Prospective, longitudinal assessment of subchondral bone morphology and pathology using standing, cone-beam computed tomography in fetlock joints of 2-year-old Thoroughbred racehorses in their first year of training.
Authors: Ciamillo Sarah A, Wulster Kathryn B, Gassert Taryn M, Richardson Dean W, Brown Kara A, Stefanovski Darko, Ortved Kyla F
Journal: Equine veterinary journal
Summary
# Editorial Summary Catastrophic fetlock fractures in young Thoroughbreds are invariably preceded by stress-induced subchondral bone injury, yet early detection remains challenging with conventional radiography. This prospective cohort study followed 41 two-year-old racehorses through their first year of training using standing cone-beam computed tomography (CBCT) at baseline, 6 months and 12 months, quantifying subchondral bone sclerosis (measured as increased radiodensity) and identifying pathological lesions consisting of hypodense areas within sclerotic bone. Over the 12-month period, all horses demonstrated significant increases in sclerosis within both medial and lateral condyles of the third metacarpal/metatarsal bones and the parasagittal grooves, whilst subchondral pathology emerged and progressed predominantly in the palmar condyles, parasagittal grooves and the ridges of the proximal phalanx. For practitioners involved in managing young racehorses—whether veterinarians, farriers or trainers—standing CBCT offers a non-invasive, practical screening tool that can detect bone remodelling and early pathological changes before catastrophic failure occurs, potentially enabling timely modifications to training load or therapeutic intervention; however, the study's lack of control for training variables and husbandry differences means findings represent natural training-related changes rather than dose-response relationships.
Read the full abstract on PubMed
Practical Takeaways
- •Standing CBCT can be used as an efficient screening tool to detect early subchondral bone changes in young racehorses before they progress to catastrophic injury—consider recommending this imaging modality when evaluating 2-year-olds entering race training
- •Subchondral bone sclerosis and pathology develop progressively during the first year of race training; early detection may allow for training modifications or interventions to prevent irreversible bone failure
- •This imaging protocol does not require sedation or general anesthesia, making it practical for on-site use at training facilities and breeding operations to monitor multiple horses
Key Findings
- •Subchondral bone sclerosis increased significantly over 12 months in medial and lateral MC3/MT3 condyles and parasagittal grooves in 2-year-old Thoroughbreds during race training
- •Subchondral bone pathology (hypodensity within hyperdensity regions) increased significantly in palmar condyles, parasagittal grooves, and dorsal condyles of MC3/MT3 and ridges of P1 over the 12-month training period
- •Standing cone-beam computed tomography (CBCT) effectively detected longitudinal changes in subchondral bone morphology and pathology in fetlock joints
- •Standing CBCT is a practical screening tool for early detection of bone pathology that may facilitate timely intervention to prevent catastrophic fetlock injuries in young racehorses