Oseoarthritis is characterised by the erosion of articular cartilage Joint disease is prevalent in horses because their joints must handle extreme weight loads on a very small surface area. In most cases, OA begins after trauma to the joint. This trauma could be an obvious accident (e.g. a chip fracture), but in performance horses it is often more insidious – wear and tear damage from everyday training.

When trauma causes inflammation in a joint, the blood supply to the cells that produce cartilage and joint fluid are disrupted, leading to less, poorer quality joint fluid and cartilage. Inflammatory cells and destructive enzymes are activated within the joint, which degrade proteins and GAGs in the cartilage and joint fluid.

Eventually lubrication, resilience, and shock absorption qualities of the cartilage and joint fluid decrease, and the underlying bone (subchondral bone) starts to respond to the abnormal stresses it is now absorbing by laying down extra bone. This results in the production of rough, bony spurs at joint edges.

It is important to understand that osteoartritis is progressive and cannot be cured, only managed. The treatment goal in early OA is to manage the disease- reduce pain and inflammation, reduce cartilage breakdown, and encourage cartilage and subchondral bone healing.