Navicular Disease
Navicular disease...you hear about that a lot these days. You hear about it from vets and farriers, you read about it in magazines, and you probably talk about it with fellow horse owners. There almost seems to be an epidemic of navicular disease, with more and more horse owners either being told their horses have it or being advised to maintain the hooves in a certain fashion to prevent it. So let's think about navicular disease.
First of all, what does the term "navicular" refer to? Well, there is a bone in the horse's foot called the "navicular bone." The navicular bone is a little wedge-shaped bone that sits basically above and behind the coffin bone right at the back of the foot. In the picture it's the bone colored in red. It's purpose is to act as a sling, or pivot point, for the deep flexor tendon as it comes down and curves to attach to the coffin bone. The navicular bone also contains blood channels that help provide blood flow to the hoof.
So what is navicular disease? It's essentially any lameness that supposedly comes from abnormalities in the area of the navicular bone. Why is it talked about so much? Well, navicular disease has come to be sort of a catch-all term for any kind of lameness they can't find any other cause for. It's sort of the "fad diagnosis" today, much like Irritable Bowel Syndrome in humans. If you go to the doctor with some kind of stomach or digestive problem and they can't find anything wrong, they tell you that you have Irritable Bowel Syndrome, which means nothing more than that you have some sort of digestive problem that they can't pinpoint. Similarly, if your horse has some sort of lameness problem, and they can't find any obvious cause, then your horse has "navicular disease." Most of you reading this whose horse has been diagnosed with navicular disease will fall into this category. Yes, I know...your vet or farrier may have done some tests that he/she uses to make the diagnosis and you may have been told that these tests "show" that your horse has navicular disease....but the fact is , the tests notwithstanding, you horse still has lameness for which they can't genuinely point to a cause. Even if your horse failed their test, it's still a big leap of assumption to conclude that the reason it failed the test is necessarily causing the lameness which your horse is experiencing. Whatever caused your horse to fail the test may or may not be causing the lameness...it may be perfectly harmless and causing no symptoms. Making big leaps of assumptions may end up causing you and your horse a lot of unnecessary trouble.
There are a lot of assumptions made about navicular disease and a lot of theories have been floated around. Unfortunately, many people operate on those assumptions as if they were fact. According to conventional wisdom and common assumptions, horses with navicular disease were assumed to have certain changes in the navicular area...and vet and farrier practice operated for years on those assumptions. However, recent imaging studies of the feet of horses euthanized for supposed navicular disease have proven those assumptions to be not true. In other words, a lot of what was assumed to have been going on in the navicular area and causing this thing called navicular disease simply wasn't there. Not surprisingly, though, even in the face of that, the same old assumptions and old wives' tales about navicular disease are still being circulated by vets, farriers, and horse owners.
Let's look at one of those old wives' tales...high heels. According to what's still popular opinion in some quarters, low heels cause navicular disease while high heels prevent it. This belief basically developed in the following way: First, people gradually noticed that a lot of the horses shod according to traditional farriery; that is, with underslung heels and a long, extended toe, developed lameness problems as they got older, around 12 to 15 years old. And somebody found out, just by experimenting, that if you raised the heels on these horses, the lameness temporarily diminished somewhat, i.e., the pain was temporarily reduced. So they made the assumption that it was the low heels causing the pain, since raising the heels temporarily reduced the pain. But that's faulty logic. Think about it this way: Suppose my back is hurting and I go home and put a heating pad to my back and it feels better. Does that mean that my back was hurting because I didn't have a heating pad to it? No...the heating pad just soothed the symptom; the lack of a heating pad wasn't the reason my back was hurting. It's the same with navicular disease...just because raising the heels temporarily eased the symptom of pain doesn't mean the fact that the heels were low caused the pain in the first place. Yet a whole theory and practice of how to prevent and treat navicular disease, one that's actually fairly popular, is based on this faulty logic.
This is a hoof after several years of being shod according to the recommendations of a veterinarian and certified farrier who assured the owner that this was what was needed to prevent navicular disease. This horse was shod for years with high heels and a dubbed toe...and see what the result was. This horse's hooves are grossly deformed, and it'll take years for them to recover...if in fact they ever do. And yet all over the country, vets and farriers are still recommending this high heel/dubbed toe setup to "prevent navicular"...and horses' hooves are being transformed into something similar to the picture. And they scratch their heads and wonder why the heels are curling inward...and wonder what happened to the frog!
From conventional vet practice and farriery, other theories and treatments are also popular, and just like all conventional medical approaches, they all sound so complicated that we as average horse owners might want to give up ever understanding it all and just let the medications and treatments and complicated shoes be applied in blind faith. After all, if such an approach is written about in a magazine or endorsed by someone with credentials, it must be OK. And, for those with an interest in alternatives, the personalities from the natural hoof care/barefoot trimming movement have come in with their claims of miracle cures based on the magic trim that only they and those they have instructed know about.
