Triple Pelvic Osteotomy (TPO)

A CORRECTIVE PROCEDURE FOR YOUNG DOGS TO MAINTAIN JOINT CONGRUENCY

The Triple Pelvic Osteotomy (TPO) is a surgery that preserves the natural hip joint, eliminates the subluxation (laxity) and prevents the progression of arthritis. This procedure involves cutting the pelvis in three places (Triple Osteotomy) and rotating the acetabular segment (socket) to provide better coverage of the femoral head (ball portion of the hip joint). The resulting joint is stable and pain free.

In young dogs, the primary abnormality in canine hip dysplasia is joint laxity (Fig. 1&2). This may lead to inflammation within the joint, resulting in pain and lameness. Specifically, the laxity in young dogs initiates a vicious cycle wherein movement and weight-bearing force the femoral head (ball portion of the hip joint) into an abnormal position. This causes interference with ossification (the formation of bone or bony substance) of the acetabular (hip socket) rim, erosion and fibrillation of the joint cartilage, stretching of the round ligament, inflammatory changes in the synovial membrane (joint lining), thickening of the joint capsule (joint casement), and formation of osteophytes (bone spurs). The end result is an abnormally shallow acetabulum, a flattened femoral head and progressive arthritis.

The acute and prolonged pain and crippled movement in young dogs are the result of the sudden occurrence of microfractures (small cracks or fissures) on the acetabular rim. These fractures are not visible radiographically, because they are hidden behind the femoral head. They occur as a result of prolonged fatigue and bending of the immature bone of the acetabular rim while weight-bearing and in motion. The changes seen in young dog’s gait may include reluctance to jump, a "bunny hop" gait when running, and limping. Some dogs may cry out in pain with movement of the hip

In young patients, with minimal evidence of arthritis, a stabilizing reconstructing of the hip joint is recommended. This involves reconstructing the joint into a more normal position, allowing joint congruency and stopping the subluxation and laxity that leads to severe arthritis (Fig. 1&2). This technique centers around the Triple Pelvic Osteotomy. It has been established as a reliable, predictable mode of treatment in those cases which meet the case selection criteria.

The Triple pelvic Osteotomy is a surgical procedure which rotates the shallow acetabulum to provide improved coverage of the femoral head. By seating the hip more deeply into the socket, the primary problem of joint subluxation and the painful changes it produces are controlled.

Three to four osteotomies (bone cuts) are performed from three small incisions (Fig. 3&4). The socket (acetabulum) is rotated to the predetermined position which allows seating of the femoral head into the acetabulum. With the femoral head (ball) now captured in the socket, a special stainless steel plate is applied to the hip joint in its now normal configuration.

This procedure is performed on young dogs, ranging in age from approximately 4 to 15 months old, before the joint subluxation has become too severe or has led to arthritic changes. This is documented on radiographic examination as well as palpation prior to surgery. The specific angle of acetabular rotation is established in each patient by using both radiographs and a physical examination called the Ortolani test. This usually requires a mild sedative to allow for an adequate evaluation of the degree of the laxity of the hip.

The object of the Triple Pelvic Osteotomy is to allow joint congruency between the ball and socket so that appropriate joint development will proceed without further damage. It is important to note that while age is important, it is not as critical for success as the condition of joint surfaces. Thus, individuals with arthritic hips are not candidates for the Triple Pelvic Osteotomy.

Back to Pet Information