Ringbone in Horses: Causes, Signs and Long-Term Management

Reviewed by Dr. Khurrum Shahzad Khosa, DVM

Ringbone is one of the most common causes of forelimb lameness in horses and a condition that owners frequently encounter as their horse ages or accumulates the wear of work. It is a form of degenerative osteoarthritis characterised by new bone formation — periosteal proliferation and osteophyte development — around either the pastern joint or the coffin joint. Understanding the anatomy, the distinction between different types of ringbone, and the management options available is essential for any owner dealing with a diagnosis.

What is Ringbone?

Ringbone is new bone growth around the joints of the lower limb — specifically either the pastern joint (proximal interphalangeal joint, or PIP joint) or the coffin joint (distal interphalangeal joint, or DIP joint). The term "ringbone" describes the bony proliferation that can develop around the pastern area, which in advanced cases encircles the joint like a ring.

At its core, ringbone is a response to abnormal mechanical stress on the joint. When the cartilage and subchondral bone within the joint experience excessive or abnormal loading, the body responds by laying down new bone at the joint margins. This new bone — osteophytes — is initially a stabilising response but over time narrows the joint space, limits movement, and causes pain as the degenerated joint surfaces move against each other.

True Ringbone vs False Ringbone

A distinction is made between true ringbone and false ringbone that is clinically important. True ringbone affects the articular surface of the joint — the cartilage-covered surfaces that move against each other. Osteophytes grow on or adjacent to the joint surface, progressive cartilage loss occurs, and the prognosis for sustained ridden work is more guarded. Most clinically significant ringbone is true ringbone.

False ringbone involves new bone growth at the attachment sites of tendons and ligaments around the pastern, but does not directly involve the joint surface itself. Because the joint cartilage is not involved, false ringbone can sometimes be managed more successfully, and some horses remain in regular work with appropriate farriery and management. However, the distinction is not always clear-cut on radiography, and the clinical significance depends on the specific location and extent of the bony changes.

High Ringbone vs Low Ringbone

High ringbone affects the proximal interphalangeal joint — the pastern joint, sitting between the long pastern bone (P1) and the short pastern bone (P2). It is visible and palpable above the hoof capsule in more advanced cases. The pastern joint has moderate range of motion and can, in some horses, fuse naturally or surgically to a pain-free state.

Low ringbone affects the distal interphalangeal joint — the coffin joint — which sits almost entirely within the hoof capsule. Low ringbone involving the coffin joint is generally considered to carry a more guarded prognosis for high-level ridden work. The coffin joint bears the full load of each footfall, has a relatively large range of motion, and its position within the hoof capsule means that significant osteophyte development can distort the hoof wall and sole.

Causes of Ringbone

Ringbone develops as a result of abnormal mechanical loading on the pastern or coffin joint. Several factors contribute:

Repetitive concussion is the most common cause — horses in regular work on hard surfaces accumulate concussive forces through the lower limb that gradually exceed the cartilage's capacity for repair. Competition horses, horses worked extensively on hard ground, and horses in heavy work at an early age are all at elevated risk.

Conformational faults are a significant predisposing factor. Horses with upright pasterns — which reduce the shock-absorbing angle of the pastern and transmit more concussive force directly to the joint — are predisposed. Narrow, upright hooves reduce ground contact area and concentrate loading. Base-narrow or base-wide conformations create uneven loading across the joint surface.

Previous injury to the pastern or coffin area, including fractures, ligament injuries, and joint infections, can trigger degenerative changes that progress to ringbone over time. Even a single significant traumatic event can initiate an osteoarthritic process that becomes clinically apparent years later.

Poor foot balance maintained over a long period — through infrequent farriery, inappropriate shoeing, or neglected hoof care — places uneven loading on the joint surfaces and accelerates degenerative change.

Signs of Ringbone

The clinical presentation of ringbone varies considerably depending on the joint affected, whether the disease is unilateral or bilateral, and the stage of progression. Early cases may present with subtle, intermittent lameness that is easily attributed to other causes. As the condition progresses, signs become more consistent and recognisable.

Common signs include a shortened, choppy stride — the horse moves with reduced extension through the lower limb, protecting the affected joint. Positive flexion tests of the lower limb are typical, with the lameness worsening after the pastern or coffin joint is held in flexion for 60 to 90 seconds. Palpable bony swelling around the pastern area may be present in cases of high ringbone, though low ringbone within the hoof capsule is not visible. In bilateral cases, the horse may appear to have a stiff, pottery gait affecting both forelimbs rather than a clear unilateral lameness.

Diagnosis

Diagnosis requires a systematic lameness investigation. The veterinarian will first observe the horse in walk and trot on hard and soft ground, in straight lines and circles. Flexion tests applied to the lower limb assess joint pain. Diagnostic nerve blocks — injecting local anaesthetic around the palmar digital nerves or into the coffin joint or pastern joint directly — localise the pain source to the specific region.

