Risk factors for superficial digital flexor tendinopathy in Thoroughbred racehorses in steeplechase starts in the United Kingdom (2001–2009)

https://doi.org/10.1016/j.tvjl.2012.06.033Get rights and content

Abstract

The objective of this study was to identify risk factors for superficial digital flexor (SDF) tendinopathy in Thoroughbred horses in steeplechase races in the United Kingdom. Potential risk factors for SDF tendinopathy were studied between 1st January 2001 and 31st December 2009 using a cohort study design with 648 injuries sustained in 102,894 starts. Potential risk factors were screened using univariable logistic regression prior to multivariable model building.

In the final multivariable model, 12 statistically significant risk factors were identified. Variables that increased the odds of SDF tendinopathy included firmer going, increased horse age, and racing in the summer compared to other seasons. Variables that decreased the odds included having a higher official rating and the number of starts in the preceding days.

Fewer and different risk factors were identified than in an equivalent model of SDF tendinopathy in hurdle racing, highlighting potential differences between these disciplines. Further collection of training and racecourse information would be beneficial and may help to explain further some of the associations identified in this study. The results will facilitate the development of strategies to improve overall safety of horses in UK steeplechase racing.

Introduction

Tendon injuries are common in Thoroughbred racehorses (Thorpe et al., 2010), with the superficial digital flexor (SDF) tendon being the most commonly injured (Marr et al., 1993, Williams et al., 2001, Ely et al., 2004, Ely et al., 2009, Pinchbeck et al., 2004, Takahashi et al., 2004, Lam et al., 2007a, Avella et al., 2009). Whilst multiple studies have investigated risk factors for SDF tendinopathy (Mohammed et al., 1991, Mohammed et al., 1992, Cohen et al., 1997, Takahashi et al., 2004, Perkins et al., 2005a, Lam et al., 2007b, Reardon et al., 2012), the studies performed in the United Kingdom either were focussed on training related factors for relatively small cohorts of trainers and horses or were not focussed solely on steeplechase horses. Although steeplechase racing has been recognised as the racing discipline in which SDF tendinopathy occurs most frequently (Williams et al., 2001), no previous studies have looked specifically at the risks of sustaining the injury in this discipline.

In a previous study using similar methods (Reardon et al., 2012), multiple risk factors for SDF tendinopathy in hurdle racing were identified. Steeplechase racing is the other major form of jump racing in the UK and whereas this is also always on a turf surface, it involves larger jump obstacles and often longer race distances than hurdle racing. It is plausible, therefore, that different risk factors exist in this type of racing. The aim of the present study was to identify risk factors associated with steeplechase racing and to compare these with those identified in hurdle racing.

Section snippets

Materials and methods

Potential risk factors for SDF tendinopathy in steeplechase starts in the UK were assessed using a cohort study. In order to allow inclusion of horse, race and track as different levels in risk factor analysis, the study was conducted at the start level (a ‘start’ being a horse starting a race) and included 648 injuries sustained in 102,894 starts. Information from all horse injuries treated at the racecourses was available from between 1st January 2000 and 31st December 2009 from the British

Results

The 102,894 study starts were represented in the study population by 15,117 horses, 1328 jockeys, 2343 trainers and 44 racecourses. The study starts occurred in 12,003 races at 4347 race meets and on 2438 race dates. Six hundred and forty-eight SDF tendinopathies were recorded in 626 horses. One hundred and thirty-one horses started in at least one steeplechase race subsequent to SDF tendinopathy, and 40 of these (31%) sustained another SDF tendinopathy and two (5%) sustained a third SDF

Discussion

This paper reports the results of the first study to identify risk factors for SDF tendinopathy specific to steeplechase races in the UK. The analysis benefits from access to a large cohort with a large number of injuries, but is limited by the reliance on diagnosis of SDF tendinopathy at the racecourse, which is likely to have resulted in under estimation of number of true cases. Along with this, the previous history of SDF tendinopathy is reliant on the horse having had the condition

Conclusions

Similar to the evaluation of risk factors in hurdle racing, it would appear from this study that firm ground, increased age and previous SDF tendinopathy injury are all risk factors for subsequent injury. The multiple risk factors identified provide information that can be used to help review current regulations and racecourse management techniques. Not all of the observed associations and differences between disciplines can be readily explained by the data currently available. As a result,

Conflict of interest statement

None of the authors of this paper has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper.

Acknowledgements

The authors wish to thank the staff at the British Horseracing Authority and Weatherbys Limited for assistance with data collection, and the Horserace Betting Levy Board for funding the research.

References (23)

  • K.H. Lam et al.

    Descriptive analysis of retirement of Thoroughbred racehorses due to tendon injuries at the Hong Kong Jockey Club (1992–2004)

    Equine Veterinary Journal

    (2007)
  • Cited by (22)

    • Factors associated with completion of Fédération Équestre Internationale endurance rides (2012–2019): Modelling success to promote welfare-oriented decisions in the equestrian sport of endurance

      2022, Preventive Veterinary Medicine
      Citation Excerpt :

      This may be due to a subclinical injury or disease, other specifics of the horse or lack of fitness for the competition levels attempted that predispose the horse to an increased risk of one or more adverse outcomes. In Thoroughbred racing, previous injury and/or placement on a ‘Vet list’ has been shown to be associated with the risk of subsequent (fatal) injury (Georgopoulos, 2017; Georgopoulos and Parkin, 2016; Reardon et al., 2013, 2012). The study found that female riders were more likely to complete the ride successfully than male riders.

    • Regenerative Therapies for the Treatment of Tenodesmic Injuries in Horses

      2019, Journal of Equine Veterinary Science
      Citation Excerpt :

      Furthermore, several studies have demonstrated a major effect of different trainers on the risk of injury [3]. Improved prevention and management of exercise-related pathology require early detection, which can be extremely difficult; however, the identification of risk factors can be used to revise guidelines and racecourse management techniques to prevent future injuries [52,58]. Various types of lesions have been described for the DDFT.

    • Risk factors for race-day fatality, distal limb fracture and epistaxis in Thoroughbreds racing on all-weather surfaces in Great Britain (2000 to 2013)

      2017, Preventive Veterinary Medicine
      Citation Excerpt :

      Previous studies have used official race rating to describe horse performance (Wood et al., 2001; Reardon et al., 2013), which correlates well with the horse’s performance index used in the current study (Compston et al., 2013). Previous GB studies identified that horses with no official race rating (i.e. lower performance horses) had a higher risk of fatality (Wood et al., 2001) or tendon injury (Reardon et al., 2013) than horses with a high rating, which is in contrast to findings in the current study. This may be due to the previous studies including horses racing on all surface types, rather than specifically on AW surfaces.

    • Prevention of Musculoskeletal Injury in Thoroughbreds

      2015, Robinson's Current Therapy in Equine Medicine: Seventh Edition
    View all citing articles on Scopus
    View full text