Arthritis is simply a term that means joint inflammation. Specifically, equine osteoarthritis is the most common reason for lameness in horses and if it is severe enough, it can end a young horse’s career. Because of the long-lasting impact on both horse and owner that arthritis can have, I thought it would be beneficial to create a comprehensive repository of equine arthritis information that can be accessed whenever needed. I hope you enjoy and that you find it helpful.
Causes and Symptoms/Signs
Internally, equine osteoarthritis is caused by the repetitive breakdown and destruction of the articular cartilage in the horse’s joint that lines the bone ends inside. Articular cartilage’s role is to allow the muscles and bones to move without rubbing, and to provide cushioning for the bones upon impact. The cartilage is supposed to be regenerated occasionally, but in an arthritic horse, the regenerative cycle starts to slow and cause destruction of the surrounding joints and bones over time. The arthritis can arise from normal forces from impact on damaged cartilage, abnormal forces from impact on normal cartilage or a mix of both.
Osteoarthritis can form in healthy horse’s joints with no previous cause, because of a bone chip or other condition, or inappropriate shoeing for the horse’s hooves. Wear on joints and tissues due to force from everyday work may also trigger the development of arthritis, and the joints most likely to suffer are those that carry the most weight, including the knee, hock, fetlock, pastern, and coffin joints of the lower leg
Symptoms/signs of osteoarthritis are joint inflammation, visible bulging of joint capsules, lameness, difficulty getting up after laying down, changes in behavior and demeanor due to discomfort, lameness, stiffness of gait, unwillingness to do usual work or lack of activity when out at pasture. Age and activity level of the horse play a crucial role in how quickly the development of arthritis occurs.
Diagnosis and Treatment
To diagnose osteoarthritis, vets will feel the horse’s legs for swelling and test them for loss of range of motion. They will also perform a lameness exam to check for lameness or stiffness in the gaits. Because it is hard to diagnose arthritis using the naked eye alone, x-rays and other forms of imaging are utilized as well. X-rays help to narrow down the infirmity by confirming or denying if a bone has been fractured, MRIs can see if anything is off with the tissues inside the joint, as can ultrasound.
Key signs to look for in an x-ray image that indicate possible arthritis are: bony growths at the joint end called osteophytes and thesophytes, sclerosis (thicker bone density), lysis or the rundown of the subchondral bone just under the articular cartilage, or thinning of the joint space. There can be a disconnect between what x-rays depict and what is noted in a lameness exam, so the x-ray may not show lameness but it is evident to the owner and vet that the horse is indeed lame
Other diagnostic tools or techniques used include nerve blocks to try and pinpoint where lameness or arthritic pain is located . The vet will anesthetize the lower limb to block the nerves from sending messages to the brain. If the lameness is eliminated once the anesthesia is administered to a specific location, the vet can conclude that this is the part of the horse’s leg that has gone lame.
There is also the option of using serum biomarkers to catch early onset of changes in the bone and cartilage. Biomarkers are substances in the body that can be used to track metabolic processes as they happen, so biomarkers inside the horse’s blood serum can be used to see joint changes. When the articular cartilage starts breaking down, so does collagen, and when collagen decomposes, proteoglycans can be found in the blood which can indicate a disease is present in the joints.
Treatment of osteoarthritis depends on the severity. Some horses can recover with a long period of rest in their stall, with hand walking and hand grazing to prevent the stiffness from worsening. In more severe cases, a mix of medications is used to slow the progression through lowering inflammation and provide pain relief. Most often, non-steroidal anti-inflammatory drugs and or shockwave therapy are combined with either corticosteroids, hyaluronic acid, or polysulfated glucosamines injected into the affected joint
Regenerative therapies have become a relatively new treatment option for osteoarthritis, where substances from within the patient’s body are used to help them heal. Autologous conditioned serum treatment is when blood has been processed and filled with a high concentration of interleukin receptor antagonist protein (IRAP) which helps fight inflammation naturally. Platelet rich plasma treatment is when blood plasma is modified to have more platelets than normal. The increased platelets help to heal the tissues and promote growth of new tissue in affected regions when injected. Mesenchymal stem cells can lead regeneration and repair of damaged tissues upon injection by recruiting stem cells to the afflicted area to heal it.
Prognosis and Prevention
The prognosis for a horse with osteoarthritis also depends on the severity just as the treatment. If it is treated early, horses can make a complete recovery and return to their normal routine, but if they do not respond to treatment, it could become a chronic condition. Arthritis can sometimes be managed with join supplements and in such case may not bring on lameness and pain. Prognosis is also based on disease progression, age of the horse, the number of arthritic joints and so on.
The risk of a horse developing arthritis can be lessened or prevented by monitoring horse activity levels and limiting trauma to the joints, addressing joint issues as they appear, and getting their hooves trimmed regularly. Administering joint support supplements to young horses has been an effective measure as well. Owners can also be an asset to their horses by learning joint anatomy and how to check their horse’s legs for pain, swelling, heat and loss of function
Popular Joint Supplements
SmartPak Equine– SmartPak has a variety of joint support supplements so every horse can get the support they need to stay healthy. All SmartPak brand supplements contain glucosamine, chondratin sulfate, and MSM for healthy and strong joints. MSM is a sulfur compound that helps relieve stiffness and discomfort. They also sell MSM separately in pellets or powder.
Lubrisyn– a brand of hyaluronic acid used as a joint supplement, they also have a version that contains MSM as well. Hyaluronic acid is naturally present in the soft tissues and its administration helps to lessen pain and improve joint mobility by promoting frictionless movement
Cosequin– Cosequin has 4 different formulas based on a horse’s activity level. The higher the activity level, the more ingredients in the supplement because the horse’s joints experience greater wear and tear. All formulas contain glucosamine and chondroitin sulfate to protect cartilage and prevent activation of cartilage degrading enzymes.
I hope this article gave you a better understanding of equine arthritis and how to treat it. Learning about equine medical conditions and their treatment and prevention is essential to being a proper and well educated horseperson.
Our horses give so much to us, and it is only right if we give back to them.