Joint disease is a broad term which covers a number of individual conditions. They are all characterised by damage, inflammation and degradation of the joint, its capsule or the synovial fluid. Some of these are related to joint trauma, following an accident or fall, whilst some are related to development.
Osteochodritis Dissecans is a developmental joint disorder and affects as many as 1 in 4 horses, though it varies in severity. It can occur in all breeds, however, we tend to associate it with rapid growth or hard work at a young age, so racing horses or large breeds are commonly noted to have the disorder. Essentially OCD is a problem with the cartilage, which isn’t laid down as it is in a healthy joint. This leads to an uneven joint surface and the bone can actually become weaker because of this, which sometimes results in small fragments of bone chipping away and moving around the joint capsule, also known as ‘joint mice’. In turn this contributes to inflammation which can develop into arthritis over the long term.
The first sign is often joint swelling in young stock, which may actually become lameness once ridden work is started. Treatment commonly involves removal of the OCD lesions through surgery, which is obviously invasive, though with rest the damage can resolve in youngsters.
Degenerative Joint Disease is also known as Equine Osteoarthritis, and as the name suggests tends to develop over time and results in the degradation of cartilage, causing bone to rub together. This affects the fluidity of movement as well as causing pain, much as osteoarthritis does in humans. Unfortunately inflammatory cells will cause breakdown of cartilage, by release of catabolic enzymes into the joint capsule, and this further exacerbates the issue. As much as 60% of equine lameness has been attributed to DJD, so it a significant factor in reduced performance and health.
