Slab fractures of the third tarsal bone: A technique for repair and results in 17 horses

The third tarsal bone is T shaped with dorsal and plantar facets on both proximal and distal articular surfaces. The proximal articular surface is undulating but predominantly concave while the distal articular surface is convex. Slab fractures of the third tarsal bone almost invariably occur through the lateral aspect of the dorsal facet with dorsomedial to plantarolateral fracture planes. They have been considered the result of failure of adaptive remodelling but it has been suggested that converging and diverging dorsolateral articular surfaces (wedging) may be a predisposing factor. Both surgical repair and conservative management have been reported. However, there has been no description of an appropriate technique that overcomes the technical and anatomical challenges.

This study will report a retrospective analysis of case records of horses that underwent repair of third tarsal bone slab fractures at Newmarket Equine Hospital from 2009 to 2014. All horses underwent radiographic evaluation of both tarsi including dorsoplantar, lateromedial, dorsolateral- plantaromedial oblique and dorsomedial-plantarolateral oblique (DM-PlLO) projections. Following identification of a slab fracture of the third tarsal bone, additional DM-PlLO projections were taken at varying degrees of obliquity until there was precise alignment with the fracture plane. This projection was then used for pre-operative measurements and for intra-operative radiographic guidance.  [...]