CNS and Thorax Injury and Associated Risks Factors in Equestrian Sports

Abstract

Context:

Equestrian sports continue to gain popularity in the United States and are associated with a high injury rate, especially involving the central nervous system and thorax. Due to this high rate of injury and the potential for long-term consequences associated with participation, an understanding of the unique risks of this sport is needed.

Objective:

To describe severe injury in equestrian sports and review the role that protective gear plays in injury mitigation.

Data Sources:

The PubMed Database was searched using the search terms “equestrian” and “horse” combined with “spinal cord injury,” “head injury,” “traumatic brain injury,” “experience levels,” and “demographics.”

Study Selection:

A total of 53 papers were selected based on their relevance of epidemiology, risk factors, and management of injuries sustained during equestrian activities. Case studies, randomized controlled trials, prospective studies, and retrospective studies were all included for further review.

Study Design:

Systematic review.

Level of Evidence:

Level 4.

Data Extraction:

None.

Results:

Injuries to the thorax, including fractures, pneumothoraces, internal organ contusions, and crush injuries, have been cited in multiple national and international trauma registries as the most prevalent injury location in equestrians; however, head and neck injuries, high cervical spine fractures, and closed head injuries are reported to be associated with the highest rates of mortality. Helmets provide protection against skull fracture and traumatic brain injury. Vests were not associated with diminished rates of spinal cord injuries; however, they may provide protection to the thorax. Riding experience also plays a role in reducing the prevalence of injury.

Conclusion:

Equestrian-related activities are associated with a high risk of injury despite protective measures. Protective gear can mitigate some injury risk but does not protect against spinal injury. Continued investigation into improving protective equipment, rider education, and preventative strategies to mitigate this risk is needed.

Equestrian sports encompass a wide variety of events, from dressage to high-speed racing, and involve millions of participants worldwide. In the United States (US) alone, an estimated 30 million people ride horses each year, with roughly 2 million participants under the age of 19 years.^29,31 Of these participants, an estimated 1 in 5 will sustain some form of injury while either riding or working with a horse. ³¹ Motorcyclists experience a serious injury once every 7000 hours of riding, whereas equestrians have a serious injury once every 350 hours, demonstrating the high potential for injury while participating in equestrian activities. ⁵² As the sport gains popularity, recreational riding is attracting more riders. These less-experienced riders account for approximately 55% of the injured population. ³⁸ For pediatric patients, equestrian injuries are often severe, and are associated with a higher injury severity score than injuries sustained from bicycle, all-terrain vehicles, or motor vehicle crashes. ³⁴

Participants in equestrian sports are very likely to sustain head injuries, with multiple mechanisms of potential injury possible during routine participation. Along with neck injuries, head injuries are the cause of 74.83% of equestrian deaths. ⁴³ When a rider is mounted, their head is approximately 9 feet (2.74 m) from the ground, creating potential for falls to be from significant heights. In addition, horses can reach speeds of up to 40 mph, increasing the potential for serious head or spinal cord injury. Working with large animals weighing in at up to 1050 lb (476 kg) and capable of producing over 10,000 N of force with a single kick adds an unpredictability that further contributes to the serious head injuries seen with participation in equestrian sports. This unpredictability of the horse is independent from the ability of the rider.^4,26

Studies have shown that 2 out of 3 horseback riding injuries could have been prevented. ¹⁶ Experience and education appear to help riders avoid injury, although rider error and unpredictability of the horse are commonly related to fall injuries. Studies suggest that traumatic brain injuries (TBIs) are more frequent among experienced riders because they were less likely to wear a helmet. ⁴³ Understanding the unique risks associated with equestrian sports is important for sports medicine providers in educating patients and advising on best practices to prevent future accidents.

Methods

A literature review was conducted during April and June 2023 using the PubMed database. Search terms used included “equestrian” and “horse” combined with “spinal cord injury,” “head injury,” “traumatic brain injury,” “experience levels,” and “demographics.” Case studies, randomized controlled trials, prospective studies, and retrospective studies were all included for further review. For each eligible piece of literature, the abstract was reviewed to determine the relevance of the contents regarding epidemiology, risk factors, and management of injuries sustained during equestrian activities. Literature originally published in a language other than English were translated to English using Google Translate software.^6,47 A total of 53 papers were found to meet inclusion criteria and were reviewed by 1 of 2 researchers.

