Caudal Heel Pain Syndrome (Navicular Disease) in Horses
Key takeaways
Caudal heel pain syndrome in horses (formerly known as navicular disease) is the degeneration of the navicular bone seen in conjunction with damage to various surrounding tendons, bursa, and ligaments.
- Common risk factors include poor conformation, hoof imbalances, and excessive work on hard ground.
- Symptoms include; intermittent or persistent lameness in forelegs, shortened/clunky stride with toe-heel pattern, altered hoof conformation, foot pointing when standing, shifting weight side-to-side when standing
- Diagnosis involves a physical exam, including lameness exam using nerve blocks, and diagnostic imaging
- Treatment is highly individual, but can include rest, medications, nutraceuticals, corrective shoeing, retirement, or surgical intervention
- Caudal heel pain syndrome is a chronic degenerative condition with no cure, but the prognosis is fair for continued performance in cases of mild disease that is treated appropriately
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A closer look: Caudal Heel Pain Syndrome (Navicular Disease) in Horses
The navicular bone is a small cartilage-covered bone located at the back of the foot between the short pastern bone and the coffin bone. Its function is to act as a fulcrum, in conjunction with bursa, to allow the distal deep digital flexor tendon to curve; changing from running down the back of the leg to running towards the center of the hoof and attaching to the coffin bone. Various other structures surround this system that assist in bearing the horse’s weight. This system is called the podotrochlear apparatus.
Caudal heel pain syndrome is the most common cause of forelimb lameness. Prognosis is fair when discovered and managed in early stages, but the disease progresses over the horse’s lifetime.
Currently there is no cure. If caudal heel pain syndrome is suspected, or if a defect of the navicular bone is found, early intervention is recommended.
Risk factors
Late stage symptoms include;
- “Broken back” hoof angle (long toe, short heel)
- Choppy stride when trotted in straight line
- Imbalanced feet
- Multiple foot conformational issues
- Forelimb lameness, often involving both legs
- Pointing of affected feet when standing
- Sudden, more severe lameness in one foot due to soft tissue injuries
Some horses, such as Quarter Horses, Thoroughbreds, Warmbloods, and large horses with small feet are more prone to caudal heel pain syndrome. It is rare in ponies and donkeys.
Caudal heel pain syndrome can occur in the rear feet, but it is very rare. Horses are typically diagnosed between 8 - 10 years of age.
Additional risk factors include;
- Participating in highly physical disciplines
- Hoof imbalance
- Improper shoeing
- Poor hoof and lower limb conformation
- Excessive work on hard ground
Possible causes
Degeneration of any of the structures within the podotrochlear apparatus fall under the umbrella of caudal heel pain syndrome. Degeneration can range from injury or inflammation of the soft tissues (bursa, tendons or ligaments) to disease or breakdown of the navicular bone itself.
Main symptoms
Symptoms are typically intermittent and slowly progress to lameness that is more pronounced when working on hard ground or in small circles.
Early symptoms include;
- Intermittent lameness that is more prominent after hard work
- Shifting weight from side to side when standing
- Shortened stride out of stall or while warming up
- Resistance to lengthening the trot
- Stopping at jumping
- Knocking jump rails
- Imbalance and head nodding while trotting in small circles
- Toe-heel stride adjustment
- More pronounced lameness when affected leg is on inside during lunging/working in a circle
Testing and diagnosis
Diagnostic tests include;
- Physical exam
- Discussion of medical history
- Lameness exam, including nerve blocks
- Diagnostic imaging, including X-rays, ultrasound, MRI, and bone scans
Steps to Recovery
Treatment includes;
- Stall or small paddock rest
- Corrective trimming and shoeing to support the heel
- Anti-inflammatory medications, both short and long term
- Medications to slow the rate of bone turnover
- Joint, tendon sheath, or navicular bursae anti-inflammatory injections
- Nutraceuticals
- Reduced workload or retirement
- Surgical intervention in late stages
Caudal heel pain syndrome is a chronic, degenerative condition with no cure, but when treated early and appropriately prognosis is fair for maintaining an athletic career. Treatment is focused on pain management to extend a horse’s functional life. Regular assessment of the efficacy of the treatment plan is recommended; changes to management plans are common as degeneration progresses. Horses with moderate to severe disease often require retirement from athletic pursuits due to unsoundness.
Prevention
Not enough is known about the cause of caudal heel pain syndrome to guarantee prevention, but maintenance of proper foot balance through shoeing and regular farriery may help reduce strain on the podotrochlear apparatus.
This condition is not contagious, but may have a hereditary component.
Is Caudal Heel Pain Syndrome (Navicular Disease) in Horses common?
Caudal heel pain syndrome is the most common cause of forelimb lameness in athletic horses.
Typical Treatment
Due to the wide amount of structures involved in caudal heel pain syndrome, and the varying severity of these injuries, treatment is individualized and multiple follow-ups may be required to find the correct therapies for each horse.
Treatment includes;
- Rest
- Corrective shoeing to support the heel
- Medications
- Nutraceuticals
- Reduced workload or retirement
- Surgical intervention in late stages
