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Equine Tendon & Ligament Injury Management

Tendons and ligaments literally hold us together, as well as our pets and equine companions.  They hold joints together and allow us the flexibility to move in many directions, often taking the impact of many stressful events through their ‘stretching’ ability.  Tendons are off shoots of muscles, connecting the muscle to the bone.  Ligaments are fibrous connections between bones and often bridge joints, helping to provide stability to that region. These structures are important for many reasons, but damage can occur often due of over-straining, leading to months of recovery and in some cases prolonged debilitation…but there are solutions!

Whether if we are referring to humans, pets or horses, the anatomy is fairly similar with tendons being tendons and ligaments being ligaments.  Sometimes their placement or orientation is different between the species, as well as differences in size/thickness, but overall the function is the same.  Dependent on the species though, we do have more predilections to various injuries of specific tendons or ligaments.

Injury and Basic Anatomy

Some common injuries in humans include injury of the Achilles tendon, shoulder and elbow ligaments as well as the cruciate ligament within the knee.  In pets, we commonly deal with cruciate ligament injury, Achilles tendon (Gastrocnemius) and even shoulder and elbow problems.  In horses, most commonly we are contending with injuries of the flexor tendons which lie on the back of the cannon bone region of both the front and rear legs, but we also can see issues with the suspensory ligaments, cruciate ligaments, stifle ligaments and the shoulder ligaments as well. 

Injuries generally occur due to over-straining of the ligament or tendon structure, essentially pushing it beyond it’s mechanical limits.  When talking with my clients, I tend to view things rather simply and often refer to tendons as being like a piece of elastic, stretching and recoiling with strain and motion.  Viewing it this way, we can then understand that the tendons are composed of many fibers, oriented in a longitudinal or longway fashion, again like elastic.  This type of arrangement allows the individual fibers to stretch lengthwise and recoil back to their original form.  Ligaments are not too dissimilar but are generally less ‘elastic’ because their main job is to provide stability to a certain region of the body such as a joint.

Injuries occur when these structures are pushed beyond their physical limits. Maybe we or our animal companions stretched a tendon too far or maybe we moved in a certain way that we put excess strain on a joint region, stressing the ligaments.  Let’s discuss some common examples.

Cruciate Injury

We also commonly see cruciate ligament or knee injuries in humans and pets as a result of increased strain on one or both of the cruciate ligaments contained inside of the knee or stifle joint.  Cruciate ligaments come in pairs and are contained inside of the knee, connecting the distal femur to the top part of the tibia.  The ligaments criss-cross in fashion and essentially hold the two bones in position, preventing one from moving too far forward or two far back.  Injury commonly occurs when forward movement is suddenly stopped.  For example, in human athletes or pets, we can be running and suddenly lock our feet in position on the ground attempting to stop or change direction.  The act of locking our feet stops movement in the lower leg, but our upper leg continues to propel forward, with a high percentage of the strain imposed on the knee or stifle joint.  If the Tibia or shin bone is locked in position, but the femur or thigh bone continues to move, something has to take that strain and that would be the cruciate ligaments.  The cruciates (anterior/posterior or cranial/caudle) are designed to minimize excessive forward and backward motion in the knee joint.  If the stress is too high, they will become injured leading to either a slight tear or complete rupture. There is generally a high degree of pain associated with the initial injury, but as time goes by the pain subsides but lameness persists often due to mechanical instability at the site.

Collateral Ligament Injury

Collateral ligaments are generally found on the sides of joints and help to stabilize the area from side to side motion.  They can be found associated with almost every joint in the body, regardless of species. Two common spots for collateral ligament injury are the ankle in humans as well as the stifle in both humans and horses.  As a simple explanation, let’s look at 2 boards put together end on end, were the junction would be the joint. The collateral ligaments would be found on the outside of the joint, essentially bonding the two boards together and preventing side to side motion, keeping the area stable.  If we bend those boards to one side or the other, the ligaments will be strained to a degree. If we push it to far, the ligaments will strain and become injured ranging from mild tears to full avulsions.  The act of damaging a collateral ligament is often seen in people twisting an ankle, in which they inadvertently fold in fully on the inside or outside of the joint, resulting in severe ligament strain.  The same can be held true for literally any joint, but the stifle or knee joint seems to also be prominent.  When we have an injury to a ligament structure, this is often referred to as desmitis.


Tendonitis is inflammation of a tendon, regardless of location or species.  The inflammation is initiated after excessive strain on a particular tendon, associated with overloading of force or excessive repetitive use.  In people, we may see tendonitis in the elbow, shoulder or even wrist region.  In pets, it can often be seen in the shoulder or other locations.  In horses, we often see it in the flexor tendons on the backside of the cannon bone region, above the fetlock joint.  Horses are somewhat unique in that in this region, we really have two tendons and one ligament coursing the backside of the cannon bone.  Moving from the skin layer deeper, they are the superficial flexor tendon, then the deep flexor tendon and then the suspensory ligament or apparatus, which are all prone to injury. We also have extensor tendons on the front of the limbs, but they are less prone to injury.