But is it really that complicated...and do we have to depend on magic? What actually IS most likely causing this epidemic of so-called navicular disease? And what's the reasonable thing for a horse owner to do if faced with such a diagnosis? Since there is no single thing that can be pointed to as defining "navicular disease"...that is, since the old wives' tales of what was happening in the navicular area have largely been proven false by imaging studies, indeed some of the horses put down for being "navicular" actually showed none of the abnormalities assumed to exist in navicular disease...it seems clear that what is called navicular disease is actually a catch-all term for lameness for which there is no clearly seen cause...no cause that can be clearly pointed to on an X-ray or MRI. So let's just use our common sense, and really, I think common sense is more valuable in many cases than advanced degrees, technical talk, and advanced imaging methods. Navicular disease is observed on horses who exhibit hoof deformity as a result of improper trimming and the effects of shoes. The hoof deformity, improper trimming, and shoes all tell us that the hoof is not functioning as nature intended, that the functions of the hoof parts have been negated or bypassed, and as a result, stresses are being brought to bear on parts of the hoof and legs that were never intended to bear them. And this happens day after day year after year.
The horse's hoof is strong and adaptable; it must be in order for the horse to survive in a variety of different environments. Because of that, you can do just about anything you want to do to the hoof for a while and get by with it, sometimes for years and years. But during that time, as natural hoof function cannot operate and as stresses are placed on parts unsuitable to bear them, damage is being done, little by little, day by day. There is a lot of reserve strength in horses, so lots of damage can be done before anything wrong is noticed. But then one day there is so much accumulated damage that the horse shows lameness. The accumulation of years of hindering natural hoof function finally shows up as noticeable lameness. But it's a general lameness all over the hoof, and nothing really terrible or out of the ordinary shows up on an X-ray or MRI...oh, maybe, you know, well, I might be able to detect a little something here in the navicular area...and so your horse becomes labeled "navicular."
I believe that what is called navicular disease is general lameness resulting from years of not having natural hoof function. The lack of hoof function means that the parts of the hoof cannot do their jobs...supporting the force of the weight of the horse and absorbing the forces generated as the hoof hits the ground. Since the hoof structures that are designed for that cannot function, these forces are transmitted to parts of the hoof and legs never intended to bear them, and over time, that causes general damage, which leads to general lameness. So in a nutshell, navicular disease should actually be referred to as "lack-of-hoof-function disease." It is the price coming due for all the years of ignoring how the hoof should function.
Dissections of horses' feet have shown that horses who had no hoof function due to shoes or improper trimming have internal hoof structures that are weaker, deformed, and of a different composition than horses whose hoof function was not interfered with. So not only do shoes and improper trimming and the associated lack of natural hoof function deform feet on the outside, they also lead to deformity and weakness on the inside. And this is general, overall, affecting all the internal parts of the hoof. The important thing to realize here is that this deformity and weakness leads to loss of function.
So what do you do if your horse gets the diagnosis of navicular disease? Well, you could follow the vet/farrier recommendations, which basically means trying to cure something by using more of the same methods that caused it in the first place. But our common sense will probably object to this. If negating and bypassing the natural functions of the hoof is what caused the problem, then our common sense will tell us that we need to stop negating and bypassing the natural functions of the hoof. To me this means pull the shoes off the horse, turn it out in something approaching a natural environment (which means not a stall or small paddock and hopefully something a little more varied than a grass pasture), and leaving it alone. In time, Nature will begin to deal with the hoof deformity and through the natural processes of splitting, chipping, cracking, flaring, and breaking off, will shape the hoof so that natural hoof functions are enabled for that particular horse in that particular environment. And then perhaps the horse will improve as the hooves naturally shed the deformity, hoof function is naturally enabled (notice the word "naturally" and not "by nippers and a rasp"), and the inside parts of the hoof become able to do their jobs.
But many people are not satisfied with that. They want a cure today, or tomorrow at the latest. They want to be able to ride their horse. And so, due to consumer demand, a whole industry of lameness treatment has sprung up. And that lameness treatment industry, from conventional vet/farrier practice on one side to natural hoof care/barefoot trimming on the other side, offers various treatments all designed more or less to allow the horse to be ridden again. They make it sound as though all the years of ignoring hoof function don't necessarily have to have a price. "OK, so you have a lame horse today as a result of eight years of this or that....no problem! Just nail on this shoe and ride tomorrow, or have this trim done, wait a few weeks, and then ride." But, as many of you have no doubt experienced, it's not quite that easy, and the treatments may help a little or work for a while, but none of them offer what they promise.
You see, there is a price for those years of ignoring hoof function, for those years of hoof maintenance designed to allow you to ride anywhere you choose whenever you choose. And that is that you run a big risk of your horse coming up lame...of developing "navicular disease" or other hoof and lameness problems. And if that happens, there will be no quick fix. You can't negate years and years of accumulated damage simply by nailing on a shoe or having a magic trim done. If you're concerned about the horse as a living being, as a fellow creature of Nature, and not just concerned with being able to ride the horse, you'll have to face the fact that all those years of accumulated harm are not going to magically disappear in a short time, and that you're going to have to give this horse, this living being, time to heal. If all you want is to squeeze another year or two of usefulness out of the horse, then go with the treatments and when they no longer work, sell the horse for dog food. But if you see the horse as a living being for whose care you are responsible, then give your horse time to heal. There really is no shortcut...despite what the advertisements and gurus say.
