Suspensory ligament injuries in horses are a common cause of lameness, particularly in racing and sport horses. It is important that they are diagnosed and treated correctly to limit the chances of recurrence or permanent lameness. Read this post to learn what the suspensory ligament is, why it's important, how to tell if your horse has injured it, how to prevent injury, and how to treat it.
Suspensory Ligament Injuries in Horses
Don't assume the suspensory ligament is a straight line either. That's part of the difficulty with suspensory ligaments in horses, they bend and have multiple parts, including branches that wrap both around and between bones. The top of the ligament is attached to the back of the cannon bone, then it connects to the sesamoid bones at the back of the fetlock joint. There it branches off between the splint bones. It looks similar to a Y, turned upside down. Most ligaments connect bones to other bones so they move the way they should. The term suspensory ligament applies to ligaments that connect other things in the body, often organs. When people talk about suspensory ligaments in horses, they are talking about a 10- 12-centimeter-long ligament below the knee that works with other ligaments to hold all the bones and other parts of the horse's feet where they should so they work as they should. Its main purpose is to prevent overextension of the fetlock joint, but it also regulates kinetic energy and plays a complex part in supporting the overall working of the limb.
Suspensory ligaments in horses are amazing things, just as the entire leg of the horse is. These powerful creatures achieve their speed and power by essentially walking on their fingers because their knees and hocks are similar to our wrists. Their long legs are made of a column of many bones supported by a complicated arrangement of several large tendons and ligaments.
A horse suspensory ligament is meant to stretch, that is how are stores kinetic energy and gives that energy to the muscles so the leg works as it should. But it works via a careful balance, intended to stretch just the right amount to provide exactly the right kind of stability.
Because of the perfect working of all the parts of the horse's legs, horses are able to achieve greater performance than we can understand. We have examined their legs and calculated the speed and efficiency with which all these parts should work in the individual horse, and each horse exceeds expectations by 10 to 20 percent. But when one of these parts doesn't work as they should, the horse can easily become lame.
Suspensory ligament injury in horses
It may not come as any shock after hearing about the complexity of the suspensory ligament horses have to imagine that many things can injure it and that the injury can be complex as well.
Injury to the proximal part of the suspensory ligament, proximal suspensory desmitis or PSD, impacts the forelimbs of a horse differently than it does the hind limbs. The symptoms, treatment, and prognosis are different. Injury to the branches requires different treatment to ensure the horse doesn't get compartment syndrome.
Suspensory ligament injury in horses occurs most often in sport and competitive horses, but any horse could potentially suffer it. In racehorses and jumping horses, the main body of the suspensory ligament is likely to be injured while other sports are more likely to damage the branches of the suspensory ligament.
Complicating matters even further, suspensory ligament injuries can occur after one traumatic event, usually because of hyperextension, or with repetitive strain, such as a horse might endure training for upper-level dressage. There may also just be degeneration as the horse ages.
While we don't fully understand suspensory ligaments in horses or injuries to them, it seems that a combination of trauma and predisposition accounts for many suspensory ligament injuries. Meaning that the horse's makeup was probably not enough to cause the problem itself, particularly not at that time and that they may also have made it through the trauma without injury had it not been for the predisposition. The part of both of these factors plays varies greatly depending on the horse and the trauma.
There are common factors that increase the likelihood of a horse suspensory ligament injury:
- the intensity of the sport the horse is engaged in, particularly jumping and racing
- repetitive movements, particularly ones involved in upper-level dressage and cutting
- the horse's shoeing
- the footing the horse is worked on, steep angles, medial to lateral imbalance, deep footing, or slippery footing, most notably.
- the age of the horse, young horses are likely to damage the ligament and older horses may just have weakened ligaments
- horses with straight hocks and a dropped fetlock are more likely than others to hyperextend and damage the ligament
There is much to learn about the equine suspensory ligament
We have learned a great deal about suspensory ligament horse anatomy and injuries. This has helped us improve diagnoses and offer better treatment, but we are still pursuing all the information we can about diagnosing the injury and rehabilitating the horse effectively.
