Ringbone

Ringbone is exostosis (bone growth) in the pastern or coffin joint of a horse. In severe cases, the growth can encircle the bones, giving ringbone its name. It has been suggested by some authors that such a colloquial term, whilst commonly used, might be misleading and that it would be better to refer to this condition as osteoarthritis of the inter-phalangeal joints in ungulates (Rogers and Waldron, 1995: 34-35).

Ringbone can be classified by its location, with "high ringbone" occurring on the lower part of the large pastern bone or the upper part of the small pastern bone. "Low ringbone" occurs on the lower part of the small pastern bone or the upper part of the coffin bone. High ringbone is easier seen than low ringbone, as low ringbone occurs in the hoof of the horse. However, low ringbone may be seen if it becomes serious, as it creates a bony bump on the coronet of the horse.

Ringbone usually occurs in the front legs but can also be in the hind legs, and is usually worse in one leg than the other. Ringbone is most often found in mature horses, especially those in intensive training.

High ringbone: The horse will have a bony growth around the pastern area, and the pastern will have less mobility. The horse will show pain when the pastern joint is moved or rotated. Early cases will have a lameness score of 1-2 out of 5, with little or no bony swelling seen, although possibly felt when compared to the opposite pastern. Lameness will worsen to a grade 2-3 on a scale of 5 as the ringbone worsens.

Low ringbone: The horse will have moderate lameness (grade 2-3), even in early cases, because of the closeness of the ringbone to the other structures in the hoof. When severe or very advanced, the bony growth will be able to be seen on the coronet.

Ringbone is degenerative (unless it is caused by direct trauma). Treatment works to slow down the progress of the bony changes and alleviate the horse's pain, rather than working to cure it.

Shoeing: The farrier should balance the hoof and apply a shoe that supports the heels and allows for an easy breakover.

NSAIDs: or non-steroidal anti-inflammatory drugs help to alleviate the pain and reduce inflammation within and around the joints. Often NSAIDs make the horse comfortable enough to continue ridden work, which is good for the horse's overall health.

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