Prevalence, location and symmetry of noncatastrophic ligamentous suspensory apparatus lesions in California Thoroughbred racehorses, and association of these lesions with catastrophic injuries.
Authors: Hill A E, Gardner I A, Carpenter T E, Lee C M, Hitchens P L, Stover S M
Journal: Equine veterinary journal
Summary
# Editorial Summary Suspensory ligament injuries in racehorses often go undetected until catastrophic failure occurs, yet understanding where these lesions develop could improve early intervention and injury prevention. This necropsy-based study examined 327 deceased California Thoroughbreds to map the distribution and severity of lesions across the suspensory ligament body, branches, and distal sesamoidean ligaments, correlating findings with cause of death and other factors. Moderate lesions (≥2 mm, visibly darker tissue) were present in 16% of horses overall, whilst milder damage affected 77%; notably, horses with moderate lesions were 4.6 times more likely to have died from suspensory apparatus failure and 5 times more likely to have suffered metacarpal lateral condylar fracture compared to those with non-musculoskeletal causes of death, with risk increasing substantially in horses aged 7 years or older. The suspensory ligament branches and oblique distal sesamoidean ligaments emerged as particular vulnerability points. For practitioners, these findings suggest that systematic ultrasonographic monitoring of these specific anatomical sites—particularly in older athletes and those showing performance decline—could identify subclinical damage before catastrophic breakdown occurs, offering a practical means of fatigue assessment and targeted rehabilitation protocols to protect both the suspensory apparatus and metacarpal structures from progression to career-ending or fatal injury.
Read the full abstract on PubMed
Practical Takeaways
- •Suspensory apparatus lesions are extremely common in racehorses; moderate lesions should be considered a significant risk factor for catastrophic failure and warrant enhanced monitoring and potentially reduced racing intensity
- •Age is a critical risk factor—older racehorses (≥7 years) show substantially higher rates of moderate lesions and associated injuries, suggesting different management strategies may be needed for aging athletes
- •Regular imaging and assessment of suspensory ligament health, particularly in the branches and oblique distal sesamoid ligaments, may allow early detection of fatigue-related damage before catastrophic failure occurs
Key Findings
- •Moderate lesions were present in 16% of racehorses and mild lesions in 77%, with similar frequency in SL branches and oblique DSLs
- •Moderate lesions were 4.6 times more likely in horses that died from suspensory apparatus failure (P=0.004)
- •Moderate lesions were 5.05 times more likely in horses with metacarpal lateral condylar fracture (P=0.012)
- •Horses aged ≥7 years were 5.33 times more likely to have moderate lesions compared to 2-year-olds (P=0.012)