Results

Epidemiology

Equestrian riding is most practiced by White female participants between the ages of 18 and 45 years, and this demographic is most likely to be injured while riding. ¹ When directly comparing rates of injury, sex was not predictive of likelihood of injury, with both male and female riders having the same rate of injury. ⁴³ Musculoskeletal injuries and central nervous system (CNS) injuries, such as concussion, are the most commonly reported injuries.^1,57 More severe injuries are associated while participating as the mounted rider than when handling the horse. ³⁵ One study found within a 12-month period that there was a high prevalence of equestrian-related injuries, with 85.8% of participants reporting symptoms. The National Electronic Injury Surveillance System (NEISS) recorded more than 48,000 equestrian-related injuries that were treated in emergency rooms in 2017. However, the real number of horse-related injuries is estimated to be much higher, as roughly 60 percent of the injured riders did not seek medical attention after being injured.^38,58

In addition to musculoskeletal injuries, CNS injuries are common in equestrian sports. These injuries have the potential to cause life-altering disability. Mild TBI is the most common CNS injury seen in association with equestrian sports, but more severe injuries are not infrequent. ⁵⁷ The costs to rehabilitate a rider from severe head or neck trauma could range between US$8189 to US$33,537 depending on the category of the TBI, evaluated from moderate (mean of 6.7 days inpatient) to critical (mean of 17.5 days inpatient). ⁴⁰ Epidemiological studies have linked equestrian sports to higher risk of severe TBI, with an odds ratio of 2.73, comparable with risk of severe head injury seen with off-road vehicular sports. ⁴⁹ One study focused on equestrians in rural locations found that female riders between 5 and 17 years and male riders of all ages were most likely to incur a TBI while participating in animal-riding activities and found that patients diagnosed with TBI were less likely to wear helmets. ³⁷

Traumatic Brain Injuries

Equestrian sports stand out among sports for their association with the highest incidence of head injuries, surpassing contact sports like football and rugby, which are typically associated with sport-related head injuries. ⁶¹ Among all equestrian-related injuries, TBIs in particular are most prevalent, constituting approximately 20% to 48% of all horse-related injuries.^7,41,59 Pediatric patients frequently experience TBIs when participating in equestrian sports, with studies estimating that TBIs constitute more than half of all equestrian injuries that require seeking care in a hospital. ⁵⁰ Further, TBI accounts for the highest cause of injury resulting in death, as reported by multiple large-scale trauma registry studies.^7,11,43

When surveyed about concussion knowledge, the majority of equestrians polled could accurately identify concussion symptoms, although only 56% of participants were aware of current guidelines, and almost half reported reusing helmets after a fall, despite being aware of the guidelines to replace helmets after each fall. ⁵⁶ Equestrians were also likely to return to working with horses immediately after a TBI, despite being aware of the risk of permanent neurological dysfunction, and without seeking medical clearance.^30,36

TBIs are severe injuries to the brain and represent a significant contributor to mortality in adults under the age of 45 years. ³ While TBIs can be categorized in various ways, closed TBIs are associated predominantly with equestrian accidents. Such injuries often result from blunt impact or compressional forces experienced during motor accidents, falls, or contact during sporting activities. ⁶³ Falls from a horse are described as the most common mechanism of injury throughout the literature.^1,49,63

The pathophysiology of TBIs involves tissue damage resulting in compression and reduction in cerebral blood flow, creating both localized contusions and diffuse damage throughout the cortex. The complex nature of these injuries is associated with long-term neurological disabilities and represents a significant burden to both patients and public health. Clinical manifestations of TBI may include mild symptoms such as headaches or nausea, but can also include severe presentations with aphasia, seizures, amnesia, prolonged comas, and behavioral abnormalities, including anxiety and aggression. ³⁸

The incidence of head injuries in equestrians is high. A study reported that out of 189 equestrian riders who suffered injuries, 139 riders experienced head injuries. ²⁰ Concussions represented the majority (91%) of head injuries reported, with other injuries including skull fractures, diffuse axonal injuries, subdural hematoma, and cerebral edema. ²⁰ This study demonstrated that 73% of equestrians in this population sustained traumatic head injuries with almost half of these injuries occurring without any appreciable damage to the rider’s helmet. ²⁰ Without visible damage to a helmet, many riders assume that they were not injured, and the helmet can continue to be used, although current guidelines recommend its replacement after a fall. ⁵⁶

