Arthroscopic visualisation of the third metacarpal and metatarsal condyles in the horse.
Authors: Vanderperren K, Martens A, Haers H, Duchateau L, Saunders J H
Journal: Equine veterinary journal
Summary
# Arthroscopic Visualisation of the Third Metacarpal and Metatarsal Condyles in the Horse Whilst arthroscopy of the fetlock is routine in equine practice, the extent of condylar cartilage accessible via different portal approaches has not been systematically defined—information essential for distinguishing true lesions from blind spots during diagnostic examination. Using cadaveric forelimbs and hindlimbs, researchers performed three distinct arthroscopic approaches (dorsal with flexion, standard palmar/plantar, and a supplementary sesamoid-base portal with extension) on 20 specimens of each, marking the furthest-reachable condylar surface with curette-created lesions and subsequently calculating visualisation angles from radiographs. The dorsal approach with flexion provided notably superior visualisation in hindlimbs (-23.4°) compared to forelimbs (+2.7°), whilst palmar/plantar approaches and sesamoid-base portals visualised significantly more cartilage in forelimbs than hindlimbs (−60.4° and −36.3° versus −70.7° and −47.6° respectively); even combining all three techniques left a blind spot of approximately 39° in forelimbs and 24° in hindlimbs, both located palmaro/plantarodistally. These findings highlight critical anatomical limitations in fetlock arthroscopy—surgeons should recognise that complete visual inspection is unattainable, particularly in forelimbs, and that judicious use of flexion and extension combined with multiple portals maximises diagnostic accuracy whilst informing realistic expectations about lesion detection in therapeutic procedures.
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Practical Takeaways
- •Use multiple arthroscopic approaches (dorsal with flexion, palmar/plantar, and sesamoid portal with extension) sequentially to visualise the majority of fetlock condylar cartilage and avoid missing lesions
- •Be aware that a small palmaroplantar-distal area of the condyle cannot be visualised arthroscopically in any approach—consider radiography or ultrasound for this region if lesion suspected there
- •Forelimb fetlock arthroscopy requires more aggressive approach variation than hindlimbs due to greater nonvisible area
Key Findings
- •Dorsal approach with flexion visualised significantly larger areas in hindlimbs (-23.4°) than forelimbs (+2.7°)
- •Palmar/plantar approach visualised more cartilage in forelimbs (-60.4°) than hindlimbs (-70.7°)
- •Combined three-approach technique leaves 38.9° nonvisible in forelimbs and 24.2° in hindlimbs, both in palmaroplantar-distal regions
- •The nonvisible section of condylar cartilage is consistently smaller in hindlimbs compared to forelimbs across all techniques