PrintWhen you call the veterinarian to help you pinpoint the intermittent lameness in your horse, the last two words you want to hear are “suspensory injury.”
“Like tendons, suspensory ligaments can take a very long time to heal,” said Lisa Fortier, DVM, PhD, ACVS, associate professor of large animal surgery at Cornell University (N.Y.). “When the suspensory ligament does heal, re-injury is very common. Most people, when they hear their horse has a suspensory injury, have the same gasping response because there’s no quick fix.”
According to a 1999 study performed by the University of California, Davis, Center for Equine Health, suspensory ligament injuries were the most common injuries or conditions affecting horses, second only to colic. Despite the commonality of the diagnosis, researchers and veterinarians haven’t been able to speed up or perfect the healing process.
But a better understanding of the causes behind the injury and evolving stem cell research is giving what mayhave once been a career-ending injury a chance for a full recovery.
Primary Function Of The Suspensory Ligament
The suspensory ligament consists of a strong band of fibrous tissue that begins at the top and back of the cannon bone between the splint bones. Approximately two thirds of the way down the cannon bone, the suspensory ligament splits into two branches (medial and lateral), each of which inserts into one
of the paired proximal sesamoid bones at the back of the fetlock. Smaller extensor branches run to the front of the limb to join the major extensor tendon of the limb.
The suspensory ligament’s function is crucial to a horse’s movement since it prevents excessive extension of the fetlock joint during the weight bearing or stance phase of the stride.
Unnecessary stress can occur to the suspensory ligament when a horse travels at fast speeds, lands wrong after a jump or applies too much force to the area. Typically, the damage is cumulative over a period of time and may be considered a repetitive strain injury.
The suspensory ligament is much like the structure of cable on a bridge. Small bundles of wire are grouped together in small units before being combined with others to form larger and larger parallel bundle groups. The suspensory ligament is composed in a similar fashion but instead of bundles of wire, it’s bundles of fibers that are aligned longitudinally. It’s the parallel alignment of the fibers that allows for maximum strength and elasticity.
Injury to the suspensory ligament occurs when the load placed on it exceeds the collective strength of the entire fiber bundle groups, causing tearing, fraying or rupturing of the individual fibers or fiber bundle groups.
“The suspensory supports most of the back of the fetlock so it’s more prone to injury because it holds so much strain,” explained Fortier. “Injuries to the suspensory branches seem to take longer to heal and can often be career-ending because they are smaller in diameter than the main body of the suspensory ligament, meaning that there are fewer fibers holding up the back of the fetlock.”
Identifying A Suspensory Injury
