Patterns of injury following equine trauma: a non-trauma centre experience

Introduction

Horse riding is a popular recreational and competitive sport in the United Kingdom. It is estimated that up to 3 million people regularly ride horses. ¹ Furthermore, many communities in rural Scotland have equestrian festivals in the form of Common Ridings which further increases interest and participation in horse riding. Like any sport however there is a risk of injury. With a reported frequency of 0.49 injuries per 1000 hours riding ² and a high rate of hospitalisation following Emergency Department attendance (20–30 per cent of adults and 50 per cent of children) ³ horse riding is associated with more injuries than skiing, rugby, motorcycle and automobile racing. ⁴ The nature of the sport puts the rider at a high risk for blunt trauma in particular. Up to 3 meters off the ground, injury can occur following a simple fall. However, with a significant weight and kicking force, ⁵ un-mounted injury is also possible. To date, the majority of the literature is based on the experience from major trauma centres^3,6–8 and originates from either North America or Australasia. The geography of Scotland results in many rural communities which do not have immediate access to a major trauma centre. This carries potential significance as up to a quarter of all trauma activity will be at a non-trauma centres. ⁹ We aimed to characterise the patterns of injury in patients following equine trauma at a single, Scottish, district general hospital.

Methods

A retrospective review of patients admitted with equine related trauma was performed from December 2019 until electronic patient records began in September 2014. Patients were identified from prospectively maintained local coding. All patients were admitted to a single, medium sized, Scottish district general hospital providing both emergency general and orthopaedic surgery. A major trauma centre is located approximately 30 miles away and provides support for neurosurgical and complex trauma. Demographics and mechanism of injury were recorded. The number and nature of injuries was recorded as was management and outcomes.

Statistical analysis was used to determine associations between mechanism and nature of injury, ITU admission and age. All analysis was performed using Microsoft Excel ® version 16.35 (Microsoft, Redmond, Washington, USA) with a p value <0.05 considered to be statistically significant. Continuous and categorical data were analysed using Student T-Test and Chi-squared test respectively.

Results

One hundred and sixty-two patients were identified during the study period. Regional trauma data was not available for comparison as its collection began at the end of our study period. Patient demographics and mechanism of injury are shown in Table 1. There was a bimodal distribution of ages with 35 (21.6 per cent) being aged 11 to 20 and 32 (19.8 per cent) aged 51 to 60. Over the study period there was a decrease in the number of admissions per annum (Figure 1).

OPEN IN VIEWER

Table 1.

Patient demographics and mechanism of injury.

	Number (%)
Age (years)	37 (18.5)*
M:F	41:121
Mechanism of injury:
Fall from	140 (86.4)
Fall from then crushed by	9 (5.6)
Crushed by	3 (1.9)
Un-witnessed	3 (1.9)
Kicked by	2 (1.2)
Dragged by	2 (1.2)
Caught in stirrup	2 (1.2)
Fall from then kicked by	1 (0.6)

*Mean (S.D.).

OPEN IN VIEWER

Figure 1.

Admissions per year. 2014 not complete year.

Forty-four (27.2 per cent) had more than one injury. The commonest injury sustained was a head injury with concussion (Table 2). Overall, 49 different injury classifications were identified.

OPEN IN VIEWER

Table 2.

The 10 commonest injuries.

Injury	Number (%)
Head injury (simple)	29 (17.9)
Rib fracture	25 (15.43)
Clavicle fracture	14 (8.64)
Pneumothorax*	12 (7.41)
Distal radial fracture	11 (6.79)
Thoracic vertebral fracture	8 (4.94)
Abdominal visceral injury	8 (4.94)
Lumbar vertebral fracture	7 (4.32)
Soft tissue injury	6 (3.70)
Open wound	6 (3.70)

*Includes haemothorax.

Complex head injuries were represented by 4 (2.5 per cent) subarachnoid and 3 (1.9 per cent) subdural haematomas and 1 (0.62 per cent) temporal lobe contusion. There was an associated flail segment in 4 (16 per cent) patients with a rib fracture. Of patients with a pneumothorax, 4 (40 per cent) were complicated by a haemothorax and 1 (8.33 per cent) by tension.

Abdominal visceral injury was seen most commonly following a crush or kick injury rather than falling (22.7 vs 0.7 per cent, p = <0.05) and comprised 4 liver, 2 splenic and 1 kidney laceration and 1 pancreatic contusion. Liver lacerations were graded I (n = 1), II (n = 2) and III (n = 1), splenic lacerations graded I (n = 1) and III (n = 1) and the single kidney laceration was graded II. Twelve (7.4 per cent) were admitted for observation only with no injury identified.

Sixty-two (38.3 per cent) underwent a surgical procedure. The commonest operation was open reduction and internal fixation (ORIF) (Table 3).

OPEN IN VIEWER

Table 3.

Operations performed.

Operation	Number (%)
Open reduction and internal fixation	36 (58.1)
Manipulation under anaesthetic	13 (21)
Arthroscopy	4 (6.5)
Intramedullary nail	3 (4.8)
Chest drain	2 (3.2)
Splenectomy	1 (1.6)
Craniotomy	1 (1.6)

Fourteen (8.6 per cent) required admission to the intensive care unit. This was for management of pneumothorax (n = 6), rib fractures alone (n = 4), intra-abdominal visceral injury (n = 2), complex head injury (n = 1) and thoracic vertebral fracture (n = 1). ITU admission was seen in patients who were older (48.4 vs 35.8 years, p = <0.05) and were more likely to have been crushed or kicked when compared to falling alone (18.2 vs 6.4 per cent, p = 0.06). Eight (4.9 per cent) patients required transfer to a major trauma centre after resuscitation. This was for management of complex fractures (n = 5), neurosurgical intervention (n = 2) and for potential radiological management of a liver laceration.

