High and Low Ringbone (Interphalangeal Joint Arthritis) in Horses

Key Takeaways

“Ringbone” refers to ring-shaped bony protrusions formed due to osteoarthritis in either the pastern joint or coffin joint in horses. 

• High ringbone involves the pastern joint. Low ringbone affects the coffin joint

• Symptoms include lameness, pain, and if advanced, visible, firm protrusions around the pastern

• Development of ringbone is linked to irregular conformation, injury, ongoing stresses incurred in certain sporting activities, or work on hard surfaces

• Physical examination, flexion tests, nerve blocking, and diagnostic imaging are used to confirm diagnosis

• Treatment aims to mitigate clinical symptoms through pain medications, joint care, and adjustments to shoeing

• The prognosis for high ringbone is good, however chronic lameness commonly develops over time, resulting in retirement from athletic work

• Low ringbone is difficult to treat and the prognosis is poor

A Closer Look: What is Ringbone in Horses?

Ringbone is a common symptom in horses, especially ones used for sport or work. It is a progressive disease that affects one or more limbs, most often the forelimbs.  Ringbone results from stress on the joints. Stress creates an inflammatory reaction in or around the joint. Inflammation releases toxins that continue to damage the tissue and dilute the joint fluid, which results in cartilage loss. New bone forms to stabilize the joint. These bony protrusions rub against each other and the other structures of the joint, causing damage, disability and pain. 

Ringbone is either articular (within the joint) or periarticular (within the structures that support the joint). In cases where ringbone is periarticular, as long as the horse remains sound and the structures around the joint are undamaged, ringbone requires no treatment. 

In cases where the ringbone is articular, particularly when the coffin joint is involved, ringbone can permanently lame the horse. In some cases, ringbone curtails the activities a horse can perform.

Risk Factors

Once symptoms such as lameness and visible bony protrusions have developed, it is usually too late to reverse. Horses showing signs of mild lameness require prompt veterinary assessment to identify the underlying cause and prevent further structural damage. With appropriate management, most horses can be kept comfortable for light to moderate work. Over time, the progressive changes reduce the horse’s soundness, ultimately resulting in chronic lameness and retirement. 

Ringbone is progressive, even with proper management. Over time, it can lame the horse beyond recovery. In some cases, pain and disability are unmanageable and euthanasia is the most humane option.

Possible Causes

The instigating causes of ringbone are not always known. In some cases, injury or overuse causes damage to the joint. In other cases, an infection or developmental orthopedic disorders, including osteochondritis dissecans, are the cause. Lifestyle factors identified in the development of ringbone include:

• Sports involving quick turning or abrupt stopping, such as jumping, reining, polo, roping, or barrel racing

• Working on hard surfaces, such as roads • Upright pastern conformation • Improper shoeing or trimming

• Degenerative changes associated with aging

Main Symptoms

The main symptoms of ringbone include:

Lameness • Heat and swelling at the joint • Pain when the joint is manipulated (limited mobility)

Testing and Diagnosis

Since early detection is critical to improving long term outcomes, veterinary attention is required for horses suspected of suffering from ringbone. Diagnostic tools include:

• Physical exam • Regional nerve or intra-articular block to identify the afflicted joint

• Diagnostic imaging, including X-rays, ultrasound, bone scan, or MRI

Steps to Recovery

There is no cure for ringbone. Treatment aims to mitigate the progression of the disease and to ease clinical signs. Strategies include:

• Anti-inflammatory medication • Joint injections for low ringbone • Joint health support medications 

• Biologic injections • Bone remodeling medications • Changes to shoeing or trimming to support the joint

• Nutraceuticals to support joint health • Alternative therapies, such as acupuncture and chiropractic

• Light, consistent exercise to maintain joint mobility 

In the case of low ringbone, joint fusion (ankylosis) may occur naturally after the disease has progressed sufficiently. In the case of high ringbone, surgical fusion (arthrodesis) or chemical fusion are possible. Surgical fusion immobilizes the joint with a combination of screws and plates. This procedure offers the possibility of complete recovery and even a return to work or sport. Chemical fusion immobilizes the joint via the injection of a caustic substance. This substance accelerates the deterioration of the cartilage and fuses the bone surfaces. This treatment is less invasive and expensive, but surgery generally has better outcomes. Contamination of surrounding tissues is possible when undergoing chemical methods.   Ringbone is incurable and progressive. Most horses can be kept comfortable for light riding or a reduced workload. Horses suffering from advanced ringbone may need to retire from sport or work life. In some cases, horses with ringbone can no longer withstand being ridden.

Prevention

There are no proven preventative measures to avoid ringbone. It is possible that proper hoof balance, shoeing and trimming are important for long term joint health. Some sources suggest avoiding heavy work or work on hard surfaces, and adequately warming up prior to strenuous exercise are beneficial to preventing ringbone.

Is Ringbone Common in Horses?

Ringbone is a common complaint for all types of horses. Horses involved in sporting activities that require quick turns or abrupt stop are especially susceptible to ringbone. Horses who work on hard surfaces, like carriage horses or police mounts, as well as older horses, horses with irregular conformation, or those that have been improperly shod, are also at risk.

Typical Treatment

• Anti inflammatory medications • Joint injections • Bone remodeling medications • Biologics • Nutraceuticals

• Acupuncture • Chiropractic • Shoeing and trimming adjustments • Retirement • Light, consistent exercise

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