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From: email@example.com (Linda B. Merims) Subject: Club Foot (Long) Date: 29 Nov 1993 23:58:55 GMT Organization: Advanced Visual Systems Inc.
Jonas Herbertsson wrote: :I have a 9 yo Swedish WB mare with a strange front foot. I haven't :found out why this foot is different from the other but have some :theories about it. Has anyone else seen this phenomenon and/or :have any theories about it? : :- The right front foot is slightly smaller than the left one. : :- It grows significantly faster than the left one. : :- It has a slightly concave side profile at the toe. : :- If left unattended by the shoer the heel will be too high and : the back of the foot will be very narrow.
This is, alas, something I know all too much about. The condition is called "club foot." It is widely thought to be an inherited defect, though it can easily skip generations. No studies have been done that document and describe its heritability. Indeed, the entire state of formal research on this defect is abysmal. This may change as it is becoming a significant problem in thoroughbred racing lines.
I know about it because the weanling Morgan filly I purchased began to display this defect at about 9 months of age. This set me off on a long, confusing, discouraging, but ultimately somewhat enlightening search for information. This included a literature search through the Cornell Vet School library.
WHAT IS IT?
You will never get anybody who can tell you exactly what is wrong. All you will get is a description of the phenomena, to whit:
|| ||_ canon bone (base--fetlock) // Normal foot //_ first distal phalanx (P1--pastern) //_ second distal phalanx (P2--short pastern) // third distal phalanx (P3--coffin bone) || ||_ canon bone // Club foot //_ first distal phalanx (P1--pastern) //_ second distal phalanx (P2--short pastern) || third distal phalanx (P3--coffin bone)
The third distal phalanx (P3--coffin bone) is not in a smooth line with the first two phalanxes. It is rotated to _some_ degree behind the line it should be. Therefore, the bottom of the coffin bone is not parallel to the ground. The horse is therefore standing to some degree on its toe.
Appearance and Onset
There are degrees of club-footedness. The best article I ever saw on this was by a research vet named Rooney at the University of Kentucky at Lexington, published in _The Blood Horse_ about three years ago. Rooney taxonomized the condition like this:
Grades I's and mild II's can often compete without "the bad stuff" starting to occur. Racehorse Easy Goer has a Grade I-II club foot (which ain't going to help his value at stud). Grade III's are likely to have have significant problems with anything more than the very lightest use. Grade IV's are in very bad shape. Rooney said that an estimated 20% of thoroughbreds foaled now display club footedness to some degree.
Club Foot Not the Same As Contracted Tendons
A club foot is _NOT_ the same thing, though it is similar, to contracted tendons. (Contracted tendons are bilateral instead of unilateral, occur earlier in the foal's development (about 6 months), are affected by environment, and are more amenable to corrective surgery. This is also an inherited tendancy. For example, in Morgans, it is rampant in the Waseekas In Command horses.) Vets will, however, often refer to a club foot as "a contracted tendon," or "deep flexor contracture." Get them to clarify which they mean. Unilateral is the tip-off. Also be aware that there is something called a contracture of the superficial flexor tendon--but that's a different story.
WHAT IS REALLY WRONG?
What actually seems to be wrong here is that, for some reason, the deep flexor tendon, which attaches to the back of the coffin bone, is pulling the coffin bone back from where it should be. What's wrong? Nobody knows. Theories abound:
Two treatments exist:
Treatment 1 is now being discredited by research (that was one of the main points of _The Blood Horse_ article) as being counterproductive. However, that's what most farriers have been taught and you're going to have a devil of a time talking them out of it.
The Bad Stuff--What Eventually Goes Wrong with a Club Footed Horse?
The reason this therapy is being discredited has to do with all "the bad stuff" that can start happening to a club-footed horse undergoing use heavier than the leg can stand:
The problem with Treatment 1 is that it rests on the theory of gently "stretching" the deep flexor tendon. An attractive theory. Rooney says this is nonsense. By shaving the heels:
I agree with Rooney. This is _exactly_ what happened to my filly (a Grade III) after her various "therapeutic" heel trims. After a trim, you could slip a piece of paper 3/4 of the way under her foot. She was standing on her toe. No deep flexor "stretching;" the rotten dynamics set up by this situation only slowly corrected itself as the heel grew out again. By 18 months she had coffin deterioration and separation from the hoof wall. By 2 she was a lame horse.
The downside to letting the heels get long is another side effect:
High ringbone, however, is not as serious as the effects of trimming heels too much.
Trim--But Not Too Much
You _do_ have to trim the heels on a club foot more often than on a normal foot. The trick is to only trim the excess and never so much that the horse is not bearing weight and landing unevenly on the foot. This way, you avoid putting strain on the deep flexor/laminae. Never try to "carve" a normal looking foot out of a club foot. Never try to make it match the other foot. (Good luck debating this with your farrier.) Honest, they do better with a long heel. (Jonas, if your horse is healthy and happy with how she's being trimmed now, great, don't change.)
Efficacy of Desotomy Questioned
Treatment 2, desotomy of the inferior check ligament, was originally developed as a treatment for bilateral contracted tendons. When performed when the horse is very young (before 2), it can help the situation. However, studies on the efficacy of the surgery have not distinguished between club foot and contracted tendons. It is now being thought that it is more effective for contracted tendons, and only moderately effective to ineffective for club feet. (It helped my filly only a little.) It is also questionable whether a horse without an inferior check ligament should be racing or jumping.
A horse with mild club footedness can lead an active, athletic life. But, the greater the degree of rotation, the worse the skill exercised with heel trimming, the harder the use given the animal will all contribute to development of "the bad stuff." (I havn't heard of navicular problems being associated with this defect, but all that means is that I havn't heard it.) Too much bad stuff and you have an unusable horse.
If you breed such a horse, you may luck out and get a normal foal. But somebody down the line is going to start scratching their head when _their_ foal is about 9 months old when they begin to notice that one of their feet (probably the off fore) is starting to look awful funny.
Linda B. Merims Waltham, MA
(I guess you can tell this got to be a bit of an obsession with me.)