Thursday, January 01, 1998

Club Foot - Linda B. Merims

One of the most entertaining--and if you are a victim, maddening-- aspects of club foot is the *lack* of hard knowledge that surrounds it, and the extraordinary set of stories that float around about what causes it.

I had my first experience with a club footed weanling in 1985. Since that time I have researched and watched the evolution of thought on this topic in both veterinary and farrier circles. There are few hard answers. What vets and farriers were saying in 1985 is not what they are saying now. It is probable that what they say now is now what they will be saying 10 years hence.

Current thought has two broad causes for club foot:
1. Genetic. There is some inherited *something* (nobody knows what) that causes the foot in a growing foal to slowly go wrong. It happens very gradually over the foal`s first year. The vet is often called in around the time the foal is 9 months old because by that time the foot has become so obviously dished and the tendancy of the heel to grow so much faster so unignorable that the owner finally decides he`d better ask the vet about it.

What the inherited something is, as I said above, completely unknown. Theories range from the old "grass foot" theory that somebody put forward here to bones growing faster than tendons to one leg being shorter (or longer) than the other and half a dozen more.

2. Contracted tendon. What happens is that the foal experiences pain in a foot. The pain can be due to injury, or it can be due to a developmental joint disease such as epiphysitis. (All of the nutrition-based theories of club foot are actually statements of how to prevent, mitigate, or remedy a developmental joint disease such as epiphysitis.) To relieve the pain in the foot, the foal takes its weight off the foot. Something happens (again, people aren`t dead sure exactly what) that appears to be the muscle in the forearm contracting, pulling up the deep digital flexor tendon, which pulls back the coffin bone in the foot.

Suddenly, and indeed in some cases overnight, the horse goes up on its toes, and even over onto the front of its foot. This can be unilateral, and it can also be bilateral, and in varying degrees in both feet. You`ve now got a contracted foal.

The remedies for this are a combination of surgery (desmotomy of the inferior check ligament), shoeing (extended toe shoes), the administration of antibiotics and pain relievers, and--to remedy the original joint ailment that caused the pain--change in diet, usually away from the rich growth-promoting diets often fed to young foals and back to something much more spartan.

However, many contractions never go back all the way back to normal, and the result over time as the foal matures is the dished, high-heeled distorted appearance of a club foot.

Acquired contracted tendons are in their own way genetic. It is thought that the tendancy to develop joint disease on any particular diet is probably inherited, and the tendancy to react to this pain by contracting is also probably genetic.

In the mid 1980`s, the particular diet culprit held to be culpable in most developmental joint diseases was excess protein. Around the early-to-mid 90`s the theory changed to be simply excess carbohydrates (i.e., just plain too much grain). I see that somebody else has put forward the theory that it is a calcium/phosphorus imbalance. I havn`t checked the literature recently and that may very well be a the latest theory, although assuming there is only one dietary cause for developmental joint disease is also probably overly-simplistic.

I won`t get in to the farrier remedies to club foot (because I want to go ride my horse) except to say that in the mid 1980`s slowing shaving the heels to stretch the tendon was the accepted practise. This has since been discredited and even held as counter productive because the laminae in the foot give long before the deep digital flexor tendon ever "stretches" and you`ve got a mechanically foundered horse. Now the accepted practise is to bring the healthy foot into closer alignment with the club foot by growing out its heel, or shimming it up with pads. The long term effects this has on the healthy foot is an unstudied area. My horse is mildly club on one foot and has had his healthy foot trimmed to match. After 18 years, it is interesting to see the price the healthy foot has had to pay for its misshapen brother.

I would never buy a club-footed horse without X-rays that told me the degree of rotation and most particularly how the foot has fared over the years with its deformity. Is there a mechanical founder (coffin bone pulled away from the hoof wall)? What is the degree of remodeling the coffin bone has undergone? Is the toe still in good shape? Has high ringbone set in yet (all the joints pulled out of alignment can eventually cause this)? And most importantly, how does the horse travel? Is he sound and even when he has even feet? Is he in any way tied in or restricted in his movement?

Linda B. Merims Massachusetts, USA

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