Dealing with Ringbone

Ringbone is the common term for osteoarthritis of the pastern joint or the coffin joint. Todd Allen, a farrier in Vandergrift, Pennsylvania, has dealt with many cases of ringbone, and says this problem occurs most often in the front limbs, and can be very painful if it is articular (in the joint). “When I am working with a horse that has ringbone, the first thing to determine is whether it is articular or non-articular. Is it in the joint, or near or next to the joint? Does it affect the joint, or not?” he asks.

“If it does not affect the joint, I don’t worry about it in terms of soundness, and consider it a blemish,” he continues. “The bony growth or calcification deposit may grow and expand, but if it isn’t causing pain and lameness, it’s not much concern.” 

If it affects the joint, however, the horse needs medical help from a vet and mechanical help from a farrier to alleviate the pain and lameness as much as possible. “The veterinarian will take x-rays, since that’s the only way to know exactly where it’s located and what’s going on. From a shoeing standpoint, I need to know what I am dealing with and how bad it is.” The veterinarian can also recommend treatments that might help reduce the pain and lameness.

If ringbone is in the joint, where it is located can make some difference in how the farrier can help the horse move more comfortably by means of special trimming and shoeing.

“Age of the horse can also be a factor, but the bottom line is that ringbone is ringbone,” says Allen. “I do my best to figure out how to deal with it and find comfort for the horse. If the horse is lame, we do what we can to relieve that discomfort. The best thing we can do as farriers is work with the vet and what he/she finds, whether it’s high ringbone, low ringbone, etc., and the exact location, and then see what we can do to make the horse more comfortable in its movement.”

Causes

Dr. Troy Herthel of Alamo Pintado Equine Medical Center in Los Olivos, California, says high ringbone involves the pastern joint, whereas low ringbone involves the coffin joint. “High ringbone seems to be more common and can develop from a number of different causes. Ringbone is an osteoarthritic condition—a degenerative joint disease that can be caused by an acute injury to that region, with cartilage damage or instability of supportive ligaments of the joint, or it can be due to chronic repetitive use such as continual concussion and wear. Other issues, such as pastern joint subchondral bone cysts or chronic subluxation of the joint, can also lead to ringbone,” he says.

“Chronic repetitive trauma is a common cause, especially in horses that perform in athletic careers,” says Herthel. All breeds are susceptible to pastern injuries that could lead to ringbone. Conformation, such as straight, upright pasterns or toed-in stance, may play a role in whether or not the joint has more stress. Regardless of pastern angle, however, any active athletic horse can suffer injury. 

“Any increase in concussion and pressure can lead to joint trauma. Over time this cumulative effect may damage the cartilage and lead to arthritis. Another cause, which is less common, is anatomical abnormalities which could lead to juvenile arthritis in a young horse,” says Herthel. “The joint may not be developed appropriately, and we may start to see lameness or pastern joint swelling in a weanling or yearling with early-onset ringbone. The young horse may also have developmental abnormalities within the joint cartilage, such as OCD (osteochondrosis dessicans), that may lead to ringbone.”

Fused Pastern Joint

 “Whenever the pastern joint is disrupted and develops severe arthritis, the body tries to immobilize the joint to halt the instability and pain,” Herthel says. “This process produces a significant amount of bony reaction around the joint, which produces the ring-like appearance to the lower limb, hence the name ringbone. Some horses, especially those not being used for athletic purposes, can be allowed to self-heal and fuse that joint themselves. This is called ankyloses and some of them do surprisingly well, but this process can take a long time and most horses would have some degree of observable lameness.” It is amazing what the body can do to heal itself.

Horses in which the joint has fused either surgically or naturally, may travel sound and without pain, but may have an altered gait due to lack of motion in the joint. “There may be a mechanical lameness, but the horse is not uncomfortable, and the coffin joint may overcompensate for lack of motion in the pastern joint. The stride may be changed, though the horse is no longer experiencing discomfort,” Herthel says. Often the horse is quite comfortable, but simply doesn’t have enough movement in that joint for a completely normal stride. Thus, the stride may be shorter.

Treatment

If the horse is suffering pain and lameness from arthritis in the pastern joint, it can be treated medically or surgically. The pastern joint itself is a low-motion joint, but it can move about 20 degrees. “This makes it challenging to treat,” says Herthel. “It is low motion, but it takes a substantial load carrying the weight of the horse at each stride. When trying to manage ringbone, we may not have the best outcome for long term soundness with just medical intervention. It’s an unforgiving joint. Once it suffers trauma or cartilage damage, it keeps degenerating. Other joints can be managed with neutraceuticals or intra-articular injections, but the pastern joint does not seem to respond as well.

