Bone Damage in the Fetlock Region of Sport Horses Using Low-Field MRI:

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

Animals (Basel). 2025 Dec 2;15(23):3468. doi: 10.3390/ani15233468.
Authors
Donatella De Zani 1 , Vanessa Rabbogliatti 1 , Silvia Rabba 2 , Luigi Auletta 1 , Maurizio Longo 1 , Davide D Zani 1
Affiliations

1 Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy.
2 Freelance, 28075 Novara, Italy.

PMID: 41375526
DOI: 10.3390/ani15233468

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.

Keywords: bone marrow lesion; bone pathology; equine; metacarpo/metatarsophalangeal joint.