Navicular syndrome in horses
What is navicular syndrome?
In the horse, the navicular bone is located directly behind the coffin bone and is held in place by tendons and ligaments.
The navicular bone has two functions:
- To protect the joint and tendons from pressure and concussion (the navicular bone acts as a pulley on the deep digital flexor tendon, which takes some of the stress off the coffin bone).
- To act as a valve for blood flow to the coffin bone and corium inside the hoof.
If the hooves are not properly cared for, the navicular bone becomes immobile, resulting in poor blood flow within the hoof. Specific problems that are likely to result in immobilization of the navicular bone include high heels, overlaid bar, long toes and improper shoeing. Navicular syndrome, also known as Caudal Heel Syndrome, is a degenerative process that can affect the bone, bursa or tendon. Navicular disease occurs almost exclusively in the front feet and usually affects both feet.
Is my horse likely to develop navicular?
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 navicular disease as early as one year old, however, navicular disease 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.
The symptoms of navicular syndrome
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 and bursa. 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
Dressage horses with navicular syndrome may have trouble coming onto the bit or may refuse to perform a maneuver with which they have demonstrated ease in the past.
Racehorses with navicular syndrome may quit during the race, slow down noticeably at the 3/4 pole or exhibit loss of form.
Jumpers with navicular syndrome may refuse or take down the rails.
Event horses with navicular syndrome may exhibit poor recovery (including a prolonged rapid heart rate, respiratory rate and temperature) from the strenuous phases of the event or may have trouble making times.
Pleasure horses with navicular syndrome may stumble or show signs of irritation (tail swishing, head bobbing).
Endurance horses with navicular syndrome, like event horses, may show poor recovery or inability to finish rides.
Navicular treatment options for your horse
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. These include:
TRIMMING THE FEET
Currently, the most effective treatment for navicular syndrome appears to be good foot care. Numerous styles of shoes have been developed to help relieve pressure of the deep flexor tendon, therefore relieving pain in a horse with the condition. Horses showing signs of navicular disease should be shod more frequently than other horses (every six to eight weeks). Each horse should be trimmed according to the particular conformation that needs correction.
RAISE THE HORSE’S HEEL
One recommendation for shoeing a horse with navicular syndrome is to raise the heel. By raising the heel, less pressure is exerted by the deep flexor tendon when the horse lifts his foot to walk. Although raising the heel can relieve the pain of navicular disease, the rest of the foot is strained due to the new, steeper angle. Wedge shoes and wedge pads will both raise the horse’s heel.
ROUNDING THE TOE
Another recommendation for shoeing a horse with navicular syndrome is to round the toe. By doing this, pressure is taken away from the deep flexor tendon as the horse attempts to walk. The shoe allows the horse to “roll” or “rock” up off of the heels instead of having to forcefully pick up the foot. A rolled toe shoe or rocker toe shoe allows for “rocking” or “rolling.”
SETTING THE SHOE UNDER
Yet another common practice in shoeing a horse with navicular syndrome is “setting the shoe under.” This entails leaving hoof beyond the edge of the shoe, and then rounding it, so that it acts as a rocker. When the hoof is rounded it takes less effort for the horse to pick up their foot and move.
Click here for information on hoof care to treat & prevent navicular.
Medications are frequently prescribed to horses with navicular syndrome to help relieve pain temporarily. Many oral and injectable drugs are available for temporary use. It is the opinion of Biomedica that drugs should be a last resort as they are not without serious side-effects. Prolonged use of many of these drugs can cause damage to the horse and their use may be illegal in competitions.
For mild to moderate navicular disease your veterinarian may recommend isoxuprine. This drug dilates the small peripheral blood vessels, thereby improving circulation.
Isoxuprine does not decrease damage to the joint and is usually only successful in the early stages of navicular syndrome. Isoxuprine therapy is a long course of regular drug therapy which can become expensive and time-consuming.
Warfarin (Blood thinner)
For mild to moderate navicular disease, your veterinarian may also recommend warfarin. This drug decreases blood clotting, potentially improving circulation.
Like isoxuprine, warfarin is a permanent course of therapy. The horse must be watched carefully for bleeding problems, since the drug reduces normal clotting throughout the body.
Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs help reduce the pain and swelling of the joints and decrease stiffness. When taken at a low dose, NSAIDs reduce pain; when taken at a higher dose, NSAIDs can also reduce inflammation.
NSAIDs do not prevent joint damage and when used long-term, may accelerate joint breakdown. Taking more than one NSAID at a time increases the possibility of severe side effects such as ulcers and bleeding. NSAIDS affect normal blood clotting and therefore may interact with other blood-thinning medications, such as warfarin.
Many NSAIDs require a prescription including Phenylbutazone® (Bute) and the newer sub-class of NSAIDs called Cox-2 Inhibitors currently used for treatment of companion animals, (Rimadyl® (carprofen), Metacam® (meloxicam) and Etogesic® (etodolac).
Cortisone is a corticosteroid that reduces inflammation and swelling. For severe pain and inflammation, veterinarians may inject a corticosteroid, such as cortisone, directly into the affected joint. Cortisone mimics the anti-inflammatory effects of cortisol, which is a hormone naturally produced by the body. Although corticosteroids closely resemble cortisol, they exert a much more powerful anti-inflammatory effect. An injection can provide almost immediate relief for a tender, swollen and inflamed joint.
Visco-supplementation is the process of injecting a gel-like substance into the joint. This substance lubricates the cartilage, reducing pain and improving flexibility. Visco-supplementation decreases friction within the joint, thus reducing pain and allowing greater mobility. This method of treatment requires ongoing injections as benefits are only temporary. Substances used in visco-supplementation include hyaluronic acid, or HA (Legend®, Hylartin® and Synacid®), and poly-sulfated glycosaminoglycans (PSGAGS) such as Adequan®
If your horse requires surgery
Surgery may be the only option for horses with long-standing navicular syndrome
Neurectomy is a drastic treatment, usually reserved for long-term cases of navicular disease. A small piece of the two nerves that penetrate the navicular area is cut below the fetlock. This numbs the entire foot.
Problems resulting from this surgery involve stumbling due to the fact the horse has lost sensation in the foot and does not know where it has been placed. Since equine health problems involve the foot, and the horse will be lacking sensation in the foot, horses that have undergone neurectomy should be closely monitored for hoof and leg problems.
Sometimes, the severed nerve may grow back, but can be cut as many times as necessary to keep the horse pain-free.
A new surgical treatment that involves cutting the navicular suspensory ligament may result in long-term improvement for some horses.
Finally, for horses with advanced navicular syndrome, retirement may be the only recourse. This should include daily turnout to maintain regular blood flow and promote healthy hoof growth.
Reducing the risk of navicular syndrome
Excess weight puts pressure on the weight-bearing joints. If overweight is contributing towards your horse’s pain, your veterinarian will recommend a suitable diet.
Exercise is an important component of healthy living. Exercise helps reduce pain, prevents further joint damage and can help your horse maintain a healthy weight. Disuse of a sore joint will cause the muscles around it to weaken, resulting in pain. A little exercise taken frequently is recommended.
Some horses, particularly working animals, do not get adequate rest for optimum healing. Your veterinarian will be able to advise you on how much rest your horse requires during the healing period.
Improper shoeing can cause many joint and muscle problems and is a significant factor in the progression of navicular disease. An experienced farrier can help assess whether your horse’s shoeing is contributing towards the condition. Your veterinarian may be able to suggest a farrier who is capable and well respected.
Natural ways to help your horse with Navicular Syndrome
Recovery®EQ with Nutricol®, is an elite proprietary performance and wellness supplement for horses that enhances quality of life.Recovery®EQ improves healing by increasing circulation of nutrients to affected cells and extracellular structures, halting tissue damage and modulating inflammation. It may be usedin combination with prescribed medications. Always consult with the veterinarian prior to adding a new natural lifestyle supplement to a horse’s feeding program.
Review in the prestigious Horse Journal in October and December 2003
Recovery®EQrated as “Best Performer Overall” as a pain-relieving supplement for joint pain, back pain and tendonitis – comparison of natural joint care supplements.
Review in the prestigious Horse Journal inJune 2006
“You get what you pay for” – Horse Journal quote about Recovery®EQ used as a performance enhancing supplement – comparison of natural performance enhancing supplements
Refer to Tips for a Healthier Horse