Triple Pelvic Osteotomy

Triple pelvic osteotomy (TPO) is a surgery that preserves the natural hip joint, eliminates 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 and result in pain and lameness. The laxity in young dogs initiates a vicious cycle wherein movement and weightbearing force the femoral head (ball portion of the hip joint) into an abnormal position. This causes interference with ossification (bone formation) of the acetabular rim (hip socket), 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, and formation of osteophytes (bone spurs). The result is an abnormally shallow acetabulum, a flattened femoral head, and progressive arthritis.

The acute and prolonged pain and crippled movement in young dogs is 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 weightbearing 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 is called triple pelvic osteotomy. It has been established as a reliable mode of treatment in cases which meet the case selection criteria.

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 a predetermined position which allows seating of the femoral head. With the femoral head (ball) now captured in the socket, a special stainless steel plate is applied to the hip joint to maintain the new configuration.

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

The object of triple pelvic osteotomy is to allow joint congruency between the ball (femoral head) and socket (acetabulum) so that appropriate joint development will proceed without further damage. While age of the animal is important, it is not as critical for success as the condition of the joint surfaces. Thus, individuals with arthritic hips are not candidates for the triple pelvic osteotomy