Microstructural features of subchondral radiolucent lesions in the medial femoral condyle of juvenile Thoroughbreds: A microcomputed tomography and histological analysis

Thibeaut Lemirre, Elizabeth M. Santschi, Christiane A. Girard, Ursula Fogarty, Jennifer G. Janes, Helene Richard, Sheila Laverty

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Background: The aetiology of equine medial femoral condyle (MFC) subchondral bone radiolucencies (SR) is unknown. Objectives: Characterise the microstructural structural features of MFC SR in juvenile Thoroughbreds with microcomputed tomography (μCT) and histology. Study design: Cross-sectional post-mortem study. Methods: Distal femurs were collected at post-mortem. Conventional tomodensitometry was employed to scout for MFCs with and without SR lesions (SR+ and SR−, respectively). Group 1 were CT MFC SR+ and Group 2 age-matched SR− controls. Both underwent μCT and histological analysis. Group 3 CT MFC SR− foals, <6 months, were selected to search for chondronecrosis. Histological sections, processed from the lesion (Group 1) and a corresponding site in Groups 2 and 3, were assessed for chondronecrosis, fibrin, fibroplasia and osteochondral separation. Group 3 sections were surveyed for chondronecrosis alone. Results: A total of 178 femurs from 89 Thoroughbreds were harvested. Of these horses 19.1% (95% CI: 10.9%-27.3%) were CT MFC SR+ (17/23; 7.46 ± 4.36 months) and met the inclusion criteria for Group 1. Group 2 included 30 CT MFC SR− specimens (5.00 ± 2.73 months) and Group 3 had 44 CT MFC SR− s (2.68 ± 1.74 months). SR were located axially in foals <7 months of age, and centrally thereafter. All SRs had areas of thickened cartilage on histology and separation at the osteochondral junction containing fibrin (acute event) and fibroplasia (chronicity) in 73.9% (17/23; 95% CI: 56%-91.9%). In Group 1 specimens, chondronecrosis was present in 82.6% (19/23; 95% CI: 67.1%-98.1%) but four MFC SR+ had no evidence of chondronecrosis. Chondronecrosis was not detected in the Group 3 foal MFCs. Main limitations: No longitudinal follow-up. Conclusions: The absence of chondronecrosis, pathognomic of osteochondrosis, in four MFC SR+s and in all of the CT MFC SR− foals suggests that osteochondrosis is not the cause, or the only cause, of these lesions and favours trauma as an alternate aetiological hypothesis.

Original languageEnglish
Pages (from-to)601-613
Number of pages13
JournalEquine Veterinary Journal
Volume54
Issue number3
DOIs
StatePublished - May 2022

Bibliographical note

Funding Information:
This study was supported by grants from Fonds en Santé Équine de la Faculté de Médecine Vétérinaire de l'Université de Montréal et Zoetis. S. Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network – ThéCell (a thematic network supported by the Fonds de recherche du Québec–Santé).

Funding Information:
This study was supported by grants from Fonds en Sant? ?quine de la Facult? de M?decine V?t?rinaire de l'Universit? de Montr?al et Zoetis. S. Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network ? Th?Cell (a thematic network supported by the Fonds de recherche du Qu?bec?Sant?). We thank the technical staff at the Irish Equine Centre and University of Kentucky Veterinary Diagnostic Laboratory for specimen collection.

Publisher Copyright:
© 2021 EVJ Ltd.

Keywords

  • condyle
  • cyst
  • horse
  • juvenile osteochondral trauma
  • osteochondral junction
  • osteochondrosis
  • subchondral radiolucency

ASJC Scopus subject areas

  • Equine

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