Soft Tissue Injuries of the Western Performance Horse's Foot

Injuries to the collateral ligament of the DIP most commonly occur in horses that do a lot of turning, placing significant torque on the hoof capsule.

Photo: Photos.com

Nearly 100 veterinarians gathered to discuss how they diagnose and treat soft tissue injuries in the feet of Western performance horses during a table topic at the 2016 American Association of Equine Practitioners' Convention, held Dec. 3-7 in Orlando, Florida.

Vern Dryden, DVM, CJF, of Bur Oak Veterinary and Podiatry Services, in Lexington, Kentucky, and Brian Beasley, DVM, CJF, from the University of Georgia College of Veterinary Medicine, in Athens, led the conversation.

They defined Western performance horses as primarily Quarter Horses competing in everything from barrel racing to hunt seat. Soft tissue issues they said they commonly see in these horses’ feet include injuries to the deep digital flexor tendon (DDFT), impar ligament, suspensory ligament of the navicular bone, navicular bursa, and collateral ligament of the distal interphalangeal (DIP) joint. They broke the discussion into three parts:

Injuries to the DDFT, Impar Ligament, and Suspensory Ligament of the Navicular

During the initial physical exam of a horse with a foot problem, Dryden said he looks for wear patterns on the horse’s hooves or shoes, watches to see if the horse’s hoof lands toe-first or heel-first when moving, feels for a digital pulse on either the medial (inner) or lateral (outer) side of the fetlock, and applies hoof testers.

Attendees agreed that they then try to localize the source of pain using palmar/plantar digital nerve blocks (in which they inject anesthetic at specific points along the lower limb nerves). Once they know which part of the foot to focus on, they use radiographs, ultrasound, and even MRI to visualize the affected area. Pinpointing the exact cause, however, can be challenging. “Some lamenesses take several days to properly work up,” said Dryden. This diagnostic process is the same for all soft tissue injuries to the foot.

He noted that many soft tissue injuries in the back part of the foot tend to occur in horses with very upright or very low-heeled hoof conformation.

When shoeing a horse with one of these (or any) foot issues, Dryden said his goals are to remove the forces on the injured area, restore hoof balance, improve morphology (shape and structure), and protect the injured area while it heals. He might use wedges to raise the heel to relieve tension on the DDFT and/or ease breakover (the point at which the heel lifts off the ground during movement), gradually decreasing the amount of wedge until it can be removed completely.

“The severity of the lesions dictates the amount of wedge,” he said, noting that the highest wedge he uses is 10-12 degrees, reducing that by 3 to 4 degrees every three to four weeks depending on the case. “You’re looking at six to eight months for these to heal.”

Navicular Bursa

Dryden said he uses a more conservative wedge when rehabilitating navicular bursa injuries, as too much wedge can make the horse sore. He works on a case-by-case basis to find the heel angle the horse is most comfortable with. Attendees from regions with soft ground, such as Florida, said they’ve also had success using heel extensions.

Dryden said his go-to navicular bursa treatment is hyaluronic acid and steroid (e.g., triamcinolone, betamethasone) injections at no more than six-month intervals. If he sees radiographic evidence of bony changes, he might administer bisphosphonates. Although these drugs are intended to prevent bone resorption, they might also have an analgesic effect on soft tissues. Attendees said they’d also had success treating these injuries with biologics such as platelet-rich plasma or IRAP (interleukin-1 receptor antagonist protein).

Collateral Ligament of the DIP

These injuries occur most frequently in horses that do a lot of turning, placing significant torque on the hoof capsule. When shoeing these horses, Dryden said he likes to create a wider web (the shoe’s dimensions) on the affected side to support the ligament, reducing its width in gradual increments until the horse is back in work. Beasley said shock wave and/or stem cell therapy can also benefit these injuries.

When asked what his non-steroidal anti-inflammatory of choice is for any of these horses, Dryden said he prefers Equioxx (firocoxib) long-term. He administers Bute (phenylbutazone) early in the healing process, then tapers it down and switches to Equioxx.

About the Author

Alexandra Beckstett, The Horse Managing Editor

Alexandra Beckstett, Managing Editor of The Horse and a native of Houston, Texas, is a lifelong horse owner who has shown successfully on the national hunter/jumper circuit and dabbled in hunter breeding. After graduating from Duke University, she joined Blood-Horse Publications as Assistant Editor of its book division, Eclipse Press, before joining The Horse.

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