FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Equine veterinary journal2023; doi: 10.1111/evj.13945

Subchondral lucencies of the medial femoral condyle in yearling and 2-year-old Thoroughbred sales horses: Prevalence, progression and associations with racing performance.

Abstract: Subchondral lucencies (SCLs) in the distal aspect of the medial femoral condyle (MFC) of young Thoroughbred horses are a source of controversy on presale radiographs. There is limited scientific evidence regarding the risk of progression and impact on future racing performance. Objective: To (1) identify the prevalence of MFC SCLs on sales repository radiographs in yearling and 2-year-old Thoroughbreds; (2) identify any association between grade of MFC SCL and future racing performance and (3) monitor changes in MFC SCL grades between yearling and 2-year-old sales. Methods: Prospective cohort study. Methods: Radiographs were obtained with consignor permission from a 2016 yearling sale and five 2017 2-year-old sales. Stifle radiographs were evaluated and MFC SCLs graded on a scale of 0-3. Axial MFC lucencies were recorded separately. Maximum MFC grades per horse were analysed for associations with racing performance outcomes, adjusted for sex, to the end of the horses' 4-year-old racing year. Analysis was via logistic, negative binomial or linear regression as appropriate, with the threshold for significance set at α = 0.05. Results: Radiographs from 2508 yearlings (5016 stifles) and 436 2-year-olds (872 stifles) were included in the study. MFC SCLs of grades 1-3 were observed in 242 (9.65%) yearlings and 49 (11.2%) 2-year-olds. Bilateral MFC SCLs of grades 1-3 were observed in 54 (2.2%) yearlings and 12 (2.8%) 2-year-olds. Grade 1 MFC SCLs in yearlings either remained unchanged (14/31), progressed to a grade 2 (6/31) or resolved (11/31) by the 2-year-old sale. Grade 2 MFC SCLs in yearlings remained unchanged (6/10), progressed to a grade 3 (2/10) or improved to a grade 1 (2/10). Yearlings with a grade 3 MFC SCL had a 78% probability of starting a race (95% confidence interval [CI] 58.2-89.6%), compared with an 84% probability of racing for grade 0 yearlings (95% CI 82.7-85.8%). Six of the seven yearlings with axial MFC lucencies raced. Conclusions: This study may underestimate the prevalence of severe lesions in the general yearling population of U.S. Thoroughbreds. However, the convenience sample used is representative of the population of interest at sales. The study design could not address exclusions prior to sale. Conclusions: Grade 1 MFC SCLs are the most common type seen in yearling and 2-year-old sales horses. The majority of yearling grade 1 MFC SCLs resolved or remained static by 2-year-old sales. It was also possible for grade 2 and 3 MFC SCLs to improve one grade between sales. Fewer sales yearlings with a grade 3 MFC SCL raced, but in those that did race there was no evidence of worse performance compared to unaffected peers. Axial MFC lucencies did not affect racing performance.
© 2023 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.
Get Full Text
Publication Date: 2023-06-22 PubMed ID: 37345448DOI: 10.1111/evj.13945Google 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.
LinkedInCopy
  • 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 primarily investigates the prevalence of subchondral lucencies in the medial femoral condyle in young Thoroughbred horses, their potential progression, and any possible impact on the horses’ future racing performance.

Study Design and Methodology

  • The study is a prospective cohort study where researchers used radiographs taken from a yearling sale in 2016 and five 2-year-old horse sales in 2017.
  • The research team graded the subchondral lucencies in the medial femoral condyle (MFC SCLs) on horses with a 0-3 scale.
  • The team used regression models to analyze the Max MFC grades in relation to future racing outcomes.
  • The study looked at potential variables like sex and adjusted for these in their analysis.

Results of the Study

  • The researchers included radiographs from 2508 yearlings and 436 2-year-olds in the study.
  • The study found MFC SCLs in approximately 10% of the yearlings and 2-year-olds, with about 2% showing bilateral MFC SCLs.
  • There was evidence of possible progression in the condition of the MFC SCLs between the yearling and two-year-old sales.
  • Yearlings with grade 3 (the highest severity grade) MFC SCL had a slightly lower probability of starting a race as compared to those with grade 0.
  • The axial MFC lucencies did not appear to impact racing performance.

Conclusions of the Study

  • The researchers suspect that their study may underestimate the prevalence of severe lesions in the general yearling population of U.S. Thoroughbreds due to the sample size and limitation in their study design like limitations to account for exclusions before the sale.
  • Among MFC SCLs, grade 1 is the most commonly observed in yearlings and 2-year-olds being sold.
  • The majority of the yearlings having grade 1 MFC SCLs either had resolved or remained static by the time of the 2-year-old sale. And for higher-grade MFC SCLs (grade 2 and 3), a one-grade improvement between sales was possible.
  • There was no evidence suggesting worse performance in racing for those horses that raced despite having a grade 3 MFC SCL, compared to their unaffected peers.

