Medial condylar fractures of the third metatarsal bone in horses.

Fifteen longitudinal fractures involving the medial condyle of the third metatarsal bone were diagnosed in racing Thoroughbreds and Standardbreds. Twelve were repaired surgically with lag screws placed through stab incisions. Two of the horses suffered catastrophic fracture of the third metatarsal bone during recovery from anesthesia, and 3 more sustained complete fractures within 4 days of the repair. Of 3 horses with fractures treated without surgery, 2 healed without complication. Preoperative radiography did not demonstrate a nonlongitudinal fracture component in any of the horses that sustained complete fractures. The complete fractures were uniformly "Y" shaped. Horses in which the fractures healed had a good prognosis for return to racing.