Ringbone in Horses

Ringbone in Horses

This radiograph demonstrates the bony abnormalities seen with high ringbone (involving the pastern joint). This film is of the left hind foot of a 10-year-old Quarter Horse used for barrel racing.

Photo: Patricia Hogan, VMD

Q. My horse has been diagnosed with ringbone. The veterinarian said there is no real cure, but that my horse can stay in competition if I take care of the condition. What can you tell me about ringbone?

A. Ringbone, a lameness disease of the pastern and coffin joints, is a degenerative disorder that has no cure. Once the condition occurs, it's always there and will progressively worsen. Fortunately, with treatment and good management, disease progression can be slowed, allowing the horse to remain competitive.

"On a descriptive level, ringbone is a circumferential enlargement that occurs at the level of the pastern joint or coffin joint," says George Martin, DVM, MS, MBA, Dipl. ACVS, an Associate Professor and surgeon at Louisiana State University. "High ringbone refers to the condition when it affects the pastern joint, and low ringbone refers to the condition when it affects the coffin joint."

In simple terms, says Martin, ringbone is similar to arthritis, with the affected area showing bony spur formation and evidence of degenerative joint disease (DJD).

Traditionally, ringbone is subdivided into periarticular and articular ringbone. Horses with periarticular ringbone have bone spurs near the joint surface, but these spurs do not affect joint structures, i.e., cartilage or synovium, says Martin. "Articular ringbone involves the cartilage or synovium and, in my experience, is more common and more serious."

The disease occurs in front and hind legs, but is more commonly seen in the front.

Ringbone has many causes. The most prevalent include injury, sudden or chronic strain from athletic activity, and irregular conformation.

"Most commonly, we see ringbone associated with a particular trauma, such as a horse that wrenches its ankle or has a subluxation that occurs inside the pastern joint," says Patricia M. Hogan, VMD, an associate surgeon at New Jersey Equine Clinic who handles primarily orthopedic surgery and lameness cases. "In an acute situation where an injury has occurred, the effects of what you radiographically see as ringbone won't occur for one to two months, as it takes some time for the bone to respond by proliferating or degenerating."

Activities which call for sudden maneuvers as well as some dressage elements stress the coffin and pastern joints, predisposing these horses to ringbone.

"We rarely see it in a racing Thoroughbred or Standardbred," notes Hogan, "but we do see it more commonly in the Western performance horse, dressage horse, and polo pony."

Horses with upright legs and foals with uncorrected, inwardly crooked legs from the fetlock down have greater forces placed on the pastern or coffin joints, consequently increasing their risk for ringbone. The same is true of young horses suffering from osteochondrosis (OCD), a common developmental bone disease which can damage the cartilage in the pastern joint.

In rare cases, injection of medications or anesthetics into the coffin or pastern joint can cause infection, which then might lead to ringbone in the joint, says Martin.

The first sign of ringbone an owner usually sees is lameness. "When you first have an injury to the area, you may notice an intermittent lameness," says Hogan. "The tissue around the area may be soft and painful. But as the condition becomes chronic, the soft tissue around the joint becomes very firm, very cool, and there's no pain on palpation."

In chronic cases, horses might have swelling around the pastern or on top of the coronet band associated with the coffin joint. "The swelling is most noticeable on the front and sides and less apparent on the back surface of the leg," says Martin.

Diagnosis is based on history of the problem, external appearance, palpation, and radiographs.

Prognosis depends on the severity of the disease. "Ringbone can sometimes be managed for many years, if you treat the horse medically and are careful with use and shoeing," says Hogan. "But it is a degenerative condition, so it will progress. In many cases, the end result is chronic lameness."

"The foundation of treatment is rest," says Martin, "but treatment is also dependent on the cause. In addition, early stages of ringbone may be helped with leg wraps, topical application of DMSO, systemic administration of a polysulfated glycosaminoglycan (Adequan), and perhaps a gelcast applied to further protect the joint."

Adds Hogan, "Medications used for joint disease such as hyaluronic acid (Legend) are most useful in cases where ringbone is developing, but where there are very little radiographic changes. Adequan is a potent inhibitor of some of the degradative enzymes seen in arthritis, so it's probably helpful in slowing the disease process."

These agents are most effective early on, prior to a lot of bony changes. "In later stages, you've got significant cartilage damage, and cartilage heals very poorly, if at all," says Martin.

Anti-inflammatories such as Bute, ketoprofen (Ketofen) and Banamine can help break the inflammatory pain cycle, but must be used judiciously because of side effects--gastric ulcers, kidney damage, and colitis-that occur with long-term use.

Surgery might be effective for high ringbone when medical management fails. Explains Hogan, "The pastern joint is fused with a plate, screws, or a combination of both. The bone fuses, there is no pain, and since that joint does not have a lot of motion, once you fuse it, it becomes one complete bony column."

Owners also can be pro-active by minimizing their horses' risk of ringbone. Avoid selecting horses with conformation problems for high-risk sports. Horses with joint injuries should never be rushed back to work. "If the tissues are not strong enough to support the horse, he will put additional stress on that area," warns Hogan.

Finally, take care to adequately warm up a horse before competing or strenuous exercise. "A period of just walking, then trotting, then loping," says Martin, "will stretch the tendons, ligaments, and muscles, resulting in greater flexibility."

About the Author

Les Sellnow

Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.

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