What is it ?
Osteoarthritis sets in when the damage is too great and cannot be repaired. This occurs particularly when the joints are subject to significant strain (e.g. during sport), and as the body ages.
The cartilage lifespan relies primarily on chondrocyte activity, and involves a series of destruction phases when the joint is working, followed by reconstruction phases. As long as chondrocyte activity is balanced and the damaged cartilage has time to rebuild, it remains healthy and functional. Osteoarthritis sets in when the damage is too great and cannot be repaired. This occurs particularly when the joints are subject to significant strain (e.g. during sport), and as the body ages.
b. Systemic effects
In the early stages of the disease, the cartilage becomes disorganised. Fissures appear at the surface and gradually turn into deep cracks. As it cracks, small pieces of cartilage come away and are released into the joint synovial fluid. They form foreign bodies, like grains of sand, which cause extensive irritation on the surface of the joint. Gradual widening of the cracks causes the cartilage to thin and, in some areas, it disappears completely. The bone is then exposed to friction, and this is what causes pain. Reconstruction processes around the joint edges often spiral out of control, and the edges begin to "bud" and osteophytes ("parrot beaks") to form.
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Horses with osteoarthritis experience constant pain upon moving the affected joint. This tends to be worse at the start of exercise when the joint has not had time to warm up, and may improve after warming up or during exercise. It is more or less severe depending on the horse, and often comes on in episodes that vary in duration and are unpredictable.
The joints may become deformed to a greater or lesser extent, either by osteophytes (which can sometimes be felt as hard masses under the skin at the edge of the joint upon palpation), or by areas of inflammatory effusion such as "windgalls" or synovitis at the more mobile joints (fetlocks, knees, top, hock).
After a quick general examination, the vet will take a close look at the horse's limbs and spine. He or she will feel all of the joints to see if they are painful or deformed, before moving them to see how well they are working.
After a quick general examination, the vet will take a close look at the horse's limbs and spine. He or she will feel all of the joints to see if they are painful or deformed, before moving them to see how well they are working. The vet will then watch the horse move at three different speeds, going in a straight line and around in a circle, and observe at which point the horse experiences discomfort and/or starts taking lame steps. Once the painful joint has been identified by observation and confirmed by local anaesthesia, where applicable, X-rays and possibly an ultrasound will be carried out.
b. Possible further tests
Your vet may recommend additional tests to refine or confirm the diagnosis. These tests are especially useful for assessing the progression of the disease and the horse's prospects (racing and sport horses):
Ultrasound : used to assess the condition of the cartilage (particularly thickness) in certain limited areas of the joint (periphery)
Arthroscopy : surgery under general anaesthesia, used to explore the inside of the joint in detail using a camera
Scanner, MRI scan or bone scan : high-performance and very costly, these examinations are used in complex cases
To relieve pain and treat inflammation, the vet will use systemic anti-inflammatory drugs (intravenous injection or oral route). The vet will also recommend using products to protect the cartilage.
a. Main treatment guidelines
To relieve pain and treat inflammation, the vet will use systemic anti-inflammatory drugs (intravenous injection or oral route). The vet will also recommend using products to protect the cartilage. Generally, depending on the context, he or she may recommend treatment with a series of injections, to be administered once per week or once per day, depending on the medicinal product.
b. Nutritional solutions
Your vet may also recommend a daily supplement containing GAGs (a natural component of cartilage) and hydrolysed collagen.
EKYFLEX ARTHRO (by Audevard Laboratoires) is a supplement enriched with GAGs, collagen, turmeric and other ingredients that contribute to joint structure. This product has been specially designed to support joints. Ask your vet for advice.
c. General health and safety measures
The farrier plays an essential role in supporting horses with osteoarthritis. The shoe should take into account the straightness of the horse's legs, the terrain on which the horse usually lives and works, and the type of exercise it undertakes.
To minimise joint damage, the horse should preferably be taken out on soft, good quality terrain. The horse should warm up before exercise and its weight must be monitored (like in humans, excess weight puts strain on joints)