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EQUINE VETERINARY EDUCATION / AE / MAY 2015


TABLE 1: Time from initial injury to return to different elements of training Variable First swim


Number of horses 5*


First ridden work First gallop


First barrier trial First race First win


7† 8


6‡ 7§ 6¶


Median (days) 33


58 74


130.5 137


270.5


(n = 1), open wounds (n = 1) and trainer preference not to swim any horse (n = 1). † Missing variables due to lack of facilities at the convalescence property delaying return to training (n = 1). ‡ Missing variables due to trainer preference (n = 1), musculoskeletal issues unrelated to fractured withers (n = 1). § Missing data due to musculoskeletal issues unrelated to fractured withers (n = 1). ¶ Did not win a race prior to retirement (n = 2).


reported (Jeffcott and Whitwell 1976; Jeffcott 1980). Consequently, few clinicians will have experience in the management of this injury. As such, documented evidence of a favourable outcome for racing is important. In 6 of the 8 cases, there was record of the horse rearing up


and flipping over backwards, striking its withers directly on hard ground. While an accident was not witnessed in the other cases, the relevant history included a component that was likely to be associated with a traumatic incident. Similar to previous studies, the third to eighth thoracic vertebrae were most frequently affected, with T6 most commonly fractured (Driver and Pilsworth 2009). Presumably this is because the DSP of this vertebra is the highest and hence most exposed (Jeffcott and Whitwell 1976; Piat et al. 2012). Fractures occurred some time after arrival, implying that


the horses had become established in Hong Kong prior to injury and thus the fractures were not specifically related to the transport associated with importation. Fracture of the withers should be suspected whenever


there is localised painful swelling over the dorsal and lateral withers, especially following a history of trauma. However, in one case reported here, swelling of surrounding soft tissues was not apparent for several hours. Consequently fracture should not be ruled out in the absence of acute swelling. Occasionally crepitus can be detected on palpation of the region and the horse may be lame or show a stiff gait. Definitive diagnosis is established radiographically, which is relatively straight-forward, even with a lower-power generator. While previous studies have reported problems associated


with proper saddle fit and impingement of the saddle on the back after fracture of the withers (Jeffcott 1980; Jeffcott and Haussler 2004; Driver and Pilsworth 2009; Piat et al. 2012), this was not an issue identified in this study. Special saddles were not required for any injured horse. This may reflect the fact that racing saddles are smaller and lighter than those used for nonracing purposes or that this problem is overestimated as a complication. Although 4 weeks of stable confinement was recommended by veterinarians in all cases, 2 horses returned to swimming exercise and all horses were exercised at the walk in-hand within one month of injury. Similarly, the majority of cases had begun work under saddle sooner than the initial recommendations of 8 weeks. The decision was made to delay the return to ridden work of 2 horses that still showed clinical signs of discomfort due to instability of the fracture fragments 2 months post injury. All other cases suffered no negative repercussions from the early resumption of work


© 2015 EVJ Ltd


under saddle. Thus it is noteworthy that despite initial recommendations for a period of complete box rest followed by an absence of ridden work for 2 months post injury, this advice was ignored by trainers to no apparent ill-effect. These findings are in contrast with previous studies, where ridden work is not recommended until 6 months post injury (Molnar et al. 2012), with 8.5–12 months required for horses to return to their previous level of activity (Molnar et al. 2012; Piat et al. 2012). In the current study, the median interval between injury and first gallop was <2.5 months, and the majority of horses were back racing within 6 months of wither fracture. A fast return to work is particularly important for young Thoroughbreds, where the opportunities for racing may be relatively few and the expense of remaining out of competition high. In addition, there is increasing awareness that just as the skeleton adapts to increase in loads associated with training, so it resorbs bone when loads are reduced during inactivity. Protracted rest periods are likely to exacerbate this phenomenon, which may be a concern under certain circumstances. In the current study, all horses returned to their previous


level of performance, or better, after injury. Prior to the resumption of racing, horses were required to pass a prerace veterinary inspection, performed independently of the attending clinician, including observation of the horse at a gallop. Consequently, horses were free of significant clinical signs at the time of racing. This finding contrasts with Piat et al. (2012) where fewer than half of the affected horses returned to their previous level of activity. All cases reported in the current study were seen on a first-opinion basis, whereas those reported by Piat et al. (2012) reflected a referral population. Consequently, the results of the previous study may reflect referral bias, where a higher number of horses with more severe injuries were enrolled into the study. Additionally, the after-effects of the injury may influence some exercise activities more than others. Fracture of the withers does not affect the speed or distance run in races by Thoroughbred racehorses, but could have a greater effect on performance in other equestrian disciplines, a population more indicative of that reported by Piat et al. (2012). The favourable prognoses reported in the current study


may be due to the onsite veterinary clinical service, which permitted regular contact between attending veterinarians and trainers and allowed for the close monitoring of cases. Recommendations for changes in exercise could be made based on frequent evaluation of the status of the injury and comfort levels of the horse. In one horse, ridden work was


Interquartile range 24–71.5


42–76 54–90


83–192 101–200 217–433


* Missing variables due to horses being unable to swim due to lack of facilities at the convalescence property delaying return to swimming


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