Equestrian-Related Pelvic Trauma in Women of Childbearing Age — a Review of the Experience of a National Pelvic & Acetabular Referral Centre

Equestrian sport in Ireland is an extremely popular sport undertaken by many and considered by most to be a relatively safe pursuit. The aim of this study was to identify the incidence and severity of pelvic injuries in female amateur horse riders, referred to the Irish National Pelvic & Acetabular Referral Centre. The study was particularly focused on women of childbearing age, given the potentially catastrophic adverse outcomes associated with these injury patterns and the profound impact these injuries can have on both lifestyle and future childbirth. We conducted a retrospective review of all patients referred to the National Centre for Pelvic and Acetabular Trauma over a 30-month period from January 2018 through July 2020. Information was garnered from the national referral database, patient specific chart analysis and a review of images from the National Integrated Medical Imaging System (NIMIS). We identified a cohort of 16 females of childbearing age who sustained pelvic injuries while horse riding during this period. Four of these patients warranted surgical intervention, and with a minimum 6-month follow-up period, all were progressing satisfactorily. A review of the literature outlined the potential for profound adverse outcomes in young females suffering pelvic fractures, particularly in relation to genitourinary and pregnancy related complications. Caution should be exerted by all women of childbearing age engaging in recreational equine pursuits, and we would emphasise the importance of safety messaging and increased protective equipment for these athletes.


Introduction
Equestrian sport in Ireland is extremely popular having a long and prestigious history with thousands of professionals and amateurs engaging in equine sports year-round. While considered by most to be a relatively safe pursuit, any activity where high speed is combined with the inherent unpredictability of an animal carries significant risk. The purpose of this study was to identify the incidence of pelvic injuries in females of childbearing age, engaging specifically in amateur equestrian activity, with a particular focus on the potential adverse outcomes associated with these injury patterns given the profound impact these injuries have on both female lifestyle and future childbirth.

Methods
This paper is based on a retrospective review of all patients referred to the National Centre for Pelvic and Acetabular Centre based in Tallaght University Hospital over a 30-month period from January 2018 through July 2020.
Data was garnered from the National Pelvic and Acetabular Referral Database encompassing all patients referred to the service on a national level over the period outlined.
Inclusion criteria were all referrals relating to trauma as a result of falling from a horse and/or being crushed by a horse between the dates outlined above.
Information including specific mechanism of injury, patient riding level and demographics were garnered from a This article is part of the Topical Collection on Surgery. patient-specific chart review along with operative details if relevant. Postoperative functional status, as assessed in the outpatient department, was also documented. The National Integrated Medical Imaging System (NIMIS) was utilised to characterise each specific fracture pattern and to monitor postoperative radiological progression. Treatment outcomes were subdivided into "operative" and "nonoperative" groups.
Pelvic ring injuries were classified as per Young and Burgess [1] while the Judet and Letournel classification was applied to acetabular injuries [2].

