Last Updated on February 19, 2022 by Allison Price
Ringbone is a common diagnosis. All horses, including those that are young or old, as well as backyard pets and athletes of high caliber, can be affected by the disease. Some horses are not affected; others experience arthritis that causes lameness or pain. It’s a deal-breaker for me as a vet if it is found on a prepurchase exam. Even for the most experienced horseman, telling a horse owner that he has it can cause anxiety. You can do a Google search for ringbone to find thousands of websites. There are many opinions about how it develops, how to treat and what the prognosis is. Here is the latest information on ringbone.
What is Ringbone?
The horseman’s term Ringbone refers to osteoarthritis or bony arthritis of the pastern or coffin joints. In the pastern joint, the ringbone is high ringbone and in the coffin joint it is low ringbone. Arthritis refers to any condition that causes joint inflammation. Osteoarthritis occurs when joint inflammation causes enough damage for the body to lay down bone to repair the damaged tissue. The bone development usually occurs near the joint surface, or at the attachment points of the joint capsule to bones. Degenerative joint disease (DJD) is another term for this type of joint damage.Get our weekly Enewsletter about horses
For high ringbone, osteoarthritis (or DJD) of the proximal Interphalangeal Joint (pastern joint) is the preferred terminology. In the case of low-ringbone, osteoarthritis (or DJD de la distal interphalangeal Joint (coffin joint), is the preferred term. I will refer to the condition simply as ringbone.
Others classify the type ringbone as either articulating (meaning involving the joints surfaces) or nonarticulating (meaning not involving any joint surfaces but the capsule that attaches to it). Ringbone can begin as nonarticulating, and then progress to articulating. Non-articulating, which doesn’t involve the joints surface where weight bearing occurs, is considered less painful and therefore less serious.
All four legs have the pastern and coffin joint located on the lower limb. The coffin joint, which is located in the lower limb of all four legs, is a large joint with high-motion within the hoof. The pastern joint is the next. The pastern joint, a small joint that moves very little but can carry a lot of weight, is the next. It’s located between the top and bottom of the hoof. It is located between the top of the hoof and the fetlock.
What is Ringbone?
Ringbones are most commonly caused by abnormal stress on the joints. This causes joint surface damage and bony development. Poor conformation, unbalanced shoeing, or work on uneven ground surfaces can all lead to abnormal stress. A toed in or out stance combined with a base-wide or narrow conformation can increase the weight-bearing force on the inside or exterior of the joint. This causes the horse to land on the outside or inside leg. Microdamage of the cartilage can occur on the joint surface, as well as microtearing of the ligaments (stabilizing ligaments) on either side. This microdamage is initially referred to as inflammation by the body. Inflammatory cells produce toxins which cause more tissue damage and thin out the joint fluid. Inflammatory cells that cause tissue damage are more likely to produce more tissue damage, which leads to an increasing cycle of damage. The body attempts to heal itself initially by creating scar tissue. This then leads to bony growth.
It depends on many factors and the length of time that it takes for this to happen. The disease progresses faster if there is more trauma and more severe conformational abnormalities. This disease is influenced by hoof balance, proper trimming, shoeing, footing, and exercise. Balanced hooves and a long toe/low heels can put severe strain on the joints. To reduce stress on the joints, shoring horses with shorter toes can increase breakover. It can also help to decrease inflammation and slow down the progression of disease. Hard footing causes more trauma to the joints. Deep footing can cause overflexion, which could lead to damage to the joint capsule.
Other causes of ringbone are blunt trauma, lacerations to the joints, and osteochondritis disecans (OCD). OCD refers to a condition that causes large cartilage flaps within the joint. A cartilage flap, or “chip”, in a joint can cause inflammation. A single trauma event such as a direct hit to the joint, or a laceration can cause initial joint damage, and initiate the cycle of inflammation.
How do we diagnose Ringbone?
The best way to diagnose the condition is with radiographs (Xrays) of your leg. Although the joint surfaces are typically very smooth, extra bone can be seen on Xrays if there is ringbone.
It’s not always easy. The bony changes might not be apparent in the initial stages of the disease. Sometimes, a “spur” can be seen at the joint’s front. Or some calcification may be visible near the joints where the collateral ligaments or joint capsule attach to the bone. Inflammation within the joint can cause pain and lameness. This stage can make a horse more lame.
Your vet will need to determine if lameness is due to a joint problem or another disease process. It’s important to conduct a thorough lameness examination. The exam should include watching your horse move on both hard and soft ground, as well as jogging in circles and straight. Diagnostic nerve blocks and flexion tests are also essential. Horses with ringbone have flex positive in their lower limbs, which means that lameness occurs when the lower leg is held in flexion for a minute before being jogged off.
