Epiphyseal cartilage canal blood supply to the metatarsophalangeal joint of foals.
Authors: Olstad K, Ytrehus B, Ekman S, Carlson C S, Dolvik N I
Journal: Equine veterinary journal
Summary
# Epiphyseal Blood Supply and Osteochondral Fragmentation in the Foal Metatarsophalangeal Joint Whether cartilage ischaemia contributes to osteochondral fragmentation in the equine metatarsophalangeal (MTP) joint has remained unclear due to the lack of detailed microvascular studies in this region. Olstad and colleagues used barium perfusion techniques on eight Standardbred foals euthanised between birth and seven weeks of age, examining cleared bones radiographically and histologically to map the developmental pattern of blood supply to the epiphyseal growth cartilage of the distal third metatarsal and proximal phalanx. Key findings included a positive correlation between cartilage thickness and perfused vessel density, with cartilage canal vessels initially oriented parallel or perpendicular to the ossification front before becoming incorporated into it and shifting to rely on subchondral arterial supply. Notably, one seven-week-old foal exhibited an area of chondronecrosis (cartilage death) with surrounding fibrovascular granulation tissue in the lateral proximo-plantar eminence of the proximal phalanx—the same anatomical vulnerability documented in tarsal osteochondrosis. These findings suggest that compromised blood supply during the critical transition of cartilage canal vessels across the ossification front may predispose the MTP joint to osteochondrosis via the same vascular mechanism identified in the tarsus, with significant implications for understanding joint cartilage fragmentation and developing preventative strategies in foal management.
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Practical Takeaways
- •Osteochondrosis in the metatarsophalangeal joint may develop through the same vascular mechanism as in the tarsus, suggesting the condition warrants similar clinical attention and monitoring in young foals
- •Early detection of osteochondral changes may require histological examination as macroscopic lesions may not be visibly apparent during the developmental window
- •Understanding that cartilage ischaemia may play a role in osteochondral fragmentation could inform preventive strategies during the critical growth phase in foals
Key Findings
- •Regions with thicker epiphyseal cartilage contained more perfused vessels than thin cartilage regions in the metatarsophalangeal joint
- •Cartilage canal vessels are incorporated into the ossification front during growth and become dependent on subchondral arterial supply
- •Vessels traversing the ossification front to supply cartilage canals share the same anatomical vulnerability in the metatarsophalangeal joint as previously identified in the tarsus
- •Chondronecrosis with fibrovascular granulation tissue was found histologically in one 7-week-old foal despite no macroscopic lesions being detected