Sports Injuries

Summer  2000
Volume 11, Number 1

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Sports and recreation are an integral part of life in Colorado. Traumatic brain injury is the leading cause of death and serious injury in sports and recreation related accidents. Many head injuries can be prevented or mitigated through the use of protective helmets. There is still significant work to be done in the areas of helmet design and testing, public awareness and education, and policy formulation in order to maximize head injury prevention.

Introduction. Despite significant efforts to improve safety, traumatic brain injury (TBI) continues to be the leading cause of death and serious injury in most sports and recreational activities. Nationwide, there are an estimated 1.5 to 2.0 million new TBI’s sustained each year from all mechanisms.1, 2 Approximately 230000 people are hospitalized with TBI annually; 50000 die each year, and 80000 are left with long-term disability. Sports and recreation associated TBI’s account for 5% to 20% of all TBI’s, with higher proportions among children, adolescents, and young adults. Thurman et al, estimated that in 1995 there were more than 216000 sports and recreation associated head injuries in the United States.2 They conservatively estimated that nationwide 900 TBI-related deaths occurred annually in association with sports and recreational activities.

Many head injuries are potentially preventable through simple interventions and precautions. For motor vehicle accidents, the leading cause of head injuries in most series, simply wearing a seatbelt and driving responsibly can significantly reduce the incidence of head injury and death, yet only 40% to 70% of people wear seatbelts and 20% to 40% of drivers in fatal accidents are intoxicated.3 Similarly, the incidence and severity of head injury associated with sports and recreational activities can be significantly reduced through the utilization of protective helmets, and through safe responsible participation.

Organized Team Sports. According to estimates by Thurman et al, competitive sports accounted for 111000 head injuries in the US in 1995, with basketball (23908), baseball (20583), and football (20128) as the leading mechanisms.2 The large number of injuries reported for basketball and baseball reflect the large number of overall participants and include a significant number of extracranial head injuries. The US Consumer Product Safety Commission (CPSC) has provided a breakdown of this data with a separate count of concussions to better estimate TBI occurrence.4 According to the CPSC there were an estimated 12589 concussions from football, 9589 from basketball, and 7810 from baseball. Soccer resulted in an estimated 9269 head injuries (5384 concussions), and there were 5303 head injuries (2794 concussions) from hockey nationwide.

Football. Football ranks 1st in frequency and incidence of head injuries among organized competitive sports.5 Concussion or TBI occurs in 5% to 20% of players, or 6.1 concussions per 100 athletes each season, and there are approximately 10 deaths per year from football related head injuries in the US. Helmets have been used routinely in football for many decades, and significant improvements in helmet design in the 1960’s resulted in a decrease in the incidence of serious brain injuries. Following the introduction and widespread use of rigid shell helmets there was unfortunately an increase in serious cervical spine injuries, as players began to use the helmets as a battering ram. With the introduction of rules prohibiting “spear tackling”, the rise in cervical spine injuries ceased. As the level of intensity continues to increase on the playing field, brain injuries remain a significant problem for football players. Additional helmet design improvements, such as the Procap cover placed over the helmet to mitigate impact forces, are under study in the hopes of further reducing the incidence and severity of head injuries in football.

Soccer. Soccer is the most popular team sport in the world, and is growing rapidly in popularity in the US. Head injuries constitute approximately 10% of all soccer related injuries, and estimates of the incidence for concussion range from 1.6 per 100 athletes5 to 0.6 per 1000 athlete-exposures.6 With increased awareness of and interest in soccer related brain injury, there is significant controversy with regard to recommendations for protective head gear. There is mounting evidence that soccer players are at significant risk for brain injuries, both acute and chronic, through several potential mechanisms. Repetitive blows from heading the ball may result in a cumulative effect similar to that seen with boxing. Alternatively, acute concussions, serious brain injury and even death have been reported after single blows from heading, especially with old leather balls that got heavier when wet. Collisions with other players or goalposts, and falls to the ground are other common mechanisms for head injuries.6 Soft lightweight protective headgear could potentially dissipate the force from heading the ball and provide some protection against collisions and falls, without increasing risk to other players or fostering a more aggressive level of play. If the medical and soccer communities can work together toward a consensus recommendation, and develop safe effective headgear to protect the brain of soccer players, then there is significant potential to reduce the incidence and severity of brain injuries associated with soccer.

