Caudal heel syndrome Stockton describes cause and treatment for caudal heel syndrome

Riverton – Caudal heel syndrome describes a broad spectrum of conditions that affect the navicular bone, the bursa and the flexor tendons in a horse’s foot. 

“Anything in the area of the navicular bone that causes pain is called caudal heel syndrome,” says Amy Stockton of Stock Doc Vet Clinic in Riverton, noting afflictions used to be called navicular disease, which was incorrect. 

Anatomy

When looking at the horse’s foot, the navicular bone is located behind the coffin bone and short pastern bone. It sits on the navicular bursa, which Stockton described as a small pillow between the tendon and the bone, designed to protect the tendon. 

“If the bursa is inflamed, we call it bursitis, and it hurts,” Stockton described. “We can also have inflammation in the impar ligament, the tendon or the joint.”

“Pain in any of these areas is called caudal heel syndrome,” she says.

Horses from four to nine years old, typically geldings, may be afflicted with caudal heel syndrome in their front limbs. 

“Usually, it’s related to conformation, or if they were trimmed or shod in a manner that puts too much stress and strain on their heel region,” Stockton describes. “The most common presentation of caudal heel syndrome is bilateral lameness affecting the front foot.”

She adds, “It’s a big deal, and we see a lot of it.” 

Cause and symptoms

Stockton notes, often, veterinarians don’t know what causes caudal heel syndrome, but she says, “Small feet can be an issue, and overweight horses may see caudal heel syndrome more often.” 

She further notes a horse that is low in the heel with a long toe are more likely to be affected. 

“It is important to have a farrier trim our horses because improperly trimmed hooves can result in caudal heel syndrome,” Stockton says. 

Lameness is the first sign of caudal heel syndrome, and after rest, horses get better. Usually one foot is more severely impacted than the other, and horses may even wear their toe off because they don’t want to land on the sore heel.

“They may stumble a bunch, too,” she explains. “When we put hoof testers on, we often find the horse is sore over their heel or their frog, or they might not be sore at all.”

The shape of the foot may change with caudal heel syndrome, as the heels get thinner and they contract and get a narrower foot. 

Diagnosis

To identify caudal heel syndrome and the root cause of the syndrome, Stockton notes several strategies may be used

“We block the heels with lidocaine and make sure it is numb. If the horse walks out more comfortably, we know the lameness is from the heel and they likely have caudal heel syndrome,” Stockton says. “We can also see radiographic changes if the disease is in the bone.”

However, because the changes are gradual, there may be no observable changes in an x-ray until six months, a year or longer. 

In larger, more urban clinics, MRIs or contrast-enhanced CT scans are used to determine caudal heel syndrome has resulted from the ligament, tendon, bone or join, but Stockton said they don’t have that technology in many Wyoming clinics. 

Rather, she is able to utilize an ultrasound machine to help target the cause of caudal heel syndrome. 

“We can see changes in the deep digital flexor tendon or the bursa. Then, we can block whichever part may be affected with lidocaine. Then, if the horse walks out soundly, we know that part is involved,” Stockton comments. “Using an ultrasound is a bigger process and more time intensive, but it can help us identify the cause of caudal heel syndrome.”

Biology

Stockton also says there are several theories as to why caudal heel syndrome results.

“The biomechanical theory says repeated concussion between the deep digital flexor tendon and the navicular bone can cause it,” she explains. “Basically, repeated hard hits, in conjunction with upright conformation, small feet or improper shoeing may cause caudal heel syndrome.”

An additional theory hypothesizes that thrombosis of the small blood vessels supplying blood to the foot result in caudal heel syndrome.

Finally, degenerative joint diseases, like arthritis, may result in caudal heel syndrome.

Treatment

Treating caudal heel syndrome can be a challenge, adds Stockton, particularly if the exact cause of the pain has not been identified.

“We’ll start treating by raising the heel because, when there’s pressure in foot, it causes pain,” she explains. “If we increase the heel height, we take some of the pressure off of the foot, relieving pain.”

Stockton emphasizes the importance of attaining the correct balance when shoeing horses, and says, “We use a farrier to shoe our horses to make sure they get the feet right. We can keep a horse sound for a long time with the correct shoes on.  

Additionally, managing a horse’s weight to make sure they aren’t too heavy is also important for alleviating caudal heel syndrome. 

“Acupuncture has been used at Colorado State University with a 40 to 50 percent improvement in cases, but there wasn’t a control,” she says. “When we use acupuncture, we are looking at balancing the whole system.” 

Non-steroidal drugs can be used, along with peripheral vasodilators to improve blood flow to the area, and other new drugs are available as well. 

“Several new drugs also target changes in the bone, says Stockton. “If we see bony changes on the navicular bone, we use a couple of different drugs that can prevent osteoclasts from breaking down the bone.”

Anti-inflammatory drugs can be used, as can steroids, stem cell therapy or platelet-rich plasma to treat caudal heel syndrome.

“Nerving is a last-ditch effort,” Stockton adds. “If we nerve a horse, it can step on a nail, for example and not know, so there are other complications we have to watch out for.”

Saige Albert is managing editor of the Wyoming Livestock Roundup. Send comments on this article to saige@wylr.net.