Abstract
Background: Complete fractures of the third metacarpal / metatarsal bones (Mc/t3) are not common, but can occur in various situations and all types of horses, contributing for approximately one third of all long bone fractures in the horse, mostly related to external trauma or to high energy injuries. To stabilize Mc/t3 fractures in the horse, conservative management with walking casts and/or open reduction and internal fixation techniques are referred in the scientific literature, these last one generally by double platting application to bone surface in 90º. In the present case will be described a Mt3 complete diaphyseal fracture stabilization on an adult pony from a circus by applying only one bone plate. This work pony could return to its previous activity fully recovered 3 months after fracture stabilization.
Case Description: A 7-year-old, male, Shetland pony (103 kg), used for performance work at a circus was admitted to the Veterinary Teaching Hospital of UTAD, presenting on lateral recumbency after being struck by a truck. On physical examination a penetrating wound of small dimension was detected at the medial aspect of the right hindlimb. After radiographic examination, a complete diaphyseal fracture with slight obliquity of the right Mt3 was confirmed. The owner opted for surgical repair thus fracture stabilization was achieved by the placement of just a single 8-hole broad 4.5 mm dynamic compression plate applied to the lateral face of Mt3 in compression function with 7 cortical screws (4.5 mm). Post-operatively a full limb cast was performed and maintained for 4 weeks while the animal was kept under movement limitation at the hospital facilities for this period of time although the animal stayed until his full recovery 3 months’ post-surgery.
Conclusion: A complete recovery was achieved and the animal returned to the previous level of exercise without any significant postoperative complications or degree of lameness. In the authors knowledge, this is the first case report where stabilization of a complete Mt3 diaphyseal fracture was attain using a single compression plate contoured to the lateral face of the bone, instead of double plating, on an adult work pony from a circus subjected to a very demanding and intense physical activity.

Key words: dynamic compression plate, internal fixation, complete diaphyseal metatarsal III fracture, pony