Equine Suspensory Apparatus Dysfunction
in the form of
Degenerative Suspensory Ligament Desmitis


What is DSLD?
Degenerative Suspensory Ligament Desmitis is a syndrome; a degenerative bilateral condition whereby there is inflammation and faulty healing of the suspensory ligament, resulting in typical thickening or hardening of the mid-body of the ligament or the suspensory branches resulting in loss of integrity of the suspensory ligament and its ability to do its intended job of supporting the horse.

What causes DSLD?
There is speculation that the horse develops an abnormal response to normal stresses on their suspensory ligaments by failing to "manufacture" new collagen for repairing tiny tears and strains. Instead of new collagen fibres being laid down in line with the stesses on the ligaments, cartilage is laid down in the suspensories resulting in loss of tissue strength or elasticity. Without the ability to stretch, even normal weight-bearing on the limbs can become too much, and over time, the ligements lengthen and break down. It is important to remember that no matter how the injury or stress occurs, DSLD cases improperly heal the ligament injury with cartilage instead of collagen.

What symptoms will a horse with DSLD exhibit?
Generally a bi-lateral (both front legs or both hind legs) lameness, although the severity of the lameness varies among horses and may go undetected in some until the condition becomes fairly well advanced. There is generally painful response to palpation of the branches of the suspensory ligement, particularly in the area where the ligament branches. In more advanced stages the fetlocks seem to be sinking more when the horse moves. As the condition worsens, the pastern area becomes increasingly parallel to the ground, and ringbone can develop. In later stages, one of the most telltale signs of DSLD is in the horse affected in the hind legs; the pasterns level out making the fetlocks appear dropped and the stifle and hock gradually straighten, making the horse reticent to move even to its feed or water. Some horses will dig a hole in their stall or paddock and stand with their toes pointing down and the heels elevated. On hard surfaces, horses may rock back and forth, relieving one leg and then the other. Some horses find the condition painful enough to spend a more than normal amount of time lying down.

How is DSLD diagnosed?
Palpation of the suspensory ligaments reveal bilateral pain response and thickening or hardening of the mid-body or branches. Ultrasound imaging will show poor fiber pattern at the origin of the suspensory or at the bifurcation and branches. The branches' circumference might be enlarged bilaterally. In radiographs, the sesamoid bones will be lower than normal in relation to the fetlock joint, with possible bilateral mineralization of the suspensory branches visible. Degenerative joint disease might be visible in the pastern joint; subluxation of the pastern joint will worsen. Themography will show significant bilateral warming over the branches of the suspensory. Nuclear scintigraphy in both the soft tissue phases will show the suspensory branches as quite reactive; in the bone phase, the proximal sesamoid bones and pastern joint will "light up."

What breeds of horses are affected?
DSLD has been diagnosed in the following breeds: Arabian, American Saddlebred, National Show Horse, Paso Fino, Peruvian Paso, Quarter Horse.

Is there a genetic link?
Though DSLD has been diagnosed in several breeds, early findings are that it seems to be more prevalent in certain bloodlines within those breeds. In spite of these early findings, there are some who speculate that DSLD is related to mismanagement and improper care. Others feel it is related to poor conformation. So far, attempts to find a genetic marker have been met with resistance from breeders unwilling to cooperate with full disclosure of affected animals pedigrees or lists of related affected animals, so little progress has been made on that front. So for now, this question remains unanswered.

My horse was diagnosed with DSLD; What do I do now?
First, be sure that the diagnosis has been determined by a qualified veterinarian. There are a number of different types of leg problems--more specifically suspensory problems--that may at first look appear to be DSLD. Once certain that indeed your horse has DSLD, much depends on how advanced the condition is. There has been success in a number of cases with the addition of methyl sulfonyl methane (MSM) and other supplemental aids to the diet, using shoeing techniques that raise the heels of the hooves on the affected legs to relieve pressure on the suspensories, and the use of stall rest followed by hand-walking (See DSLD and Dietary Supplementation). With early diagnosis and working closely with your veterinarian, many horses have the chance of returning to some riding and many more are able to be kept pasture-sound.

Return to the Equine Suspensory Apparatus Dysfunction home page.

Image coming soon!.