Results
Our review yielded a cohort of 31 patients (Fig. 1). One patient was a professional athlete and thus, excluded from our analysis. Of the remaining patients, 12 were male and 18 were female (60%). Two of the females were deemed outside the scope of "childbearing age" as per the World Health Organisation definition, 15-49 years [3]. This yielded a definitive cohort of 16 patients, with mean age of 25.68 years. There were five cases involving isolated acetabular fractures and 12 isolated pelvic ring injuries with one patient sustaining fractures both in their pelvis and acetabulum. Within the pelvic fracture cohort, eight LC1 type injuries were identified and two each of both LC2 and LC3 injury patterns. Regarding acetabular fractures we identified three elementary fracture types, involving a single column, one associated pattern and another combination of both pelvic and acetabular injuries.
Four of the 16 patients required surgical reduction and stabilisation of their injuries, while one underwent an examination under anaesthesia to assess fracture stability and was subsequently treated nonoperatively by means of protected weight bearing.
Of those warranting surgical intervention, two underwent posterior sacral stabilisation with percutaneously placed, fluoroscopically guided, sacroiliac screws using the Asnis® III Cannulated Screw System (Stryker, Mahwah, NJ, USA). Stabilisation of the anterior pelvic ring was augmented with the use of a supraacetabular external fixator employing the Hoffmann® II, External Fixation System (Fig. 2).
In both cases of open reduction and internal fixation, reduction was achieved with a plate and screw construct using Matta Stryker Acetabular System (Fig. 3); injury patterns in these scenarios were a posterior column acetabular fracture (Fig. 4) and one Tile A1 ilium fracture [4].
Associated injuries in this cohort consisted of one concomitant spinal injury, a lumbar burst fracture with no   associated neurological dysfunction that was successfully managed in a thoracolumbar orthosis and two urological injuries. The urological injuries consisted of incomplete urethral injuries that were managed conservatively.
Medium-term follow-up of these patients was wholly positive with fracture union noted in all four cases, with no case warranting an unexpected return to theatre. Patients requiring anterior external fixation in addition to posterior stabilisation underwent routine removal of the same, 6 weeks following their index procedure. Examination under anaesthesia was concomitantly performed and fractures were deemed stable. On routine outpatient follow-up, no patient complained of any significant pain or discomfort impacting their lifestyle and all were beginning to, or had returned to, their preinjury levels of activity.
Interestingly two of the operative cohorts were identified as having other significant horse riding-related injuries within 18 months of their pelvic fractures. One of these had occurred prior to their pelvic injury while the other patient was injured in the postoperative period. The preceding injury was a blunt abdominal trauma with an associated liver laceration and haemorrhagic ascites, while the individual who fell from the horse postoperatively sustained a significant intra-articular distal radius fracture, which warranted open reduction and internal fixation.