Ice Hockey. Ice hockey provides an environment extremely conducive to the occurrence of head injuries, with multiple opportunities for high speed collisions with other players, fast moving objects, and unforgiving surfaces. Not surprisingly, head injuries constitute 10% to 40% of all hockey related injuries, with TBI’s accounting for 10% to 15%. The annual incidence of concussions is 3.7 per 100 athletes.5 Following concerns for ocular and dental injuries, full face masks became required for secondary school and collegiate hockey players in the 1970’s and 1980’s. Protective headgear recommendations followed, and helmets are now required at all levels of play. Widespread use of helmets with face masks has essentially eliminated ocular, facial, dental, and extracranial head injuries in amateur leagues, but brain injuries remain a serious concern. With the increased utilization of protective gear, there appears to have been an associated increase in the level of aggressive play and a concomitant rise in the occurrence of concussions and spinal injuries.5 It seems that the hockey helmet is primarily effective in preventing extracranial impact injuries, and is suboptimal in protecting the brain against acceleration/deceleration forces. Perhaps it is time for design improvements in hockey helmets to achieve more dissipation of impact energy and improved absorption of acceleration/deceleration forces. Finally, more strict enforcement of penalties, and intensive education regarding responsible play, limitations of protective equipment, and injury avoidance techniques are necessary to further reduce injury occurrence.

Recreational Sports. In the area of recreational sports, physicians and other health care professionals have the greatest potential to influence helmet use, and thereby decrease head injury rates, through education, public awareness, and direct advice to patients and parents. Unlike organized team sports, there are no requirements for helmet use in recreational activities, and participants are often uninformed or even misinformed regarding the utility of protective head gear.

Recreational sports are an integral part of life for many Coloradans, and the brisk tourism industry brings people from all over the world to enjoy the many recreational opportunities that Colorado offers. In the winter, Colorado ski slopes log more than 10 million skier visits every year,7 and those same slopes host countless mountain bike riders through the summer months. Even more bicyclists ride trails outside of ski areas, or take to the streets and highways throughout Colorado. Rollerbladers and skateboarders can be seen all over the streets, sidewalks, and bike trails throughout our cities, especially as the weather grows warm and sunny. The high country lures the adventurous with ample opportunity for rock or ice climbing, whitewater rafting or kayaking, and horseback riding. Overall these recreational activities can be safe, but injuries do occur, and head injury is by far the leading cause of serious injury and death. Many of these injuries are potentially preventable through the use of helmets, in conjunction with the practice of safe responsible behavior.

In a 3 year study of recreational fatalities in Colorado, the Colorado Department of Public Health and Environment reported climbing, bicycling, and snow skiing as the top 3 causes of recreational fatalities in our state.8 There were 69 deaths from climbing/hiking accidents; 54 (78%) died from falling and 3 were struck by falling objects. Bicycle accidents accounted for 36 fatalities, and there were 32 deaths from snow skiing. Among children in the 0 to 9 years and 10 to 19 years age ranges, bicycle accidents were the leading cause of death. Canoeing/kayaking and rafting resulted in 19 deaths, and horseback riding was the mechanism for 18 fatalities. The cause of death was not reported in this study but we know from other reports that head injury is the most frequent cause of death in trauma related fatalities. For bicycling fatalities head injury is the primary or contributing cause of death in 70% to 80% of fatalities.9 Reports of fatalities from the ski slopes indicate head injury as the cause of death in 50% to 90% of fatalities among skiers and snowboarders.10-14

Serious and fatal head injuries from recreational activities are certainly alarming and often gain attention in the media, but even more alarming are the huge numbers of mild and moderate brain injuries occurring every day from recreational activities. These injuries rarely gain attention from the media or the public, and in fact often are not even reported to medical personnel, yet they can impart lasting effects on the lives of brain injury survivors and their families.

