Osteochondral fragmentation of the palmarolateral/plantarolateral aspect of the distal phalanx in four horses: A novel location

Four horses presenting for lameness were diagnosed with unilateral osteochondral fragmentation (OCF) of the palmarolateral/plantarolateral aspect distal phalanx within interphalangeal joint (DIPJ). Histological evaluation one case supported a diagnosis osteochondritis dissecans (OCD), patient age and history from two cases suggesting traumatic origin. Lesion appearance on conventional radiography, computed tomography (CT), nuclear scintigraphy magnetic resonance imaging (MRI) are described. Fragmentation was best identified dorsal 65° proximal-palmaro/plantarodistal oblique (D65°PrPDiO/D65°PrPlDiO) lateral (D65°Pr45°L-PDiMO/D65°Pr45°L-PlDiMO) radiographic projections foot, but articular pathology appeared more severe cross-sectional modalities. In all cases, refractory to conservative management. Arthroscopic DIPJ performed in three horses, although lesion inaccessible two. horse, access possible due increased laxity, presumably concurrent soft tissue injury. One horse euthanased after failed management, pasture sound following palmar digital neurectomy 12 months initial presentation, returned racing lost follow-up. Osteochondral at this location has not previously been described, treatment options limited prognosis appears be poor.