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loud crack and the horse will try to pull up. Prompt assistance by the jockey at this time is thought to be a major factor in limiting the severity of comminution, degree of displacement and consequently the articular and soft tissue insults that follow. Horses are severely, i.e. non- or minimally weightbearing, lame and sometimes will fall. Proximal phalangeal fractures can occur in both fore-


and hindlimbs. They are most common in the forelimbs and while sagittal and parasagittal fractures may occur in the hindlimbs during training and racing, comminuted fractures of the hindlimb proximal phalanges are rare training and racing injuries (Smith and Wright 2014). Distension of the metacarpophalangeal joint by


haemorrhage quickly follows, its severity and tension roughly proportional to the degree of articular damage. Unstable comminuted fractures may exhibit visible shortening of the pastern, instability frequently is evident and they generally are readily palpable. Circumferential pitting swelling due to haemorrhage ensues. Fractures that extend into the proximal interphalangeal joint will usually produce palpable distension of the same. Non- or minimally displaced fractures can be equally lame.


Swelling, including distension of the metacarpophalangeal joint, is less dramatic. In the acute phase, horses usually exhibit pain on firm digital (thumb) pressure dorsoproximally between the extensor branches of the suspensory ligament. The initial presentation of fractures of the palmar processes


of the proximal phalanx is similar to that of parasagittal fractures. However, pain is usually elicited directly over the affected palmar process(es). Twisting the proximal phalanx on the third metacarpal bone also may be resented but other proximal phalangeal fractures will react similarly. Since the principal distracting forces associated with


sagittal and parasagittal fractures of the proximal phalanx appear to be mediolateral, appropriate techniques for temporary immobilisation include a Robert Jones bandage, medially and laterally splinted Robert Jones bandage, a compression boot, bandage cast or cast (Fig 1). Mediolateral stability is enhanced by flat (solar) foot ground contact and, whenever possible this should be prioritised. A Robert Jones bandage is sufficient for incomplete fractures while complete fractures may benefit from the additional mediolateral or circumferential support offered by the other techniques. Incomplete fractures that extend from the sagittal groove of the proximal phalanx into the mid diaphysis before coursing laterally should be managed as complete fractures since propagation (at least from the appearance on acute phase radiographs) to the lateral cortex is common. Load on, and displacement of, fractures of the


palmar processes are diminished by flexion of the metacarpophalangeal joint. Optimal emergency support is provided by a Kimzey Leg Saver Splint1 or dorsal splint. Most animals with comminuted fractures of the proximal


phalanx will bear little weight on the limb. Confident determination of principal distracting forces commonly is not possible and circumferential support with a compression boot, bandage cast or cast is recommended. If there is evidence of dorsopalmar instability, then flexion of the metacarpophalangeal and interphalangeal joints is appropriate. This can be achieved by incorporation of a dorsal splint into the bandage cast or cast together with a heel wedge to provide mediolateral stability.


Fig 1: Sagittal fracture of the proximal phalanx (a) diagrammatic representation of principal distracting forces; (b) counter action by a Robert Jones bandage.


Fractures of the distal condyles of the third metacarpal bone


Fractures of the metacarpal condyles are the most common training and racing longbone fractures worldwide, and fractures of the lateral condyle are the single most common site (Jacklin and Wright 2012). If complete, these disarm the lateral collateral ligament of the metacarpophalangeal joint leading potentially to luxation and creation of an open fracture. Fractures of the metacarpal condyles that do not result in metacarpophalangeal luxation exhibit a wide variation in clinical compromise, which is not necessarily proportional to the severity of the injury. Some will be unable to continue to gallop, others will complete the race and exhibit lameness on pulling up while other horses will be recognised only later during or after cooling off. Fractures of the metacarpal condyles can occur bilaterally although lameness and clinical signs may dominate, at least initially, in one limb. Careful clinical evaluation is an important guide to


fracture location and configuration. Most fractures of the metacarpal condyles result in early distension, due to haemorrhage, of the metacarpophalangeal joint. In the acute phase, incomplete fractures may exhibit little else. Pitting swelling (haemorrhage) in the distal lateral metacarpus usually accompanies complete fractures of the lateral condyle (Fig 2). Firm digital (thumb) pressure at this site commonly is resented. Signs of pain on digital pressure further proximally in the metacarpal diaphysis is a sign of considerable concern as a warning of the potential presence of a proximally propagating fracture. These are most common medially. There may or may not be visible or palpable evidence of soft tissue swelling (haemorrhage; Fig 2). Such cases demand careful radiological scrutiny of the whole metacarpal diaphysis particularly if a cortical exit point for the fracture cannot confidently be determined. The principal distracting forces are lateromedial (Fig 3). Additionally, complete fractures frequently rotate (with dorsal


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