The researchers conclude that while MFC SCLS are prevalent in yearling and 2-year-old Thoroughbreds and could progress, they do not necessarily impact the horses’ future racing performance.

Cite This Article

APA
Peat FJ, Kawcak CE, McIlwraith CW, Keenan DP, Berk JT, Mork DS. (2023). Subchondral lucencies of the medial femoral condyle in yearling and 2-year-old Thoroughbred sales horses: Prevalence, progression and associations with racing performance. Equine Vet J. https://doi.org/10.1111/evj.13945

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Peat, Frances J
  • Orthopaedic Research Center, C. Wayne McIlwraith Translational Medicine Institute, Colorado State University, Fort Collins, Colorado, USA.
Kawcak, Christopher E
  • Orthopaedic Research Center, C. Wayne McIlwraith Translational Medicine Institute, Colorado State University, Fort Collins, Colorado, USA.
McIlwraith, C Wayne
  • Orthopaedic Research Center, C. Wayne McIlwraith Translational Medicine Institute, Colorado State University, Fort Collins, Colorado, USA.
Keenan, David P
  • Matamata Veterinary Services, Matamata, New Zealand.
Berk, Jeffrey T
  • Equine Medical Associates, Lexington, Kentucky, USA.
Mork, Daniel S
  • Department of Statistics, College of Natural Sciences, Colorado State University, Fort Collins, Colorado, USA.

Grant Funding

  • Grayson-Jockey Club Research Foundation
  • Keeneland Association Ltd
  • Fasig-Tipton Ltd
  • Barbara Banke
  • Bridlewood Farm
  • Flaxman Holdings
  • Maria Niarchos
  • John & Jerry Amerman
  • Foxwood Stables
  • Three Chimneys Farm
  • Ashford Stud
  • John Magnier
  • Dr Mark Dedomenico
  • Consignors & Commercial Breeders Association (Lexington, Kentucky)
  • Marty & Pam Wygod
  • Gary West
  • Dr Ryan Carpenter
  • Antony Beck
  • Gainesway Farm
  • Spendthrift Farm
  • Denali Stud
  • Victoria Chapman

