Vancouver Animal Hospital: Modification of the Joint by Triple Pelvic Osteotomy or Juvenile Pubic Symphysiodesis.

In the young growing patient without significant osteoarthritis, the surgeon may recommend trying to improve the joint and stop the subluxation. Subluxation is when the ball (femoral head) begins to move out of the socket (acetabulum) as the animal walks or runs. Subluxation leads to destruction of the cartilage and malformation of the joint as the dog matures. In young dogs, the pain of hip dysplasia comes mainly from the subluxation. This abnormal movement of the joint causes tension on the soft tissues around the joint, resulting in great pain and dog limping. 

The surgical procedure involves twisting the socket (acetabulum) by cutting and rotating the bone. This results in decreased subluxation and therefore less pain. It may also dramatically decrease the progression of arthritis later in life. In very young dogs, this may be achieved with a technique called juvenile pubic symphysiodesis, but for the most benefit, the hip dysplasia must be diagnosed before the dog is 20 weeks of age. In older dogs, modification of the joint is accomplished ina surgical procedure called triple pelvic osteotomy (TPO). In this procedure, the pelvis is cut in three places to permit rotation of the acetabulum, to stop the femoral head from subluxating. The success of this procedure depends mainly on careful patient selection . The deciding factors include:

• Age
• Severity of subluxation
• Severity of osteoarthritis
• Function of the dog

Removal of the Joint by Femoral Head Ostectomy
In severe cases of hip dysplasia with luxation or severe arthritis, removal of the joint may be chosen. This procedure is called a femoral head (and neck) ostectomy (FHA). In this procedure, the ball of the ball and socket is removed so that the femur and the pelvic bone no longer make contact. The femur and the leg are supported by the strong muscles surrounding the hip joint, making the hind leg work like the foreleg does – the foreleg has no joint connecting it to the spine.

The success of the FHO procedure depends mostly on the size of the dog and the strength of the muscles around the hip. Smaller dogs tend to have better outcomes than larger dogs, but the outcome in larger dogs can be significantly improved by keeping body weight low and encouraging activities that strengthen the muscles around the hip.

The success of an FHO should not be judged for several months after surgery, because dogs tend to improve over time as the hips adjusts by forming scar tissue and strengthening the muscles The use of physical rehabilitation may dramatically improve the outcome of FHO in dogs.