The mean length of stay was 2 days (range 0–16 days). Thirty-day mortality was 0.6 per cent. This patient had a prolonged ITU stay with multi-organ failure having sustained rib fractures with an associated flail segment. In addition, they underwent a negative laparotomy for suspected delayed traumatic splenic rupture.

Discussion

The injuries sustained following equine trauma are varied and for the majority are inconsequential. However, a small number of patients experience significant injury which can result in mortality. Our mortality rate of 0.6 per cent is similar to that reported in other case series. ³ The population served by our hospital has more horses per head than any other region in Scotland ¹⁰ and therefore our experience is likely to be most representative of the patterns of injury seen.

With a mean age of 37 years and a strong predisposition towards females, our cohort is similar demographically to that reported elsewhere. ⁴ It is unsurprising that most of our patients were female as they make up the majority of horse riders in Scotland. ¹¹ Interestingly, we found a bimodal distribution for the age of patients with a peak at 11 to 20 years and again at 51 to 60 years. This trend is similar to previous studies. ⁶ It is likely that the first peak is attributable to the large numbers in this age group involved in horse riding ¹ and their inexperience in doing so. As it is a legal requirement in Scotland for children under 14 years of age to wear a helmet, ¹² injury in the under 10 category is likely to be prevented somewhat. It is possible that the second peak is due to the increase prevalence of comorbidities in this group as they only account for 19 per cent of horse riders in Scotland ¹¹ and so it is unlikely due to the proportion of the overall number of riders they comprise.

We found that that the most common mechanism of injury was to fall from a horse. Interestingly, the incidence of falling from a horse in our population is notably higher than seen elsewhere ⁷ although is similar when compared with a paediatric population. ⁸ Unsurprisingly, the pattern of injury is strongly associated with the mechanism of injury. With an average weight ranging from 380 kg to a tonne and a kicking force of up to 10,000 newtons ⁵ a horse can inflict a significant primary injury when compared with secondary injury from falling alone. Indeed, we found that abdominal visceral injury and ITU admission were more likely to occur following a crush or kick injury when compared with falling from alone.

Over the study period, we found a decrease in the annual incidence of equine related trauma, with 41 admissions in 2015 and just 17 during 2019. This could be explained by a year on year increase in government funding for equestrian sports. ¹³ It could be that there is a greater availability of safety equipment and improved facilities for those undertaking horse riding in such settings. In addition, recent changes to legislation with regards to the standard of protective helmets ¹⁴ may also be reflective in the year on year reduction in admissions.

With 26.5 per cent sustaining more than one injury, it is important to ensure that thorough primary, secondary and tertiary surveys of patients are undertaken in accordance with the current trauma guidelines. ¹⁵ Whilst the commonest injury seen in our cohort was a simple head injury, the majority of patients suffered a bony fracture. Upper limb and rib fracturs were most commonly seen and would be consistent with falling from height. ¹⁶ No patient died or required ITU admission with an upper limb fracture suggesting that outcomes are favourable in this group, a trend which has been shown previously. ¹⁷ Despite this, up to 55 per cent of patients have reported chronic physical impairment following equine trauma. ¹⁸ In contrast to previous studies ² we found a low incidence of spinal cord injuries. Whilst not mandatory in Scotland, the use of body protection is strongly advised by The British Equestrian Trade Association. They offer free fittings to help further promote the use of body protection and also provide riders extensive material on how to ensure body protection is worn correctly and how to identify damage which may leave them vulnerable to future injury. This may be reflected in the lower incidence of spinal cord injuries in our cohort as the majority of literature describing equestrian injuries comes from out with the United Kingdom. In addition, many of the horse riders in our population do so for leisure and not for sport. It is therefore likely that injury occurs at lower speed and thus the forces involved are reduced.

Given the high proportion of patients sustaining a bony fracture, it is unsurprising that fracture fixation was the commonest surgical intervention performed. Although indicative of significant trauma, intra-abdominal visceral injury was largely managed conservatively as only 1 patient required a laparotomy and splenectomy. In addition, complex head injuries were also managed non-operatively with only 1 patient requiring transfer to a major trauma centre for neurosurgical intervention.

Conclusion

Injuries following equine trauma have a variety of patterns and encompass both general surgical and orthopaedic specialties. Our experience is similar to that of major trauma centres in terms of demographics, mechanism and outcomes and highlights the importance of a fully trained trauma team in a district general hospital. Little is known about the functional outcomes despite orthopaedic injuries being prevalent in this group. Future work is needed to better understand the longer-term, functional, prognosis. Prevention of injury through education and legislation should be the primary aim in order to reduce morbidity and mortality. Whilst this has somewhat been addressed with the use of helmets in those under 14 years of age being mandatory, this could be extended to all horse riders. Body protection has become more affordable and comfortable to wear in recent years however there is currently no legal requirement for its use. Given we have shown that crush and kick injuries are associated with abdominal visceral injury and ITU admission, the adoption of body protection could greatly reduce the risk of significant injury and should be a focus for improvement.