Is Hip PAO Surgery a Bad Idea?

By /

I have my list of surgeries that when I first learned of them, my reaction was, “They did what to you!?” Hip PAO surgery has been on that list for years. Why? Its goal is to replace the need for a hip replacement, but it’s far more invasive than the surgery it seeks to prevent. Let me explain by way of following up on Hip PAO patient I blogged about years ago.

What Is Hip PAO Surgery?

To understand hip PAO surgery, you need to understand the structure of the hip joint. This joint is made up of a ball, which is the head of the long bone in the upper leg called the femur, and a shallow socket in the pelvic bone called the acetabulum. Periacetabular osteostomy (PAO) is a surgery in which the acetabulum is repositioned by cutting the bone around it and rotating the socket downward to try to get better coverage for the ball of the joint. The surgery is typically done in younger patients who have a small hip socket, and the idea is that it is supposed to prevent the need for an early hip replacement.

However, hip PAO surgery is incredibly invasive all on its own and can have serious complications as well.

Learn about Regenexx procedures for hip conditions.

A 33-Year-Old Professional Athlete Follows PAO Surgery with Hip Replacement!

In 2012, I was asked to see a 33-year-old professional athlete who had received hip PAO surgery. He had been having a difficult time with his recovery and was in a lot of pain. Why? His pelvic bone was not healing following the surgery, leaving him with no physical connection between his leg and the rest of his body. Think about that for a minute, as I’ll repeat that point, this patient had no real structural connection between his leg and his pelvis!

In my video above, you will see a moving X-ray of this patient’s pelvis and the fractured bone created during his PAO surgery to reposition the acetabulum (hip socket). In the video, I’ve indicated the fracture line and the area of the pelvis that should not move; however, as you will see, the area does experience subtle movement (slight giving and collapsing). This pelvic bone, especially so many years after surgery (six years) should not be moving at all. This sloppy structural bone connection is likely the source of his pain.

Despite the fact that hip PAO surgery is pushed as a better alternative to surgery, this patient still ended up having bilateral hip replacements, and with a pelvis that is now only partially connected, thanks to his Hip PAO surgery complications, he is still in significant pain.

Hip PAO Surgery Complications: High Percentage of Hips Still Replaced Despite PAO Surgery

You might think this patient’s case of needing hip replacements anyway must be a rare and isolated outcome; however, it is actually the norm rather than the exception as a study published in Clinical Orthopaedics and Related Research last year found.

The study investigated the outcomes of 75 hips that had undergone PAO surgery and found that only 29% were spared conversion to hip replacement surgery or advancement to arthritis within the 30-year follow-up period. In other words, a staggering greater than 70+% of hips receiving PAO surgery still needed to be replaced or had arthritis that got worse.

The Opposite Results

While the above paper showed very poor results for the procedure, this study out of the University of Washington showed the opposite. The UW study showed that instead of only 29% of hips not progressing, 92% of hips didn’t advance to replacement or severe arthritis.

So how can we reconcile these results? One showing a procedure that likely should never be offered and the other showing almost miraculous results? Without any higher level studies being published, there isn’t any way to do that. Meaning, nobody has a clue whether doing nothing is just as good, better, or worse than hip PAO surgery. However, the informed consent process for this procedure surely needs to make sure that patients understand that there is conflicting evidence over whether this surgery works.

Join us for a free Regenexx Hip Webinar

The Risk Matrix

This raises a very important question. If PAO surgery is more invasive than the surgery it seeks to replace (hip replacement) and only works less than one in three times, why bother with PAO surgery? If the results are miraculous with few side effects, then maybe the added risk of chopping off and reattaching the pelvis is worth it?

The upshot? Every patient needs to make his or her own decision. I do not send patients for this procedure given the severe complications I’ve been asked to treat. Based on the research on Hip PAO surgery results, as you can see, it’s either not very effective or magic. Either way, it’s also far more invasive than a hip replacement surgery, so if you end up needing that procedure, it will be less invasive than the PAO procedure.

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile

If you have questions or comments about this blog post, please email us at [email protected]

NOTE: This blog post provides general information to help the reader better understand regenerative medicine, musculoskeletal health, and related subjects. All content provided in this blog, website, or any linked materials, including text, graphics, images, patient profiles, outcomes, and information, are not intended and should not be considered or used as a substitute for medical advice, diagnosis, or treatment. Please always consult with a professional and certified healthcare provider to discuss if a treatment is right for you.

Get Blog Updates by Email

By submitting the form, you are agreeing that you read and consent to our Privacy Policy. We may also contact you via email, phone, and other electronic means to communicate information about our products and services. We do not sell, or share your information to third party vendors.

Copyright © Regenexx 2021. All rights reserved.



9035 Wadsworth Pkwy #1000
Westminster, CO 80021


*DISCLAIMER: Like all medical procedures, Regenexx® Procedures have a success and failure rate. Patient reviews and testimonials on this site should not be interpreted as a statement on the effectiveness of our treatments for anyone else.

Providers listed on the Regenexx website are for informational purposes only and are not a recommendation from Regenexx for a specific provider or a guarantee of the outcome of any treatment you receive.