Racecourse Fracture Support System
/
By Ian Wright
Figure 1: The fracture support system is provided in two mobile impact-resistant carrying boxes that protect the equipment and allow it to be checked before racing. All boots and splints are permanently labelled with individual racecourse identification to ensure return of equipment that may have left the racecourse.
The year 2022 heralds a major step forward in racehorse welfare and a world first for British racecourses. With a generous grant from the Racing Foundation and additional support from the RCA, ARVS and NTF, all British racecourses are to be provided with fracture support systems (Figure 1). These consist of two compression boots and two flexion splints—both for use in the forelimbs—and a set of aluminium modular adjustable splints. One size of each compression boot and flexion splint fits the majority of flat racehorses and the other larger jump racehorses. Together, these provide appropriate rigid external support for the vast majority of limb fractures that occur during racing. The general principles are that management of all fractures is optimised by applying rapid and appropriate support to provide stability, reduce pain and relieve anxiety.
In the last 25 years, there have been major improvements in fracture treatment due to significant advances in surgical techniques (particularly with internal fixation), minimally invasive approaches (arthroscopy) and the use of computed tomography (CT). Arthroscopy and CT allow accurate mapping and alignment of fractures, which is important for all horses and critical for athletic soundness. All have contributed to improving survival rates; and it is now safe to say that with correct care, the vast majority of horses that sustain fractures in racing can be saved. Equally importantly, many can also return to full athletic function including racing.
Fracture incidences and locations vary geographically and are influenced by race types, track surfaces and conditions. There is good evidence that the majority of non-fall–related fractures (i.e., those occurring in flat racing and between obstacles in jump racing) are caused by bone fatigue. This is precipitated by the absolute loads applied to a bone, their speed/frequency and the direction of force application. As seen with stress or fatigue, failure in other high-performance working materials such as aeroplanes or formula one cars—in which applied forces are relatively consistent—fractures in racehorse bones occur at common sites, in particular configurations and follow similar courses. Once the fracture location has been identified, means of counteracting forces that distract (separate) the bone parts can therefore be reliably predicted and countered.
Worldwide, the single most common racing fracture is that of the metacarpal/metatarsal condyles (condylar fracture). In Europe, the second most common fracture is a sagittal/parasagittal fracture of the proximal phalanx (split pastern). Both are most frequent in the forelimbs. In the United States, particularly when racing on dirt, fractures of the proximal sesamoid bones (almost always in the forelimbs) are the most common reason for on-course euthanasia. They occur less frequently when racing on turf but are seen at increased frequency on all-weather surfaces in the UK.
There is no specific data documenting outcomes of horses with sustained fractures on racecourses. However, there is solid data for the two commonest racing injuries. The figures below are a meta-analysis of published data worldwide.
CONDYLAR FRACTURES
Repaired incomplete fractures; 80% returned to racing
Complete non-displaced fractures; 66% of repaired fractures returned to racing
Displaced fractures; 51% raced following repair
Propagating fractures; 40% raced following repair
SPLIT PASTERN
Short incomplete fractures; 65% returned to racing
Long incomplete fractures; 61% returned to racing
Complete fractures; 51% returned to racing
Comminuted fractures in most circumstances end racing careers but with appropriate support and surgical repair, many horses can be saved. There is only one comprehensive series of 64 cases in the literature of which 45 (70%) of treated cases survived.
Figure 2: Newmarket Compression Boot.
The science behind the development of fracture support systems comes from two directions. The first is data collected from racecourse injuries and the second, improved understanding of fracture courses and behaviour. Data collected from UK flat racecourses between 2000 and 2013 demonstrated that 66% of fractures occurred in the lower limb (from knee and hock down); and of that, over 50% of fractures involved the fetlock joints. Condylar fractures are most common, representing 27% of all reported fractures; and of these, approximately two-thirds occurred in the forelimbs. Split pasterns were the second most common, accounting for 19% of all fractures with three quarters of these occurring in the forelimbs. These fractures have predictable planes and courses which means that once recognised, they can effectively be immobilised in a standard manner that is optimal for each fracture type. For condylar fractures and split pasterns, this principally involves extension of the fetlock joint. By contrast, in order to preserve soft tissues and blood supply to the lower limb, fractures of the sesamoid bones (which represent 7% of recorded fractures in UK flat racing) require fetlock flexion.
Figure 3: Compression boot fitted to a horse with a condylar fracture, allowing safe comfortable movement.
