Navicular Syndrome

Vets don't agree as to what Navicular disease really is, prefering to call it "navicular syndrome," which signifies that a variety of problems can cause the disease. It is not always possible to pinpoint the exact cause of the navicular syndrome. Because there are a variety of causes, no one treatment is successful.

Navicular syndrome is a degenerative process that can affect the bone, bursa or tendon. It occurs almost exclusively in the front feet and usually affects both feet.
Horses that are at high risk for developing navicular problems are usually confined or stall-kept, and have strong physical demands placed on them.

Younger horses tend to be affected by navicular syndrome more often. Definite symptoms of navicular syndrome are usually detected between the ages of three and 16 years. Horses have shown signs of developing the condition as early as one year old, however, it more commonly develops in horses between the ages of ten and 13 years.

Quarter horses are particularly prone to navicular disease and it is unknown whether this is due to some hereditary factor or is related to conformation. The more pressure that is applied to the navicular bone from the deep flexor tendon, the more likely the horse will suffer from navicular disease. Overweight horses, and horses with small feet (proportionally to the size of their bodies) are more likely to develop navicular problems. Quarter horses and Thoroughbreds have proportionally small feet and high body weight, which may explain the tendency towards development of navicular disease in these breeds.
Navicular syndrome causes a gradual and progressive increase in lameness of the front legs. Due to the gradual nature of onset, navicular problems are difficult to detect until the condition is advanced.

While walking, the horse with navicular syndrome tends to place its weight on the toe to avoid placing pressure on the heel area, which contains the inflamed navicular bone. Since the horse will not place weight on the heel, it takes longer to stop the stride. While standing, a horse with navicular syndrome tends to shift its weight continuously to relieve pressure and pain within the heel. A horse with navicular syndrome is often lame after work; however, the lameness may disappear with rest. Due to comparably poor circulation in the feet of many horses with this condition, the heels and adjacent hooves may become smaller and contract.

X-rays do not always detect early signs of navicular disease since the soft tissues are usually the first problem areas.

Other navicular syndrome signs in horses to watch for include:

• Shortening of the stride
• A continual shifting of body weight when resting
• A stumbling gait
• Slight unevenness on turns
• Reluctance to go forward properly or lengthen the stride
• Pointing - the horse will stand at rest with one leg extended, the weight resting on the toe
• When the foot is pressure tested, the horse will usually indicate heel pain
• General irritability

Treating a horse with navicular disease is a very controversial issue. Many horse owners believe that, in time, the condition will correct itself, while others try every type of navicular syndrome treatment available. The method chosen depends on the demands put upon the horse and the severity of the condition.

Navicular syndrome will not directly shorten the length of the life of a horse. There are many ways to relieve the pain of navicular disease so that the horse will be able to continue on as normal.