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Ringbone is known as "osteoarthritis", or "bony arthritis". It occurs when there is damage to the periosteum, the outer layer of tissue that covers bones. Damage to this tissue can occur from a wide variety of issues, which will be discussed shortly. The term “ringbone” refers to the formation of new bone around these damaged areas, namely in the region of the horse’s pastern and coffin joints. It is a painful and irreversible disorder and can lead to permanent lameness.
Below is a picture of the long and short pastern bones from a horse affected with ringbone. Notice the bony growths encapsulating the area around the joint.
A body's natural response to pain and discomfort, both human and equine, is to try to fix it. When a joint in a horse is strained, the body may choose to compensate for it by growing bone at the point of stress.
Ringbone is classified by "high ringbone" and "low ringbone", depending on the location of the bone mass. "High ringbone" affects the pastern joint, made up of the lower part of the large pastern bone and the upper part of the lower pastern bone. "Low ringbone" affects the coffin joint, which involves the lower part of the lower pastern bone and the upper part of the coffin bone. High ringbone is much easier to deal with, as low ringbone is located inside the hoof. You can see the growths below in the diagram I borrowed from http://www.horseshoes.com/.
1) Conformation is key! Horses with natural, abnormal stress on their joints will be predisposed to the condition. This includes those with long, upright pasterns, those with long toes and low heels, splay-footed and pigeon-toed horses.
2) Horses with degenerative joint disease are, needless to say, more likely to have ringbone. Over the course of years, a horse's body will produce bone in an attempt to immobilize a painful joint. This can progress to a point where the joint is completely fused together.
3) Horses injuring or having excessive strain on ligaments near the pastern joint are also at risk. Similar to above, they will grow bone to help stabilize the area.
4) Proper trimming and shoeing is also a factor! Make sure your farrier knows what he or she is doing. Ask your vet to evaluate your horse's hooves and, if need be, speak with your farrier about making changes.
Treatments: Unless it is caused by an injury, ringbone is typically degenerative. Treatments for ringbone are not meant to cure it, but to hinder the additional growth of bony masses and to make the horse comfortable.
1) Corrective shoeing can make a huge difference in the level of comfort in a horse suffering from ringbone. Natural balance shoes are frequently used as they support the heel and allow for an easier, more natural breakover, thus lessening the stress on the affected joints.
2) Joints can be directly and individually injected. Commonly used is a HA/Depo mix. The hyaluronic acid lubricates the joint, and the Depo-Medrol reduces the inflammation and subsequent pain. A joint injection can last anywhere from 3-6 months, at which time the lameness will reappear and the treatment will need to be repeated. The biggest benefit is a nearly immediate response. The biggest downfall is that you can only treat one joint at a time.
3) A systemic injection is another option. Adequan (intramuscular) or Legend (intravenous) are the most commonly used to treat joint pain disorders. The biggest benefit is that this is a systemic treatment - it will help every joint in the horse’s body. The disadvantages? It may take a few weeks for noticeable improvement, and the treatment is ongoing and can be quite costly.
4) Obviously rest will make a huge difference in the comfort of the horse.
Ringbone is a serious disease that is both painful and incurable. However, with proper management, pain can be reduced and some horses can continue to perform.
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Have any of our readers dealt with ringbone? Any suggestions that you could share with us?
Feel free to add your own suggestions, comments, questions, etc into the comment section!