Chronically Laminitic Horses and Restoring P3 Alignment (AAEP 2003)

"Chronic laminitis is a frustrating and, at times, disheartening condition to manage," said Stephen O'Grady, BVSc, MRCVS, during the 2003 American Association of Equine Practitioners convention. "Treating chronic laminitis is always a challenge; here we move a bit away from veterinary medicine into the mechanics of farriery. We're putting the skills of both professions together."

With chronic laminitis, O'Grady explained that toe-downward rotation of P3 (the coffin bone) often occurs, which results in more pressure placed on the solar corium (the highly vascular tissue from which the sole grows) under the apex of P3. This pressure can disrupt blood flow, altering the rate and even the direction of sole growth.

Apparent rotation of P3 can be a result of two processes--capsular or phalangeal rotation. Capsular rotation is when the wall pulls or grows away from the coffin bone; he said it is the easier of the two to resolve with proper trimming and shoeing. Phalangeal rotation, on the other hand, occurs when P3 rotates compared to the first and second phalanges (P1 & P2). O'Grady said that cutting the DDFT (tenotomy) or the inferior check ligament (desmotomy) is often needed in these cases to help realign P3."These problems can be ameliorated only by restoring the alignment of P3 relative to the bearing surface of the foot (i.e., to the ground surface)," he said. "The method used must achieve these key goals:

  • "Re-establish weight-bearing along the entire solar surface of P3 (rather than being concentrated at the apex of P3);
  • "Aid breakover by moving the functional breakover point palmarly (heelward); and 
  • "Decrease tension in the deep digital flexor tendon (DDFT).

"These goals are achieved by trimming the heels, applying a shoe that places the functional breakover point near the apex of P3, gluing the shoe to the foot so that the shoe and the solar margin of P3 are parallel, and raising the heels using wedge-shaped rails (wider at the heels to elevate them) attached to the shoe," O'Grady explained. This results in less tension from the DDFT and less tension on the laminae at the toe, allowing more blood flow for healing the laminae.

He noted that it also reduces sole pressure from P3, alleviating some degree of pain rather quickly in most cases.

O'Grady stated that this procedure should only be undertaken when the horse is relatively comfortable, off medication and stable with no radiographic deterioration for at least 10 days.

Shoeing Procedure

He said that he prefers gluing on shoes for these horses rather than nailing because gluing is less traumatic and "allows greater flexibility and precision in realigning P3 than any other technique I have used." In addition to the shoeing, O'Grady also uses an elastic polymer to fill the sole and allow it to bear weight.

He explained to the audience the importance of beginning with a lateral radiograph to direct the shoeing work, then described in detail the procedures of foot preparation, shoe fitting, and shoe application. Afterward, he said the horse should be stall rested for three weeks, and then hand walking can begin. Non-steroidal anti-inflammatory medication should be used as needed.

Clinical Cases

This realignment procedure was done by O'Grady in 32 horses with chronic laminitis of over three months duration, significant P3 rotation, positive hoof tester response, and at least Obel grade two of lameness (this scale runs from one to four).

Nine horses also received a DDFT tenotomy, and two received an inferior check desmotomy.

"Twenty (62.5%, including the two desmotomy cases) returned to some level of usefulness, although below their former level of athletic ability," O'Grady reported. "The remaining 12 horses (37.5%) were pasture sound (including the nine tenotomy cases).

"Clinical experience has shown the glue-on shoeing technique described here to be a simple and atraumatic method of effectively realigning P3 and thus improving comfort and hoof growth in horses 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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