Originally published on TheHorse.com
Not all horses have symmetrical feet, and one of the more common problems horses develop is a "club foot" appearance. This problem might appear at birth or develop later in life. Horse owners and veterinarians can identify it based on classic signs and grades of severity.
Robert Hunt, DVM, MS, Dipl. ACVS, of Hagyard Equine Medical Institute, in Lexington, Ky., recently tackled the topic of club feet in horses during the in-depth seminar "The Foot from Every Angle" at the 2012 American Association of Equine Practitioners' (AAEP) Convention, held Dec.1-5 in Anaheim, Calif.
He defined a club foot as having an angle greater than 60 degrees (the angle the dorsal hoof wall makes with the ground). Usually there is at least a five-degree discrepancy between the affected foot and the opposite foot.
"Initially, an owner may recognize a space between the heel and the ground that develops slowly over two to three hoof trims," Hunt explained. "The second sign is that the coronary band appears square and full. Then, the foot appears boxy with a dish in the front of the hoof wall. And eventually, the frog becomes quite recessed, the hoof contracts, and the horse appears 'back at the knee.'"
With this change in its biomechanics, Hunt said, "The foot is prone to injury since loading on the foot moves forward, altered from its normal, heel-first landing."
A more accurate description of a club foot is to call it a flexural limb deformity of the coffin joint. Hunt reported that, in most cases, shortening of the musculotendinous unit (which runs down the back of the leg) that shifts the load dorsally (forward) in the foot causes the horse to develop a club foot. The musculotendinous unit (deep digital flexor muscle and tendon) can shorten, for example, due to chronic pain that reduces weight-bearing on the limb or due to nutritional imbalances.
Veterinarians have used multiple club foot classification systems: Type 1 refers to a club foot with a hoof axis less than 90 degrees; Type 2 is greater than 90 degrees. Or, they can use a grading system of the hoof axis relative to the opposite limb as a way to define severity: Grade 1 is 3-5 degrees; Grade 2 is 5-8 degrees; Grade 3 has a broken-forward hoof-pastern axis (HPA)--in which the angle of the hoof wall is steeper than that of the pastern, hoof wall dishing, and irregular growth rings; Grade 4 has a hoof angle greater than 80 degrees, a severely broken-forward HPA, marked concavity to the dorsal hoof wall, and the coronary band height at the heel is the same as at the toe.
Veterinarians consider this condition congenital if a horse has a club foot at birth. "Usually these cases are self-correcting with minimal treatment other than toe protection," Hunt said. Veterinarians can also treat congenital cases by administering systemic oxytetracycline, but he says too much oxytetracycline treatment can cause excessive laxity of normal joints.
"An acquired flexural deformity usually shows up between 4 to 6 months of age," he said. "It may result as a primary problem possibly due to a genetic predisposition. However, it is often secondary to other lameness issues, such as pain elsewhere in the limb that alters weight-bearing on that leg."
"Treatment varies depending on age of horse, severity, and client expectations," stressed Hunt. "The guiding principle is to improve comfort and minimize toe trauma while trying to reestablish load bearing on the heels."
He cautioned against using external shoe devices that improve the 'look' but don't achieve a long-term solution. In assessing an adult horse with a club foot, Hunt urged veterinarians to carefully consider the horse's intended use and to pay careful attention to current management including farrier care and nutrition.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.