Analyze Diet
Equine veterinary journal2018; 50(5); 602-608; doi: 10.1111/evj.12810

Ultrasonographic-based predictive factors influencing successful return to racing after superficial digital flexor tendon injuries in flat racehorses: A retrospective cohort study in 469 Thoroughbred racehorses in Hong Kong.

Abstract: Superficial digital flexor tendon (SDFT) injury is an important health and welfare concern in racehorses. It is generally diagnosed with ultrasonography, but predictive ultrasonographic features have not been reported. Objective: To determine ultrasonographic features of forelimb SDFT injury at initial presentation in Thoroughbred racehorses that could predict a successful return to racing (completing ≥5 races). Methods: Retrospective cohort study. Methods: Digitised ultrasonographic images of 469 horses with forelimb SDFT injuries from the Hong Kong Jockey Club (2003-2014) were evaluated, using a previously validated ultrasonographic scoring system. Six ultrasonographic parameters were evaluated (type and extent of the injury, location, echogenicity, cross-sectional area and longitudinal fibre pattern of the maximal injury zone [MIZ]), as well as horse signalment, retirement date and number of races before and after injury. Data were analysed by generalised linear regression with significance at P<0.05. Results: Cases were divided into two groups: 1) For cases of SDFT tendonitis with core lesions, cross-sectional area at the MIZ was the most significant factor determining a successful return to racing (P = 0.03). If the lesion was <50% of the total cross-sectional area, horses had 29-35% probability of successfully racing again, but if it was ≥50% this decreased to 11-16%. 2) For cases of SDFT tendonitis without a core lesion, longitudinal fibre pattern at the MIZ best predicted a successful return to racing (P = 0.002); if the affected longitudinal fibre pattern was <75% of the total, horses had 49-99% probability of successfully return to racing, but if it was ≥75% this decreased to 14%. Conclusions: Prognostic information may not be applicable to other breeds/disciplines. Conclusions: This is the first study to describe ultrasonographic features of forelimb SDFT injuries at initial presentation that were predictive of successful return to racing. The outcomes will assist with early, evidence-based decisions on prognosis in Thoroughbred racehorses.
Publication Date: 2018-02-23 PubMed ID: 29352495PubMed Central: PMC6099230DOI: 10.1111/evj.12810Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article looks into the potential to predict the successful return of racehorses to racing after suffering from superficial digital flexor tendon (SDFT) injuries. Specifically, the study investigates how certain ultrasonographic features observed at the time of initial injury assessment can serve as indicators of the horse’s ability to resume racing.

Research Methodology

  • The retrospective cohort study is based on ultrasonographic images of 469 horses which sustained forelimb SDFT injuries at the Hong Kong Jockey Club between 2003 and 2014.
  • A validated ultrasonographic scoring system was used to evaluate each case.
  • The researchers studied six ultrasonographic parameters: type and extent of the injury, its location, echogenicity, cross-sectional area and longitudinal fibre pattern of the most injured zone (MIZ).
  • In addition, each horse’s signalment (age, breed, sex), retirement date and number of races before and after the injury were recorded.
  • The data was then analysed using a generalised linear regression model where any result with a P value of less than 0.05 was considered statistically significant.

Study Findings

  • Two groups emerged from the study: In the first group (cases with SDFT tendonitis and core lesions), the most critical factor that determined a successful return to racing was the cross-sectional area at the MIZ. Particularly, if the lesion was less than 50% of the total cross-sectional area, there was a 29-35% probability of resumption of racing activities. Conversely, if the lesion was 50% or more, the probability dropped to 11-16%.
  • For the second group (cases of SDFT tendonitis without a core lesion), it was observed that the longitudinal fibre pattern at the MIZ best predicted a successful return to racing. If the damaged longitudinal fibre pattern was less than 75% of the total, the horses had a 49-99% chance of successfully returning to racing. However, if the affected fibre pattern was 75% or more, this dropped to 14%.

