Bit & Bridle

Equine Navicular Disease

Other Names

  • Navicular syndrome
  • Caudal heel pain syndrome
  • Podotrochlosis
  • Podotrochlitis
  • Palmar foot pain

What is Equine Navicular Disease?

Equine navicular disease — more accurately described today as navicular syndrome or caudal heel pain syndrome — is a degenerative condition affecting the structures of the horse’s heel. It involves the navicular bone (the distal sesamoid bone), the deep digital flexor tendon (DDFT) where it passes over the navicular bone, the navicular bursa (the synovial sac between the DDFT and the navicular bone), and the various supporting ligaments of the podotrochlear apparatus.

The term “syndrome” is now preferred over “disease” because caudal heel pain in horses almost always involves multiple structures simultaneously rather than pathology confined to the navicular bone alone. Advances in MRI technology have transformed understanding of this condition, revealing that horses previously diagnosed with navicular disease often have a complex of lesions — including DDFT damage, navicular bursa inflammation, collateral sesamoidean ligament desmopathy, and navicular bone changes.

Navicular syndrome is one of the leading causes of chronic forelimb lameness in horses, particularly in working Warmbloods, Quarter Horses, and Thoroughbreds. It can affect one or both forefeet and tends to be progressive over time without appropriate management. Related foot conditions are discussed in our sidebone guide.

Causes

Navicular syndrome results from a combination of conformational, mechanical, and vascular factors:

  • Conformation: Small, narrow feet relative to the horse’s bodyweight, upright pasterns, long toes with low heels, and a broken-back hoof-pastern axis all increase pressure on the navicular apparatus
  • Hereditary predisposition: Certain bloodlines show higher prevalence, suggesting a genetic component to susceptibility
  • Chronic mechanical overload: Repeated concussive forces on hard ground, work on a continuous circle, or sports with high concussive demand (showjumping, barrel racing) are associated with accelerated degeneration
  • Poor shoeing: Long toes, low heels, inadequate breakover, and infrequent farriery all increase strain on the navicular apparatus
  • Impaired vascular supply: The navicular bone has a relatively poor blood supply, and evidence suggests that ischaemia (reduced blood flow) contributes to bone degeneration over time
  • Deep digital flexor tendon tension: The DDFT exerts continuous compressive force on the navicular bone during weight-bearing; increased DDFT tension from poor foot balance magnifies this

Symptoms and Signs

  • Forelimb lameness: Often bilateral (both forefeet), which can make it appear as stiffness or a reduced, stilted trot rather than a clear one-leg lameness
  • Pointing: Resting one or both forefeet alternately, pointing a foot forward to reduce heel pressure — a classic but non-specific sign
  • Shortened cranial phase of stride: The horse lands toe-first rather than heel-first to avoid loading the painful heel
  • Worse on hard ground and circles: Lameness typically worsens on firm surfaces and when working on a circle (the inside foot is under greater load)
  • Improves after warm-up: Many horses with navicular syndrome appear worse when first worked and improve after 10–15 minutes, only to deteriorate again with continued exercise
  • Positive response to palmar digital nerve blocks (PD nerve block): Diagnostic nerve blocks that anaesthetise the caudal foot region will typically improve or abolish the lameness

Diagnosis

Diagnosis requires a systematic lameness investigation by a veterinary surgeon:

  • Lameness examination: Trot-up on hard and soft ground, lunging, flexion tests, and response to wedge testing (a wedge placed under the toe or heel helps identify the source of pain)
  • Nerve blocks: Palmar digital nerve blocks or navicular bursa analgesia confirm pain localisation to the caudal foot. Intra-bursal anaesthesia is particularly useful for confirming navicular bursa involvement.
  • Radiography: X-rays of the foot from multiple angles assess the navicular bone for changes including new bone formation (enthesiophytes), lucent “lollipop lesions” (synovial fossae), fragmentation of the distal border, and changes in bone density
  • MRI: The definitive diagnostic tool for navicular syndrome. Low-field standing MRI allows detailed assessment of the DDFT, navicular bursa, collateral ligaments, and bone marrow of the navicular bone. MRI frequently identifies lesions not visible on radiography and guides targeted treatment.
  • Ultrasound: Limited for structures within the hoof capsule but useful for the DDFT proximal to the hoof

