Horses exhibiting heel pain are often diagnosed with navicular syndrome. [1] It is a common – and frustrating – issue to deal with, but it no longer spells immediate retirement for the horse.
With early diagnosis and proper treatment, a horse with navicular syndrome may still have a useful life for a considerable period of time.
Navicular syndrome is a chronic degenerative condition that can cause lameness in the front legs. It is most commonly seen in competition horses and quarter horses.
It may be caused by repetitive mechanical stress on the navicular bone, resulting in degeneration of tissues and ligaments in the heel.
Horses with navicular syndrome may have a shortened stride length, exhibit signs of pain or experience changes in their gait such as toe landing.
Proper hoof care and maintaining a good body condition for senior horses can help to reduce the risk of this condition. Once it has been diagnosed, a number of treatment options are available.
What is Navicular Syndrome?
Also known as caudal heel pain or podotrochlear syndrome, navicular syndrome was long referred to as navicular disease.
The latter term is no longer used since a syndrome (concerning a series of issues) is a more accurate term for the condition than disease.
Navicular syndrome often results in degeneration of the navicular bone, generally in the front feet. Navicular syndrome in the rear hooves is unusual but does occur.
Because it is a degenerative problem, it is not curable. Proper management of the condition can help to improve your horse’s comfort and mobility.
This syndrome may not actually involve the navicular bone per se. Besides the navicular bone, navicular syndrome may involve the:
- Navicular bursa
- Coffin bone
- Impar ligament
- Suspensory ligament
- Deep digital flexor tendon
- Digital cushion
- Frog
- Heel bulbs
The Navicular Bone
The small, flat navicular bone is located at the rear of the heel at the back of the coffin joint.
The navicular bone attaches to the pedal bone via the short impar ligament and to the pastern joint via the suspensory ligaments.
Over the navicular bone’s lower surface lies the deep digital flexor tendon (DDFT). The DDFT then turns and goes up the leg. As the animal moves, the DDFT is under tension.
Heel pain can result from anything causing strain on the tendon or interfering with the tendon’s action. Under some circumstances, adhesions between the DDFT and the navicular bone may occur.
Signs and Symptoms
Horses with navicular syndrome typically exhibit low-grade, chronic lameness. Rarely, navicular syndrome lameness comes on suddenly.
What starts as a horse being somewhat “off” progresses over time. The lameness may appear to switch legs.
Suspect navicular syndrome if the horse displays any of the following:
- Pointing a toe while at rest
- Development of short-strided gait
- Difficulty when turning
- Problems going downhill
- Increased stumbling
- Rigidity in the neck and poll
- Gait changes when trotting circles
- Becoming uncooperative with the farrier
Unlike laminitis, when a horse tries to keep weight off the toe, equines with navicular syndrome try to put their toes down first to avoid weight on their heels.
Navicular syndrome does not normally present with heat in the hoof, an increased digital pulse, or the swelling so frequently found in other hoof lameness. If such symptoms are involved, they are generally subtle.
Navicular Syndrome Causes
Exactly what causes navicular syndrome is uncertain. Hoof trauma plays a role in some cases, as can anything interfering with the blood supply to the navicular bone.
Horses with small hooves and large bodies are more likely to experience navicular syndrome. The “classic” navicular presentation is a long toe and low heel combination. This type of hoof threatens the soft tissues in the back of the structure.
Risk Factors
Any horse may develop navicular syndrome. However, heavier, stock-type horses appear more vulnerable. Upright pasterns combined with small hooves may contribute to navicular syndrome.
Incidence of navicular syndrome is highest in quarter horses, thoroughbreds, and warmbloods. [2] Because navicular syndrome is so much higher in these breeds, a genetic component is possible.
The condition affects sport horses more frequently. It is likely that wear and tear plays a role in navicular syndrome development.
Navicular syndrome is uncommon in ponies, as well as Arabians.
Work involving concussion, especially of the front legs, exacerbates the problem. Thus, horses engaged in activities such as jumping, reining, and cutting or ridden on rocky surfaces are at increased risk.
Horses kept in stalls the majority of the time are more likely to develop navicular syndrome than those living out. That is because there is less blood flow to the hoof when the horse is not moving continuously.
Young horses are not usually affected. Most horses diagnosed with navicular syndrome are between ages 7 and 14.
Prevention
It is not always possible to prevent navicular syndrome, but regular farrier care maintaining hoof balance and heel support can reduce the odds. Keep to a strict trimming or shoeing schedule.
Riding or exercising the horse on good footing can help keep navicular syndrome at bay.
Do not allow your horse to become overweight or obese. An overweight horse experiences more stress on hooves and tendons.
Carrying excess body fat can also contribute to joint issues, metabolic dysfunction and other health problems.
Nutrition plays a critical role in hoof health. Feeding your horse a balanced diet that provides sufficient amino acids, biotin and trace minerals will help to support hoof health.
You can learn more about feeding your horse to promote hoof growth here.
Navicular Syndrome Diagnosis
If you suspect your horse is dealing with navicular syndrome or other hoof problems, consult with your veterinarian to obtain a diagnosis.
The vet starts the diagnostic process by observing the horse move, followed by joint flexion and the use of hoof testers. The horse may exhibit pain when the latter is used on the heel area or frog.
The veterinarian may watch the horse move on both hard and soft surfaces, such as pavement or sand.
The initial step in getting to the bottom of suspected navicular pain is ensuring the heel is the actual source of pain. [3]
The veterinarian performs a digital nerve block on the palmar digital nerves. These two nerves run along the back of the pastern, supplying sensory perception to the navicular bone and other structures, including the heels, bars, and so