The Glasgow Coma Scale (GCS) is commonly utilized to assess the level of impairment in TBI patients. Scores of 3 to 8 are classified as severe neurological impairment, 9 to 12 are classified as moderate impairment, and 13 to 15 are classified as mild impairment. According to an analysis completed between 2007 and 2016, the GCS scores of 21,971 patients with equestrian-related injuries were compared. A total of 888 patients scored in the severe range, likely due to head and neck injuries. Moderate impairments were observed in 258 patients, and mild impairments were observed in 21,917 patients. A GCS score of 15 is considered to be normal with no impairments. Due to this, it is difficult to differentiate between patients with mild impairment and patients at their neurological baseline. Of the patients enrolled, 4508 had a documented head or neck injury. ⁴³

Mild TBIs, such as concussion, are most common. However, more severe TBIs are also seen in association with equestrian sports, with neurosurgical intervention required in some cases. ⁴⁵ The ability of helmets to protect against severe TBI has been questioned, with some studies suggesting that helmets offer varying levels of TBI protection, and a study by Carter and Richardson finding helmets offered no reduction in risk of intracranial injury.^17,57 However, there are both laboratory-based and trauma registry studies that support the mitigation of intracranial injury among equestrians who properly utilize helmets.^11,23 One study identified helmet non-use as an independent predictor of TBI in pediatric equestrians. ⁵⁰ Severe sport-related TBIs are associated with prolonged hospital stay, medical complications, and increased risk of death in both pediatric and adult populations.^61,63

Spinal Cord Injuries

Spinal cord injuries carry a high rate of mortality, morbidity, and associated disability. It is difficult to document injury rates, as the data available in many trauma registries often do not differentiate between spinal cord injury and spinal column injury. In these national and multinational studies, spine injuries were reported to account for approximately 25% of the equestrian injury patterns described.^11,59 Multiple European studies have found equestrian sports to be responsible for the majority of sport-related spinal cord injuries, with 1 study reporting 41.8% of all sport-related spinal cord injuries in Ireland resulting from equestrian events, and noted that almost all injuries occurred in recreational riders.^10,14 In the US, equestrian sports are responsible for a greater number of spinal cord injuries than American football. ⁴⁴ Additionally, equestrian sports are responsible for a large number of spinal cord injuries seen in female patients.^13,29,62 Previous studies have reported anywhere from to 63.7% to 84.6% of injured riders are female, and female riders have an increased injury rate.^2,42 Hyperextension of the cervical spine upon impact as well as spinal instability caused by rotational forces, such as a kick from a horse, have been described in multiple papers as contributing injury mechanisms.^10,14,48 No study reported direct measures to decrease the risk of spinal cord injury, with no piece of protective equipment proving effective at preventing spinal cord injuries.

Spine

Injuries to the spinal column predominantly occur between thoracic vertebra 11 and lumbar vertebra 2 (T11-L2). European studies of equestrian spinal injuries have reported that approximately 80% of injuries occur in this location. ⁵¹ This is hypothesized to occur due to the axial loading forces sustained when a rider falls. Protective equipment currently does not offer significant protection against these injuries. In fact, 1 trauma registry study reported that vertebral body fractures, pelvic fractures, and nonvertebral body spinal column injury occurred at higher percentages in equestrians wearing protective vests when compared with riders not wearing vests. ¹¹ Another German study concluded that vests offered limited protective benefit against specific types of spine injury. ³² Continued rider education regarding safe handling of horses, correct use and upkeep of all equestrian equipment, and other risk reduction techniques have been suggested as a way to decrease the incidence of spine injuries.^15,16,28,48

Thorax

Thorax injuries constitute a broad range of injury patterns including rib fractures, pneumothorax, solid organ contusion, and crush injuries.^2,11,27 Although most studies agree that head injury is the leading cause of mortality associated with equestrian sports, some studies have reported that thorax injuries occur even more frequently than head injuries.^7,43 Several trauma registry studies reported high rates of thoracic injuries, ranging between 37.7% and 54% of equestrian injuries, compared with the reported rate of head injuries in equestrians ranging from 22.95% to 48%.^2,7,43 Rib fractures have been identified as the most prevalent of these thorax injuries.^11,27,59 Further, a relationship with age has been identified, with increasing risk of rib fracture associated with increasing age. ²⁷

