Ringbone in Horses
Your riding horse has just been diagnosed with ringbone, a degenerative disorder that affects the pastern and/or coffin joints and has no cure. But before you automatically consign him to pasture ornament status, consider the related advances in diagnosis, treatment, and shoeing. Many horses today can continue to perform athletically with this arthritic condition.
If you don't believe it, take a look at the record of Travis Tryan's multiple champion roping horse, Precious Speck. Before his death of an aneurysm this past April at age 20, "Walt" was named the Team Roping Heading Horse of the Year four times by the Professional Rodeo Cowboys Association and the American Quarter Horse Association. Three of those titles came after 2004, when Walt developed ringbone in the pastern joint of his right front leg. Tryan earned more than $1 million on the circuit in 2009, much of it aboard Walt.
"Walt had so much heart and overcame a lot," says Hillary Tryan, Travis' wife. "He loved his job so much. That foot was big and ugly, and he had to wear two different-sized bell boots. But that didn't matter to Walt."
The Tryans, Gregg Veneklasen, DVM, and farrier Eric Thomas helped Walt continue his roping career by carefully managing his ringbone. Veneklasen fused the joint, and Thomas used special shoes and paid close attention to the angle of the foot.
The pastern joint acts as a shock absorber for the horse's lower limb, says Mark C. Rick, DVM, of the Alamo Pintado Equine Medical Center in Los Olivos, Calif.
"There is not a great deal of motion of this joint," Rick says. "But the minor degree of motion is very important and helps to soften the weight-bearing component of loading of the limb."
Larry D. Galuppo, DVM, Dipl. ACVS, professor and chief of equine surgery at the University of California, Davis, likens the joint to a round ball in a cup.
"The bone structure doesn't help the stability of the joint as much as in other joints," Galuppo says. "If the ligaments are injured, the joint can become unstable, which predisposes it to developing arthritis."
What is Ringbone?
Ringbone is an osteoarthritic condition that most commonly affects the pastern joint (high ringbone), but also can affect the coffin joint (low ringbone).
"The term gets its name from the ring or enlargement that can, in the more severe cases, form a true ring or enlargement surrounding the pastern joint just above the coronet band," says Rick.
As with any arthritis, calcification and degeneration of the normal joint surface cause pain.
"If the pastern joint is painful, the horse protects the limb to avoid the compression of the joint and hence demonstrates a weight-bearing lameness," says Rick.
Since arthritis tends to accumulate as horses age, ringbone doesn't usually show up until horses reach middle age (around 15 years). Ringbone also affects horses based on their conformation and use.
"Horses predisposed to ringbone often toe in, have upright pasterns, and have small feet," says Galuppo.
Repetitive stress on the feet can lead to ringbone. Jumpers that hit the ground hard after an obstacle, barrel horses that put torque on their limbs with sharp turns, and horses that work on pavement, such as carriage or cart horses, might develop the condition more readily than others. Galuppo says he also sees ringbone in many dressage horses.
"By no means does every upright-conformed horse or every horse that works on the pavement develop ringbone," says Rick. "Conversely, a heavy-weighted, upright pastern and fetlock horse that works continually on very hard surfaces certainly faces a much greater chance of developing many lower leg lameness conditions. Ringbone would be one of the more common ailments to befall this type of horse."
Rick adds that a horse that suffers acute trauma to the pastern joint could develop arthritis earlier than he would normally.
Ringbone can range from mild to severe, and each horse deals with the pain differently. Corrective shoeing can help manage ringbone, especially if it is diagnosed early. But that can be tricky because horse owners aren't often looking for ringbone until after the horse becomes lame.
Perhaps the best way to avoid ringbone is to select horses with good conformation. Bypass toed-in horses with upright pasterns and small feet; this might help ensure you don't have to deal with ringbone in a horse's later years.
But what if you bred the horse? Or perhaps he descends from such a championship line of barrel horses, reiners, or jumpers that his natural athletic ability trumps any conformational flaw he might have. What then?
In those instances, knowing a horse's conformation could lead to ringbone can give you an edge.
"If you have a young horse whose conformation predisposes him to developing ringbone, and it begins showing lameness localized to the foot, we could take X rays or do an MRI of the pastern region," says Galuppo. "If we saw abnormalities in the soft tissue structures surrounding the joints, we would know to rest the horse."
Galuppo says ligament abnormalities are difficult to diagnose without MRI because the horse typically will only show mild lameness, and an abnormality might go undetected.
In addition to MRI, nuclear scintigraphy (bone scanning) can help with early diagnosis, says Rick. Nuclear scintigraphy "has the capability of discovering early subtle bone and cartilage abnormalities before they become radiographically evident," he explains. "These diagnostic tests can help to sort out the horse that is slightly lame, blocks somewhere in the lower regions of the leg, and has no clear radiographic lesion."
