Hip Dysplasia Surgical Option 3. Triple Pelvic Osteotomy (TPO)

Question 1

What does TPO involve?

Answer 1

This involves cutting the pelvis in three places and rotating the free bone so that the acetabulum rotates over the femoral head, the bones are then stabilised with custom plates and screws.

Question 2

Patient Prep TPO

Answer 2

The patient is clipped from the dorsal midline to the tarsus including the circumference of the limb.

Question 3

Patient Positioning TPO

Answer 3

The patient is placed in lateral recumbency with the affected limb uppermost.

Question 4

Instrumentation / Materials for TPO

Answer 4

Oscillating saw
osteotome
mallet used to make the three bone cuts.
Bone plates and screws are required for bone fixation.
A Hohmann retractor and Rongeurs may also be needed and a general kit.

Question 5

Surgical Procedure TPO

Answer 5

The pelvis is cut in three places: The shaft of the ilium, the pubis, and the ischium. The free segment is then rotated to a point that allows the acetabulum to sit nicely over the femoral head. Custom implants are then used to stabilise the cut bones. Patient size is important for this procedure due to the relatively fixed size of the implants. Dogs over 20kg is preferred. The procedure has good results in clinically immature patients (8 months-1 year) as the cartilage, acetabulum, and femoral head rim won’t be excessively worn. This procedure alters the alignment of the acetabulum in relation to the femoral head so the femoral head is forced more deeply into the acetabulum as the patient walks. The acetabulum deepens due to the increased weight bearing pressure from the femoral head

Question 6

Post op care of TPO

Answer 6

Strict rest for 6-8 weeks following the procedure is necessary. Repeat radiographs are required at 6 weeks to access healing of the surgical site.