Fractures in the Horse. Группа авторов

would justify the abandonment of a horse with fractured leg, and that is it being a compound fracture, i.e. the integument and muscular parts being lacerated; then, indeed the case is hopeless. The cure of a fracture of the pastern or the shank bone may be undertaken with a fair prospect of success. All that is to be done is to cut the hair closely from the parts; to bring, – and as gently as may be, – the divided edges of the bone in apposition; to retain them there by a pitch plaister; and then to bind on splints, which shall reach a considerable way above and below the injured part. This should be done in the box in which it is intended that the horse should remain. He should be bled, and a dose of physic should be given to keep down inflammation, and then he should be left to himself. He will take care of his broken leg; he will not press upon it for many a day; and not at all, until he can do so without much pain: and, in many more cases than some have imagined, the fractured bone will unite, and the horse will do well. A sling should rarely, I would say almost never, be used. The sad excoriations, and other inconveniences occasioned by the long use of a sling, have, more than anything else, brought the treatment of fractures into disrepute. The horse does not like pain, and will generally take all the care of his injured limb that we could wish him to take. Fractures of the hind extremities are more serious affairs, and should be undertaken with caution.’

      Fitzwygram (1869) [20] described bone structure, as far as it was understood, and gave a rudimentary classification of fractures. The following paragraphs provide a summary that endured. ‘In the human subject, the treatment of broken bones is comparatively easy, because the patient can be placed without difficulty or opposition on his part on his back in bed, the position most favourable for relieving the broken limb of all weight and pressure. Whilst in this position splints and other restraints can be conveniently imposed, and the patient is blessed with sense enough to induce him to submit to such restraints and to remain quiet. In the horse, we have none of these advantages. We cannot without hurtful violence throw the animal on his back, nor can we by any persuasion induce him voluntarily to remain in that position. Hence fractures of important bones are generally incurable. In most cases therefore of such injuries it is better to have the animal destroyed at once. Again the horse is an animal, whose value as a general rule consists in his power of locomotion. In man on the other hand the surgeon, though he may not be able to make a perfect cure, is often well content, if he can produce such re‐union of the bones, as may enable the patient, in case of broken leg for instance, to walk about. A horse is of no value, unless he can walk, trot and gallop sound and level. An exception however to this general rule occurs in the case of valuable brood mares or stallions.’

      Fitzwygram [20] also understood the concepts of monotonic and fatigue (cumulative stress/strain imbalance) fractures, and described fractures caused either by violence to the bone or from excessive strain. Diagnosis was entirely clinical. Treatment objectives were reported as ‘setting’, i.e. the bringing together of the broken ends and when the bones were ‘thus adjusted … to keep them in their place’, which was described as ‘a very difficult matter and needs expertise and ingenuity’ which is equally applicable today. Splints padded with tow (flax or hemp), bandages and strips of adhesive plaster were described. The starch bandage, which had been in human use since Roman times (reported by Celsus in 30 CE), was considered particularly useful and could be stiffened with an external wooden splint. It was also suggested that in some cases the horse may be slung with a view of taking the weight off the part affected.

      In 1884, Smith [21] reported sling management of horse, which was non‐weight‐bearing on a hindlimb and which subsequently (at post‐mortem) was found to have an axial fracture of the lateral condyle of the femur. The first surgical repair of an equine fracture appears to be in 1891 when Prieur [cited in 22] referred to repair of an equine jaw fracture with a drilled wire suture in Cairo, Egypt.

Around 1800, William Eton [23] described the creation of a gypsum (calcium sulphate) plaster mould to immobilize fractured legs that he had observed in Turkey. First documented use in man is attributed to a Dutch surgeon Antonius Mathijsen in 1852 and it was adopted into military service in the 1850s during the Crimean War by a Russian surgeon Nikolai Pirogor (1810–1881). The earliest reference to attempted use of plaster of Paris in horses was in 1872 [24], although it was not recommended. However, in 1883 plaster of Paris splints were described as a successful method of fracture management [25].

      Near the end of the century, one of the first identifiable movements to reduce the incidence of fractures in horses was the 1889 formation of the Horse Accident Prevention Society (Slippery Roads), which campaigned against asphalt road surfaces.

      The Twentieth and Twenty‐first Centuries

      The Farm Vet published by an anonymous veterinarian in 1914 noted that ‘chloroform can be used to render animals insensible and relaxes muscles which oppose the necessary extension of limbs in order to get fractured bones in apposition’. Horses are noted as ‘the worst subjects for fractures and sheep the best. Horses must be able to work sound. Sheep and cattle need only to put on sufficient flesh to bring them to the block.’

      In 1905, Wotley Axe [26] commented on the emergency care of equine fractures; ‘if an ambulance cart can be procured without much delay, it would be desirable to convey him at once where he may be required to go’ and that ‘it should be kept in mind that the success of treatment is greatly facilitated by the speedy readjustment of the broken bone’. Potential limitations of temperament were also recognized; ‘a horse's highest intelligence fails to realise the advantage of that perfect quiet upon which the surgeon sets so much store, in guarding against an extension of the injury and in bringing about its reparation. The moment the fracture is suspected every means should be adopted at once to restrain the animals movements and to provide as far as possible against any undue use or disturbance of the injured limb.’

      Röentgen discovered X‐rays in 1895 and the potential of radiographic diagnosis in horses was first recognized as early as 1927 [27]. Radiographs produced on photographic films were first documented in equine fracture evaluation in 1950 [28]: until this time diagnosis was entirely clinical [20]. Radiographic diagnosis came to public attention in 1966 with the diagnosis of a distal phalangeal fracture in champion steeplechaser Arkle.

      The 1962 publication of the eponymous ‘Lameness in Horses’ [29] signalled the arrival of the speciality. It also provided a series of radiographic images of equine fractures and recommended specific treatments including suitability for fragment removal. Although at this time the desirability for reconstruction was recognized, techniques and suitable equipment were not yet available. In 1963, Salter and Harris [30] described a classification of growth plate fractures in children. Its applicability to horses was soon recognized, and its adoption into veterinary orthopaedics was rapid and enduring.

Internal fixation of fractures was first reported by Lambotte in 1913 [cited in 31]. Techniques for active repair of fractures in horses appeared in the first half of the twentieth century, but progress was slow. Roberts [cited in 17] concluded that intramedullary pins were impractical in horses because of fragment rotation and implant bending. Problems associated with plates available at this time included bending at screw holes and shearing of screws. These issues were addressed by the combined mathematical, physical, engineering and medical collaboration in establishing the Arbeitsgemeinschaft fűr Osteosynthesfragen (AO) group in 1958. This was translated in the United States into the Association for the Study of Internal Fixation (ASIF). The terms are synonymous, interchangeable and sometimes used concurrently (AO/ASIF). Central to the early AO goals were accurate anatomic reconstruction, fracture compression, rigidity of fixation and preservation of blood supply [32]. This promoted primary bone healing, a concept first published in 1947 [33]. In 1968, an osteotomized third metacarpal bone was repaired in vivo with a human plate [22]. AOVET was founded in 1969, and in the following year a report documented the repair of diaphyseal fractures of third metatarsal bones in two ponies using primordial compression plates and cortical screws [34]. Initial progress was slow. In a well‐documented seven‐hour marathon surgery in 1972, a third metacarpal lateral condylar fracture was repaired in Derby winner Mill Reef. The owner was charged £25 000 [35] (which equated to approximately £330 000 in 2020). As interest increased, an exponential growth in the publication of papers on equine fractures followed (