“Currently, the method of choice regarding treatment of ringbone that fails to respond to medical intervention is to surgically fuse the joint by using several techniques. The most common is to use a bone plate and screw combination using a locking plate system.” After the surgical site heals and there is no more instability and inflammation, these horses are generally significantly improved.

“The majority of these horses do quite well. We’ve found that horses with issues in the hind limbs tend to do better. More of them experience a full recovery, since those joints bear less weight than the front legs. The ultimate goal for these horses is to get back to athletic performance. About 80 to 90% of horses that undergo surgery to fuse a hind pastern go back to athletic function. Horses with surgery in the front limbs do well, but have a lower chance for full athletic function due to more weight-bearing and biomechanics of the front leg though there will be improvements in lameness,” he says.

Some horses do better than others. “Some horses that we think would do great, don’t respond as well as we’d hoped, and others that we had less hope for surprise us. At our hospital, pastern joints are the most common type of bone plating procedure that we do.”

There are some other techniques for fusing this joint, including chemical methods. “Injections are sometimes given to try to stimulate fusion. At this point in time they are not really a good alternative to surgical fusion. However in severe cases, these injections can provide relief,” he says.

Nutritional supplements that promote joint health may have some benefit, especially when trying to prevent these types of injuries. “Omega-3’s, Glucosamine, MSM, ASU and hyaluronic acid may help to a certain degree, though once the joint is damaged or arthritis has set in, these cases are much more difficult to manage with nutraceuticals or medications alone,” Herthel says. The most common medications used to reduce the pain and inflammation associated with ringbone are the non-steroidal anti-inflammatory drugs, such as phenylbutazone (Bute) or firocoxib (Equioxx).”

The pastern joint can be difficult to manage medically, so surgical fusion is often the best choice. “If we can get the pastern to fuse, we can hopefully get these horses back to comfort and athletic use. It is a long process and we generally give them six months to a year off from work for optimum chance for healing. It’s a significant surgery. The lower limb stays in a cast for two to three weeks, and then is protected with heavy bandaging for a bit longer. We’ve had remarkable success with this procedure,” says Herthel.

Low Ringbone

“Surgical fusion for high ringbone is very successful, whereas fusion for low ringbone is rarely done and is purely a salvage procedure. When there is osteoarthritis in the coffin joint, it can be very problematic because of this joint’s higher range of motion. Corticosteroid and hyaluronic acid joint injections can help alleviate some of the pain and inflammation, though they are purely palliative. Newer products may be more beneficial for health and longevity of the joint,” he says.

“Regenerative therapies such as PRP (platelet rich plasma), stem cells, and autologous conditioned serum (ACS), which is the same as IRAP (interleukin-1 receptor antagonist protein), have shown some significant benefits for treating joint disease. Another new treatment modality gaining popularity is injection of a long-acting hydrogel into the joint, which acts as a synthetic lubricant. This product, which has been used predominantly in Europe and is in the process of gaining FDA clearance in the U.S., has shown benefits in horses with osteoarthritis of the coffin and pastern joints,” he says.

Horses with abnormal hoof-pastern angles or hoof wall imbalances can be prone to repetitive trauma to the coffin joint, which can lead to low ringbone. “Proper hoof care and therapeutic shoeing can help alleviate these abnormalities,” says Herthel.

There is often a lot of pain with low ringbone, since this joint is inside the hoof. Any swelling or enlargement creates pressure and pain due to the restricted space within the hoof wall. 

“There are surgical techniques to fuse the coffin joint, but these are just salvage procedures. Those horses will not be able to return to an athletic career. These efforts are simply aimed at making the horse more comfortable for pasture soundness or breeding,” he says. Even this would be done on a case-by-case basis because a broodmare will have more weight and pressure on the joint when she is heavily pregnant, which could result in more discomfort. Pain is a form of stress, which can alter hormone profiles for reproduction and negatively affect fertility.

Diagnosing Ringbone

A traumatic injury will be immediately obvious as acute lameness, and a veterinarian can determine the location of injury. If the joint problem is not acute but rather due to cumulative or repetitive stress, the first thing you might notice is mild to moderate lameness. “Observable signs of ringbone, such as enlargement around the joint, would not be evident until a much later stage of the disease,” says Herthel. 

“In early stages with mild or acute lameness, the veterinarian’s job would be to determine where the pain is coming from. Pinpointing the source may entail palpation and flexion of the limb, and possibly some regional or intra-articular nerve blocks. Usually radiographs of that area are adequate to confirm the diagnosis. Though if the injury is acute, the veterinarian may need to use other diagnostic methods such as an ultrasound, bone scan, CT, or an MRI examination to confirm the diagnosis, especially if it’s an acute injury or a small cartilage defect that we are unable to see on radiographs,” he explains.

