Keep an eye on your horses’ fetlocks

Hey there, time traveller!
This article was published 22/12/2016 (3238 days ago), so information in it may no longer be current.

Few conditions in a horse are as difficult to manage as suspensory ligament disease, particularly, degenerative suspensory ligament desmopathy/desmitis (DSLD).

It results in a characteristic drop of the fetlock and laxity of the suspensory ligament. The exact cause is not known but the effects are devastating for many horses

Some basic anatomy review of the equine limb is needed to fully understand the degree of severity that can accompany tendon and ligament conditions in horses.

A horse’s bone structure is much different than that of a human in that a horse essentially walks on its middle fingers and the tendons and ligaments that allow us to curl our fingers into the palms of our hands represent the flexor tendons and suspensory ligaments of a horse. In a horse, these tendons and ligaments are absolutely vital to allowing the horse to move and articulate the leg. Without the tendons and ligaments supporting the bony column of the leg, the horse would fall down.

Specifically, the suspensory ligament is a soft tissue structure that runs between the back of the carpus (front leg) or hock (hind leg) and the sesamoids bones at the back of the fetlock below. Its main function is to support the back of the fetlock and allow the horse to keep the fetlock joint from coming in contact with the ground. When a horse is affected by a suspensory ligament degeneration, the ligament lengthens and becomes more lax which results in the fetlock dropping and, in severe cases, contacting the ground, causing pain and discomfort.
Degenerative suspensory ligament desmitis is often found in both hind legs, and occasionally in the forelimbs. It is seen in all ages of horse but often in mid-age to older horses.

It is thought to be closely related to a human condition called Ehlers-Danlos Syndrome, which is a genetic disease of the connective tissues of the body. The most characteristic symptom of the disease in horses is the dropped fetlock in both hind legs.

Unfortunately, there is no cure or treatment. Management includes anti-inflammatories, corrective farrier work including wedge shoes and shortened toes, along with restricted exercise or retirement. Methyl-sulfonyl-methane (MSM) supplementation can be helpful to horses with DSLD to improve connective tissue condition.

If you suspect your horse has this condition, get your equine veterinarian to examine your horse so appropriate management can begin.

Chris Bell is an equine veterinarian and surgical specialist who operates Elders Equine Veterinary Service, with clinics in Cartier and Winnipeg. See www.eldersequineclinic.com.