Radiography is the primary imaging tool for ringbone and will show osteophyte formation, joint space narrowing, subchondral bone changes, and new bone growth at tendon attachment sites. The degree of radiographic change does not always correlate precisely with clinical lameness — some horses with significant radiographic changes are mildly lame, while others with moderate changes are severely affected.

In early cases where nerve blocks localise the lameness but radiographs appear relatively normal, MRI allows assessment of cartilage integrity and early subchondral bone changes that are not yet visible on radiograph. This is increasingly available at equine referral centres and provides valuable information for prognosis and treatment planning.

Farriery: The Cornerstone of Management

Appropriate farriery is the most important ongoing intervention for the management of ringbone. The goal is to reduce the mechanical stress on the affected joint during each stride, minimise the pain of each footfall, and slow the progression of degenerative change.

Key farriery approaches include rolling or rockering the toe to ease breakover — reducing the period during which the coffin joint is maximally extended at the end of each stride. A square toe shoe achieves a similar effect. Heel elevation reduces the load on the coffin joint and can provide significant comfort for low ringbone cases. Bar shoes and wide-web shoes distribute load more broadly across the solar surface. The specific farriery approach is tailored to each horse's conformation, the joint affected, and the veterinarian's assessment — farriery and veterinary management should always be coordinated.

Medical Management

Phenylbutazone (bute) remains the most commonly used NSAID for ongoing pain management in ringbone. Long-term use requires monitoring for gastric and renal effects, and rotation with other NSAIDs — such as meloxicam or flunixin — reduces cumulative organ burden. Intra-articular injections of corticosteroids combined with hyaluronic acid directly into the affected joint can provide periods of significant improvement, allowing horses to remain comfortable and in work. Injections are typically repeated at intervals of several months, guided by the horse's clinical response. Joint supplements containing glucosamine, chondroitin, and methylsulfonylmethane (MSM) have variable evidence but are widely used and occasionally helpful.

Joint Fusion (Arthrodesis)

Joint fusion — arthrodesis — is both a natural endpoint of severe ringbone and a deliberate surgical treatment option. As osteophytes proliferate and bridge the joint, the joint eventually fuses into a solid bony union. Once complete, the degenerated joint surfaces are no longer moving against each other, and the pain from the arthritic joint is eliminated. Many horses that reach full natural fusion of the pastern joint become significantly more comfortable.

Surgical arthrodesis — using screws or other implants to accelerate or complete fusion — is performed in selected cases, particularly for the pastern joint where spontaneous fusion is more predictable. It is not generally performed for the coffin joint due to the technical challenges and the high load this joint bears. Following successful pastern joint fusion, many horses return to light to moderate ridden work, making it a genuinely meaningful option for appropriately selected horses.

Prognosis

Prognosis varies significantly by location and severity. Low ringbone involving the coffin joint is generally more challenging to manage and more commonly leads to retirement from serious ridden work, though many horses remain comfortable for light hacking and paddock life. High ringbone offers more variable outcomes — some horses manage for many years with appropriate farriery and medication, and pastern joint fusion can be a route to a pain-free, workable horse. Early diagnosis, prompt and consistent farriery adjustments, and appropriate veterinary management all improve outcomes regardless of location.

Frequently Asked Questions

What is the difference between high and low ringbone?

High ringbone affects the pastern joint (proximal interphalangeal joint) between P1 and P2, visible above the hoof. Low ringbone affects the coffin joint (distal interphalangeal joint) within the hoof capsule. Low ringbone involving the coffin joint generally carries a more guarded prognosis for sustained ridden work due to the high loading and limited management options compared to the pastern joint.

Can a horse with ringbone still be ridden?

Many horses with ringbone, particularly early high ringbone, can continue in light to moderate ridden work with appropriate farriery and anti-inflammatory support. Horses with severe low ringbone or advanced joint deterioration may need retirement from serious work. Pastern joint fusion — natural or surgical — can allow some horses to return to light work with markedly improved comfort. Each case requires individual assessment.

Does ringbone always get worse?

Ringbone is degenerative and cannot reverse, but progression varies enormously. Some horses remain stable for years with appropriate management. Addressing conformational loading, maintaining consistent good farriery, and managing inflammation all slow progression. In some cases, complete natural joint fusion eliminates ongoing deterioration of the joint surface.

What is joint fusion in horses?

Joint fusion is when the joint surfaces fuse into a solid bony union, eliminating movement and the pain that comes from degenerated surfaces moving against each other. In the pastern joint it can occur naturally as ringbone advances, or be performed surgically. Many horses become significantly more comfortable after pastern joint fusion and some return to light ridden work.

How is ringbone diagnosed?

Diagnosis involves clinical examination, flexion tests, diagnostic nerve blocks to localise the pain source, and radiography to confirm new bone growth, osteophytes, and joint space changes. Early cases with positive nerve blocks but minimal radiographic change may benefit from MRI to assess cartilage and subchondral bone before bony changes are visible.

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Disclaimer: This article is for educational purposes only and does not constitute veterinary advice. Always consult a licensed equine veterinarian for diagnosis and treatment.