Hip dysplasia is a degenerative disease of the hip joint meaning that, without intervention, the disease will get progressively worse. Hip dysplasia is a relatively common cause of limping, lameness, hind leg pain and arthritis in many dogs, especially medium and large sized dogs from Bulldogs to Saint Bernards. However, smaller dogs can also develop hip dysplasia.

Understanding The Hip Joint
The hip joint is the connection point between each of your dog’s hind legs and the rest of his body. The hip joint is shaped like a ball and socket with the ball portion, technically called the femoral head, located at the highest point of your dog’s upper leg. The socket, called the acetabulum, is a hollow area located at the base of your dog’s pelvis. The socket should have a smooth surface coated with cartilage, a spongy connective tissue. The ball should be able to fit perfectly into the socket and be able to rotate seamlessly within the socket when your dog moves. Several other mechanisms also help to make the ball and socket function well. These mechanisms include ligaments which are bands of tissue that run from the ball to the socket to help support the joint and a ribbon of connective tissue called the joint capsule that surrounds the ball and socket and secretes joint fluid to keep the joint lubricated.

If your dog has hip dysplasia, his hip joints may appear normal at birth. However, during his growth period, usually somewhere between 4 to 12 months old, the joints begin to develop abnormally. Instead of fitting smoothly together, the ball and socket become loose or badly aligned. The ligaments and joint capsule surrounding the joint become stretched furthering worsening the connection between the ball and the socket. Over time, this bad connection creates abnormal wear and tear on the joint, leading to arthritis.