Conclusions

  • The study concludes that this is the first exploration of ultrasonographic parameters of initial SDFT injuries in predicting a successful return to racing for Thoroughbred racehorses.
  • The results can be used to make early, evidence-based prognostic decisions.
  • However, the researchers note that the findings may not be applicable to other horse breeds or disciplines.

Cite This Article

APA
Alzola R, Easter C, Riggs CM, Gardner DS, Freeman SL. (2018). Ultrasonographic-based predictive factors influencing successful return to racing after superficial digital flexor tendon injuries in flat racehorses: A retrospective cohort study in 469 Thoroughbred racehorses in Hong Kong. Equine Vet J, 50(5), 602-608. https://doi.org/10.1111/evj.12810

Publication

ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 50
Issue: 5
Pages: 602-608

Researcher Affiliations

Alzola, R
  • Oakham Veterinary Hospital, Oakham, Rutland, UK.
Easter, C
  • Oxtex Ltd, Witney, Oxfordshire, UK.
Riggs, C M
  • Veterinary Clinical Services, Hong Kong Jockey Club, Hong Kong.
Gardner, D S
  • School of Veterinary Medicine and Science, University of Nottingham, Loughborough, Leicestershire, UK.
Freeman, S L
  • School of Veterinary Medicine and Science, University of Nottingham, Loughborough, Leicestershire, UK.

MeSH Terms

  • Animals
  • Cohort Studies
  • Female
  • Hong Kong / epidemiology
  • Horse Diseases / diagnostic imaging
  • Horse Diseases / epidemiology
  • Horse Diseases / pathology
  • Horses
  • Male
  • Retrospective Studies
  • Risk Factors
  • Running
  • Sports
  • Tendon Injuries / diagnostic imaging
  • Tendon Injuries / epidemiology
  • Tendon Injuries / pathology
  • Tendon Injuries / veterinary
  • Ultrasonography / veterinary

