SIDEBONE

QUESTION: 

Hi Dr. Teskey,

I attended a seminar that you gave at the beginning of the month. It was wonderful! I plan to follow up with more learning and hope to attend more clinics in the future. I am seeking input about a pathology I recently discovered in a draft horse that I ride. This horse has side bone in both front feet. The ossification process is complete and clearly occurred some time ago. However, I am not sure about the time frame as he is 8 years old and have owned him ~ 2 months. It is particularly severe on the side of one foot with an ossification approximately the size of half a golf ball. Currently, he is sound and barefoot. His hooves are being trimmed by a hoof groom. I found little in the literature about the prognosis and treatment of side bone, but did discover that it may cause lameness due to its ability to compromise the hoof's normal function (loss of flexion in what would be a cartilaginous structure and interference with other structures if large enough). Other than keeping this horse barefoot with as good hoof function as possible, do you have any other recommendations? I have considered using boots on this horse's feet to aid him in shock absorption, since his ability to absorb concussion is reduced. I thank you for any input you can provide. And again, THANKS for the wonderful clinic.

Sincerely,

Tiffany

DR. TOM'S ANSWER:

Hi Tiffany,

Thanks for the compliments on the seminar...it was exciting for me to do it and we're planning on having another one at the university before long. That's great to have a hoof groom on your team.

Sidebone, as you have noted, is ossification, or "changing to bone", of the lateral cartilages which extend rearward from the palmar processes, or "wings" of the coffin bone. Cartilage tissue will ossify for two main reasons in mammalian species: continuous trauma and/or lack of movement. Horses that constantly interfere or over reach or get wire cuts over their lateral cartilages often end up with scarring and ossification. Concussion from the presence of steel shoes is also traumatic and contributes to the formation of these bony protrusions. The other reason sidebone forms, lack of movement, is common in hooves that are overgrown, have poor form or are shod. Cartilage cells get their nourishment by "diffusion". There are no blood vessels that supply nutrients to cartilage cells, rather the nutrients must move from surrounding tissues to these cells, and this can only happen through physical vibration and movement. Extra sole, wall and bar material and steel shoes slow down hoof movement or mechanism, and the resulting lack of physical movement of the entire foot and hoof capsule starves cartilage of the nutrients it needs...ossification then sets in.

It is important to note that nailed on steel shoes contribute to the formation of sidebone for BOTH of the reasons listed: direct concussive trauma and prevention of normal expansive movements.

Draft horses are pretty forgiving when it comes to their feet as long as you trim on them every month or so once they have some proper form started. I believe the ossification of the cartilages will reduce to some degree if you bring more circulation and mechanism in to the area, which is what you're doing by having a natural trim done. Keeping them moving is also critical...the more walking and trotting the better...it seems like you can never have too much when you think that horses move a minimum of 10 to 15 miles per day if given enough space. Maybe you can get another x-ray taken in a year and compare it to the original and see some differences? I think the hoof will compensate quite a bit for the ossified cartilages. True, the shock-absorbing character of the foot will be compromised, but maybe not so much that you will have a performance problem or lameness. If an area can calcify, it can decalcify--it's very straightforward and both are normal physiologic processes that occur every day of our lives. By promoting more circulation and mechanism the body will sense that the calcified areas are not appropriate and begin to reduce them, although very slowly. I've heard some say that homeopathic silica is helpful in getting the body to "clean up" an area...they talk about it being able to break up and "clean up" sidebone...you might want to check in to that and research it. Using the hoof boots, as you mentioned, is an excellent idea. Boots offer honest protection for horses' hooves, where steel shoes only damage them and give us a false appearance of protection.

Historically, sidebone has been largely ignored as being a problem. In fact, many veterinarians will say that it doesn't generally cause any problems and one shouldn't worry about it. It's so common one could consider it epidemic, just like poor hoof form is epidemic amongst our horses. This is because shoeing is so common and ignorance of proper hoof form so common. Barefoot horses that have properly shaped feet and are allowed freedom of movement, (and stay out of the barbed wire) do not ever get sidebone--this should be a powerful example to all. The fact is that sidebone does cause some severe problems in the normal physiology of the equine foot. Energy dispersion, heel support and circulation all suffer dearly when the lateral cartilages are not supple and yielding. We are understanding more and more how important healthy cartilages are for the hoof, where historically their function was largely misunderstood or simply ignored. This is why traditional veterinarians are able to honestly say that sidebone is not a problem. If a part of the anatomy is misunderstood or has an unknown role, it's simple to dismiss it as being unnecessary. You're in the minority, as am I, when it comes to knowing what's best for a horse's feet. Let's keep each other strong and keep learning and spread the word to those who are interested.

Take care,

Dr. T.