OCD is a disease of the cartilage and affects various joints most commonly the shoulder, elbow and hock. Normally the cartilage provides a smooth layer which cushions and protects the underlying bone but with OCD the cartilage is damaged or abnormally grows. It will start to separate from the bone and crack and in some cases a loose flap or an entire piece will break off and float free which is known as joint mice. Once this happens the fluid builds up around the joint and calcification occurs causing the joint to become inflamed and swollen, nerves around the joint become irritated and the dog will be in pain.

 

OCD tends to affect larger dogs and happens during  the process of endochondral ossification so is therefore normally diagnosed between five and ten months of age. It is also common in quick growing breeds as the rapid cartilage growth can outstrip its blood supply. This causes abnormal development of cartilage which then leads to pain, lameness and often Osteoarthritis. Having said that it can be seen in various breeds and it can develop in older dogs as well.  This condition is hereditary but too much stress on the bones of a young dog, diet, obesity and restricted blood flow to the cartilage or bone, trauma, hormone imbalances can also be factors.