TPO and DPO Surgery for Canine Hip Dysplasia
Among several surgical treatments for puppies diagnosed with CHD are the Triple Pelvic Osteotomy (TPO) and the Double Pelvic Osteotomy (DPO). Both procedures involve bone cuts (osteotomies) made through specific areas of the pelvic bones. This alteration may improve hip joint conformation, stability and function by changing the orientation of the acetabulum (hip socket).
The goal with TPO and DPO is to improve hip joint conformation and function and to reduce instability, pain and future progression of hip degenerative osteoarthritis. Both procedures may be indicated in puppies from 6-12 months old that have mild to moderate hip joint laxity and have no evidence of pre-existing hip osteoarthritis. Dogs that do not meet the criteria for TPO or DPO surgery may benefit from a Total Hip Replacement (THR).
The Triple Pelvic Osteotomy (TPO) involves making three pelvic bone cuts through areas adjacent to the hip socket: the ilium, ischium, and pubis. Once the cuts have been made, the section containing the hip socket is rotated outward so the femoral head (the “ball” of the hip joint) is more readily covered. The new geometry and orientation of the acetabulum is then maintained and secured with a specialized TPO bone plate and screws until the ilium bone has healed.
The DPO procedure involves two bone cuts made at the ilium and the pelvic symphysis. The surgeon performs each osteotomy and rotates the portion of the pelvis where the socket is allowing it to more thoroughly cover the femoral head (the “ball” of the hip joint). The ilium bone cuts are carefully secured using a specialized bone plate and screws pending ilium bone healing.
Prognosis
TPO and DPO may provide a very good outcome for patients under a year old, with mild to moderate hip joint laxity and without hip osteoarthritis. Patients that are over a year old with severe laxity and degenerative joint changes are less likely to experience the intended benefits of either procedure; dogs in this category may benefit from Total Hip Replacement (THR).
Complications
The additional bone cut with TPO may result in more postop discomfort compared to DPO. Each procedure comes with a moderate risk of complications including but not limited to:
- hemorrhage during surgery
- loosening or breakage of bone screws
- limited hip range of motion
- sciatic nerve damage
- a narrowed pelvic canal
Recovery
Following surgery, most patients spend several days in the hospital to ensure that pain medications are effective and that they can walk with the assistance of a sling before going home. Postop activity restriction is crucial for the first six to eight weeks. Controlled, low-impact exercise is slowly introduced weeks after surgery. Additional postop radiographs are valuable in evaluating bone healing and implant integrity. A return to normal physical activity is only allowed after bone healing is complete.
