Bit & Bridle

Equine Navicular Syndrome

Other Names

  • Navicular disease
  • Caudal heel pain
  • Podotrochlear syndrome
  • Palmar foot pain

What is Navicular Syndrome in Horses?

Navicular syndrome is a common cause of forelimb lameness in horses, characterised by chronic pain arising from the structures in the caudal (back) part of the foot. The term “navicular syndrome” is now preferred over the older term “navicular disease” because imaging advances — particularly MRI — have revealed that the navicular bone itself is often only one of several structures involved. Damage to the deep digital flexor tendon (DDFT), navicular bursa, impar ligament, and other soft tissues within the heel region are frequently implicated.

The condition is typically progressive and bilateral in the front feet, with one leg often more severely affected than the other. It is more common in sport horses, particularly those doing high-impact work such as showjumping, reining, and eventing, and in certain breeds including Quarter Horses, Thoroughbreds, and Warmbloods with upright conformation.

What Causes Navicular Syndrome?

The underlying cause is multifactorial and not fully understood, but the following factors are known to contribute:

  • Repetitive mechanical stress: Activities involving repetitive concussion and high loading of the deep digital flexor tendon — particularly jumping, sliding stops, or any work on hard or deep surfaces — gradually damage the navicular apparatus.
  • Poor hoof conformation: Small hooves relative to body size, upright heels, contracted heels, and long toes all alter the biomechanics of the foot, increasing stress on the caudal structures.
  • Reduced blood supply: The navicular bone has a relatively limited blood supply. Interference with this — through repetitive compression or degenerative changes — can lead to ischaemia and bone changes.
  • Hereditary factors: There is a genetic component, with certain conformation types being predisposed. Inherited hoof shape and limb conformation both play a role.
  • Irregular farriery: Infrequent or inconsistent hoof trimming and shoeing allows imbalance to develop and persist, accelerating degenerative changes.
  • Age-related degeneration: While navicular syndrome can occur in young horses, it becomes more common and more severe with age as cumulative wear accumulates.

Signs and Symptoms

Navicular syndrome typically presents as a subtle, progressive lameness that horse owners often attribute to “just being stiff” for some time before diagnosis. Key signs include:

  • Intermittent bilateral forelimb lameness: The horse may appear lame on one leg one day and the other the next, because both feet are affected. It often looks worse after rest (when the horse first comes out of the stable) and may warm out of the stiffness with exercise.
  • Short, choppy stride: The horse tends to take shorter steps than normal, particularly on hard ground, to reduce the heel-loading phase of the stride.
  • Pointing: A resting horse may repeatedly rest one or both front feet with the toe pointing forward and the heel off the ground — this relieves pressure on the navicular bursa.
  • Stumbling: The horse may trip frequently due to the shortened breakover and reluctance to fully extend the foot.
  • Worsening on circles: Lameness typically worsens when the horse is worked on a circle on a hard surface, particularly when the affected limb is on the inside.
  • Positive response to palmar digital nerve blocks: A significant improvement following desensitisation of the palmar digital nerves (heel blocks) is a strong indicator of navicular pain.

Diagnosis

Diagnosis involves a systematic lameness workup by a vet and often specialist imaging:

  • Lameness assessment: Evaluation at walk and trot on straight lines, circles, and different surfaces, with and without flexion tests.
  • Nerve blocks: Palmar digital nerve blocks and intrasynovial (navicular bursa) blocks help localise pain to the caudal foot region.
  • Radiography (X-rays): Standard views of the navicular bone can reveal shape changes, enlarged vascular channels (lollipop lesions), enthesophytes, and bone erosion. However, radiographic changes correlate poorly with clinical severity — some horses with severe radiographic changes have mild lameness and vice versa.
  • MRI (Magnetic Resonance Imaging): Now considered the gold standard for diagnosis. Standing low-field MRI, available at many equine hospitals in the UK, allows detailed assessment of the navicular bone, deep digital flexor tendon, bursa, and ligaments. It frequently reveals significant DDFT damage or bursal pathology that is not visible on X-ray.
  • Ultrasound: Useful for assessing the DDFT in the pastern region above the foot.

Treatment

Navicular syndrome is managed rather than cured. Treatment aims to reduce pain, slow progression, and maintain the horse’s quality of life and usefulness. The approach must be tailored to the individual horse based on the structures involved and the severity of changes found on imaging.

