Apical fracture of the proximal sesamoid bone in standardbred horses: 43 cases (1990-1996).

This research article explores whether the size of a fracture fragment, suspensory ligament damage, and a Standardbred horse’s racing status at the time of injury can predict the outcome when the horse has an apical fracture of the proximal sesamoid bone. The study indicates that these factors do not significantly affect the prognosis, and it seems that horses which have raced before injury have a good chance of returning to racing soundness.

Study Design

• The researchers conducted a retrospective study on 43 Standardbred racehorses that sustained an apical fracture of the proximal sesamoid bone.
• Each horse’s medical records, racing records, and radiographs were reviewed, and ultrasonographic findings were assessed.
• Measurements were taken of the fractured part of the proximal sesamoid bone in each horse.

Findings

• Out of the 43 horses, the majority, 74% (32 horses), were pacers while the rest, 26% (11 horses), were trotters. However, no significant differences were found between these two types when it came to the ability to start, the number of starts, or money earned after the injury.
• Interestingly, the study found that female horses earned significantly more per start after injury than male horses.
• The largest percentage, 86% (37 horses) of the injuries, involved hind limbs, whereas only 14% (6 horses) suffered forelimb injuries, showing a potential difference in injury distribution.
• Furthermore, it was noted that horses that suffered forelimb injuries earned less money per start after the injury.
• The study found that the severity of suspensory ligament damage did not affect the horse’s post-injury racing performance.
• Horses that were actively racing when the injury occurred were more likely to return to racing after surgery compared to horses that hadn’t raced before injury, although no significant difference was detected between the two groups.
• A higher proportion, 88% of the horses that had raced before the injury, raced after the injury, as opposed to only 56% of the horses that had not raced before the injury.
• The size of the fracture fragment was found to have no effect on the outcome of the injury.

Conclusion

• The study concluded that the size of the apical fracture fragment of the proximal sesamoid bone and the degree of suspensory ligament damage in Standardbred horses did not affect the outcome.
• It also suggested that the prognosis for the return to racing soundness is generally good for horses that had raced before the injury, but only fair for horses that had not raced prior to the injury.