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Introduction

I.M. Wright

Newmarket Equine Hospital, Newmarket, UK

Over the course of the last 50?years, the concept of fractures in horses has emerged from an association with inevitable euthanasia to an expectation, in many cases, for restoration of full athletic function. This has been the result of major developments in understanding pathogenesis, imaging, anaesthesia, internal fixation, pharmacology and minimally invasive surgical techniques. However, although previous progress was slow, there were inklings of latent knowledge. This should not be surprising: in 1722 W. Gibson [cited in 1] wrote, 'As the general use and service of horses has rendered them more worth the notice and regard of mankind than any other of the brute creatures; so there has in most ages of the world been a more than ordinary care taken, not only to model and fit them for their respective services, but also of their breed and preservation.'

Historical Review

The following review makes no claim to be comprehensive but aims to be sufficiently representative to illustrate the temporal recognition, development of understanding, diagnosis and treatment of fractures in horses.

The Ancient World

Fractures have occurred in wild (non-domesticated) animals throughout their evolution. It has been suggested that horses were initially domesticated in the late Neolithic period: first for food and later for transportation and war [2]. Domestication of Equidae introduced new environments and circumstances particularly as horses were used for work, often were ascribed special value (both economic and emotional) and played important cultural roles in human civilization. There is a dearth of documentation of equine fractures by the ancient Syrian, Egyptian, Persian and Greek civilizations, although in the latter Xenophen (380 BCE) described 'Rules for the Choice, Management and Training of Horses' and Aristotle (333 BCE) in 'The History of Animals' introduced the concept of gaits. An ancient Greek treatise called the Mulomedicina Chironis has been ascribed to a healer Chiron. There is evidence that this was a real person circa 700 BCE, but confusion is produced by later elevation to the mythologic status of centaur.

In paleopathologic investigations, three healed metacarpal bone fractures dating from the Iron Age (800 BCE-43 CE) have been found in different parts of Europe [3]. These included a compound fracture of what was considered most likely a working mare buried in a human cemetery of the fourth to seventh century BCE at Sindos, Greek Macedonia. The bone was markedly distorted but the animal is thought to have survived for at least three to four years after the injury, and it was suggested that this lame mare may have pulled her 'loving owner's' cart to the grave before being sacrificed and laid next to him [4]. A rib fracture in a horse from the Roman Imperial period (27 BCE-284 CE) was found at a site near Seinstedt, Germany [5]. The same group reported a 'neatly healed' fractured third metatarsal bone in a horse from the Iron Age sacrificial site of Skeddemosse, Sweden [6], and a fractured metacarpus from a similar period was found in a horse at Tiel-Passewaaij, the Netherlands [7].

According to Harcourt [cited in 8], an archeologic study of the Roman site of Tripontium, England, found a healed fractured humerus in a horse although there was no evidence to indicate intervention. The paucity of healed fractures in large animals was considered direct evidence of the associated bad prognoses [3]. No archeologic evidence of therapeutic intervention during this period has been found [7, 9]. The possibility had been suggested in a healed metacarpal of an Iron Age horse from Manching [10]. However, the specimen had a complicated fracture that healed with 'distortion of the bone and development of an enormous callus', which appears to make this tenuous.

The writings of Hippocrates (considered the father of medicine) in the fourth to fifth century BCE included a text 'De Fracturis', which is the first known treatise devoted to the subject. The Hippiatrika, a text compiled in the fifth or sixth century CE, was a compilation of extracts of Greek technical literature on the care and healing of horses. This included a contribution from Apsyrtus, a 'well-known horse specialist' from the fourth century CE [10], who was of the opinion that 'all fractures below the knee have a good chance of healing'. Later manuscripts published as Hippiatria (1531) or Hippiatrica (1543) also cite Apsyrtus treating fractures below the knee with splints and bandages with cures expected in about 40?days (which must question the diagnosis), while fractures above the knee were considered incurable [11].

The Romans appeared to document little in veterinary medicine until the end of their Western empire when the Byzantine Publius Vegetius (circa 450-500 CE) recognized that diseases of the horse were similar to those suffered by men. Vegetius is often considered the first to have documented hippiatric beliefs and practices. These were almost certainly preceded but records are lacking.

Middle Ages/Mediaeval Period

Throughout the Middle Ages (circa 500-1500 CE), horses continued to play a major role in warfare with increasing numbers employed in agriculture and transport. In the early Middle Ages, Western medicine in general was dominated by religious (Christian) doctrine; science in the currently accepted sense was neither considered nor applied. Further discussion on fractures is found in republications of the ancient works of Chiron the Centaur (circa 400 CE) and Vegetius Ranatus (450-500 CE). The latter was translated from Latin to English in 1748 as 'Distempers of Horses' and includes a chapter (two pages) on fractures. Open limb fractures were recognized as 'almost incurable'. For closed fractures, bandages, splints and slings were recommended. The latter fitted so that the horse 'may not touch the ground with his foot, lest the fracture should move to and fro in a lamentable manner'. Vengetius Ranatus instructed that the horse must not be allowed to stand on the fractured limb for 40?days 'for that is the time when things that are broken, or torn asunder, or disjoined, are consolidated' [11].

The Mamluks, who ruled Egypt and Syria between 1250 and 1517, are thought to have used orthopaedic bandages containing resins from Boswellia plants and pitch from cedar and tannub trees to heal broken bones in horses [12]. There is also iconographic evidence of care of horses with fractures: binding a fractured metacarpus in a horse suspended in a sling is illustrated in Mending the fractured metacarpal of the horse (1390) from Libro de menescalcia e de albeyteria et fisica de las bestias (a Spanish text from the Middle Ages) and in the fifteenth-century work of Johan Alvares de salami Ella's. A fractured pelvis from the fourteenth to sixteenth century was recovered from the Cumanian settlement of Karcag-Organdaszentmiklós, Hungary. The fracture involved the ilial shaft and was displaced, but there was sufficient adjacent new bone to suggest that this was of multiple months' duration during which period the horse was considered to have been 'immobilized' [13].

The Renaissance/Reformation

From a medical/scientific perspective, the Middle Ages may be considered to have ended with the introduction of mechanical printing at the end of the fifteenth century. 'Proprytes and medicynes of hors' was thought to be first printed in 1497 or 1498. This was followed by 'Medicines for Horses' somewhere between 1510 and 1560. There are no ascribed authors to either. However, such texts made little comment on traumatology, concentrating on remedies, topical applications, bloodletting and similar (now considered illogical) insults [1].

Equine fractures were mentioned by a French author Rusius in 1559 and Thomas Blundeville, an English mathematician (who invented the protractor), in The fower chiefyst offices belonging to Horsemanshippe published in 1565 described fractures as a form of 'evil' that, in common with wounds and ulcers, causes a 'loosening or division of the unity' [14]. Gervase Markham made comment on veterinary matters in books commencing with 'A Discourse of Horsemanshippe' in 1593. This was followed by Thomas De Grey's 'The Compleat Horse-man and Expert Farrier' in 1639 and 'The Anatomy of a Horse' by A. Snape in 1674.

The Enlightenment and Industrial Revolution

Reference to anaesthesia and analgesia (albeit not in such terms) occurs in a series of experiments in the 1650s and 1660s when animals were injected with a solution of opium [A H Machle 1998 cited in 1].

The concept of musculoskeletal biomechanics appears in print in the mid-seventeenth century when individuals like the physician Giovanni Alfonso Benelli (1608-1679) applied the concepts of physics and mechanics, thus viewing bones and joints as levers. Further reference is made in 'The Compleat Horseman' [15], a 1702 translation by Sir William Hope of 'Le...