DISTAL PHALANX FRACTURES IN HORSES. A Survey of 274 Horses with Radiographic Assessment of Healing in 36 Horses

The case records of 274 horses with fractures of the distal phalanx were reviewed. Fifty‐two horses had bilateral forelimb fractures, for a total of 326 distal phalanx fractures. The fractures were classified into one of five previously described types, based on the radiographic anatomic configuration of the fracture. Solar margin fractures, which have been briefly described in other reports and previously classified as type V fractures, were identified in 132 horses. This type of fracture is distinct from other distal phalanx fractures. Due to the high incidence of solar margin fractures, these fractures were classified as a separate type (type VI). Follow‐up radiographic examinations to assess fracture healing were available for 36 horses. Twenty‐two horses with distal phalanx fractures (three type I, nine type II, two type III, one type IV, one type V, and six type VI) had radiographic evidence of complete bony union of the fracture at a mean of 11 months after injury. Eight horses with complete type II fractures involving the articular surface had bony union of the body and solar margin, but not the subchondral bone at the articular surface, a mean of 11 months after injury. Six horses (four type II and two type IV) had little radiographic evidence of bony healing during the follow‐up period. All fractures that eventually healed had evidence of progression toward bony union by 6 months after injury.