Protective Equipment

Helmet use has become accepted widely in all fields of equestrian activities and, in many cases, has become mandatory for participants. ²⁵ Evidence describing the benefits of protective helmet use is conflicting. In general, correct use of protective riding helmets has been associated with positive outcomes, such as a 5-fold decrease in risk of traumatic cerebral hemorrhage, reduced length of stay in the hospital, and reduced severity of TBI.^12,57 However, some studies question helmet efficacy in protecting against concussion.^{18 -20}

Most recently, the International Federation for Equestrian Sports (FEI) has dictated that all equestrians wear a properly fitted helmet that either meets or exceeds standards set by the American Society for Testing and Materials (ASTM) and Safety Equipment Institute (SEI). ²⁵ Helmet use is mandatory for participants at all levels and of all ages at sanctioned events. However, rules are not standard across all subdisciplines, and do not dictate a rider’s use of protective gear during their time riding outside of formal events. Notably, the felt cowboy hat is the historic standard of western-style riding and continues to be seen during events, despite the fact it offers no protection against head injury. ²⁴ Current literature estimates that somewhere between 9% and 40% of riders were wearing protective headgear at the time of the injury, which suggests that a large proportion of riders do not wear helmets unless mandated. ⁸ Direct survey of equestrians shows 75% wear helmets regularly, with belief that helmets are unnecessary being the most common reason for non-use. ⁵⁴

Proper helmet use alone does not protect against all CNS injuries. Although helmets have demonstrated efficacy in protecting riders from linear forces, there is less demonstrated protection offered against rotational forces, which become relevant when considering both falls and kicks from a horse to the rider’s head. ²⁸ Previous studies have demonstrated that helmet use decreases risk of skull fracture and intracranial bleeding, estimating a 96% relative risk reduction for intracranial hemorrhage with proper helmet use. ²⁸ Helmets also lack protection against facial injuries, such as facial fractures, and cervical spine injuries, which are other common injuries in equestrian sports. ³¹ A study evaluating pediatric head injuries in Germany demonstrated that helmet use reduced the risk of loss of consciousness at the time of head injury, but found that helmet use did not appear to have any association with concussion symptoms. ⁸

A study by Connor et al ²⁰ evaluated helmets worn by equestrians during accidents and analyzed both the helmets and injuries sustained by the rider. Notably, a third of helmets worn by riders who sustained a significant head injury, most commonly concussion, did not show any damage, suggesting helmets that were adherent to more stringent testing criteria were less protective against concussion. ²⁰ Further studies question the efficacy of helmet testing when replicating falls on real-world surfaces, such as sand or turf.^18,23,28

The United States Eventing Association requires that riders wear a protective vest for cross-country events only, which is a specific modality of equestrian discipline. ²⁵ Protective vests are also commonly worn in rodeo settings, on an elective basis, where there are fewer guidelines on protective equipment use and helmets are not commonly worn. ²⁴ Vests may decrease injury to the thorax, with a trauma registry study reporting that rib fractures were sustained in 25% of equestrians wearing vests, compared with 53.3% of equestrians who were not wearing protective equipment. ¹¹ However, spine injuries occurred more frequently in equestrians wearing vests, compared with equestrians who were wearing only helmets at the time of injury. ¹¹ Vertebral body fractures (25% vs 7.7%) and nonvertebral spinal column injuries (50% vs 23.1%) occurred more frequently in equestrians wearing vests. ¹¹

Overall, the benefits of protective vests are not well characterized, with some studies reporting a decreased risk of rib fracture and other chest injuries and a decrease in overall injury severity, while others reporting no significant change in injury patterns with protective vest use.^{5,33,35,44,55} There have even been reports of increased rates of vertebral fractures and nonvertebral spinal column injuries in equestrians using protective vests. ¹¹ Although these vests offer some theoretical protection to the thoracic and lumbar spine, they have not been shown to significantly reduce spinal injuries, and they leave the cervical spine vulnerable to injury. ³³