References

This article includes 28 references
  1. Kasashima Y, Takahashi T, Smith RK, Goodship AE, Kuwano A, Ueno T, Hirano S. Prevalence of superficial digital flexor tendonitis and suspensory desmitis in Japanese Thoroughbred flat racehorses in 1999.. Equine Vet J 2004 May;36(4):346-50.
    pubmed: 15163043doi: 10.2746/0425164044890580google scholar: lookup
  2. Lam KH, Parkin TD, Riggs CM, Morgan KL. Descriptive analysis of retirement of Thoroughbred racehorses due to tendon injuries at the Hong Kong Jockey Club (1992-2004).. Equine Vet J 2007 Mar;39(2):143-8.
    pubmed: 17378443doi: 10.2746/042516407x159132google scholar: lookup
  3. Goodship AE, Birch HL, Wilson AM. The pathobiology and repair of tendon and ligament injury.. Vet Clin North Am Equine Pract 1994 Aug;10(2):323-49.
    pubmed: 7987721doi: 10.1016/s0749-0739(17)30359-0google scholar: lookup
  4. Rossdale PD, Hopes R, Digby NJ, offord K. Epidemiological study of wastage among racehorses 1982 and 1983.. Vet Rec 1985 Jan 19;116(3):66-9.
    pubmed: 3976145doi: 10.1136/vr.116.3.66google scholar: lookup
  5. Marr CM, McMillan I, Boyd JS, Wright NG, Murray M. Ultrasonographic and histopathological findings in equine superficial digital flexor tendon injury.. Equine Vet J 1993 Jan;25(1):23-9.
  6. Dyson SJ. Medical management of superficial digital flexor tendonitis: a comparative study in 219 horses (1992-2000).. Equine Vet J 2004 Jul;36(5):415-9.
    pubmed: 15253082doi: 10.2746/0425164044868422google scholar: lookup
  7. Smith RK. Tendon and ligament injury. Proc. Am. Ass. Equine. Practnrs. 54, 475‐501.
  8. Wilmink J, Wilson AM, Goodship AE. Functional significance of the morphology and micromechanics of collagen fibres in relation to partial rupture of the superficial digital flexor tendon in racehorses.. Res Vet Sci 1992 Nov;53(3):354-9.
    pubmed: 1465509doi: 10.1016/0034-5288(92)90139-sgoogle scholar: lookup
  9. Patterson-Kane JC, Wilson AM, Firth EC, Parry DA, Goodship AE. Exercise-related alterations in crimp morphology in the central regions of superficial digital flexor tendons from young thoroughbreds: a controlled study.. Equine Vet J 1998 Jan;30(1):61-4.
  10. Atta MG, Longenecker JC, Fine DM, Nagajothi N, Grover DS, Wu J, Racusen LC, Scheel PJ Jr, Hamper UM. Sonography as a predictor of human immunodeficiency virus-associated nephropathy.. J Ultrasound Med 2004 May;23(5):603-10; quiz 612-3.
    pubmed: 15154526doi: 10.7863/jum.2004.23.5.603google scholar: lookup
  11. Padaliya NR, Ranpariya JJ, Kumar D, Javia CB, Barvalia DR. Ultrasonographic assessment of the equine palmar tendons.. Vet World 2015 Feb;8(2):208-12.
  12. Alzola R, Riggs CM, Gardner DS, Freeman SL. Ultrasonographic scoring system for superficial digital flexor tendon (SDFT) injuries in horses: intra‐ and inter‐rater variability of a standardised system. Equine Vet. J. 48 , Suppl 50, 17.
  13. O'Meara B, Bladon B, Parkin TD, Fraser B, Lischer CJ. An investigation of the relationship between race performance and superficial digital flexor tendonitis in the Thoroughbred racehorse.. Equine Vet J 2010 May;42(4):322-6.
  14. Genovese RL, Longo K, Berthold B, Jorgenson J. Quantitative sonographic assessment in the clinical management of superficial digital flexor injuries in thoroughbred racehorses. Proc. Am. Ass. Equine Practnrs. 43, 285‐290.
  15. Kalisiak O. Parameters influencing prevalence and outcome of tendonitis in Thoroughbred and Arabian racehorses.. Pol J Vet Sci 2012;15(1):111-8.
    pubmed: 22708365doi: 10.2478/v10181-011-0121-9google scholar: lookup
  16. Parkin TD, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Analysis of horse race videos to identify intra-race risk factors for fatal distal limb fracture.. Prev Vet Med 2006 Apr 17;74(1):44-55.
  17. McGuigan MP, Wilson AM. The effect of gait and digital flexor muscle activation on limb compliance in the forelimb of the horse Equus caballus.. J Exp Biol 2003 Apr;206(Pt 8):1325-36.
    pubmed: 12624168doi: 10.1242/jeb.00254google scholar: lookup
  18. Avella CS, Ely ER, Verheyen KL, Price JS, Wood JL, Smith RK. Ultrasonographic assessment of the superficial digital flexor tendons of National Hunt racehorses in training over two racing seasons.. Equine Vet J 2009 May;41(5):449-54.
    pubmed: 19642404doi: 10.2746/042516409x391042google scholar: lookup
  19. Perkins NR, Reid SW, Morris RS. Risk factors for injury to the superficial digital flexor tendon and suspensory apparatus in Thoroughbred racehorses in New Zealand.. N Z Vet J 2005 Jun;53(3):184-92.
    pubmed: 16012588doi: 10.1080/00480169.2005.36503google scholar: lookup
  20. Takahashi T, Kasashima Y, Ueno Y. Association between race history and risk of superficial digital flexor tendon injury in Thoroughbred racehorses.. J Am Vet Med Assoc 2004 Jul 1;225(1):90-3.
    pubmed: 15239479doi: 10.2460/javma.2004.225.90google scholar: lookup
  21. Reardon RJ, Boden LA, Mellor DJ, Love S, Newton JR, Stirk AJ, Parkin TD. Risk factors for superficial digital flexor tendinopathy in Thoroughbred racehorses in hurdle starts in the UK (2001-2009).. Equine Vet J 2012 Sep;44(5):564-9.
  22. Welsh CE, Lewis TW, Blott SC, Mellor DJ, Lam KH, Stewart BD, Parkin TD. Preliminary genetic analyses of important musculoskeletal conditions of Thoroughbred racehorses in Hong Kong.. Vet J 2013 Dec;198(3):611-5.
    pmc: PMC3899015pubmed: 23746478doi: 10.1016/j.tvjl.2013.05.002google scholar: lookup
  23. Birch HL, Smith TJ, Poulton C, Peiffer D, Goodship AE. Do regional variations in flexor tendons predispose to site-specific injuries?. Equine Vet J Suppl 2002 Sep;(34):288-92.
  24. Strömberg B. The normal and diseased superficial flexor tendon in race horses. A morphologic and physiologic investigation.. Acta Radiol Suppl 1971;305:1-94.
    pubmed: 4947686
  25. Wilson AM, Goodship AE. Exercise-induced hyperthermia as a possible mechanism for tendon degeneration.. J Biomech 1994 Jul;27(7):899-905.
    pubmed: 8063840doi: 10.1016/0021-9290(94)90262-3google scholar: lookup
  26. Birch HL, Rutter GA, Goodship AE. Oxidative energy metabolism in equine tendon cells.. Res Vet Sci 1997 Mar-Apr;62(2):93-7.
    pubmed: 9243704doi: 10.1016/s0034-5288(97)90127-2google scholar: lookup
  27. Genovese RL, Rantanen NW, Simpson BS, Simpson DM. Clinical experience with quantitative analysis of superficial digital flexor tendon injuries in Thoroughbred and Standardbred racehorses.. Vet Clin North Am Equine Pract 1990 Apr;6(1):129-45.
    pubmed: 2187567doi: 10.1016/s0749-0739(17)30560-6google scholar: lookup
  28. Pickersgill CH, Marr CM, Reid SW. Repeatability of diagnostic ultrasonography in the assessment of the equine superficial digital flexor tendon.. Equine Vet J 2001 Jan;33(1):33-7.
    pubmed: 11191607doi: 10.2746/042516401776767494google scholar: lookup