Based on function and definition, tendons stretch to allow movement and to absorb forces.  Taking horses as an example, if the fetlock joint is overloaded due to extreme exercise or weight forces, the tendons can be pushed beyond their limits, which results in injury. Dependent on the area that has taken the impact, we can either impact the superficial, the deep, the suspensory or even a combination of structures.  Repetitive motion can create long term strain, but some equine disciplines are more likely to encounter tendon injuries due to excessive loading of those structures.  As an example, Hunter/Jumpers are obviously more predisposed to flexor tendon injury due to loading upon landing.  Racehorses are also predisposed due to excessive loading when at a full gallop.  Have you ever watched a slow motion video of a horse landing after a jump or a racehorse in full stride?  In many cases, the back of the fetlock actually touches the ground surface, which signals the amount of stretch needed in the tendons to accomplish that feat and makes more apparent the risk for damage.


Tendon and ligament injuries can be difficult to diagnose in all species, but in some species we have the luxury of more definitive types of testing such as MRI’s.  In many cases, acute tendon and ligament injuries can create severe lameness and pain, often mimicking a broken bone.  From my perspective as a veterinarian, one main criteria that I use initially to differentiate is to determine if the patient can bear weight on that particular limb?  If they can, then often we can rule out a fracture, but x-rays are generally taken to evaluate the bone in that region to make sure we are not missing the obvious.  X-rays or radiographs are also important in evaluating ligament injuries due to the fact that in some cases, the ligament can actually tear away from the bone leading to bone damage. 

As part of the cursory examination, a hands on palpation of the bones in that region help to rule out fracture, but during the palpation, we can put pressure on the ligaments or tendons trying to elicit a painful response.  In acute cases, swelling can exist which helps to localize us to a specific area, but again, we have to determine which structure is injured.  Often, after palpation and x-rays, we have a pretty good idea if a ligament or tendon is involved.  The next step in veterinary medicine is often the use of an ultrasound to evaluate the structures, looking for fluid accumulation and signs of specific damage.  Often with an ultrasound, we can grade the injury and further use this tool to follow healing and recovery.  If the ultrasound exam is inconclusive, then in some species we can resort to imaging techniques such as the MRI, which gives us detailed images of the soft tissue structures.   In horses, another helpful tool to localize the cause of the lameness is diagnostic nerve blocks which are performed often dependent on the area affected.  They are strictly a diagnostic tool and not therapeutic.

Treatment & Management

The course of treatment is really dependent on the severity of the injury.  In cases of minor injury or strain, we will often resort to cold therapy,often being through the use of cold water, to aid in controlling inflammation, administration of non-steroidal medications to help with pain and plenty of rest.  In horses, we often also include topical therapies such as DMSO, which is often mixed with various anti-inflammatories and used as a sweat, helping to remove accumulated fluid and reduce inflammation.  In more severe injuries, therapies can be as invasive as localized injections of corticosteroids, hyaluronic acid, IRAP therapy or even stem cell implantation, especially in more long term injuries or those failing to respond.  Surgery may actually be a course of action if the condition warrants it, which is often seen in complete avulsions of ligaments or cruciate injuries. 

No matter the course of therapy, there are several things we must keep in mind to be true to ourselves regarding long term prognosis.  First, these structures, especially ligaments, were intended to provide stability to joints and absorb forces.  If the structures are damaged, then they are likely no longer able to do their jobs, which means that undue stress is being transferred to the joint or other areas of the body.  Let’s look at a cruciate ligament as an example.  If the cruciates are injured, then there is a likewise instability within the knee or stifle joint.  When there is an instabiliity, there is increased forces on the joint, which contribute to inflammation and joint degeneration.  No matter the course of action, there are generally long term negative implications for that joint which often means an increased risk of degenerative joint disease or arthritis.  Second, ligaments and tendons contain fibers oriented in a specific manner to allow for stretch. When an injury occurs, often the healed fibers are oriented in a opposite or a more perpendicular manner, which lowers the ability of that region to stretch properly.  Even when healed, an injured tendon is less likely to handle the normal forces and is actually more predisposed to reinjury in that particular area for this reason. So, essentially the truth is that if we, our pets or our horses succumb to an injured tendon or ligament, the injured area will always be at a higher risk of future damage.  The longer the injury has been present, the more difficult it is to manage and the poorer the prognosis. How the healing process is managed will dictate the end result and low term prognosis.

Given these points, we must understand that many modern forms of therapy, including stem cell replacement, IRAP therapy and even PRP often fail in the long term, in my experience.  I do believe that one of the main reasons for this is due to failure to provide for that tissue what is needed in order for it to heal.  We can infuse a region with stem cells or other therapies, but if the environment isn’t right, or there is ongoing inflammation, the treatment will not produce results.  I also believe that in several cases, there are many connecting factors that have led to the predisposition to injury, but are not addressed during the therapuetic process. One of the biggest factors in my experience is conformation and foot/hoof angulation, with many of these horses having low heels or negative palmar angles, which increase tendon strain and predisposition to injury.