According to estimates there were 105000 head injuries from recreational activities in the US in 1995.2 Playground activities accounted for the largest number (39265), followed by swimming and water sports (16106). Skiing and other snow sports resulted in an estimated 14414 head injuries nationwide. There were 3924 concussions from skiing accidents, and 1334 from snowboarding.4 In-line skating, roller skating, and skateboarding accidents caused 10247 head injuries, and horseback riding accidents resulted in 8341 head injuries; 5048 of those were concussions. There were 2494 mountain bike related head injuries with 1099 concussions. Road bike injuries were considered separately from the other recreational injuries and resulted in 64583 head injuries with 29094 concussions. The magnitude of the problem is staggering, but we can significantly reduce the incidence and severity of head injuries from recreational activities through increased public awareness, education, and promotion of helmet use where appropriate.

Snow Skiing and Snowboarding. Head injuries constitute only 5% to 15% of all injuries from ski and snowboard accidents, yet are the primary cause of serious disabling injuries and death.10-14 There are approximately 10 fatalities per year in Colorado from accidents on the ski slopes,7 and among the fatally injured that we have studied head injury was the cause of death in 87.5%; none were wearing helmets.10 In over 400 skiers and snowboarders with TBI’s serious enough to warrant transfer and admission to our level I trauma center, only 5 were wearing helmets. All 5 patients had mild injuries and made full recoveries despite some very major mechanisms. Our most severely injured helmeted patient to date was a snowboarder who went off a 40-foot cliff and landed on his head, cracking his helmet in half. He sustained a severe concussion (or mild diffuse axonal injury) with loss of consciousness, but had a negative CT scan of the head. He did require inpatient rehabilitation, but ultimately has made a full recovery and is now attending college. All the rest of the helmeted skiers and snowboarders had mild concussions and negative CT scans. Among the unhelmeted only 69% had simple concussions with negative CT scans of the head. The rest had more severe injuries such as cerebral contusions, or subdural, epidural or intracerebral hematomas. Severe TBI, with coma and Glasgow Coma Scale (GCS) score of 3 to 8, occurred in 15% of the unhelmeted skiers and snowboarders with head injuries, and their overall mortality rate after admission to the hospital was 4%.

Our experience with ski and snowboard helmet use is still too limited to draw conclusions regarding effectiveness, but the preliminary data are certainly suggestive of a significant protective effect. As helmet use increases on the ski slopes of Colorado (it has already increased from 1% to 5% in the 1997-98 season to 15% to 35% in the 1999-2000 season), we will be more able to study their effectiveness and will hopefully demonstrate a significant reduction in the incidence and severity of brain injuries. Unfortunately, in the meantime we can only speculate regarding the effectiveness of ski helmets, and as a result there are also speculations regarding their ineffectiveness and risk.

A popular criticism of ski helmets is that they do not provide protection in collisions over 12 to 14 mph. This figure is often cited as a reason not to wear or endorse helmets. This figure comes from a laboratory test in which a helmet is secured to a metal test headform and dropped from a height to achieve a specified impact velocity onto a solid steel anvil.11 The reported impact speeds are misleading if interpreted literally, and helmets are felt to provide effective protection against brain injury at speeds beyond the test velocity. For example, motorcycle helmets are tested at flat anvil impacts of 13.4 mph, yet there is overwhelming clinical evidence that they provide substantial protection against brain injury at much higher speeds.15-17 Similarly, impact velocities specified for bicycle helmets range from 10 to 14 mph, yet again clinical experience clearly indicates significant protection in collisions at higher speeds. Thompson and Patterson found that bicycle helmets reduce the risk of head injury by 85%, brain injury by 88%, and severe brain injury by 75%, and that they are just as effective in collisions involving motor vehicles.18 Finally, the helmeted skiers and boarders in our series who made full recoveries despite major mechanisms, provide direct clinical evidence that ski helmets can afford protection in collisions exceeding 12 to 14 mph. Helmets may not prevent every injury, but in all the cases we have seen to date, they have mitigated potentially fatal or disabling head injuries into fully recoverable injuries.

