Is Hip PAO Surgery a Bad Idea?

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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.

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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.

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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.

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.

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17 thoughts on “Is Hip PAO Surgery a Bad Idea?

  1. Gregorio Kort

    Rotator Calf tear

  2. David Handler

    All I want to know is stem cell available for degenerative dics in your back????

  3. Bonnie

    Although this PAO surgery is a bigger surgery, the same is true of the Knee.
    I have had several friends who had surgery for torn meniscus and wound up with a knee replacement or bilateral knee replacements.
    I am trying stem cells for a badly torn lateral meniscus (6 mo out) and while it is taking some time, I’ve seen how long recovery takes from a knee replacement, and I am hanging in.
    Thank you for sharing your great knowledge.
    Bonnie W

    1. Regenexx Team

      It can take time, thanks for hanging in. Please keep your treating Doctor in the loop about your progress. You are very right about meniscus surgery. Please see:

  4. Mary O'Connor

    Dr. Centeno,
    Measuring the ‘success’ of PAO by only whether the patient required conversion to THA within 30 years does not, in my opinion, provide a full picture. If PAO delays the need for THA for some reasonable period of time (to me this would be 10 years) and allows the patient to have a reasonable level of function without or with minimal pain during that time, then it may be worth it. THA in a young adult may not last their lifetime, and of course there are complications with THA as well as PAO. Unfortunate that the patient you saw had a nonunion—every surgery has risk. As we all know we need better biologic treatments for arthritis. But I do think PAO has a role in select patient.

    1. Chris Centeno Post author

      Mary, I think the big issue is patient consent. Every patient who has had a severe and serious complication from this procedure that I have seen has stated that they had it to “fix” their hip. meaning they believed this was a lifetime fix. While I can see the rationale for having this in the decision matrix for very young patients with early OA and dysplasia, the patients need to know: 1. long-term outcomes are poor, but we may be able to push a THR down the road a bit 2. The procedure to prevent a THR is more invasive than the THR 3. While unlikely, serious side effects can include a permanent inability to ambulate 4. There is not a 100% chance you will need an early THR, so we may be putting you through an invasive procedure that doesn’t change the natural course of your disease treatment. My patients with severe side effects knew none of this when they signed up and I suspect most patients don’t get this type of expanded informed consent. For example, not a consent form, but counseling that is one on one with the physician prior to the procedure.

      1. Chris Centeno Post author

        BTW, that informed consent also needs to include that we have no high-level evidence that this procedure is better than doing nothing. Meaning the great results from the shorter follow-up time Washington study may have well have happened without the procedure, we just don’t know that yet.

  5. Sophia

    I am currently 3 weeks post op from PAO. I spent a full 12 months with doctors, sports physicians and two orthapaedic surgeons before going ahead with this procedure. The surgery was undertaken by both surgeons together. I was told very clearly about the risks and that it is likely I could still need a THR in 10-20-30 years time but the PAO is to help preserve the hip and help at least delay the need. At 31 I was told I’m at the older end of the patient range however no indication yet of OA. I accepted all of this because the pain and impact on my life was not worth waiting until the hip joint degraded enough for a THR. My recovery is very conservative and I have a long period of no weight bearing, 10 degrees abduction and internal rotation and knee not above 90 degrees. I then progress over the period of 6 months to full movement and strengthening of the muscles. I have a goal to climb a mountain at the 11 month period and I’ve been told full impact sports are at 12 months. I am however in NZ and we may very well have different practices here. Your discussion doesn’t explain if there might have been any other underlying reason for the non union. Was the patient weight bearing too early, are they are smoker, is this the confirmed reason for pain and if so then why is there no intervention to reattach this piece of bone? The patient doesn’t seem shy of surgical intervention to have proceeded with two THRs. I can’t say how successful mine will be only being 3 weeks out but I can say the surgical pain has reduced by half already in this time and I am positive of the long term outcome.

