hoof testers

Different but often related: Here’s how to address common heel conditions in horses

Think about the size of a horse. Now think about the size of his hoof. When you compare one to the other, it’s dazzling to consider how much something so small can carry. Then factor in the speed and height at which equine athletes perform—there’s no doubt your horse’s feet withstand enormous amounts of weight, strain, pressure, and impact. With each footfall the heels are the first part of the equine digit to hit the ground. Their sponginess and flexibility allow them to expand and absorb some concussion, dissipating shock before it travels upward. This mechanism helps protect bones and joints in the hoof capsule from the damaging effects of repetitive high-impact forces. With such an important role to fill, it’s easy to see why distorted, injured, or painful heels can hurt the horse’s overall performance and ­soundness.

One Region, Multiple Conditions

Too often, disparate causes of equine heel pain are clumped together under the dreaded term “navicular.”

“But prognosis and treatment for various caudal (toward the rear) hoof conditions are drastically different, so it is imperative to parse out the actual cause of the pain,” says Jaret Pullen, DVM, owner of JP Hoofworks, an equine podiatry veterinary service that serves the greater New England area. Much like you would treat a cut or blister on your heel differently than an injury to your calcaneus (heel bone), distinguishing between lameness stemming from the heels of the horse versus the deeper, more complex podotrochlear apparatus is crucial.

Step 1: Localizing Lameness

Before all else, your veterinarian must determine where the lameness is coming from. While seeking answers, ­practitioners conduct physical and lameness examinations, which generally involve hoof testers and wedge tests. Then they use regional analgesia (nerve blocks) and radiographs as needed.

Accurately and precisely locating the problem area is key, as our sources emphasize throughout this article. “On the one hand, general heel pain refers to the actual heel structures: heel bulbs, bars, digital cushion, and the palmar processes of P3 (the branches of the coffin bone that extend backward and to which the lateral cartilages attach),” says Pullen. “As for the navicular or podotrochlear apparatus, it includes much more than the navicular bone, as some may think. Along with the navicular bone and bursa, the podotrochlear region of the foot also contains suspensory ligaments, impar ligaments, and the distal end of the deep digital flexor tendon (DDFT).” These parts work together to create a pulleylike system; injury to or degeneration of any of them qualifies as podotrochlosis.

Getting a Podotrochlosis Diagnosis

The pathophysiology of podotrochlosis was first recognized in the late 1980s. Researchers knew the DDFT placing abnormal pressure against the flexor cortex (the underside surface) of the navicular bone caused remodeling. This bone remodeling is associated with edema (swelling) inside the bone, along with blood flow disruption and vascular bone pain responsible for the clinical signs observed, most notably lameness (Pool et al.,

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