Size and geometry of apical sesamoid fracture fragments as a determinant of prognosis in Thoroughbred racehorses.

This study investigates whether the size and shape of apical sesamoid fractures in Thoroughbred racehorses can determine their prognosis. The results suggest no correlation between fracture size, shape, and a horse’s post-operative performance.

Objective and Methods

• The objective of this study was to determine if there’s a difference in the size or shape of apical fractures between the anatomical locations of the proximal sesamoid bones (PSBs) that affect the prognosis. Additionally, the research sought to understand if these factors could predict the prognosis for racehorses with these fractures.
• To achieve this, the study involved 110 weanlings and yearlings and 56 training racehorses that had undergone surgery to remove apical PSB fractures.
• Radiographs of the fractures were examined to measure the abaxial and axial proportion and the abaxial to axial ratio. Race records were also analyzed to determine average earnings per start (AEPS) and total post-operative starts.
• Analysis of variance and regression statistics were used to compare fracture sizes between specific PSBs on each of the four horse limbs and to compare size and configuration of the fractures in relation to prognosis.

Results

• The research found a significantly more transverse fracture (larger abaxial to axial ratio) for the forelimb medial sesamoids compared to all other sesamoids in untrained racehorses.
• No other significant differences in size were discovered, and there was no relationship between fracture size or configuration and AEPS, nor total post-operative starts.

Conclusion

• The study concludes that apical fractures in weanlings and yearlings are more likely to be transverse in the forelimb medial PSBs than the other PSBs.
• However, the size and shape of an apical fracture does not influence the prognosis for apical sesamoid fractures.
• This indicates that horses which undergo surgery to remove larger apical fractures do not necessarily have poorer outcomes than horses with smaller fractures.