Steve O’Grady, BVSc, MRCVS, of Northern Virginia Equine, said a sheared heel is a “created situation” and a “poorly understood phenomenon.” He said the condition was first described by Bill Moyer, DVM, in 1975. “The diagnosis and treatment is the same now as it was then, and we’re into the mechanism as to how it happens,” said O’Grady.

He said sheared heels can be defined as a hoof capsule distortion resulting from displacement of one heel bulb proximally relative to the adjacent heel bulb. He said the disparity between the lateral and medial heel bulbs is usually 0.5cm or more. Sheared heels can be acquired, but most often occur because of the horse’s conformation. The horse’s conformation causes the horse to land on one side of the hoof, resulting in uneven loading on the foot and limb. “It’s rare to see a quarter crack without a sheared heel,” he noted.

O’Grady said selective trimming and therapeutic shoeing should decrease the compressive forces on the distorted heel by altering the strike pattern of the foot. He said in horses where the cause is trimming, if caught in time, it can be corrected. Over time, however, the changes can become permanent and shoeing maintenance for soundness is the only solution.

The foot can be radiographed to determine if there is a medial/lateral imbalance present, but most times the distal phalanx (P3) is horizontal relative to the ground. Before trimming, the foot should be held off the ground and the metacarpus held horizontally and the foot allowed to hang naturally. This allows visualization of the mediolateral orientation