A review of third phalanx fractures in the horse: sixty-five cases.

Sixty-five cases of third phalanx (P3) fracture were retrieved from 20,638 case records at Michigan State University's Veterinary Clinical Center between Feb 1, 1964 and July 1, 1977. The fractures were classified by anatomic location, using a numbering system. Data from case records indicated the most common P3 fracture involved the articular surface of the coffin joint (53 of 65 cases; 81.5%). The greatest occurrence of P3 fracture was in Standardbreds (31 of 65 cases). Thirty-three of the 65 fractures were in geldings of all breeds; 57 of the cases were distributed among racing horses of four breeds; and the mean ages at time of fracture for these groups were 4.9 to 5.3 years. The most common cause of P3 fracture was racing injury. Of 57 P3 fractures of the forelimb, 51 (89.5%) involved the lateral aspect of the left limb or medial aspect of the right limb--the part of each foot supporting most of the horse's weight in turns, while racing counterclockwise. Methods and response of treatment were evaluated by questionnaires obtained from 31 of the 65 owners. This questionnaire solicited information from owners and trainers as to: (1) cause, (2) treatment, (3) outcome, and (4) the use of the horse. Results were tabulated for: (1) questionnaire information obtained, (2) a classification system for P3 fractures, based on the anatomic location of the fracture, and (3) distribution of fractures between limbs and position (medial vs lateral) within limbs.