The term “clubfoot” gets thrown around a lot when describing the way a horse, particularly a sale prospect, looks. But what does the term mean, and what actually constitutes a clubfoot on a horse?
A clubfoot is a conformation flaw thought to have both a genetic and mechanical component. You can recognize a clubfoot by its upright appearance in comparison to the pastern angle. Clubfeet are classified in four grades, depending on severity, with Grade 1 being the mildest form and Grade 4 being severe. Treatments range from therapeutic farriery to surgery.
A congenital clubfoot may be genetic, or it may result from the position of the foal in the uterus and usually is associated with a contracted tendon. When the foal stands, the taut tendon draws the heel upward and forces the toe to bear the load. Over the next several months, the added load on the toe causes the hoof to bulge at the coronary band and the heels to contract, forming the clubfoot. If caught early, the condition can be adequately treated with medication and splints to relax the tendon. In some foals, the limb deformity is so severe that it requires surgery to cut the check ligament to allow the heel to descend.
Dr. M. Phyllis Lose, author of the indispensable books Blessed Are the Broodmares and Blessed Are the Foals, believes she was the first veterinarian to perform an inferior check ligament desmotomy to resolve clubfootedness caused by a flexural deformity. Her paper, published in 1981, was the first to document the procedure.
“I transected the inferior check ligament, just a little bit below the knee,” she said. “Within 12 hours, and even shorter than that, the foal would have its foot on the ground, and that would be the end of it. Those foals went on to become show horses or racehorses on the flat or over fences.”
Young horses may develop a clubfoot in response to pain in the shoulder or elbow caused by osteochondritis dissecans (OCD) lesions, a defect in the cartilage that affects the smooth action of the joint. But anything that makes the horse place more weight on its toe can cause a clubfoot. Clubfeet are prone to toe abscesses and inflammation of the coffin bone (pedal osteitis) from the added weight.
Dr. Richard Mansmann, who operates Equine Podiatry & Rehabilitation in Chapel Hill, North Carolina, is co-author of the textbook Equine Podiatry and a retired clinical professor at North Carolina State University. He said sometimes a clubfoot develops from the way a young horse grazes.
“Horses seem to graze in two ways: one, ambidextrously, like they are walking; others develop a laterality to grazing by habitually putting one front foot more forward, more often than the other,” Mansmann said. A horse that tends habitually to put the same foot out front all the time needs a closer diagnostic look.
He referred to a study in the Netherlands of the developing grazing pattern of two dozen Warmblood foals.
“The foals that developed a propensity of having one specific foot forward seemed to be the taller, longer-necked, and longer-headed foals,” he said. “Thus, the 'forward' foot generally has more weight on it and the 'back' foot has less weight. Thus, over time, the 'back' foot becomes narrower and clubbed.
“Some form of reduced weight bearing to the narrower foot is the reason for a clubfoot,” Mansmann said. “It could be genetic, nutritional, or I've seen it with thrush in a baby. You can see it with trauma, also.”
An injury to the foot is a common cause of clubfoot, since it may cause a horse to shift weight to the toe to compensate for pain elsewhere. Sometimes such an injury will rob the horse of an athletic career, but there have been notable exceptions. The most famous clubfooted horse was 1946 Triple Crown winner Assault. In her book Racing through the Century, Mary Fleming Simon writes:
“As a foal, Assault stepped on a sharp object and permanently deformed his right forefoot. (The nickname-loving press later dubbed him the Club-Footed Comet.) Trainer Max Hirsch shook his head when he first saw Assault. 'When he walks or trots, you'd think he's going to fall down,' Hirsch marveled. But in full stride, Assault was Mr. Smooth, with speed aplenty to wrap up the 1946 Triple Crown.”
Dr. Robert Hunt, a surgeon and podiatrist at Hagyard Equine Medical Center in Lexington, offered this advice:
“One important principle of clinical management is to determine if discomfort or lameness is present, and if so, to localize the source of the lameness and determine the association of the lameness to the clubfoot—primary or secondary. If the foot is improperly loaded, a normal-contour hoof capsule will not be possible to obtain, and the underlying lameness may be the limiting factor on the future athletic capacity.”
There is hope for horses with clubfeet, even if they're not treated as foals. In a 2015 study, Dr. Scott Morrison, head of Rood & Riddle's Podiatry Center, successfully treated clubfeet in Thoroughbred yearlings by gluing on aluminum hinged shoes to spread the heels. Morrison reported that after three months, the severity of the clubfoot decreased in 70 percent of the horses. He added that the exact mechanism by which the aluminum hinged shoes accomplished the change is unknown and requires more study.
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