22
EQUINE VETERINARY EDUCATION / AE / JANUARY 2017
Case Report
Tendonitis of branches of the superficial digital flexor tendon in Standardbred racehorses: 15 cases
C. Tricaud, M. Cousty*, A. Alexandre , C. Tessier and F. David Clinique Equine de Livet, St Michel de Livet, France; Oniris, Nantes, France; and Mid-Atlantic Equine Center, Ringoes, New Jersey, USA. *Corresponding author email:
cousty@celivet.com This work was presented at: AVEF Annual meeting 11–13 December 2013 Deauville, France (oral presentation).
† †‡ †
‡ Keywords: horse; tendonitis; superficial digital flexor tendon; insertion; branch; pastern; lameness
Summary This case report describes the clinical and ultrasonographic findings and performance outcome of distal tendonitis of the superficial digital flexor tendon (SDFT) in Standardbred racehorses. Cases with distal tendonitis of the SDFT in isolation (not associated with a metacarpal lesion) were reviewed retrospectively. The clinical and ultrasonographic findings and performance outcome were reviewed. The injury was located on the left forelimb in 67% (10/15) of horses and on the right forelimb in 33% (5/15). None of the horses were affected bilaterally. The lateral branch was involved in 80% of the cases (12/15) and medial branch in 20% (3/15). None of the horses were affected biaxially. Mean time between injury and first start ± s.d. was 302 ± 142 days. Returning to racing was observed in 93% of the horses (14/15), with a reinjury rate of 22% (2/9). For horses which raced after the injury, the number of starts, shows and wins was not significantly different before and after injury, regardless of the location of the lesion. Tendonitis of branches of the SDFT in isolation carries a good prognosis in Standardbred racehorses. A higher return to racing and a lower reinjury rate may be expected compared to lesions in the metacarpal region.
Introduction
Tendonitis of the superficial digital flexor tendon (SDFT) is a common injury in sport and racehorses. Tendonitis usually occurs in the metacarpal/tarsal region of the tendon. The forelimb is more commonly affected. A core lesion is the most common ultrasonographic finding (Ross et al. 2011). Return to athletic performance is fair but reinjury is a common outcome (Reef and Genovese 2011; Ross et al. 2011). Tendonitis of the distal branches of SDFT is less commonly
observed. These injuries are more common in the forelimb (Reef and Genovese 2011). It may occur in isolation, without an injury to the SDFT in the metacarpal/tarsal region or it may present as an extension of a more proximal tendon injury (Reef and Genovese 2011). Abnormal conformation such as a long pastern, an underrun heel or an axially-displaced heel may predispose to injury of a SDFT branch (Gibson et al. 1997; Reef and Genovese 2011). A poorer prognosis has been suggested in a post mortem study (Webbon 1977). A high rate of reinjury has also been advocated in eventers and steeplechasers (Dyson and Denoix 1995). In a study performed on 14 Thoroughbred racehorses, 70% of horses returned to previous use and were able to compete without further tendon injury. The performance outcome was only briefly described (Gibson et al. 1997). However, in this study, only the number of starts
© 2015 EVJ Ltd
after the injury was given without comparison of other performance parameters before and after injury. The objective of this study was to describe the clinical presentation, ultrasonographic findings and performance outcome of distal tendonitis of the SDFT in Standardbred racehorses.We hypothesised that isolated SDFT branch lesions in Standardbred racehorses would carry a more favourable prognosis than that observed in Thoroughbred racehorses.
Materials and methods
Cases of distal tendonitis of the SDFT in isolation in Standardbred racehorses presented at the hospital between 2004 and 2011 were reviewed. Cases with concomitant lesions in the metacarpal/tarsal region were excluded from the study. Age at the time of injury, sex, affected limb, location
of the lesion (medial or lateral), abnormality on physical examination at the time of injury, grade of lameness (American Association of Equine Practitioners grading system), ultrasonographic findings (7.5 MHz linear transducer), rehabilitation schedule and rehabilitation duration (time between injury and first start) were recorded. The clinical outcome (sound vs. lame) and appearance of the leg was determined based on a telephone conversation with the horse’s professional trainer. The performance outcome (number of starts, number of shows [horses finishing within the purse distribution], number of wins and earnings) was analysed over 2 periods using an online national horse racing database (SECF): 12 months before injury and between 12 and 24 months after injury. Nonparametric methods were used to analyse the data as
normality assumption could not be reached with the Shapiro-Wilk test. A pairedWilcoxon test was used to compare the performance parameters 12 months before and 24 months after injury. A Mann–Whitney U test was used to compare performance parameters in horses with a medial vs. a lateral SDFT branch injury. The level of significance was set at P<0.05.
Results
Fifteen cases were recorded during the study period. There were 6 stallions, 6 geldings and 3 females. Mean age ± s.d. at the time of the injury was 5.9 ± 1.3 years (range: 4.1–8.4).
Clinical and ultrasonographic findings at the time of diagnosis The injury was located on the left forelimb in 10 horses (67%) and on the right forelimb in 5 horses (33%). None of the horses
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72
