Lag screw fixation of noncomminuted sagittal fractures of the proximal phalanx in racehorses: 59 cases (1973-1991).

Medical records of 59 racehorses with noncomminuted midsagittal proximal phalanx fractures repaired by means of lag screw fixation between 1973 and 1991 were reviewed. Fractures were classified as short incomplete fractures (7), long incomplete fractures (32), complete fractures extending into the proximal interphalangeal joint (13), and complete fractures extending through the lateral cortex of the proximal phalanx (7). Time from fracture repair to first race following fracture repair, number of racing starts, and fastest race times before and after surgery were obtained from race records and compared among horses grouped by fracture type and between horses that returned to racing and those that did not race. Five horses with short incomplete fractures, 21 horses with long incomplete fractures, 6 horses with complete fractures extending into the proximal interphalangeal joint, and 5 horses with complete fractures extending to the lateral cortex returned to racing. A significantly lower percentage of horses returned to racing following repair of complete fractures extending into the proximal interphalangeal joint (46%), than following repair of short incomplete fractures (71%), long incomplete fractures (66%), or complete fractures extending to the lateral cortex (71%). Time from fracture to repair for horses that returned to racing (mean, 14.7 days; range, 1 to 60 days) was not significantly different from that for horses that did not race (mean, 5.8 days; range, 1 to 21 days). For all fracture groups, median number of races before injury was not significantly different from median number of races after repair, and median fastest race time before fracture was not significantly different from median fastest race time after fracture repair.