More accurately described as a syndrome, navicular disease is a form of lameness which is caused by degeneration of the navicular bone in the heel and occasionally by inflammation in this area. Also known as "palmar foot pain", the condition usually affects horses over 7 years of age. An MRI scan can confirm the presence of the condition.
How to Recognise Navicular Disease
The condition will normally affect both of your horse's front hooves but one foot is often worse than the other. This means that your horse may initially seem to be lame on one leg. You might notice that he lands on the toe of the hoof first to avoid experiencing pain in the heel. Exercise exacerbates the condition and rest improves it. If you spot these symptoms and feel that your horse may be suffering from navicular disease, consult your vet at the earliest opportunity.
Diagnosis
Your vet will perform flexion tests and may nerve block the area to see if this reduces your horse's lameness. An X-ray or MRI scan of the heel area will confirm the diagnosis. The vet might look for lesions within the navicular bone, degeneration of the surface of the bone and calcification of the ligaments associated with the bone.
The Causes of the Condition
It is thought that stress to the bone usually causes the condition. It is competition horses that tend to suffer from navicular disease. An injury to the bone's supporting tissue or problems with the bone itself can cause the lameness. All breeds are known to suffer from this condition but it is most prevalent in quarter horses, thoroughbreds and warmbloods. Horses with underrun heels, sheared heels, contracted heel, mismatched hoof angles and abnormally small feet are also prone to the condition.
Treatment
Navicular disease is a chronic condition from which few horses make a full recovery. It is a case of managing the condition rather than treating it. You will probably need to experiment with a variety of options to address the lameness in order to see which offers the most benefits for your horse. Therapeutic shoeing can help but sometimes removing the shoes altogether is a more effective approach. Therapeutic shoeing will lift and support the heel whilst removing the shoes may improve blood flow to the affected area. Anti-inflammatory drugs will probably also be an element of the treatment regime. You will need to reduce your horse's workload if the pain persists and consider the option of surgery. This involves a procedure called "nerving". The palmer nerves are severed so that your horse loses sensation in his heel. Surgery should clearly be a last resort and isn't without its risk.