Severe cases of CHD can be diagnosed as early as 7 weeks of age. But puppies with tight hips can also develop CHD too. There is a fibrous structure filled with synovial fluid that surrounds and protects the joint. The cushioning effect of the fluid, the fluid pressure and the elastic nature of the structure help stabilize the joint as well as keeping out contaminants. Synovial fluid contains the nutrients that are diffused from the blood supply and keep joint tissues alive.
Hyaluronic acid provides lubrication and helps prevents erosion of the cartilage.
Dogs with CHD undergo structural changes in the joint, lose hyaluronic acid, and nourishment to the joint. Then the acetabular rim and the femoral head begin to erode. Tiny micro-stress fractures appear in the bone. The body tries to heal these fissures which makes the acetabulum fill in and become shallower. Perfectly smooth cartilage is gone, lesions develop at the site of abnormal pressure and physical signs appear.