Trimming and Shoeing The Horse With Ringbone

Allen says corrective shoeing can often help horses affected by ringbone. “I always start with a good base trim. Then I prefer to put shoes on the horse, so I can control the hoof wear. If the horse is lame, he probably needs shoes to control the wear and to influence the way the foot breaks over and moves. This enables us to give the horse some relief from too much stress on the affected joint.” Allen always tries a conservative approach at first, but if that doesn’t work, he doesn’t hesitate to “go outside the box” and try other things that might help. Sometimes the weight of a shoe can be a disadvantage, so it’s always a case-by-case situation.

“More than likely, the foot is going to wear the opposite way from how I need to trim it and keep it trimmed, so shoes can help. The foot needs enough shoe to support and complement the trim. It usually needs a little more support on the rear of the foot.” Heavy shoes may be a disadvantage, however, so an aluminum shoe might be best.

“Paying attention to break-over is very important. We move it back, making it as easy as possible for that horse to break over. Right before the foot breaks over, that’s when those joints have the most pressure and tend to close up a little. I want that foot off the ground quicker, so it is non-weight-bearing as quick as possible,” Allen says.

“Another important thing is to have plenty of support on the back of the hoof so that the heels don’t sink into the ground as far. We often use a pour pad to help keep the foot on top of the ground. I pour all of my ringbone horses. I believe that the bones descend as that foot loads, and I think there’s sometimes a little pinching as those bones/joints descend. They press together in the load phase of the stride. So, I always try to ‘open’ the affected joint to alleviate that pinching, which is what I believe causes the most pain. If ringbone is on the front, whether it’s low or high, I raise the angle of that foot to normal or slightly above normal to have less pressure on that joint,” Allen explains.

“So, I use a lot of pour pads or Equi-Pak to prevent or minimize some of that downward movement of the joint and the bony column. For support in the heel area, we can use a bar shoe or an open heel shoe with pour pads. Frog and sole support with a pour pad reduces the amount of downward movement within the foot and the joints.”

If a horse has ringbone on the side rather than the front, he may trim a little more on the opposite side to “open up” the affected joint. “This is a tricky situation because I am talking about putting the foot slightly out of balance. I always start by putting the foot in balance with a basic trim, but if I am not getting satisfactory results, I tweak it a little by using super-fast glue on one heel, or on both heels, to raise the angle a little more. I can modify the balance with this method. The nice part about using the glue to change the balance is that if I don’t like the result, I can rasp it off the shoe without having to reshoe the horse,” he explains.

Allen often uses a wedge pad on these horses, which raises the angle. But if it needs a bit more tweaking, he can add a bit more to the shoe with the glue. “I can also monitor it from one shoeing to the next, which gives me a lot of flexibility to be able to adjust or modify the angle to make it more exact for what that horse needs. I can squirt it on there, give the horse 24 hours or several days, and see how he does with it. This is better for the horse than leaving him barefoot to see how the foot wears. Everyone wants to figure out how it wears and where it is most comfortable and experimenting with the glue added onto the shoe lets us figure out that comfort zone,” he says.

The glue is durable and almost as strong as the hoof wall. “It holds up very well, especially if you make sure the shoe is clean when you apply it. It sticks to an aluminum shoe even better than steel.”

Allen has had good luck with a number of cases that have gone from being very lame to being comfortable after a couple shoeings. “One horse was so lame he could hardly walk from one barn to the other. After we started working on him, he was getting better and better. We felt good about that because at first the owner was thinking about euthanizing that horse, so we feel we accomplished a lot with that one.” 

Extra care should also be taken when handling the foot and leg while trimming and shoeing to minimize discomfort. Horses with arthritis are often uncomfortable when their legs are handled in shoeing positions. “A ringbone horse will have discomfort when the joint is flexed. Sometimes a horse with severe ringbone can’t flex those joints very much. It’s similar to a horse that’s arthritic in the knee. We don’t bend the leg much, and we keep it as low as we can,”
Allen says.

Drugs That May Help

“There’s a relatively new drug that may help called Osphos. This is an injection in the muscle, and it’s a drug related to Tildren,” says Allen. Osphos is a biophosphonate and like Tildren is being used for treating bone-related lameness like navicular disease and ringbone. Osphos became available in the U.S. in 2014 and is administered by intramuscular injection, whereas Tildren has to be given intravenously over a period of several hours and is more expensive. 

“In some cases, Osphos will actually de-calcify the ringbone and reduce its bulk. I have not seen this personally, but the drug label says it is potentially possible for it to reduce calcium deposits. Originally, it was meant for treating navicular problems and bone remodeling, but there are many other things it can do. If I have a client who has a horse with ringbone, I tell them they should consult with their veterinarian and ask about this product. It doesn’t work for every horse, but some horses are helped tremendously,” Allen explains.