Understanding Equine Osteoarthritis

Osteoarthritis is one of the most common diseases which a horse owner may come across, in fact, most of us reading this blog will probably experience some form of Osteoarthritis during our lifetimes.

Osteoarthritis is a disease which primarily affects synovial joints, particularly those which are weight bearing such as the hock and the stifle. The process of osteoarthritis involves the break down or ‘wear and tear’ of the cartilage within the joint. As the cartilage is being worn down, small flakes of debris fall into the joint capsule. This debris is then removed by cells known as type A cells. These cells then trigger migration of lymphocytes and macrophages which are part of the immune response. This process causes inflammation of the joints, resulting in a pain response from the horse, usually in the form of lameness or an abnormal gait pattern. 

Eventually, the cartilage will become completely worn away, causing bone on bone contact, which can be extremely painful for the horse. This process also causes bony formations called Osteophytes to appear at the edges of the joints, these are most commonly found in the hock and the carpal joint. 

Diagnosis 

Diagnosis will often start with a lameness exam to assess the levels of pain a horse may be in, followed by a series of anaesthetic blocks to establish the location of pain.  

X-Ray may also be used in the later stages of Osteoarthritis, other common signs to look out for are heat, swelling and discomfort. Horses may also appear stiff at the beginning of exercise and gradually become more comfortable as they warm up.  

Treatment 

At the moment, there is no direct cure, however, a vet will often look to treat the symptom to make the horse feel more comfortable.