Surgical management of a severe congenital deformity of the hind limb in a Shetland pony foal-a case report

This case report describes the surgical management of a severe congenital deformity in a Shetland pony. A two-week-old foal was presented with the right hind limb showing a 90-degree torsion of the tarsal region towards the medial side and the metatarsophalangeal joint forced in a 90-degree extension behind the right tarsus. As assessed through radiography, the tibial malleoli and the trochlea of the talus were poorly developed, the flexor tendons inserted topographically correctly on the phalanges but due to articular torsion, the tenaculum of long and lateral digital extensor tendons were projected laterally and the common digital extensor tendon on the medioplantar aspect. At the age of one month, a corrective ostectomy of the tibial malleoli, trochlear ridge, and talus was performed to reposition the adjacent bones. The tarsal bones were repositioned through an arthrotomy and subsequently the tarsal region fused by means of two cortex screws inserted in a lag fashion. Complete correction of the torsion was achieved through metatarsal osteotomy. A 20-hole 3.5-mm reconstruction plate was used for stabilization of the tibia and metatarsus, resulting in a pantarsal arthrodesis. Partial tibia shortening was performed to improve angulation of the tarsal region. At nine months after surgery, the pony was keeping the right limb hoof sole on the ground.