Epiphyseal cartilage canal blood supply to the tarsus of foals and relationship to osteochondrosis.
Authors: Olstad K, Ytrehus B, Ekman S, Carlson C S, Dolvik N I
Journal: Equine veterinary journal
Summary
# Editorial Summary: Cartilage Canal Vasculature and Tarsal Osteochondrosis in Foals Osteochondrosis has long been suspected to involve compromised blood supply to developing growth cartilage, yet direct visualisation of these vascular changes during critical growth phases has been lacking. Using barium perfusion techniques on foals aged 0–7 weeks bred from OC-affected parents, Olstad and colleagues mapped the developmental remodelling of cartilage canal blood supply in the distal tibia and talus, identifying a crucial transition period when vessels shift from perichondrial to subchondral arterial sources as the ossification front advances. Twelve histological lesions appeared in seven foals, all characterised by necrotic vessels surrounded by necrotic cartilage, with three causing macroscopically evident delays in endochondral ossification—critically, these lesions consistently occurred where cartilage canal vessels crossed the ossification front to supply the distal canal terminus. The findings suggest this anatomical transition zone represents a genuine vulnerability window where vascular failure directly compromises chondrocyte viability, providing a plausible mechanistic explanation for tarsal OC development. For practitioners, understanding this vascular anatomy underscores why early identification of at-risk individuals (those with affected pedigrees) and careful management of growth-phase biomechanical and nutritional stressors during these early weeks may be essential to preventing lesion establishment.
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Practical Takeaways
- •OC in tarsal regions may originate from vascular failure in cartilage canals during the critical period when vessels cross the ossification front—understanding this timing helps explain why certain foals develop clinical OC lesions
- •Breeding decisions should consider that offspring from parents with OC show demonstrable vascular pathology in growth cartilage, supporting selection against OC-prone bloodlines
- •Early detection methods targeting vascular integrity in growth cartilage (0–7 weeks age) may eventually help identify at-risk foals before macroscopic OC lesions develop
Key Findings
- •Cartilage canals exist only transiently during growth and shift their arterial source from perichondrial to subchondral vessels as the ossification front advances
- •Twelve histological lesions containing necrotic vessels and necrotic cartilage were identified in 7 of 9 foals, located specifically at the ossification front crossing point
- •Three lesions caused macroscopically visible delays in endochondral ossification in the distal tibial epiphysis and talus
- •Cartilage canal vessels are most susceptible to vascular failure where they traverse the ossification front, compromising chondrocyte viability in predilection sites for osteochondrosis