Another popular argument against the use of helmets has been that they may increase the risk of cervical spine injury, especially in young children because of the added weight to an already disproportionately large head. In a series of 187 skiers and snowboarders with serious spinal injuries19, we found that only 2 were wearing helmets. One snowboarder had a rolling fall, striking his head, shoulder and back. He sustained a T6 compression fracture with no neurologic deficit, and did not have a head injury thanks to his helmet. The other patient was a skier who sustained an L2 burst fracture after a jump. Of 52 cervical injuries none were wearing helmets, and there were no patients with spinal injuries under the age of 13 years. Thus we found no evidence that helmets increase the risk of spinal injuries in children or adults.

There has also been concern that the use of helmets will instill a false sense of security and lead to more aggressive skiing/boarding and more risk taking behavior, which in turn could lead to an increase in injuries. Analogies have been made with ice hockey in which increased use of protective gear resulted in more aggressive play and increased injury rates, and with driving on snow with 4-wheel drive or anti-lock brakes. This phenomenon may indeed occur with some individuals, but with proper education and continued emphasis on individual skier/boarder responsibility the effect should be minimal or absent. Furthermore the analogies are flawed. Hockey is inherently an aggressive competitive sport with expected (even encouraged) violent physical contact, so that when players wear protective gear they simply increase a behavior already integral to the sport. It seems unlikely that a similar effect will occur on the slopes. Skiing is more analogous with bicycling, and there is no evidence that the introduction and now widespread use of bicycle helmets have resulted in increased injury rates. In fact all evidence demonstrates a clear and significant reduction in head injuries with the use of bike helmets.

With regard to the sense of security afforded by 4-wheel drive and anti-lock brakes, these features are in fact performance enhancing, and therefore may be more analogous with shape skis than with ski helmets. Injury rates may in fact increase as shape skis and other performance enhancing equipment allows skiers and snowboarders to advance to higher skill levels more rapidly than ever before. Helmets on the other hand are not performance enhancing and therefore will not, and should not be expected to, decrease the risk of an accident, but instead are protective devices designed to decrease the risk and severity of injury in the event of an accident. In this way they are more analogous to seatbelts and airbags. Most people do not drive more aggressively or take more risks simply because they are wearing a seatbelt or have an airbag, and if we properly educate the public with regards to ski helmets then there will not be an increase in aggressive skiing or risk taking as a result of helmet use.

In a 1999 report, the CPSC determined that ski helmets would potentially address 44% of head injuries in skiers and snowboarders overall, and 53% of head injuries for those under 15 years of age. In the study there were 6 skiers and snowboarders wearing helmets. According to the report, none of the 6 injuries appeared to have been caused by the helmet, and 5 of the injuries appeared to have been mitigated by the use of a helmet. They concluded “that the use of skiing helmets will reduce the risk of head injury associated with skiing and snowboarding”.11 Several other authors studying head injuries in skiers and snowboarders have advocated the use of ski helmets as well,20-24 and a study of ski injuries in Sweden noted more than a 50% reduction in head injuries among helmeted skiers, with a head injury rate of 9% in helmeted skiers compared with 18.6% in the unhelmeted.20 From the available information and our preliminary data, we agree with the conclusion of the CPSC report and feel certain that there is significant potential to reduce the incidence and severity of head injuries on the ski slopes through more widespread use of ski helmets.

Bicycling. Bicycling is an extremely popular recreational activity in Colorado, and the use of bicycles as a mode of transportation is increasing. Each year there are more than 500000 emergency room visits related to bicycle injuries nationwide; 350000 of those injured are children.25 One-third of all emergency room visits for bicycle related injuries, and two-thirds of all hospital admissions are for head injuries.5, 9, 25 An estimated 900 people die each year in the US from bicycle accidents; about 200 of those killed are children under 15 years of age.25 Head injury is the cause of death in 70% to 80% of bicycle related fatalities.9 Bicycle helmets have been shown to reduce the risk of head injury by 85%, brain injury by 88%, and severe brain injury by 75%, and were found to be just as effective in preventing injuries involving collisions with motor vehicles as for any other type of accident.18 According to a CPSC 1999 bicycle helmet use survey, 50% of riders regularly wear bike helmets; 43% reported wearing a helmet all the time and 7% wear a helmet more than half the time they ride.25 About 38% of adults reported regular helmet use, and 69% of children wear helmets regularly, according to their parents. This represents a significant increase in helmet use since the CPSC’s last survey in 1991, in which only 18% of riders wore a helmet regularly. Clearly, education and public awareness efforts have paid off with increased helmet use, but there is still significant room for improvement.