Diagnosing suspensory ligament injury in horses
There are many reasons that it is difficult to diagnose horse suspensory ligament injury: Suspensory ligament injuries in horses are notoriously difficult to diagnose because the symptoms are the opposite of obvious and injuries to the ligament are so complex.
- there is little to no swelling visible
- the horse's symptoms may be sporadic
- these horses rarely limp as often both the fore or hind limbs are injured at the same time
- lameness is barely detectable in tests and doesn't even appear on radiographs
You can understand from these points how many horse owners delay seeking treatment for horses with suspensory ligament injuries and how, even when they do, the injury often gets misdiagnosed. Both of these situations are very unfortunate though because the horse needs treatment to heal effectively. Thankfully, there are ways to determine that a horse has injured one or more suspensory ligaments and we are becoming even more familiar with them all the time.
While horses with suspensory ligament injuries usually don't limp, there will be differences in the way they move. Their stride will be shortened, and they may appear weak.
Their symptoms will likely decrease or disappear with rest and return when the ligament is worked again.
They may be sore on their back or in the sacroiliac region. When the suspensory branch is damaged, this part of their leg may be sore and the vet may be able to feel damage during palpation.
There may also be a pain in other related areas like the foot. There may be PSD in one leg and pain in the opposite foot. This can further confuse vets when trying to diagnose the condition. As we learn more about suspensory ligament injury, this becomes more readily associated with the injury and will actually help with diagnosis.
Horses with suspensory ligament injuries show short term improvement when given joint injections and systemic medications. This has confused many vets because it appears that their problem is joint-related.
The vet will need to see you walk and trot the horse in a straight line and for the horse to walk, trot, and canter in circles. Having the horse walk on various footings will help as well. They may also need to see the horse walk, trot, and canter with a rider in case this makes the lameness more visible.
The vet may also deaden the pain with localized anesthesia in various parts of the suspensory ligament to see which one is causing the problem. If the pain goes away, does the horse's lameness disappear or lessen? This proves which part of the ligament is causing the horse pain.
Ultrasounds can show enlargement of the ligament and other signs of abnormalities. MRIs are also effective at detecting injury and the severity of the injury to the suspensory ligament.
Suspensory ligament horse rehabilitation
Three months is the optimum amount of time to allow the horse to rest for mild to moderate injuries. More severe injuries will require longer, maybe as much as a year. Nine months is another common time to rest the horse. Have the horse rest, rest, rest, and rest some more. Their pain will go away in a relatively short period of time and they'll feel ready to go back to working and performing, and you will be ready for that too. But don't give in. If you let the horse stress the ligament again too soon, they'll damage it and cause the problem to just get worse. So, you have to rest the horse beyond the point where they act better.
Make sure you are truly resting the horse also. Just free time without training is, sadly, not sufficient. They need to be kept in a box stall or a paddock. Give them a little exercise by hand walking them.
For the first 10 to 14 days, you will want to add ice or cold packs and compression to the site.
PSD in the hind limbs is harder to treat and isn't likely to respond to rest alone. Extracorporeal shock wave treatment may be necessary for these horses.
Sometimes, corticosteroids or autogenous orthokine serum are given locally to reduce inflammation. This is particularly important when the damage occurs in areas where the ligament is surrounded by bone as the swelling can lead to compartment syndrome, further damage, and delayed healing time.
Vets may also feel the need to inject the horse's bone marrow, stem cells, or platelet-rich plasma from another location in the body to promote proper healing and prevent the development of scar tissue that may permanently impact performance.
Surgeries are available for horses that don't heal from rest alone to prevent them from suffering from chronic lameness and reinjuries. One surgery, desmoplastic, and fasciotomy, encourages the ligament to heal itself by strategically cutting it. Fasciotomy and neurectomy involve cutting the ligament to reduce the pain without causing any other damage.