Discussion
Ireland has a long and prestigious history in competitive equine pursuits encompassing all disciplines, from high profile flat and jumps racing, to Olympic medal winning equestrian teams. This high performance stems from a healthy and vibrant amateur base to the sport with thousands engaged in activities from pony clubs to dressage [5].
Data from the UCD School of Agriculture and Food Science noted that there are 47,096 people involved in the Irish Sport Horse sector with the industry contributing €816 million per annum to the Irish economy [5].
Recreational horse riding is considered by many as being a relatively safe pursuit; however, evidence would suggest this is not the case. In our cohort, all but one of those injured were, in fact, amateur riders. The Hannover School of Medicine notes that equestrian sports are one of the most popular forms of sport in Germany, while also being one of the most accident-prone. Their data noted that 89.5% of horse injuries occurred in women, who's mean age was just 24.5 (± 12.5) years compared to males at 40.2 (± 23.9 years) [6]. Kuger et al. noted in a cohort of 771 patients with horse-related injuries that 87.9% were female patients with "Falling off the horse" (67.7%) and "being kicked by the horse" (16.5%) as the predominant injury mechanisms [7]. This is further supported by data from Sweden with a national audit of all equestrian injuries (29,850) noting that almost 90% of those injured were female accounting for 70% of fatalities with an average age of 26.8 years. It was also specified that absolute numbers of horse-related trauma has remained constant with time, in contrast to other common trauma mechanisms which have markedly decreased [8].
In the Irish setting, this is also evident, as highlighted by the fact that equestrian events account for the highest number of sporting-related spinal injuries in the country, at 41.8% [9].
This data would suggest that women and particularly young women, those of childbearing age, defined as between 15 and 49 years [3], are at a disproportionately higher risk of being injured, potentially quite seriously, while partaking in equestrian activities.
This fact is quite poignant as pelvic fractures and their associated complication have been demonstrated to have both short-and long-term effects on the genitourinary and reproductive system [10], confounded by the fact that women with pelvic trauma are often young and nulliparous [11]. Numerous dysfunction symptoms are noted after pelvic fractures even in the absence of any direct trauma to the relevant visceral organs. Bladder, bowel and sexual symptoms were common but were unlikely to be  Fig. 4 Preoperative AP pelvis radiograph demonstrating posterior column acetabular injury with intra-abdominal protrusion reported voluntarily [11]. Symptoms range from urinary stress incontinence to voiding difficulties, faecal urgency to tenesmus. Two of the patients in our cohort suffered urethral injuries warranting urological referral, both were treated conservatively, but the data outlined above would indicate the potential of long-term sequelae from these injuries. Odutola et al. note that rates of genitourinary complications upwards of 25% are seen in female patients post-pelvic ring fixation [12] with others noting sexual dysfunction rates as high as 39% [13] and dyspareunia rates from 13 to 24% [13]. Bilateral pubic symphysis fracture or diastasis was an injury pattern associated with a higher level of dysfunction and was observed in a number of our patients including the conservatively treated cohort. Notably, there is no correlation between the specific method of surgical intervention and potential subsequent dysfunction, nor was a correlation observed between dyspareunia and fracture stability or need for surgical stabilisation [14].
Regarding impact to subsequent pregnancies, there is large-scale debate on the progression to a normal vaginal delivery following pelvic injury. Uncomplicated pregnancies and deliveries are possible after pelvic fracture; however, the new caesarean delivery rate among this cohort is demonstrably higher, and rates upwards of 62% are reported [15] with a recent systematic review in the USA citing the figure at 42%, compared to a rate of 32% in the general population [16]. Reasons for caesarean versus vaginal delivery were varied, but the vast majority were down to obstetrician personal preference as a result of the presence of a previous pelvic injury [17] with many women not afforded a trial of labour once treating obstetricians were aware of a history of pelvic injury [10].
Fracture pattern, minor malalignment, and retained hardware were not highlighted as absolute indications for caesarean delivery, precluding a successful vaginal delivery. However others note that fixation crossing the symphysis is an absolute contraindication for proceeding to vaginal birth [15]. Therefore a significant benefit of our use of temporary supraacetabular external fixation as opposed to spanning the symphysis with a plate and screw construct may potentially alleviate this issue. If the patient has had painful sequelae from a pelvic fracture, there is a risk that such pain will recur or worsen during the course of pregnancy [18].
Also one of the greatest risks for women in this age profile is the risk of pelvic injury while pregnant as it is associated with high maternal (9%) and foetal (35%) mortality [19] as a result of direct trauma, preterm labour, maternal foetal haemorrhage, placental abruption or uterine rupture. Rates of foetal complications such as low birth weight, premature delivery and permanent neurocognitive dysfunction are higher in women who suffer pelvic trauma during pregnancy [20] though it is noteworthy this represents a small cohort of total pelvic fracture patients with rates as of 0.17% demonstrated in large-scale studies [21].
The limitations of this review are outlined below. Primarily that this is a retrospective analysis of a relatively small heterogeneous patient cohort. There is limited follow-up information on the cohort, and the review would benefit in having comprehensive follow-up data on the potential dysfunction and future pregnancy outcomes of these women. Thus larger-scale and longer-term follow-up trials are warranted to further quantify the risks and outcomes in this group in their potential future pregnancies.

Conclusion
In conclusion, amateur equestrian sport is popular both nationally and internationally and has significant social and economic implications.
Following a concise review of the literature, it can be seen, that while considered and experienced by many to be a relatively safe pursuit, the evidence would suggest that young women, particularly those of childbearing age, engaging in amateur equestrian activity are at an increased risk of injury compared to their male counterparts. This can potentially have profound impacts on their future lifestyle. Thus, we would advise that caution be exerted by all women of childbearing age engaging in recreational equine pursuits, particularly those who are or may be pregnant. We would advocate that safety messaging be available and visible in equestrian clubs or venues and that safety programmes be introduced for all amateur athletes to promote awareness.
Author Contribution PMC was the lead author primary composer of the review document. AF was a secondary author and aided substantially in data collection. FMC assisted with data collection and assimilation. BOD was a secondary senior author and surgeon. ML was the senior author, provided oversight and is the guarantor.

Funding Open Access funding provided by the IReL Consortium
Availability of Data and Materials All data can be made available upon request.
Code Availability Not applicable.

Declarations
Ethics Approval The local ethics committee in Tallaght University Hospital was contacted and advised specific approval was not necessary.

Consent to Participate
All patients undergoing treatment in the National Pelvic & Acetabular Centre consent to participate in research and publication.