Sheared heels is a colloquial term used to describe proximal displacement of the medial or lateral heel bulb when referenced to the opposite heel of the same hoof. It’s also often loosely used to describe proximal displacement of the coronet band anywhere cranial to the heel bulb up to the lateral or medial side of the toe (Figure 1).
In most cases, one can also appreciate with palpation that the collateral cartilage on the same side of the hoof is displaced proximally and axially.
Although the sheared heel phenomenon has been associated with quarter and heel cracks (O’Grady; Moyer; Johanningmeier), primary causation has not been proven. Normally, in fact, sheared heels do not appear to be a primary cause of lameness. Many horses with this condition can compete successfully without developing lameness or other problems.
However, when secondary problems — refractory heel and quarter cracks, heel bruising, thrush deep in the central sulcus, lameness with sensitivity immediately proximal to the coronet over the affected heel — exist concurrently with sheared heels, successful resolution of the secondary problems often mandates correction of the sheared heel.
In my experience, when following horses over several years, resolution of sheared heels (although not necessarily the concurrent secondary problems) via therapeutic shoeing is usually temporary if the condition is due to conformation.
Poor shoeing (Moyer et al.) and poor conformation, particularly the “toe out” conformation (O’Grady) have been suggested as possible contributing factors in this condition. In my experience, the…