Treatment

Navicular syndrome is managed rather than cured. The goal is to reduce pain, slow progression, and maintain the horse in comfortable work for as long as possible:

  • Corrective farriery: The cornerstone of management. A good farrier working with the vet can significantly improve comfort and slow progression. Objectives include correcting hoof-pastern alignment, shortening the toe to improve breakover, building heel height where appropriate, and providing frog and heel support through shoeing. Egg bar shoes, heart-bar shoes, and wedge pads are commonly used.
  • NSAIDs: Phenylbutazone or meloxicam for short-term pain relief during acute flare-ups. Long-term NSAID use requires monitoring due to gastrointestinal side effects.
  • Navicular bursa injection: Corticosteroids and hyaluronic acid injected into the navicular bursa under radiographic guidance provide significant relief and are among the most effective medium-term treatments
  • Distal phalanx joint injection: Where coffin joint involvement is identified, intra-articular injections can complement bursa treatment
  • Isoxsuprine: A vasodilator historically used to improve blood supply to the navicular bone. Evidence of efficacy is limited, but it remains in use.
  • Bisphosphonates (tiludronate, clodronate): Intravenous or intra-articular bisphosphonates reduce bone remodelling and have shown benefit in horses with navicular syndrome in controlled trials. Treatment requires veterinary prescription and is reserved for confirmed cases.
  • Palmar digital neurectomy: A surgical procedure that removes sections of the palmar digital nerves to eliminate heel pain. A last resort — it carries risks including DDFT rupture (as the horse can no longer feel the degenerated tendon), and requires careful ongoing monitoring and management.

Prevention

  • Maintain regular farriery — a minimum of every 6–8 weeks
  • Correct breakover and foot balance from a young age in breeds with known predisposition
  • Avoid consistent work on very hard surfaces for susceptible horses
  • Manage bodyweight to reduce concussive load on the feet
  • Select breeding stock carefully in breeds with high prevalence

Prognosis

Navicular syndrome is a progressive condition in most cases. However, with appropriate farriery, targeted treatment, and modified work, many horses can remain in comfortable work for years. The introduction of MRI-guided treatment has significantly improved outcomes by allowing specific lesions to be targeted rather than treating the syndrome blindly. Horses with isolated navicular bone changes often fare better than those with significant DDFT damage within the hoof capsule.

When to Call the Vet

  • Any forelimb lameness that does not resolve with a few days of rest
  • A horse that consistently points one or both forefeet when at rest
  • Bilateral forelimb stiffness or a short, pottery gait that worsens on firm ground
  • Deterioration in a horse already being managed for navicular syndrome

Frequently Asked Questions

Is navicular disease a death sentence for horses?

No. Many horses with navicular syndrome continue in comfortable work for years with appropriate management. The key is early diagnosis, regular skilled farriery, targeted veterinary treatment, and realistic adjustments to the horse’s workload and competition demands.

What is the best shoeing approach for navicular horses?

There is no single answer — shoeing needs to be tailored to the individual horse’s foot conformation and the specific structures involved. In general, the goals are to correct the hoof-pastern axis, reduce toe length, improve heel support, and ensure adequate frog ground contact. An experienced farrier working in close collaboration with the attending vet produces the best outcomes.

Can MRI change the diagnosis of navicular disease?

Frequently. MRI often reveals that what was diagnosed as “navicular disease” based on radiographs alone actually involves significant DDFT damage, collateral ligament pathology, or other soft tissue lesions. This can fundamentally change the treatment approach and prognosis. MRI is now considered essential for any horse with significant caudal foot pain where the radiographic findings are not explanatory of the degree of lameness observed.

Are certain breeds more prone to navicular syndrome?

Yes. Thoroughbreds, Warmbloods, and Quarter Horses are most commonly affected, likely due to their conformation and the intensity of their athletic demands. Small, narrow feet relative to body mass are a significant risk factor regardless of breed. Heavy cob and draught types are generally less affected. Information on breed conformation is discussed in our Thoroughbred breed guide.