the NCCSIR. References Evidence-based Medicine: Reported are primarily level III, IV, and V pro- spective cohort, retrospective cohort, and case controlled studies. There have been no level I or II prospective randomized or cohort studies assess- ing the causation or treatment of di- rect catastrophic injury in sports. 1. Mueller FO: Introduction, in Mueller FO, Cantu RC, VanCamp SP (eds): Catastrophic Injuries in High School and College Sports. Champaign, IL: HK Sport Science Monograph Series, 1996, vol 8, pp 1-4. 2. National Center for Catastrophic Sports Injury Research: Twentieth Annual Report, Fall 1982-Spring 2002. Chapel Hill, NC: National Cen- ter for Sports Injury Research, 2002, pp 1-25. 3. Cantu RC, Mueller FO: Brain injury- related fatalities in American foot- ball, 1945-1999. Neurosurgery 2003; 52:846-853. 4. Pellman EJ, Viano DC, Tucker AM, Casson IR, Waeckerle JF: Concussion in professional football: Reconstruc- tion of game impacts and injuries. Neurosurgery 2003;53:799-814. 5. Torg JS, Vegso JJ, O’Neill MJ, Sennett B: The epidemiologic, pathologic, bio- mechanical, and cinematographic analysis of football-induced cervical spine trauma. Am J Sports Med 1990; 18:50-57. 6. Torg JS, Guille JT, Jaffe S: Injuries to the cervical spine in American foot- ball players. J Bone Joint Surg Am 2002;84:112-122. 7. Torg JS, Gennarelli TA: Head and cer- vical spine injuries, in DeLee JC, Drez D Jr (eds): Orthopaedic Sports Medi- cine: Principles and Practice. Phila- delphia, PA: WB Saunders Co, 1994, pp 417-462. 8. Torg JS, Pavlov H, Genuario SE, et al: Neurapraxia of the cervical spinal cord with transient quadriplegia. J Bone Joint Surg Am 1986;68:1354-1370. 9. Torg JS, Naranja RJ Jr, Pavlov H, Gali- nat BJ, Warren R, Stine RA: The rela- tionship of developmental narrowing of the cervical spinal canal to revers- ible and irreversible injury of the cer- vical spinal cord in football players: An epidemiological study. J Bone Joint Surg Am 1996;78:1308-1321. 10. Odor JM, Watkins RG, Dillin WH, Dennis S, Saberi M: Incidence of cer- vical spinal stenosis in professional and rookie football players. Am J Sports Med 1990;18:507-509. 11. Herzog RJ, Wiens JJ, Dillingham MF, Sontag MJ: Normal cervical spine morphometry and cervical spinal stenosis in asymptomatic profession- al football players:Plain film radiogra- phy, multiplanar computed tomogra- phy, and magnetic resonanceimaging. Spine 1991;16:S178-S186. 12. Cantu RC: Functional cervical spinal stenosis: A contraindication to partic- ipation in contact sports. Med Sci Sports Exerc 1993;25:316-317. 13. Boden BP, Pasquina P, Johnson J, Mueller FO: Catastrophic injuries in pole-vaulters. Am J Sports Med 2001; 29:50-54. 14. Boden BP, Tacchetti R, Mueller FO: Catastrophic cheerleading injuries. Am J Sports Med 2003;31:881-888. 15. Boden BP, Tacchetti R, Mueller FO: Catastrophic injuries in high school and college baseball players. Am J Sports Med 2004;32:1189-1196. 16. Kane SM, House HO, Overgaard KA: Head-first versus feet-first sliding: A comparison of speed from base to base. Am J Sports Med 2002;30:834-836. 17. Crisco JJ, Greenwald RM, Blume JD, Penna LH: Batting performance of wood and metal baseball bats. Med Sci Sports Exerc 2002;34:1675-1684. 18. NCAA: 2003 Baseball Rules and In- terpretations. Indianapolis, IN: The National Collegiate Athletic Associa- tion, 2002, pp 20-21. 19. National Federation of State High School Associations: Baseball: 2002 Rules Book. Indianapolis, IN: Nation- al Federation of State High School As- sociations, 2001, p 14. 20. Crisco JJ, Hendee SP, Greenwald RM: The influence of baseball modulus and mass on head and chest impacts: A theoretical study. Med Sci Sports Exerc 1997;29:26-36. 21. Maron BJ, PoliacLC, Kaplan JA, Muel- ler FO: Blunt impact to the chest lead- ing to sudden death from cardiac ar- rest during sports activities. N Engl J Med 1995;333:337-342. Barry P. Boden, MD Volume 13, Number 7, November 2005 453 22. Strasburger JF, Maron BJ: Images in clinical medicine. N Engl J Med 2002; 347:1248. 23. Viano DC, Andrzejak DV, King AI: Fa- tal chest injury by baseball impact in children: A brief review. Clin J Sport Med 1992;2:161-165. 24. Janda DH, Viano DC, Andrzejak DV, Hensinger RN: An analysis of preven- tive methods for baseball-induced chest impact injuries. Clin J Sport Med 1992;2:172-179. 25. Janda DH, Bir CA, Viano DC, Cassatta SJ: Blunt chest impacts: Assessing the relative risk of fatal cardiac injury from various baseballs. J Trauma 1998;44:298-303. 26. Janda DH, Bir C, Wild B, Olson S, Hensinger RN: Goal post injuries in soccer: A laboratory and field testing analysis of a preventive intervention. Am J Sports Med 1995;23:340-344. 27. Boden BP, Kirkendall DT, Garrett WE Jr: Concussion incidence in elite col- lege soccer players. Am J Sports Med 1998;26:238-241. 28. Barnes BC, Cooper L, Kirkendall DT, McDermott TP, Jordan BD, Garrett WE Jr: Concussion history in elite male and female soccer players. Am J Sports Med 1998;26:433-438. 29. Boden BP, Lin W, Young M, Mueller FO: Catastrophic injuries in wres- tlers. Am J Spor ts Med 2002;30:791- 795. 30. Mölsä JJ, Tegner Y, Alaranta H, Myl- lynen P, Kujala UM: Spinal cord inju- ries in ice hockey in Finland and Swe- den from 1980 to 1996. Int J Sports Med 1999;20:64-67. 31. Stuart MJ, Smith AM, Malo- Ortiguera SA, Fischer TL, Larson DR: A comparison of facial protection and the incidence of head, neck, and facial injuries in Junior A hockey players: A function of individual play- ing time. Am J Sports Med 2002;30: 39-44. 32. Maron BJ: Sudden death in young ath- letes. N Engl J Med 2003;349:1064- 1075. 33. 26th Bethesda Conference: Recom- mendations for determining eligibili- ty for competition in athletes with cardiovascular abnormalities. Janu- ary 6-7, 1994. J Am Coll Cardiol 1994; 24:845-899. 34. DeVivo MJ: Causes and costs of spinal cord injury in the United States. Spi- nal Cord 1997;35:809-813. Direct Catastrophic Injury in Sports 454 Journal of the American Academy of Orthopaedic Surgeons . participa- tion. Functional spinal stenosis, de- fined as loss of cerebrospinal fluid around the spinal cord (documented by magnetic resonance imaging or computed tomography myelogra- phy), is a more accurate. induces ventricular fibrillation. Although the rate of res- cue from commotio cordis was ini- tially documented to be extremely low, more recent reports indicate that survival is possible with imme- diate