    1. Regenexx Team


      Hoping for the very best recovery and that you get to climb that mountain! The two major studies have very conflicting results. Some patients do very well and we’ve seen patients with severe complications. The question is always are there noninvasive procedures that can help. This procedure treats an issue usually missed and can be helpful in some patients with shallow hip sockets and loose hip joints: This is an example of a nonsurgical hip procedure:

  6. Tammie

    Ok so just reaching out for some guidance here, my daughter was diagnosed with Right hip Dysplasia at 15 years of age and was a very active athlete. She underwent the PAO surgery and was told her hip was more than 50% out of the socket. She seemed to walk through this surgery like a champ and the time appeared to do very well at that time, she completed all of her therapy and was released to full sports again. However shortly after starting to condition she complained of soreness in the gluteal area, the started her on Mobic to help with the inflammation and soreness, we expected her to have some discomfort while trying to get back into sports however as time went on the soreness continued to bothersome to the point of not hardly being able to walk and couldn’t if she didn’t take the Mobic. After multiple phone calls to the surgeons office, they kept telling me that she should not need to continue be in Mobic and needed to get her off of it which I agreed however was persistent that something wasn’t right. Finally after testing they confirmed that her ischium had fractured all the way through and would have to do a revision. The revision consisted of removing the current 4 pins and replacing with 2 long pins to stabilize the fracture. This surgery was done in June of 2016, after follow up visits my daughter had absolutely no healing process up through November, where at that time they decided to put her in Vitamin D and a bone growth stimulator. Finally in Febuary it was pretty much healed. She did OK for a bit however the soreness and the pain came back, she hs had 2 hip injections only of which 1 helped for a short time. At this point she is in constant pain, after revisiting the surgeon he says that the hip is healed and not sure why she is having pain, put her on PT and Mobic again and is referring her to a physicist to address the pelvis are as he states that were her pain is located is not hip related. This pain is very similar to what she had when her ischium was fractured for almost a year while she played basketball and softball. My daughter is now almost 19, working as a CNA and taking classes to get in nursing school. She has had to leave her job due to not being able to walk, stand, or lift without being in extreme pain. Physical Therapy says she has some weak muscles but this should not be causing this much discomfort. At this point it is affeyher mentally as much as physically, she dealt with not being able to continue in sports however this is now affecting her adult life. She battles depression and anxiety now because she can’t do the things most people do everyday with out being miserable, even simple tasks such as driving. They were not able to get her in to the other doctor until July. I feel the surgeon is not listening to her and this is now going on 4 years and no one should have to be this miserable everyday. We really thought doing the original PAO was the right thing to do because of its “success rate” and ability to return to sports. Statistically speaking less than 5%of people have the fractured ischium, her’s being the the only one that required he had to fix because of complete fracture. Any advise on where to go from here, asking as a desperate mom who wants to see her daughter do everyday normal basic activities without constantly hurting or paying the price for trying to just do anything. I appreciate any guidance as I am not upset with the surgeon I just want her to be able to fulfill her dream of being nurse and having a happy life. Any information would be appreciated.

    1. Regenexx Team


      While PAO Surgery helps some patients, we see the patients who have had significant complications. We’d need to examine her to see what’s going on. Do want our team to contact you to set that up?

  7. C Wise

    I had FAI surgery, then PAO surgery and had to have THR 4 years later, with two arthroscopic surgeries in between. Then the THR failed and I saw a new surgeon, who did revision surgery, had to fracture my femur to remove old hardware and spent a week in the hospital. 8 MONTHS on crutches. 6 surgeries in total from 2006-2012. Now looking at havng iliopsoas release surgery. And yet the PAO was still the worst thing I have ever endured. Thanks Dr. Beaule.

  8. Milly

    I am almost a year post op from a PAO, 25 year old female, and so far I have absolutely NO regrets, and my recovery has been smooth as a whole. I was in pain everyday pre-op, taking very strong painkillers just to work, now I take nothing and need nothing. I still have a lot of muscle strength to build- but participate in Pilates to help with that. Although I say I have muscle strength to build, I have no limp and work long hours at a physically demanding job with no issues.
    I understand you need to show the risks of various studies and patients, however I don’t think you should ONLY show the negative. I bet if there was a more cohesive and worldwide survey done of PAO patients you would see more varied results. I am also on the waiting list for surgery number two because I’d rather not be in constant pain everyday for the rest of my life. It’s the risk I am willing to take.

    1. Regenexx Team

      Very thankful it helped you! When we talk about a surgery being a bad idea we are talking about an unacceptable risk vs benefit profile in a large group of people. Because surgery is damage to accomplish a goal, all less invasive options, and regenerative options which cause no damage and heal tissue instead, should be tried first. That doesn’t mean that a surgery can’t help an individual patient.

  9. Jess

    i had PAO in 2014 and have worse pain now than i ever did before i initially asked for a replacement and was refused i was told this would be better due to my age my hip displaces all the time my family timed my surgery i was in the OR for 7 hours and i have a 15 inch scar with no relief at all from pain and i cannot find a Dr who will touch it to fix it

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