A Retrospective Study of Sagittal Plane Slab Fractures of the Third Carpal Bone in Racing Thoroughbred Horses

Abstract

Reasons for performing study Sagittal plane slab fractures of the third carpal bone are a recognised injury in the racehorse. One study [1] reported 32 horses with sagittal fractures, 69% raced again. Surgical management appeared beneficial, with all horses that underwent inter-fragmentary compression racing again. Objectives To document the success rate following sagittal slab fracture of the third carpal bone in UK-based racehorses, and to compare conservative and surgical management. Study design Retrospective study. Methods Inclusion criteria were Thoroughbred racehorses with a simple sagittal slab fracture of the third carpal bone. Exclusion criteria were comminuted fractures, radial carpal bone fractures and short incomplete linear lucencies. Fractures were classified as complete, incomplete or uncertain. Time from injury to next race was recorded. Success rates were compared by Fisher's exact test. Results Forty horses were identified. Two were subjected to euthanasia and 3 have <6 months follow-up. Eleven were managed nonsurgically of which 4 (36%) were complete (5 uncertain) and 7 (64%) raced, 154–508 days following injury (median 242 days). Twenty-seven horses underwent surgery to place a single 3.5 mm (n = 26) or 4.5 mm (n = 1) lag screw under arthroscopic guidance, of which 18 (67%) were complete. Thirteen (48%) raced again 147–711 days following surgery (median 256 days) P = 0.48. Of 23 horses with complete fractures 13 (57%) raced again, compared with 5/15 (33%) horses with incomplete fractures P = 0.2. Of horses with complete fractures, 10/18 (55%) underwent surgery and raced again compared to 3/4 (75%) horses managed conservatively P = 0.62. Conclusions The results confirm that the prognosis for athletic function is favourable but do not suggest that surgery is beneficial, or necessary for complete fractures. The numbers managed conservatively are small and it was not clear radiographically if the fracture was complete in 5/11 horses.