Osteoarthritis in Horses

Once thought to affect only older animals, your horse can be affected by this disease at any age. The causes are many and varied, but in a young horse it is usually trauma related. Regardless of the cause, the result is a hot, swollen and very painful joint and the loss of function (lameness). Management or preventative methods are the only course of action, as osteoarthritis is incurable. A consultation with your equine veterinarian can provide a definitive diagnosis; supplementation, cold and heat therapy, and a new treatment called IRAP may provide relief for pain that your horse may be experiencing.

Osteoarthritis affects the joints of your horse and results in the slow progression of destruction to the cartilage lining the ends of the bones.

There are two main symptoms with this disease: 

• Pain, which will be noticeable when your horse displays signs of lameness 
• Swelling of the joints

These two symptoms do not always appear at the same time. Other signs of the disease are:

• Lameness may be minor to begin with, then worsen as the disease progresses 
• Upon the beginning of exercise, your horse may be stiff then warm up to it
• Your horse may be reluctant to perform certain activities (jumping) 
• Cold damp mornings may produce stiffness or lameness
• Reduced range of motion in the joint 

Types 

• Osteoarthritis (OA) is when the degeneration of bone and cartilage causes pain upon walking or trotting; it can affect one or many joints, and can vary in severity
• Ringbone is the name given to the type of OA that occurs in the pastern as it looks like a ring of bone in severe cases 
• Bone spavin relates to the hock which causes your horse difficulty in movement causing it to hobble along 
• As bone becomes inflamed it actually creates more bone, which in a joint, results in rigidity and movement becomes painful

• In general, it is hard to find a determining cause for this disease but deterioration of the joint is the cause of the inflammation and swelling
• Inflammation is a result of the destruction of the cartilage which protects the joint   
• Trauma such as soft tissue injury or wounds over the joint may be a cause
• Loss of synovial fluid in joints which keeps the joints protected
• Fractures of the bones around the joint

If your horse is exhibiting lameness, has swelling of the joints and is reluctant to move as he used to, contact your veterinarian for an appointment in order to determine what is causing the problem. Often, the veterinarian will observe your horse at trot to evaluate what joints are being affected. Putting a shot of local anaesthetic into the joint and seeing the improvement in your horse will allow the veterinary specialist to confirm that joint as the cause of the lameness. 

Using radiographs (X-rays) will show which joints are affected and how badly. The images may show the narrowing of the joint space that results from cartilage destruction, or show a bone spur formation, or changing density within the bone. Although radiographs can show some things, it cannot show the cartilage. The use of a tool called an arthroscopy, which is a minute camera that is inserted into the joint, can show the cartilage and the damage done to this area. This process is expensive and involves surgery with the risks of anesthetizing your horse.

Treatment cannot reverse this disease, but may help restrict further development of it. Any treatment will be aimed at reducing the pain to allow better movement of the joint. Rest alone may not be enough; your veterinarian may prescribe Phenylbutazone (bute) which is a pain killer that also helps alleviate the inflammation. Used in moderation, it can help during the initial stages of the disease, but it does produce side effects with long term use so is considered a short-term remedy. Other management solutions include oral supplements for your horse, corticosteroids which are strong anti-inflammatory agents, and hyaluronic acid which may help the lubrication of the joint and may stimulate normal joint fluid production. 

Cold therapy hosing of the joint may help after exercising, or heat therapy such as bandages may help before exercise to loosen the joint up. A new therapy known as IRAP involves taking a sample of your horse’s blood, and harvesting the protein rich serum before injecting it into the affected joints. This process uses the natural white blood cell in the blood to stimulate anti-inflammatory agents. The result so far indicates an anti-inflammatory response and stimulation of the regeneration of cartilage cells. Still in its early stages, it shows a promising treatment for the early to moderate cases of osteoarthritis.

This very complex disease can be managed with an appropriate veterinary regimen. A lot depends on the severity that your horse’s joints are affected, and treatment is aimed at reducing the further development of the disease and to reduce the pain. Treatment will not cure your horse, but it can lead to a relatively comfortable life. Each horse reacts differently to treatments, so it may take time to find what works best for your horse. If the disease is in its early stages, taking precautions such as heat therapy on the joints before exercise to loosen the joint will help, as will cold therapy applied after exercising (such as cold hosing of the joint). Magnetic boots are said to increase the circulation at the site encouraging free movement and healing. It may end a career in racing or jumping, but your horse will comfortably live out his days.