Experience Levels Among Riders

Experience levels in horseback riding is a variable that has not been investigated extensively as a contributor to injury outcomes. Though many accidents are related to unpredictable horse behaviors, riders’ actions and third-party factors are not commonly recognized. Many injuries that have occurred from rider or handler errors could have been prevented. ¹⁶

A report released in 2023 from the FEI found that the risk of a fall resulting in injury ranges from 1 in every 250 starts for low-impact falls, to 1 in every 520 starts for serious injuries, which results in 83.4% of horse riding injuries.^9,16 Experience level was categorized as beginner, intermediate, advanced, and professional. Along with acquired horse riding skills, the riders learn saddling and protective care techniques to take preventative measures. A study in 2018 found that the 3 main causes of accidents were broken tack, slipped saddles, and no preride safety check to ensure all equipment was properly secured. ¹⁶ These are actions completed by a handler or rider themselves. It was also reported that TBIs were more frequent in experienced riders. This was hypothesized to occur because experienced riders were less likely to wear a helmet and more likely to ride less experienced horses.

Although experience does not correlate to lower injury rate associated with preventable safety checks, equestrian experience has been shown to be associated with a decreased risk of fall injury due to more developed musculature and balance. During the 2016 Olympic Summer Games, extremity injuries were most commonly reported, followed by thoracic injuries. ⁵³ However, no head injuries were recorded among the 200 equestrian Olympic competitors. ⁵³ Another study showed that approximately 100 hours of experience could decrease fall-related injuries. ³⁹ Novice riders had a 3-fold greater incidence of injury over riders with intermediate skills, a 5-fold increase over advanced riders, and nearly an 8-fold greater incidence over professional riders. ³⁹ Musculature in the core and lower legs strengthens over time; therefore, younger equestrians have decreased balance and grip strength. Another study showed that participants that had <10 years of experience lacked these physical factors, putting them at a fall risk over their professional counterparts. ²² These studies show that continued education and conditioning are potential risk-reduction solutions.

Discussion

Equestrian sports are accompanied by a significant risk of CNS and thoracic injury that is well-described in the literature. These injuries include a wide range of pathologies, with mild head injury or concussion and thoracic injuries cited as the most prevalent equestrian injuries. Current protective equipment likely offers protection against severe TBI, but there is ample opportunity for improvement. There is little protective equipment available to protect against mild TBI or spinal cord injury.

In addition, evidence suggests that, although riders are aware of current guidelines and recommendations, some riders choose not to follow them. Given that roughly 40% of TBI survivors will develop some form of long-term functional deficit, equestrian participants have an increased risk of both acute injury and chronic disability.^21,60 Increasing rider education as well as rider strength appears to have potential to help riders at all levels develop risk-mitigation strategies and potentially prevent severe injuries. Due to the unpredictable nature of horses, education for the rider cannot entirely reduce the risk of injury. Therefore, it is imperative to develop better injury reduction strategies, such as educating riders on the safest techniques to fall from a horse. ⁴⁶ Future research should aim to better understand how protective equipment functions, and to optimize approaches to enhance riders’ compliance with protective equipment use.

Limitations

There are major limitations that should be recognized. First, this study is limited in the availability of current literature. Literature describing efficacy of protective equipment is confined to the laboratory setting, with 0 PubMed-indexed randomized controlled trial or prospective cohort trials describing efficacy of equestrian safety equipment. Literature not available in English was translated using translation software. Though this method has been described as an accepted practice, it is possible details were omitted in translation.^6,47 Another limitation relates to the nature of trauma registries. Data specific to equestrian injury patterns and injury mechanisms are not recorded routinely in these databases, limiting the conclusions that can be drawn from retrospective trauma registry studies.

Conclusion

Injuries to the thorax, including fractures, pneumothoraces, organ contusions, and crush injuries, have been cited as the leading cause of morbidity in equestrian sports. CNS injuries are the leading cause of death, including high cervical spine fractures and closed head injuries. Protective gear can mitigate some injury risk, but has not been shown to protect against spinal injury. Head injury is the leading cause of mortality, so future efforts should focus on improved adoption of helmet use and enhanced helmet design to protect against injury. The lack of epidemiologic literature on efficacy of safety equipment in equestrian sports points to an urgent need for a large-scale injury surveillance tool, which could be employed across equestrian disciplines.