Hip Dysplasia: Diagnosis

One of the most common causes of lameness and degenerative arthritis we see in dogs is a genetic disorder known as Canine Hip Dysplasia (CHD). The disorder most commonly affects the larger breeds of dogs, but has been diagnosed in all breeds. The frequency of CHD runs between 15-50% in different breeds.

The hip joint is what's known as a "ball and socket" joint. The "ball" is the head of the femur (thigh bone) and is normally seated firmly within the "socket" (acetabulum) of the pelvis. This allows for the smooth rotation of the hip through a wide range of motions. The top left x-ray shows a patient with normal hip joints.

CHD causes an abnormal development and formation of the hip joint which compromises the mobility and stability of the hip. Frequently the socket is abnormally shallow and the ball is misshapened. The end result is progressive degenerative joint disease and osteoarthritis as the dog ages. Mildly affected dogs may show little problems until later in life. More severely affected dogs may be severely crippled at a very early age. The top right x-ray shows a dog with a severely deformed left hip joint.

The disorder can be positively diagnosed as early as 6 months of age. The diagnosis is made by radiographic (x-ray) and manipulative examination of the hips. These examinations require that the patient be sedated for proper positioning and joint relaxation. All larger breed dogs (adult weight greater that 50 pounds) should have these examinations performed between 6-8 months of age.

There are several medical and surgical options available to help pets afflicted with CHD. If diagnosed at an early age before degenerative changes occur, a repositioning surgery known as Triple Pelvic Osteotomy (TPO) can be performed to allow for deep firm seating of the ball within the socket. Once degenerative changes have occurred, the best surgical option is a Total Hip Replacement (THR). The x-ray on the bottom shows a dog that had a TPO procedure done on the left hip and a THR on the right hip (the "R" marker denotes the right side). Both of these procedures require the expertise of a "board certified" veterinary surgeon.

A less desirable, but much less expensive, procedure known as a Femoral Head Ostectomy (FHO) can be performed to remove the deformed ball and reduce the pet's discomfort. This procedure works marvelously well in the smaller dogs but has variable results in the larger dogs. The x-ray on the top right shows the appearance of the right hip following this procedure.

Pets unable to have surgery can frequently be kept comfortable by the administration of dietary supplements to support better joint function and anti-inflammatory pain relieving medications. Weight management is also critical to help prevent unnecessary stress to the hip joints.

Since this is a genetically determined disorder, all affected pets should be surgically neutered. Those pets intended for breeding should have their hips thoroughly examined for any signs of CHD and certified for breeding if normal. Never buy a large breed pet without documented proof that both parents were certified free of CHD by the Orthopedic Foundation for Animals (OFA).