Hip Preservation Clinic

Periacetabular Osteotomy (PAO)

Correcting Acetabular Dysplasia via a PAO

The hip is a ball and socket joint consisting of the acetabulum (socket) and the
femoral head (ball). Acetabular dysplasia (abnormal formation of the socket) is an
under-development of the hip socket where the acetabulum, or cup, is shallow or/and aligned poorly with the femoral head. In cases of poor alignment the upper portion or roof of the acetabulum is obliquely inclined outward, rather than having the normal horizontal concave orientation. Because of these abnormalities the femoral head is incompletely covered and abnormally high stresses on the outer rim of the socket lead to premature degeneration of the articular cartilage and labral tears.

The Periacetabular Osteotomy (PAO) is a surgical procedure aiming to correct this
deficiency of the hip socket. If the dysplasia is significant and is left untreated then there is a strong likelihood for early onset of hip osteoarthritis.

A Periacetabular Osteotomy involves performing several bone cuts (osteotomies) around  the acetabulum and redirecting it in an optimal position so that the femoral head is adequately covered. The osteotomy is then stabilized with screws. Of note, the PAO can’t add volume to a shallow socket but rather concentrate on orienting the existing socket in a way which would correspond best with the femoral head for optimal stress distribution and joint biomechanics.

Hip Procedure PAO
Figure 1: The femoral head is incompletely covered by the acetabulum. Sourcil (roof of Acetabulum) obliquely inclined outward.

Figure 2: The femoral head is now sufficiently covered by the acetabulum. Sourcil (roof of Acetabulum) is horizontal.

Preparing for PAO Surgery

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Prior to surgery, the team recommends the following:

  • Maintaining a balanced diet (including calcium and Vit D)
  • Cessation of nicotine and marijuana use (if applicable)
  • Maintain cardiovascular fitness and strength as able prior to surgery
  • Identifying a trusted person to take you home from surgery and assist in the first couple of days when still under the influence of anesthesia or pain meds.
  • Ensuring access to a stationary bike for rehabilitation
  • Acquiring crutches
  • The hospital – BCH – will call to inform you of the time you should arrive at the hospital on the day of your surgery, and the time to begin fasting
  • Our scheduler will also verify this with you a week prior to the procedure

Post-Operative Instructions
& Rehab Protocols

At discharge you will receive a post op folder with instructions on how to care for your dressings and when you may bath or shower. We ask that you do not remove your dressings unless they are saturated or leaking. If you are unsure, please review our instructional videos and call if needed. The post op folder will also include your medication instructions, a Persons With Disabilities parking privileges application and your hip arthroscopy photos. There is a pain/medication tracking sheet you will be asked to fill out and bring to the first post op appointment. A hip preservation team contact list will also be provided; use this to reach out with urgent matters.

"Dr. Mei-Dan did PAO operations on both of my hips when I was in high school. Thanks to him and his team, I've been able to come back from my injuries to compete in college soccer. Thank you to Dr. Mei-Dan for bringing me this far!"
– Evan Toth (PAO)