In addition to rest, corrective shoeing can help manage ringbone.
"If a horse had damaged ligaments or established ringbone," says Galuppo, "I'd use a shoe that allows the horse to break over in all directions and limits the torque on the joint."
Sometimes good shoeing practices can help prevent ringbone. Likewise, poor shoeing practices can exacerbate a problem. Owners who skimp on shoeing, letting too much time elapse so the horse's feet become too long and the angles change, could inadvertently cause circumstances that would allow ringbone to get started. This is especially the case with performance horses that endure repetitive stress on their limbs.
Travis Tryan, for example, always kept Walt on a strict shoeing regimen. Once Walt developed ringbone, Thomas implemented corrective shoeing to help the horse do his job.
"I rolled his toe real heavy, really hard, so that he could leave the ground as soon as he could," Thomas says. "I put a 45-60ï¿½ï¿½ roll on his toe about 7/8-inch back. I rolled the toe on both front feet so that he'd be in balance. I used a wider web aluminum shoe--about 1 inch--to spread the pressure out."
If a horse's conformation and job predispose him to ringbone, it might be impossible to avoid the condition.
"It is often an insidious onset with a slow progression of cartilage loss and no outward signs of swelling or true lameness until a threshold of cartilage damage has occurred," says Rick. "It's hard for barrel racers to say they will avoid tight corners or a polo player to say he won't put heel calks on his horse and make sudden stops and quick turns."
Owners can manage early and mild cases of ringbone not only with corrective shoeing, but also with proper weight management. Overweight horses put additional stress on their legs and feet, compounding the problem.
Depending on the horse's job, you might be able to ride him selectively to minimize the wear and tear on the joint, says Rick. Chondroprotective (protecting the cartilage) agents, such as glucosamine and chondroitin, could help with ringbone as they do with other osteoarthritic conditions.
"They can be used as a means of ramping up the cartilage metabolism and (decreasing) any inflammation that may have started," says Rick.
Rick and Galuppo also mention intra-articular medications (e.g., hyaluronic acid, corticosteroids, polysulfated glycosa-minoglycans [PSGAG]), but caution against their overuse.
"Many times the treatment regimen involves injecting hyaluronic acid and/or steroids," says Galuppo. "These can help decrease the inflammation, but they can't heal the ringbone."
A horse needs time off following such injections to allow the inflammation to subside. Galuppo warns that sometimes people continue to use the horse without a rest period, which can lead to further problems.
In advanced cases fusing the joint, usually by surgery, can help.
"This can be done with screws inserted in a compression fashion across the joint, or more commonly with a combination of a compression plate and lag screws placed across the joint surface," says Rick. "Although this procedure works well to eliminate the pain associated with the arthritis, the horse does lose the function of the shock absorber and hence is left with a more stiffened pattern of moving."
Rick also discusses a newer procedure of fusing the pastern joint by alcohol injection. "Eventually, the cartilage disappears and the distal (bottom) end of the first phalanx unites with a bony union to the proximal (upper) surface of the second phalanx," he says.
More promising are regenerative treatments with the potential to heal arthritic conditions such as ringbone. IRAP (interleukin-1 receptor antagonist protein), PRP (platelet-rich plasma), and stem cell therapies, all of which are already in use to help other conditions, might eventually target ringbone as well. Both Alamo Pintado and UC Davis are on the forefront of regenerative medicine techniques.
"We've used stem cells in other joints such as the fetlock, carpus, hock, and stifle, but the numbers are too small to make any strong statements as to the effectiveness of this procedure at this time," says Rick. "Certainly, use of stem cells is on the radar screen to treat arthritis in general."
While ringbone can compromise a horse's ability to do his job, early diagnosis, treatment, and corrective shoeing can help avoid severe cases. Whenever possible, select horses that have no predisposing conformation flaws and limit repetitive stress, especially on hard ground.
If your horse does develop ringbone, which can occur as an animal ages, be sure to have him trimmed and shod on a regular basis to keep the foot in balance. Shoes that help his feet break over, such as those with a rolled toe, can minimize the torque on the pastern joint and reduce pain. Chondroprotective agents have been shown to help, as will maintaining a healthy weight for the horse.
Regenerative therapies such as IRAP, PRP, and stem cell treatment have the potential to help ringbone and other arthritic conditions in the future.
About the Author
Tracy Gantz is a freelance writer based in Southern California. She is the Southern California correspondent for The Blood-Horse and a regular contributor to Paint Horse Journal, Paint Racing News, and Appaloosa Journal.