The vet will probably run tests to evaluate the success of the current treatment before recommending you exercise the horse again. When it is time for the horse to begin exercising again, you will want to increase their activity level in increments. Similar to human rehabilitation, 10% per week is the most common recommendation. You and the vet may determine that that number is not right for your horse and may end up planning a different strategy. This is normal. The science is still new here, so it's a learning game.
There are many kinds of equipment and tools for rehabilitating horses but the details about how to best use them for suspensory ligament injuries are still new. Your vet may want to try a treadmill, water treadmill, swimming pool, cold water bath, or automatic walker to rehabilitate your horse.
Some vets may try magnetic devices, acupuncture, light therapy, therapeutic ultrasound, and chiropractic adjustments to aid rehabilitation.
Many rechecks should be performed while rehabilitating to best determine the rate and types of rehabilitation.
Suspensory ligament recovery success rate
Minor and acute injuries have the best prognosis. The three-month rest period will probably have your horse as good as new.
More severe injuries, those from chronic overuse, or reinjuries may be troublesome. The horse may have to rest for up to a year and may require surgery. They may always be prone to reinjuries also. In the worst cases, the horse may be in such pain to have to be euthanized.
Injuries to the forelimb have a better success rate than ones in the hind limbs as well.
Preventing suspensory ligament injury in horses
This is one of those diseases where prevention is particularly helpful. Taking the time to heal, running the risk of reinjuries, and possibly losing your horse are definitely reasons to want to keep the injury from ever happening in the first place.
You can prevent suspensory ligament injuries in horses if you:
- ensure proper, balanced shoeing
- always use safe footing
- be sure to properly condition and warm up your horse for the work you are about to ask them to do
- avoiding over pushing and overproducing
- be particularly careful about acute and repetitive strain injuries in young horses and those that are uphill movers
- cross-train your horse
- build core muscle development
- minimize training on inferior surfaces and new surfaces
- don't over-train on hard, high-traction surfaces
- don't work tired horses
- be nearly obsessive about watching for signs of back pain
- regularly have your saddle fit evaluated
The second best after prevention is to have the horse seen by a vet at the first sign of a potential suspensory ligament injury so they can hopefully be treated while it is easier to treat.
How CBD Oil Might Help with Suspensory Ligament Injuries in Horses
CBD oil gains more popularity all the time for seeming to provide miraculous benefits for a dizzying array of health problems in humans, dogs, cats, horses, and more animals.
CBD oil may help with suspensory ligament injuries by:
- alleviating pain
- reducing inflammation
- easing stress
- eliminating nausea
- increasing appetite
- promoting sleep
This means CBD oil might address the pain and inflammation associated with the injury itself. It might also help a horse deal with stress from having to rest for so long or being in pain. Should the horse be on medications that cause detrimental side effects, like nausea, lack of appetite, or insomnia, CBD oil may counteract these so the horse can continue taking the medication.
CBD stands for cannabidiol. Yes, you saw that right. It comes from marijuana and hemp, but many CBD oil manufacturers extract it from naturally THC-free and legal hemp. Cannabidiol is one of the key factors in why medical marijuana helps with so many ailments, in fact, it may be better than THC for producing more consistent, longer-lasting, and trouble-free results.
Scientists have discovered that many animals have an endocannabinoid system that creates and uses its own cannabinoids to regulate the body's homeostasis. External cannabinoids like cannabidiol work much like the body's own cannabinoids, meaning they can help counteract deficiencies and provide a boost in times of need.
Using CBD oil
CBD oil manufacturers try to make a variety of products to suit the needs and tastes of each horse.
You can choose:
- oil tinctures
Oil tinctures and pellets are given orally to address ailments from the inside. Balms are applied topically to address localized or external issues.
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Sources:Suspensory Ligament Damage in Horses
Suspensory Desmitis in Horses
Suspensory Injuries in Horses
Conditions of the suspensory ligament causing lameness in horses