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EQUINE VETERINARY EDUCATION / AE / SEPTEMBER 2017


extension for transport from the racecourse is readily achieved and tolerated well by most horses.


Fractures of mid and proximal radius Fractures of the diaphysis and proximal metaphysis of the radius are uncommon racetrack injuries. When a fracture occurs in this region, both flexor and extensor muscles no longer have an intact skeletal strut and they become abductors of the distal limb about the fracture site (Fig 13a). Catastrophic medial skin perforation commonly follows (Bramlage 1983, 1996; Furst 2006; Mudge and Bramlage 2007). All racing and training related fractures in this region necessitate a guarded to poor prognosis for survival as there is little corporate experience of successful repair in horses over 450 kg. Some nondisplaced fractures, which generally are the result of external trauma, can be managed by cross tie or overhead wire restraint but complications associated with contralateral limb overload are common. The principal requirement of temporary immobilisation


techniques suitable for fractures of the radial diaphysis is to combat the distal limb abduction. This is achieved by use of a single strut that extends from the level of the proximal scapula to the ground to which it should be perpendicular. The splint will contact the lateral proximal muscle masses and a modified Robert Jones bandage is constructed over the free limb in order to maintain the splint’s proximal contact, perpendicular orientation and to fill in the dead space between the free limb and the splint (Fig 13b, c). Further cranial and/or caudal splints can then be placed at 90° to this to provide rigidity (Fig 13c). Although appearing ungainly, the technique is well tolerated and horses will move well with this in situ.


Fractures of the olecranon Fractures of the olecranon tuberosity of the ulna are not recognised training and racing injuries but can arise on the


a) b)


racecourse as a result of traumatic incidents. When complete, the triceps apparatus is disarmed and the horse cannot fix the limb in extension. This causes marked anxiety, usually accompanied by repeated lifting and placing activity. The animal also is unable to use the limb as a prop or support for balance during transport. Most are readily aided by fixing the carpus in extension. Although caudally applied splints have been described (Furst 2006; Mudge and Bramlage 2007) these are bulkier, less easy to apply and not tolerated as well by the horse as a dorsally applied splint. The latter should extend from proximal antebrachium to distal metacarpus and be applied over a relatively light bandage in order to minimise the pendulum effect. Sufficient padding should be used only to minimise splint impingement and excoriation of the limb (Fig 12).


Fractures of the humerus In racehorses, fractures of the humerus usually are catastrophic. A series of 21 complete, unilateral fractures has been described in racehorses in California; 18 Thoroughbreds, two Quarter Horses and one Appaloosa (Stover et al. 1992). Seventeen occurred during training and two while racing. The history of the other two was unknown. These typically had a spiral caudoproximal to craniodistal configuration. Ten of 13 available bones had gross evidence of pre-existing stress fracture (periosteal callus) at the site of ultimate failure; usually on the caudoproximal diaphysis. In jump racing, fractures of the humerus frequently are associated with collisions with jumps or impact from falling (Williams et al. 2001).


Horses with complete fractures are invariably


nonweightbearing. They usually displace and override to result in an uncontrolled limb with shortened brachium (Fig 14). The close proximity of the brachial artery and its major trunks means that marked haemorrhage with rapidly developing swelling commonly accompany diaphyseal


c)


Fig 13: a) Diagrammatic representation of the principal distracting forces on diaphyseal fractures of the radius; (b) diagram demonstrating the rationale for a long lateral splint to counteract distracting forces; (c) mid diaphyseal fracture of the left radius immobilised with a long lateral splint extending to the level of the proximal scapula with a cranial/dorsal splint extending from the level of the elbow to the bearing surface incorporated into a modified Robert Jones bandage.


© 2016 EVJ Ltd


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