Corrective Farriery

The cornerstone of navicular management. The goal is to reduce tension on the DDFT and improve hoof balance:

  • Egg bar shoes: Extend heel support and reduce heel pressure
  • Wedge pads: Slightly elevate the heel to reduce DDFT tension — useful in horses with collapsed or low heels
  • Rolled toes: Ease the breakover point, reducing the lever arm on the navicular apparatus during the final phase of the stride
  • Wide-web shoes with full-length pads: Protect the sole and provide cushioning on hard ground
  • Regular shoeing every 4–6 weeks is essential to prevent imbalance recurring

Medication

  • NSAIDs: Phenylbutazone (bute) or Equioxx (firocoxib) — a COX-2 selective NSAID with fewer gastrointestinal side effects — are used for pain management. Long-term daily administration is common in horses with chronic navicular syndrome.
  • Bisphosphonates: Tiludronate (Tildren) and clodronate (Osphos) work by inhibiting osteoclast activity (bone resorption) and may reduce pain and slow bone deterioration. In the UK they are licensed for different conditions: Osphos for forelimb lameness associated with bone resorption in the navicular bone, not in horses under 4, and Tildren for bone spavin lameness in horses over 3, not for navicular syndrome (VMD datasheets). They are given as a single intravenous or intramuscular injection, with effects lasting 6–12 months in many cases.
  • Intrasynovial corticosteroids: Injections into the navicular bursa can provide significant short-to-medium-term pain relief, particularly where bursal inflammation is a major component. These are usually combined with a local anaesthetic for confirmation of diagnosis.
  • Platelet-rich plasma (PRP) and stem cell therapy: Regenerative treatments are increasingly used in horses with significant DDFT pathology. Evidence is still accumulating but clinical results are promising.

Exercise Management

Regular, consistent exercise on good going is generally better for navicular horses than box rest, which allows muscles to weaken and increases the stiffness on return to work. However, deep, heavy, or very hard ground should be avoided. Many navicular horses do well with daily turnout on good quality surfaces.

Prevention

  • Regular farriery every 6–8 weeks to maintain hoof balance — never allow a horse to go overdue
  • Avoid repetitive high-impact work on hard surfaces, particularly in horses with conformation that predisposes them
  • Breed selection: consider hoof and limb conformation when purchasing sport horses intended for demanding disciplines
  • Radiograph front feet as part of a pre-purchase examination for horses intended for jumping or intensive competition work
  • Address contracted heels early, ideally through correct shoeing and regular trimming before degenerative changes develop

Prognosis and Long-Term Management

Navicular syndrome is a progressive condition, but many horses can be maintained in comfortable work for years with appropriate farriery, medication, and exercise management. The prognosis depends heavily on the specific structures involved (DDFT pathology generally carries a worse prognosis than isolated navicular bone changes), the severity of radiographic changes, and how consistently the horse is managed.

Some horses progress to the point where ridden work is no longer appropriate, but humane management at pasture — with appropriate farriery and pain management — can allow for a comfortable retirement.

When to Call the Vet

Consult your vet if:

  • A horse develops a persistent, unexplained bilateral forelimb lameness or a short, shuffling gait
  • The horse is regularly stumbling or seems reluctant to work on hard surfaces
  • You notice a horse repeatedly pointing one or both front feet at rest
  • A known navicular horse shows a sudden deterioration in soundness
  • You are considering purchasing a horse and want a baseline assessment of the front feet

Related Conditions

Navicular syndrome is one of several causes of palmar foot pain. Other conditions that can present similarly include sole bruising, laminitis, sheared heels, and hoof abscess. A thorough veterinary lameness evaluation is essential before assuming any diagnosis.

Frequently Asked Questions About Navicular Syndrome

Can navicular syndrome be cured?

There is no cure for navicular syndrome. The degenerative changes that occur within the navicular apparatus are not reversible. However, the condition can be successfully managed with appropriate farriery, medication, and exercise management, allowing many horses to remain in comfortable work for years. The key is early diagnosis and consistent, long-term management.

What breeds are most prone to navicular syndrome?

Quarter Horses, Thoroughbreds, and certain Warmblood lines have a higher prevalence, likely due to conformation predispositions (small hooves, upright foot angles). Native pony breeds are relatively less commonly affected. Sport horses in high-impact disciplines are more at risk than horses in light or mixed work.

Is navicular syndrome the same as laminitis?

No — navicular syndrome and laminitis are distinct conditions affecting different structures within the foot. Laminitis involves the lamellar tissue that attaches the hoof wall to the coffin bone, whereas navicular syndrome involves the navicular bone, navicular bursa, deep digital flexor tendon, and related structures in the heel. However, both conditions cause significant lameness and both are exacerbated by poor hoof balance and management.

How often should a navicular horse be shod?

Most navicular horses should be shod every 4–6 weeks, never longer than 6 weeks. Allowing too long between shoeings permits hoof imbalance to develop, which directly increases stress on the navicular apparatus and accelerates deterioration. Consistent, frequent farriery is one of the most important management tools available.