The chronically laminitic horse is often a very tough case to manage because displacement of the coffin bone within the foot leads to a lot of pain and damage, in addition to the damage that allowed the displacement in the first place. At the 2007 American Association of Equine Practitioners Convention, held Dec. 1-5 in Orlando, Fla., Stephen O'Grady, BVSc, MRCVS, of Northern Virginia Equine in Marshall, Va., discussed how to build and fit wooden shoes (clogs) to improve healing in three forms of chronic laminitis.

He listed several benefits of these shoes, which are made out of stacked plywood or subfloor wood:

  • Easy to build;
  • Lightweight;
  • Dissipate energy (absorb shock) better than harder metals;
  • Inexpensive;
  • Flat, solid construction allows weight bearing to be applied over specified sections of the foot;
  • Easily altered according to the horse's needs;
  • Applied nontraumatically (no impact from nailing, as they're attached with screws).

A thorough assessment of the foot with lateral and dorsopalmar radiographs (side and front views) is essential to design the shoe according to what that foot needs, he noted.

 

a wooden shoe can used in the treatment of laminitis in horses

The shoes are constructed from a wood block and can be customized in several ways, such as by adding/removing layers or routing out specific areas to alleviate pressure.

When the shoe is constructed from a wood block, the sides and toe are cut at about a 45° angle. This places weight bearing directly under the bones, allows the horse to easily choose the most comfortable hoof angle when standing, and decreases torque on the laminae (which attach the coffin bone to the hoof wall). The shoe can be further modified in several ways: Its foot surface can be "routed" out in specific areas to alleviate pressure on a dropped sole, wedge pads can be added to further elevate heels, and the overall thickness of the shoe can be modified by adding or removing layers of wood.

O'Grady went on to describe the use of this shoe for three manifestations of chronic laminitis: dorsal rotation (the most common rotation case), medial or lateral displacement of the coffin bone (sinking on the outside or inside of the foot), and dropping of the sole or prolapse of the coffin bone through the sole.

Dorsal rotation In these cases, the coffin bone has pulled away from the hoof wall at the toe and is rotating so its tip is closer to the ground. O'Grady recommended realignment of these feet so the bottom surface of the coffin bone is parallel to the ground by removing some of the heels and using the increased solar surface for weight-bearing. Once the foot is prepared, impression material is applied to the foot to recruit the sole, bars, frog, and sulci (grooves alongside the frog) for weight bearing. Then the wooden shoe is applied with 1 1/2-inch drywall screws.

O'Grady said that in some cases of coffin bone rotation and prolapse (penetration through the sole), this treatment has provided a viable alternative to deep digital flexor tenotomy (cutting the deep digital flexor tendon). He reported a favorable response (increased sole depth and wall growth at the toe) in 17/21 cases (81%) with this method.

Medial/lateral sinking Medial sinking (to the inside of the foot) is more commonly seen, although sinking to the outside has been noted in supporting limb laminitis, O'Grady reported. The approach for these feet is similar to that for dorsal rotation, except the heels might not need to be taken down to realign the foot, and a one-quarter-inch extension on the high side is used to help lighten the load on the low side.

He found a favorable response (increased wall growth on the low side) in 8/11 cases (65%) with this method.

Solar/coffin bone prolapse In these tough cases, the coffin bone is realigned as with the dorsal rotation case, heel elevation is used to decrease the pull of the deep digital flexor tendon, and the shoe is routed out to prevent weight bearing by the prolapsed sole and/or bone. The rear half of the foot is packed with impression material to help support the horse's weight.

He reported a favorable response (cornification of the exposed soft tissues and hoof wall growth) in 7/9 cases (77%) with this method.

"The wooden shoe provides another very consistent farriery option when treating a horse with chronic laminitis," he concluded.

About the Author

Christy M. West

Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.

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