AAEP Convention 2005: How To Manage Sheared Heels

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.

O'Grady prefers to trim the foot in stages, followed by watching the horse walk on a hard, flat surface. Initially, no more hoof wall is removed than is needed to level the solar surface of the foot. The foot is then trimmed according to how the foot strikes the ground when walking. Trimming is concluded with the heel and quarter on the affected side lower than the opposite side. The horse then is shod with a wide-web steel or aluminum straight bar shoe to increase the surface area of the foot and decrease the vertical movement of the heels. There usually will be a space between the affected heel and the shoe (due to that side being trimmed lower) to allow the displaced heel to drop down into a more normal configuration.

O'Grady said while selective trimming with a rigid support shoe is his treatment of choice, it does not always correct the problem. His second line of treatment consists of removing the shoe, trimming excess sole, and soaking he foot in hot water for 20 minutes. A frog support pad is taped to the bottom of the foot, and a heavy cotton bandage is applies to the entire foot, including the coronary band. The horse is stalled for 24 hours and the bandage kept moist with hot water during that time.

Keeping the hoof capsule moist allows it to be more pliable and move toward a more normal physiologic shape while supporting the coffin bone. He said the following day when the bandage is removed, the distorted heel will have assumed a more normal position. The foot is trimmed and shod as described above.

In foals, sheared heels are generally the result of a rotational deformity of the forelimbs, said O'Grady. Inappropriate trimming may also contribute to this  conformation. "These foals stand toed-out and generally have their outside hoof wall trimmed lower, regardless of the cause of their limb position," he said. "Improving the sheared heel involves gradually trimming of the foal's hoof level (the affected side is then lowered a few millimeters each time the foal is trimmed at four-week intervals).

In extreme cases, a hoof wall extension is fabricated using a composite material, and it is attached to the affected quarter/heel to increase the width of the ground surface of the hoof wall. The solar surface of the hoof is not raised with the extension.

"The extension causes the foal to break over straighter, improving the limb flight and resulting in a more uniform strike pattern," said O'Grady. "The extension also prevents further bending of the hoof wall at the heel and adds ground surface to the heel."

He noted that a large number of these foals will improve as they grow because as the chest widens, the rotational deformity improves, changing the landing pattern.

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from TheHorse.com. Learn More

Free Newsletters

Sign up for the latest in:

From our partners