References

This article includes 25 references
  1. The Consignors & Commerical Breeders Association. Success at the sales: a guide to buying Thoroughbreds at auction.. Lexington, KY: CBA; 2016.
  2. Jeffcott LB, Kold SE. Clinical and radiological aspects of stifle bone cysts in the horse.. Equine Vet J 1982;14(1):40-6.
  3. Santschi EM, Prichard MA, Whitman JL, Batten CA, Strathman TA, Canada NC. Stifle radiography in Thoroughbreds from 6 to 18 months of age.. Equine Vet Educ 2020;32(S10):78-84.
  4. Oliver LJ, Baird DK, Baird AN, Moore GE. Prevalence and distribution of radiographically evident lesions on repository films in the hock and stifle joints of yearling Thoroughbred horses in New Zealand.. N Z Vet J 2008;56(5):202-9.
  5. Pérez-Nogués M, Derham A, Marmion J, True BW. Progression of shallow medial femoral condyle radiographic lucencies in Thoroughbred repository radiographs and their influence on future racing careers.. Equine Vet J 2021;53(2):287-93.
  6. Meagher DM, Bromberek JL, Meagher DT, Gardner IA, Puchalski SM, Stover SM. Prevalence of abnormal radiographic findings in 2-year-old Thoroughbreds at in-training sales and associations with racing performance.. J Am Vet Med Assoc 2013;242(7):969-76.
  7. Cohen ND, Carter GK, Watkins JP, O'Conor MS. Association of racing performance with specific abnormal radiographic findings in Thoroughbred Yearlings sold in Texas.. J Equine Vet Sci 2006;26(10):462-74.
  8. Whitman JL, Morehead JP, Prichard MA, Hance SJ, Keuler NS, Santschi EM. Radiographic lucencies in the medial femoral condyle of Thoroughbred sale yearlings: a preliminary investigation of the effect of race records.. Proc Am Assoc Equine Practit 2006;52:416-9.
  9. Jacquet S, Robert C, Valette JP, Denoix JM. Evolution of radiological findings detected in the limbs of 321 young horses between the ages of 6 and 18months.. Vet J 2013;197(1):58-64.
  10. McIntosh SC, McIlwraith CW. Natural history of femoropatellar osteochondrosis in three crops of Thoroughbreds.. Equine Vet J 1993;25(S16):54-61.
  11. Santschi EM. Treatment options and long-term outcomes of horses with subchondral lucencies of the medial femoral condyle.. Equine Vet Educ 2021;33(7):386-8.
  12. Kane AJ, McIlwraith CW, Park RD, Rantanen NW, Morehead JP, Bramlage LR. Radiographic changes in Thoroughbred yearlings. Part 2: associations with racing performance.. Equine Vet J 2003;35(4):366-74.
    doi: 10.2746/042516403776014307google scholar: lookup
  13. Kane AJ, Park RD, McIlwraith CW, Rantanen NW, Morehead JP, Bramlage LR. Radiographic changes in Thoroughbred yearlings. Part 1: prevalence at the time of the yearling sales.. Equine Vet J 2003;35(4):354-65.
  14. Wylie CE, Newton JR. A systematic literature search to identify performance measure outcomes used in clinical studies of racehorses.. Equine Vet J 2018;50(3):304-11.
    doi: 10.1111/evj.12757google scholar: lookup
  15. Plevin S, McLellan J. The effect of insertional suspensory branch desmitis on racing performance in juvenile Thoroughbred racehorses.. Equine Vet J 2014;46(4):451-7.
    doi: 10.1111/evj.12161google scholar: lookup
  16. Spike-Pierce DL, Bramlage LR. Correlation of racing performance with radiographic changes in the proximal sesamoid bones of 487 Thoroughbred yearlings.. Equine Vet J 2003;35(4):350-3.
  17. Lepeule J, Robert C, Bareille N, Valette J-P, Jacquet S, Seegers H. A reliable severity scoring system for radiographic findings in the limbs of young horses.. Vet J 2013;197(1):52-7.
    doi: 10.1016/j.tvjl.2013.03.041google scholar: lookup
  18. Jackson MA, Vizard AL, Anderson GA, Mattoon JS, Lavelle RB, Smithenson BT. An assessment of intra- and interobserver agreement of reporting orthopaedic findings on presale radiographs of Thoroughbred yearlings.. Equine Vet J 2014;46(5):567-74.
    doi: 10.1111/evj.12150google scholar: lookup
  19. McLellan J, Plevin S. Evaluation of videoendoscopic examinations of arytenoid function in the 2-year-old Thoroughbred: can we all agree?. Equine Vet J 2019;51(3):364-9.
    doi: 10.1111/evj.13030google scholar: lookup
  20. Jackson MA, Vizard AL, Anderson GA, Mattoon JS, Lavelle RB, Smithenson BT. Identification and prevalence of errors affecting the quality of radiographs submitted to Australian Thoroughbred yearling sale repositories.. Vet Radiol Ultrasound 2011;52(3):262-9.
    doi: 10.1111/j.1740-8261.2011.01800.xgoogle scholar: lookup
  21. Axling JM, Castle K, Velie BD, Tammen I, Thomson PC, Hamilton NA. Use of diagnostic reports to estimate prevalence and distribution of skeletal lesions in young Thoroughbreds.. Vet J 2016;214:72-6.
  22. Santschi EM, Williams JM, Morgan JW, Johnson CR, Bertone AL, Juzwiak JS. Preliminary investigation of the treatment of equine medial femoral condylar subchondral cystic lesions with a transcondylar screw.. Vet Surg 2015;44(3):281-8.
  23. Contino EK, Park RD, McIlwraith CW. Prevalence of radiographic changes in yearling and 2-year-old quarter horses intended for cutting.. Equine Vet J 2012;44(2):185-95.
  24. Landis JR, Koch GG. The measurement of observer agreement for categorical data.. Biometrics 1977;33(1):159-74.
  25. Jeffcott LB, Kold SE. Stifle lameness in the horse: a survey of 86 referred cases.. Equine Vet J 1982;14(1):31-9.

Citations

This article has been cited 4 times.
  1. Boado A, Pollard D, Dyson S. A Retrospective Study of the Evolution of Orthopaedic Injuries in 70 Dressage Horses. Animals (Basel) 2025 Jun 12;15(12).
    doi: 10.3390/ani15121740pubmed: 40564292google scholar: lookup
  2. Peat FJ, Kawcak CE, McIlwraith CW, Berk JT, Keenan DP. Concurrent radiological and ultrasonographical findings in the forelimb proximal sesamoid bones and adjacent suspensory ligament branches in yearling and 2-year-old Thoroughbred sales horses. Equine Vet J 2025 May;57(3):654-665.
    doi: 10.1111/evj.14120pubmed: 39039612google scholar: lookup
  3. Peat FJ, Kawcak CE, McIlwraith CW, Berk JT, Keenan DP, Selberg KT, Ojeda A. Ultrasonography of the suspensory ligament branches in yearling and 2-year-old Thoroughbred sales horses: Prevalence, progression of findings and associations with racing performance. Equine Vet J 2025 Mar;57(2):384-397.
    doi: 10.1111/evj.14137pubmed: 39007207google scholar: lookup
  4. Pérez-Nogués M, Manso-Díaz G, Spirito M, López-Sanromán J. Treatment Comparison for Medial Femoral Condyle Subchondral Cystic Lesions and Prognosis in Yearling Thoroughbred Racehorse Prospects. Animals (Basel) 2024 Apr 6;14(7).
    doi: 10.3390/ani14071122pubmed: 38612360google scholar: lookup
Subscribe to our newsletter
Join 99,658 horse owners like you who receive our email updates on horse health and nutrition.