The nerve blocks are an invaluable tool in pinpointing the source of pain. After the pain is located to the lower leg via an abaxial nerve block (blockaround the fetlock), each joint can be blocked. If the pain is caused by low ringbone, the coffin joint can be blocked. In cases of high-ringbone lameness, the pastern joint must also be blocked. In cases where the Xrays aren’t clear, diagnostic nerve blocks are important.
There are many factors that affect the severity of the disease. Radiographic changes don’t always correlate to lameness. Horses with slight bony changes in radiographs can be very lame, and vice versa. Many sound horses have obvious ringbone in the pasterns. A horse with a high ringbone can be clearly seen in the pastern. It may appear as hard lumps on the front or sides, or a “ring”, of extra bone. It is considered advanced if the ringbone can easily be seen. The coffin joint has a ringbone that is more important and causes severe lameness because it is the highest motion joint.
As the disease progresses, it can spread to the joints, leading to severe cartilage degeneration and joint collapse. This eventually leads in complete fusion. The horse may become severely disabled. Sometimes, the horse’s condition can be so severe that it is impossible to live with him anymore. In these cases, humane euthanasia may be the best option.
How do we treat Ringbone?
Ringbone treatment is more than a one-off procedure. It is a long-term management plan that will benefit the horse for a lifetime. All treatments are designed to reduce inflammation and preserve the cartilage surface.
The first step is to balance the hoof and increase horse’s breakover. This is done by making sure that the hoof is straight from the side, and the toe is shorter so that the leg can roll up the front of your hoof faster.
Next, we treat the inflammation. This involves injecting anti-inflammatory drugs like corticosteroids into the affected joint. Hyaluronic acid is a synthetic joint fluid that replenishes the existing weak, thin joint fluid. This can stop the progression of the disease and slow down the damage to the joints surface.
Supplements, exercise management, and physical therapy are all complementary therapies to joint injections. Daily oral joint supplements, such as chondroitin, glucosamine and MSM, can help to build more cartilage and fluid.
Adequan I.M. and Legend I.V. intravenous hyaluronic acids are the two most popular forms of intravenous hyaluronic. The joint can also be saved with polysulfated glycosaminoglycan (also known as Legend I.V. and Adequan I.M. Legend is able to increase the production of joint fluid and act as an antibiotic. Adequan helps the cartilage by working at the joint surface. Both are extremely effective and often combined.
To support the joint, herbal supplements can be added to feed. Common herbal anti-inflammatory herbs include devil’s claw and Yucca. There are many other products that contain all these ingredients, as well as some that include additional ingredients not listed here. While most of these products seem to work, none appear to be particularly effective in relieving pain associated with ringbone. To avoid colic or allergic reactions, it is important to take care when giving herbal products. Many of these herbs are not well-studied in horses, so product concentrations can be inconsistent.
Horses with ringbones do well with low-level, consistent exercise. Horses who stand too long can cause inflammation and lameness in their joints. Walking around on pasture all day stimulates circulation and reduces inflammation in the joints, which can lead to lameness. The horse’s tolerance and degree of ringbone will determine the amount of exercise they need. Horses with this condition can continue their careers at lower levels. They often perform better when they are involved in a regular work program. While soft footing is better that hard, too much overflexion can cause joint swelling and increase inflammation.
These horses can also benefit from physical therapy. Warm therapy loosens joints. Linings and wraps support the joint. Although massage therapy, acupuncture and chiropractic have different degrees of efficacy and benefits, they all aim to reduce inflammation and loosen tissue.
Extracorporeal shockwave treatment (ESWT), a promising new therapy, is showing promise for horses with ringbone. Although the true nature of shockwave therapy is not yet known, it is being studied by major institutions.
ESWT is a proven therapy that can improve the health and performance of horses. It has been proven effective for horses with ringbone problems that aren’t too severe. The therapy has been effective for many horses, including my own horse.
The severity of the ringbone as well as the aftercare will determine the response to shockwave therapy. For more severe cases, you may need to have multiple treatments. Typically, one treatment per week for three weeks is sufficient. Horses with milder changes often respond to one treatment. The lameness may disappear if the horse is active again. However, if the horse sits still for too long, it can cause the horse to become more lame. This therapy is not recommended for horses with severe ringbone. Your veterinarian should discuss ESWT as with all therapies.
The Big Picture
We can help the horse with ringbone between the time a small spur forms, and when the joint fused. I combine all of the above therapies and can keep horses happy and active for many years before their ringbone becomes too severe. I have not had to put down too many horses with ringbones, but there are a few that I am certain will need to be. These cases are not painful but very lame, so I inject them once a year. It becomes more difficult to inject the joint each time, and I know that there will be times when I can’t due to severe joint collapse or bony development.
My ringbone patients who are doing well I attribute to the owner’s good management. This means that the owner caught the problem early and gave good joint support. However, some horses can become very lazy even with joint management. Unfortunately, I cannot predict which horses will be successful and which ones won’t. Ringbone can have an effect on any horse.