Distal sagittal forelimb conformation in young Walloon horses: Radiographic assessment and its relationship with osteochondral fragments.
Authors: Van Cauter Raphaël, Caudron Isabelle, Lejeune Jean-Philippe, Rousset Alycia, Serteyn Didier
Journal: PloS one
Summary
# Editorial Summary Van Cauter and colleagues conducted radiographic screening of 266 young Walloon horses (532 forelimbs) to establish whether distal forelimb conformation traits could predict the presence of osteochondral fragments, a significant cause of performance limitation and lameness in young stock. Using receiver operator characteristic analysis, the researchers identified three measurable conformational features associated with fragment presence: increased palmar angle of the distal phalanx (optimal threshold 2.95°) correlated specifically with dorso-proximal fragments of the proximal phalanx, whilst greater withers height (≥152.5 cm) and larger third metacarpal bone diameter (≥34.9 mm) predicted fragments across multiple joints, particularly the tarsocrural and metatarsophalangeal regions. Notably, 24% of the cohort exhibited asymmetrically upright feet (>2° steeper incline contralaterally), though the diagnostic accuracy of these individual traits remained modest, with areas under the curve ranging from 0.585 to 0.623. For farriers and veterinary professionals, these findings suggest that whilst foot conformation—particularly plantar angle of the distal phalanx—warrants attention during early lameness investigations, conformational assessment alone cannot reliably screen for osteochondral fragments; however, this research establishes a foundation for developing multi-trait predictive models that may eventually identify high-risk individuals during pre-purchase or breeding evaluations.
Read the full abstract on PubMed
Practical Takeaways
- •Young horses with more upright foot conformation (steeper hoof-pastern angles) and increased palmar angles of the distal phalanx may warrant closer radiographic screening for osteochondral fragments, particularly at the proximal phalanx
- •Taller horses and those with larger cannon bone diameter appear at higher risk for osteochondral fragments—consider this when selecting breeding stock or assessing lameness risk in young prospects
- •While conformation assessment shows promise for identifying at-risk individuals, relying on radiographic screening rather than conformation alone remains prudent, as single traits have limited predictive power
Key Findings
- •Increased palmar angle of the distal phalanx (>2.95°) significantly correlates with osteochondral fragments at the dorso-proximal margin of the proximal phalanx (sensitivity 77.3%, specificity 52.9%)
- •Greater height at withers (>152.5 cm) and larger third metacarpal bone diameter (>34.9 mm) are significantly associated with presence of osteochondral fragments across joints
- •24% prevalence of upright feet (>2° steeper incline vs. contralateral) observed in young Walloon horses studied
- •Diagnostic accuracy of individual conformation traits to predict osteochondral fragments remains limited (AUC 0.585-0.623), suggesting need for multi-trait prediction models