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Home / Equine Research Bank / Animals (Basel) / Subchondral and Osteochondral Unit Bone Damage in the Fetloc...
Animals : an open access journal from MDPI2025; 15(23); 3468; doi: 10.3390/ani15233468

Subchondral and Osteochondral Unit Bone Damage in the Fetlock Region of Sport Horses Using Low-Field MRI: Case Series.

Abstract: Damage to the osteochondral unit is a common cause of lameness in horses. Published descriptions of MRI findings of osteochondral unit and subchondral damage are currently lacking, and only a few reports describe outcomes in sport horses. The aims of this case series retrospective study were to describe different MRI patterns of osteochondral/subchondral pathology in the fetlock joint using low-field MRI and to provide outcome information. A total of 35 sport horses were included. Data regarding detailed clinical history, treatment and outcome were evaluated. MRI identified a total of 39 bone lesions: 14 were limited to the subchondral plate, and 25 involved the whole osteochondral unit. In 12 horses, a fissure was observed. Areas of high signal intensity on STIR sequences and low signal intensity on T1-weighted sequences within the trabecular bone were observed in association with subchondral and osteochondral unit damage. At follow-up, a persistent lameness was observed in 11 horses, all of which presented with a lesion involving the whole osteochondral unit. Different MRI patterns consistent with lesions involving either the entire osteochondral unit or only the subchondral bone plate could be identified using low-field MRI. MRI examination should be recommended in horses with inconclusive radiographic findings. Our results suggest that lesions limited to the subchondral bone are associated with a better prognosis.
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Publication Date: 2025-12-02 PubMed ID: 41375526PubMed Central: PMC12691481DOI: 10.3390/ani15233468Google Scholar: Lookup
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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.

Overview

  • This study used low-field MRI to investigate and describe bone damage in the fetlock joint of sport horses, particularly focusing on the osteochondral unit and subchondral bone.
  • The research also assessed how different types of bone lesions relate to horse lameness outcomes, highlighting the prognostic differences between lesions confined to the subchondral bone and those involving the full osteochondral unit.

Background

  • The osteochondral unit consists of the articular cartilage and the underlying subchondral bone, which together form a functional unit critical for joint health and function.
  • Damage to this unit is a common source of lameness in sport horses, impacting their performance and welfare.
  • MRI, particularly low-field MRI, is a diagnostic tool capable of detecting detailed joint and bone pathology not always visible on traditional radiographs.
  • Prior to this study, there was a shortage of detailed descriptions of MRI findings relating specifically to subchondral and osteochondral damage in the fetlock of sport horses, as well as limited information on related prognosis.

Study Aims and Methods

  • The primary goal was to characterize various MRI patterns of osteochondral and subchondral pathology in the fetlock joint using low-field MRI technology.
  • The secondary goal was to analyze clinical outcomes in relation to the type and extent of bone lesions identified on MRI.
  • This was a retrospective case series involving 35 sport horses that presented with fetlock joint issues.
  • Comprehensive clinical data were collected, including the horses’ clinical history, treatments received, MRI findings, and follow-up outcomes.
  • A total of 39 bone lesions were identified and categorized based on MRI appearance.

Findings

  • Out of 39 lesions, 14 were confined to the subchondral bone plate, while 25 involved the entire osteochondral unit.
  • Fissures, which are cracks or splits in the bone or cartilage, were noted in 12 horses indicating structural compromise.
  • MRI STIR (Short Tau Inversion Recovery) sequences showed areas of high signal intensity within the trabecular bone, revealing bone edema or inflammation associated with these lesions.
  • T1-weighted sequences showed corresponding low signal areas, which may indicate bone marrow changes or sclerosis related to the damage.
  • These MRI patterns allowed differentiation between isolated subchondral bone damage and more extensive osteochondral unit lesions.

Outcomes and Prognostic Implications

  • Follow-up revealed persistent lameness in 11 horses; notably, all these horses had lesions involving the full osteochondral unit.
  • Horses with lesions limited only to the subchondral bone plate generally had a better prognosis and improved clinical outcomes.
  • These findings suggest that the severity and extent of bone damage, particularly involvement beyond the subchondral plate, is linked to poorer recovery and continued lameness.

Clinical Significance and Recommendations

  • Low-field MRI is effective in detecting both subtle and extensive osteochondral and subchondral lesions that may not be evident on standard radiographs.
  • Horses presenting with fetlock joint lameness but inconclusive X-ray findings should be evaluated with MRI for more accurate diagnosis.
  • Recognizing specific MRI lesion patterns can help veterinarians predict clinical outcomes and tailor treatment plans accordingly.
  • This study emphasizes the importance of MRI in early and precise diagnosis, enabling better management and prognosis estimation in sport horses with fetlock injuries.

Cite This Article

APA
De Zani D, Rabbogliatti V, Rabba S, Auletta L, Longo M, Zani DD. (2025). Subchondral and Osteochondral Unit Bone Damage in the Fetlock Region of Sport Horses Using Low-Field MRI: Case Series. Animals (Basel), 15(23), 3468. https://doi.org/10.3390/ani15233468

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 15
Issue: 23
PII: 3468

Researcher Affiliations

De Zani, Donatella
  • Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy.
Rabbogliatti, Vanessa
  • Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy.
Rabba, Silvia
  • Freelance, 28075 Novara, Italy.
Auletta, Luigi
  • Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy.
Longo, Maurizio
  • Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy.
Zani, Davide D
  • Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy.

Conflict of Interest Statement

The authors declare no conflicts of interest.

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