From 1990-1999 there were 515 patients admitted to our level I trauma center in Denver with bicycle related injuries (unpublished data). Only 145 (28.2%) were wearing a helmet at the time of the accident. Of those wearing a helmet 62 (42.8%) suffered a TBI, and 3 died, for a mortality rate of 2.1%. Of those not wearing a helmet, 55.3% sustained a TBI and 3.7% died. Unfortunately, helmet use was lower among our population than noted in the CPSC survey, and helmets reduced the risk of TBI by only 23%. The severity of brain injury was reduced more dramatically by helmets, with a 62% reduction in craniotomies and a 43% reduction in mortality among those wearing helmets. The apparently low reduction in risk of TBI in this group is likely a result of selection bias in which only patients with a significant injury are referred and admitted to our level I trauma center. The low helmet use rate likely results from a combination of the same admission bias and an overall low helmet use rate in the community surrounding our facility. An informal head count revealed that helmet use in the neighborhood around our hospital is about 25%. This compares with helmet use rates as high as 75% to 90% in other regions of the metro area and in mountain communities. Hopefully with continued widespread public awareness and education efforts, and focused efforts toward communities where helmet use is lowest, we can further increase bicycle helmet use and decrease the incidence and severity of brain injuries.

Skates and Skateboards. In-line skates have experienced an explosive rise in popularity in recent years, and skateboards continue to be popular among children and adolescents. In 1997 there were 5450 head injuries from in-line skating accidents and 3295 from skateboard crashes nationwide.4 These numbers are rising rapidly as popularity increases, but unfortunately helmet use is lagging significantly behind. The CPSC reported that two-thirds of in-line skaters do not wear safety gear, which should include helmets, elbow and knee pads, wrist guards and gloves.26 Informal head counts in Denver revealed very low helmet use rates among in-line skaters, ranging only from 5% to 20%, and of 60 injured skaters admitted to our trauma center only one (1.7%) was wearing a helmet.* There is no data yet on the effectiveness of helmets for skaters, but they should provide essentially the same protection for skaters as they do for bicyclists, and we should fully encourage helmet use for all participants.

Horseback Riding, Climbing and Whitewater Sports. At least one-third of equestrian related injuries involve the nervous system, and 90% of those are head injuries.5 The risk of head injury is especially high with competitive riding and jumping. An appropriate well fitting helmet should be worn at all times.

Rock and ice climbing are inherently dangerous activities with substantial risk of head injury from falling or from being struck by a falling object, usually a rock. Helmets should be worn at all times, and it is essential that all participants be properly trained and outfitted.

White water kayaking can place participants in a particularly vulnerable position for a head injury. When a kayak turns over, the paddler will be upside down with their head underwater, still traveling downstream with the kayak until they eject. The head is in position to collide with any rocks in the path, even rocks that are deep enough underwater for an upright kayak to pass over. A helmet should be worn by all whitewater kayakers at all times. Whitewater rafting does not pose as high a risk of head injury as kayaking, but there is still significant risk especially in fast water with big drops and holes. Helmets are advised for any serious whitewater rafting.

Conclusion. Sports and recreation of all kinds are enormously popular in Colorado, and participation continues to increase. There is no way to prevent all injuries, but simple measures can significantly reduce the risk of serious injury. It is especially important to prevent brain injuries since treatment is extremely limited and recovery is often incomplete. We as health care professionals must take the lead in preventing injuries by educating the public, advising our patients, and setting examples. First and most importantly, participants must always play, ski, ride, etc, in a safe and responsible manner. When appropriate one should have proper instruction, and should always stay within his or her limits of ability. Finally, we should continue to endorse and encourage helmet use through education and public awareness, and by setting an example by wearing one ourselves. Helmets can not prevent all brain injuries and we must not become reckless or feel invincible as a result of wearing one, but there can be little doubt that a helmet is the single most effective and simplest method to substantially reduce the risk and severity of brain injury.
 

Address comments and questions to:

A. Stewart Levy, MD
4101 W. Conejos Place, Suite 225
Denver, CO 80204

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