Shapes of cervical articular process joints and association with histological evidence of osteochondrosis in Warmblood foals: A post-mortem study.
Authors: Bergmann Wilhelmina, Vernooij Johannes C M, Grinwis Guy C M, Gröne Andrea
Journal: Equine veterinary journal
Summary
# Cervical Articular Process Joint Morphology and Osteochondrosis in Warmblood Foals Cervical vertebral compressive myelopathy (CVM) represents a significant welfare concern in young horses, with osteochondrosis dissecans (OCD) of the articular process joints (APJs) implicated as a key pathological mechanism; since biomechanical loading patterns are fundamentally determined by joint surface geometry, this post-mortem study of 804 APJ surfaces from 30 Warmblood foals examined whether specific conformational variations predispose to OC development. Using systematic classification of joint shapes viewed from above (oval, pointed, elongated) and laterally (flat, convex, concave, stepped, bevelled, folded edge, raised edge), researchers found that whilst oval top-view morphology with convex, bevelled, or simple flat lateral profiles represented normal variants, caudal articular surfaces demonstrated significantly greater shape variation than cranial surfaces, and specific combinations—particularly oval surfaces with folded edges, concave profiles, or flattened surfaces with raised/folded edges—showed substantially elevated odds ratios (2.49–3.90) for histological evidence of osteochondrosis compared with typical conformations. For practitioners managing young performance horses, these findings suggest that abnormal APJ geometry may function as a biomechanical risk factor for CVM development, potentially informing early identification protocols and rearing management strategies, though the study's limitation to foals under one month of age and absence of inter-observer reliability data warrant cautious interpretation pending larger prospective investigations.
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Practical Takeaways
- •Abnormal APJ morphology (particularly concave, folded-edge, or raised-edge lateral profiles combined with oval top-view shape) represents a biomechanical risk factor for osteochondrosis and potentially CVM in foals
- •Post-mortem evaluation of APJ conformation may help identify at-risk animals, though clinical imaging correlation is needed for practical screening
- •Breeding selection against oval-shaped APJs with concave or folded-edge morphology could potentially reduce incidence of cervical OCD and CVM in foal populations
Key Findings
- •Three top-view shapes (oval, pointed, elongated) and seven lateral-view shapes (flat, convex, concave, stepped, bevelled, folded edge, raised edge) were identified in cervical APJ surfaces
- •Oval top-view shape combined with folded edge, concave, or flat with raised/folded edge (flat+) were significantly more likely to have osteochondrosis than oval with convex, bevelled, or flat shapes (OR 2.49-3.90)
- •Caudal articular surfaces had significantly higher shape grades than cranial surfaces, indicating greater morphological variation
- •APJ shape variation may contribute to cervical vertebral compressive myelopathy through increased susceptibility to osteochondrosis development