Citations

This article has been cited 6 times.
  1. Entani MG, Franini A, Dragone L, Barella G, De Rensis F, Spattini G. Efficacy of Serial Ultrasonographic Examinations in Predicting Return to Play in Agility Dogs with Shoulder Lameness. Animals (Basel) 2021 Dec 30;12(1).
    doi: 10.3390/ani12010078pubmed: 35011184google scholar: lookup
  2. O' Brien C, Pegg J. A Preliminary Investigation into Ridden Water Submersion Training as an Adjunct to Current Condition Training Protocols in Performance Horses. Animals (Basel) 2021 Sep 7;11(9).
    doi: 10.3390/ani11092629pubmed: 34573594google scholar: lookup
  3. Ikeda Y, Ishihara A, Nakajima M, Yamada K. Risk factors for superficial digital flexor tendinopathy in Thoroughbred racing horses in Japan. J Equine Sci 2019;30(4):93-98.
    doi: 10.1294/jes.30.93pubmed: 31871411google scholar: lookup
  4. Tommasa SD, Raspe S, Farí G, Imperante A, Brehm W. Autologous conditioned serum IRAP efficacy for tendon and ligament injuries in horses: An observational study. Open Vet J 2025;15(8):3787-3793.
    doi: 10.5455/OVJ.2025.v15.i8.43pubmed: 41036008google scholar: lookup
  5. Najeb M, Samy A, Rizk A, Mosbah E, Karrouf G. Regenerative biologics modulating inflammation and promoting tenogenesis in equine superficial digital flexor tendonitis: from molecular pathways to clinical translation. Ir Vet J 2025 Sep 17;78(1):21.
    doi: 10.1186/s13620-025-00309-zpubmed: 40963139google scholar: lookup
  6. Najeb M, Samy A, Rizk A, Mosbah E, Karrouf G. Clinical benefits of early-stage autologous conditioned serum and injectable platelet-rich fibrin on healing superficial digital flexor tendonitis in donkeys. Ir Vet J 2025 Jun 7;78(1):13.
    doi: 10.1186/s13620-025-00299-ypubmed: 40483508google scholar: lookup