The best option is protection and prevention.

So, how can we best manage these conditions?  First, we must catch them early in ideal cases.  The earlier we can intervene the better the prognosis.  Once the structure is damaged, inflammation sets in, which is a good thing on one hand and a bad thing on the other.  In the early phases, we need inflammation to help us protect the structure by signaling pain.  Inflammation is also needed to help recruit cells to the area for healing purposes and to remove dead tissue.  We also generally see an increased blood circulation, which creates the swelling and provides nutrients to the region.  We need the inflammatory response early, but need to control it for the long term as this process also can contribute to ongoing damage.

We must view the process of damage for what it is.  In most instances, the injury occurs due to overloading or excessive twisting.  If we can use a brace or support wrap to protect susceptible areas, then great, do it. We must also take into consideration that these are living structures, viable tissue and without proper nutrition, they can be weakened and more likely to injure.  This can never be more evident than the increased incidence of cruciate tears in young high school athletes, which I feel is a direct result of the poor diets they are consuming.  The other factor that we must keep in mind is the connection between ongoing chronic inflammation within our bodies, as well as that in our animal companions, that is contributing to increased weakening of these structures.  It is a degenerative process, but often explains why one person or animal is more likely to be injured versus another.

When viewing things from a basic standpoint, we can then intervene from a prevention standpoint as well as impact recovery from a management perspective.  I believe in nutrition and the impact on health, mainly by supplying protein, vitamins/minerals in their natural forms.  I also believe firmly in controlling the inflammatory response effectively, beyond traditional medications, and the most effective method of doing this is through the use of Curcumin combined with Boswellia, with targeted antioxidants.

In my equine patients, we will often use a combination of our Cur-OST EQ Plus anti-inflammatory formula with our EQ Immune & Repair in the initial stages of recovery.  If the patient is an easy keeper type, we will use the Cur-OST EQ Total Support in combination with the EQ Immune & Repair. The reason is that in many easy keeper types, we make the association with underlying GI dysfunction, leaky gut, which can further contribute to the inflammation and also compromised nutrient absorption/assimilation, which then can weaken the tendon/ligament structure. The anti-inflammatory formula helps to modulate the inflammatory response, taking the pressure off of the tissue and aiding recovery.  The Immune formula, I feel, helps to boost clearance of fluid and dead tissue from the region, plus provides amino acids needed to restore cellular health and repair.  For the long term, I will generally keep those patients on one of our anti-inflammatory blends plus implement our EQ Nourish formula, which continues to provide needed protein, amino acids and co-factors to strengthen the tissue and enhance cellular function. We often achieve an accelerated rate of recovery in our patients, getting them back in training in a much shorter period.

It is important to note, that at least in the horse, I feel there should be tremendous importance placed on the hoof or foot. It is true that any horse can acutely damage a tendon or ligament due to overstrain, but far too many horses experience ongoing tendon/ligament injuries with overall failure to recovery fully.  I have found that many of these horses with chronic, non-healing tendon/ligament injuries have predisposing factors which include hoof imbalance and nutritional influences.  This is important to consider.  First, a tendon or ligament is a living tissue, needing proper nutrition and cofactors to ensure and maintain strenght, integrity and ability to repair.  Many horses are on decreased plains of nutrition relative to their level of work.  A high percentage of these horses also has underlying GI problems, which may predispose to poor nutrient absorption and even inflammation. Second is hoof balance and condition.  In many of these horses, with recurrent suspensory or tendon injuries, I have noted that there is often a medial/lateral hoof imbalance or under-run heels.  These conditions, if present, place excess strain on the structure, which then can not only precipitate future injuries but also delay healing.

In companion pets, I will generally use our Cur-OST SA formula which provides anti-inflammatory support, but also provides protein in the form of spirulina blue green algae which aids in tendon repair and overall health.  In more acute cases, I will also implement our SA Immune formula for clearing of dead tissue and fluid for the short term.

In humans, we generally use and recommend our Ultimate HU formula which provides anti-inflammatory support, protein and nutrients to aid in repair and recovery.  Again, in more acute injuries, the HU Immune formula may provide additional benefits by aiding in the clearance of dead tissue and amino acids for healing of the structures.

In the end, tendon and ligament injuries are common place, especially as we get older or assume more strenuous activities. These injuries are one of the most common that we encounter in our rehabilitation program. It is not uncommon to have a horse present with an injury present for months if not years, but regain function and be under saddle in a month or two with the right approach. We can do more to support our bodies to prevent these injuries and more to help manage recovery when damage does occur.  Often, by providing nutrients to the tissue and controlling the inflammatory response, recovery can be more expedient and strength restored, helping to get us back into the game more quickly.  Prevention is the key to health, but the same philosophies can be used in management for optimal results.

All our best,

Tom Schell, D.V.M.

Nouvelle Research, Inc.

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