The compression boot (Figure 2) is readily applied “trackside” and can be used to stabilise most distal forelimb fractures sufficiently for horses to be moved off of the course. It is the temporary immobilisation of choice for forelimb condylar fractures and split pasterns (Figure 3). Radiographs can be taken with the boot in place (Figure 4), and this can be maintained for transport. The boot is a rigid construct of fibreglass made from a single mould. The divided front portion is contiguous with a foot plate on which the back of the boot is hinged. Removable foot inserts are provided to make minor adjustments for hoof size. The boot is lined with foam rubber and has a rubber sole plate, which protects the shell and provides a cushion grip for the foot. When the boot is opened, the injured limb is placed into the front of the boot while the back is closed and secured by sequential adjustment of ski boot clips. When the boot edges are opposed (it cannot be over-tightened), immobilisation is secure. It is made with a fixed fetlock angle of 150o which counteracts distracting forces and allows horses to weight-bear and load the limb to walk.
Figure 4: X-ray of horse with a condylar fracture (arrows) taken with a compression boot fitted.
Figure 5: a & b) Fitted flexion splint. c & d) X-rays of horse with bilateral sesamoid fractures taken before (c) and after (d) fitting a flexion splint, correcting hyperextension (dropping) of the fetlock and closing the fracture gap.
Flexion splints (Figure 5) are critical for the survival of horses with breakdown injuries such as sesamoid fractures. They are also suitable for other lower limb injuries, which are supported by fetlock and pastern flexion. The splints are made of aluminium with a secure footplate and conjoined foam-lined front splint, which is angled at 30o at the level of the coffin joint and extends to the top of the cannon. There is a shallow foam-covered concavity in which the upper cannon sits, allowing the horse to lean into the splint and load the leg while flexed. The splint is secured to the leg with nylon and Velcro straps.
The aluminium splints (Figure 6) are lightweight, adjustable and modular to fit individual horse and regional needs. They are spring-locked and light but rigid, secure and are tolerated well. In the hindlimb, the reciprocal apparatus that combines stifle, hock and fetlock joint positions precludes use of a compression boot. However, modular splints provide rigid support for condylar fractures and split pasterns in hindlimbs and are secured over a bandage to create a parallel sided tube, on the inside and outside of the limb. The splints can also be adjusted and assembled to splint fractures that occur less commonly above the fetlock (Figure 7).
Figure 6: Adjustable aluminium splints and application to a hindlimb to splint a condylar fracture.
Figure 7: Modular use of aluminium splint suitable for splinting (a & b) knee and (c) forearm fractures.
Appropriate immobilisation effectively stops fracture progression (i.e,. getting worse), which not only improves the horse's prospects for recovery but also provides effective relief from pain and anxiety. As flight animals, loss of limb control or function is a major contributor to stress. The relief provided by effective immobilisation is substantially greater than provided by any pain killer or sedative. It is also recognised that when fractures occur in the high adrenalin environment of racing, horses exhibit latent pain syndrome. Application of appropriate rigid support at this time (i.e., on the course) limits pain generation and allows humane movement for considered evaluation, X-ray, etc. away from the racetrack.
Techniques for application of the boots and splints are taught to racecourse veterinary surgeons at annual seminars facilitated by the Association of Racecourse Veterinary Surgeons (ARVS). The RCA has provided forms to record use and to collect data centrally which, in the fullness of time, will determine impact and help guide future welfare strategies. The equipment is currently being rolled out and will be available at all British racecourses at the start of the 2022 flat race season.
The initiative has been widely welcomed by the industry. “This new equipment will provide the best possible chance for an injury to be properly assessed while discomfort to the horse is significantly reduced [to] give the best chance of future rehabilitation.” Caroline Davies, RCA Racecourse Services Director.
“The fracture support kit is a major advance in the treatment of horses on the racetrack. It allows immediate effective support to be applied to an injured horse, resulting in pain control and stability, facilitating safe transport from the racecourse to a centre of excellence without risk of exacerbating the injury. This will optimise the chance of horses to return to athletic function. This innovation must be seen as a major step forward in horse welfare for the participants in racing and all other equine disciplines.” Simon Knapp, Horse Welfare Board
“As a clerk of the course, my number-one priority is the safety of the horses and riders who participate in racing, and we constantly seek ways to improve in that area. The equine fracture support kits are an excellent addition to the equipment available to racecourse veterinary teams and a vital step forward in horse welfare. It is so important for both the immediate comfort and long-term prognosis of a horse who suffers a fracture that the injury is immobilised, and the fracture support kits provide that stability quickly and effectively.” Andrew Cooper, Clerk of the Course, Sandown Park and Epsom Downs
“The introduction of these boots and splints to all racecourses in Great Britain represents a major advancement for the welfare of racehorses. This demonstrates the collective desire of all the sports participants to show to a wider society the ambition to continually improve racehorse welfare.” James Given, BHA Director of Equine Health and Welfare
“The importance of the fracture support kits cannot be overstated. In providing stability and support, it gives horses the best possible chance of recovery.” Emma Lavelle, NTF President
“I have no doubt that in time no racecourse in the world which purports to take equine welfare seriously will be without a set of fracture support kits.” Marcus Armytage, Daily Telegraph