Prevalence of superficial digital flexor tendonitis and suspensory desmitis in Japanese Thoroughbred flat racehorses in 1999

Abstract

Summary Reasons for performing study: Overstrain injuries to the superficial digital flexor tendon (SDFT) and suspensory ligament (SL) are among the most common musculoskeletal injuries which contribute to the considerable wastage of racing Thoroughbreds. Many epidemiological studies have demonstrated the prevalence of and risk factors for tendon injury when racing but have not included those injuries sustained during training. However, since tendon injury during training is seen commonly in clinical practice, it is appropriate to determine the overall prevalence of tendon injury sustained during both training and racing. Objective: To determine the prevalence of overstrain injury to the SDFT and SL during training and racing among Thoroughbred flat racehorses in Japan in 1999. Methods: A retrospective study was performed using a sample population of 10,262 Thoroughbred racehorses. The medical information database of Thoroughbred racehorses registered by the Japan Racing Association (JRA) in 1999 was analysed for SDFT and SL overstrain injury diagnosed by a veterinarian employed by JRA during training and racing. Jump racehorses were excluded from this study. Results: The prevalence of forelimb SDFT tendonitis and SL desmitis was 11.1% (1130 cases) and 3.61% (370 cases) of the population, respectively. In the hindlimb, there were 0.06% (6 cases) and 0.14% (14 cases), respectively. Risks of SDF tendonitis in the forelimb in 3‐year‐olds or older horses were significantly higher than in 2‐year‐olds. In contrast, the risk of SL desmitis in the forelimb at age 3 and 4 years was 2.23 and 2.11 times higher, respectively, than in 2‐year‐olds, but this increased to 5.07 times in those age ≥5 years. Entire males were at greater risk in comparison to females and geldings. Conclusions: The results suggest that the prevalence of SDF tendonitis and SL desmitis in the forelimb was associated with the horse's age and sex. The prevalence of SL desmitis increased further with age compared with SDF tendonitis, possibly reflecting a more rapid accumulation of degeneration in this structure. Potential relevance: The age‐related risk demonstrated in this study provides further support that overstrain injuries are associated with accumulated degeneration. These data provide a valuable resource for further research into the aetiology of tendon injury in the racehorse.

Platelet rich plasma treatment of superficial digital flexor tendon lesions in racing Thoroughbreds

“…According to our results the positive effect of the application of PRP was registered not only in cases with acute injury but also in the chronic as well, which was similar to the results of Sutter et al (2004) who recommended application 30 days after the initial injury. Kasashima et al (2004) showed that there was an increase in the incidence of SDFT injury in racing horses from the age of two. They found that the most risky category is the five year old horses and that the probability of injury is three times higher than in two year old racing Thoroughbreds.…”

Fascicles from energy-storing tendons show an age-specific response to cyclic fatigue loading

“…In humans, the prevalence of Achilles injury is reported as 3% in the general population under 45 years of age [22], increasing to 15-56% in elite athletes, depending on the type of sport undertaken [22,23]. Injury to the SDFT in athletic horses is also common, with SDFT pathology reported in 11-24% of thoroughbred racehorses [24,25] and shows a similar initiation and progression to human Achilles tendinopathy [26,27]. Further, tendons become more prone to injury with increasing age, with regards to both the human Achilles [22,28] and equine SDFT [29,30].…”

Parameters influencing prevalence and outcome of tendonitis in Thoroughbred and Arabian racehorses

“…The most common strain-induced injuries in horses are believed to be preceded by a phase of degeneration (Smith and Goodship 2004). Therefore prevalence of tendonitis increases with age, as shown by Kasashima et al (2004), Perkins et al (2005), Lam et al (2007).…”