PAO Surgery 101: Everything You Need to Know About PAO Surgery

Hip pain is never fun, especially if you enjoy an active lifestyle. If that pain is constant or gets in the way of your day-to-day life, you can (and should) seek help. Usually, the underlying cause is a muscle or tendon injury, and a combination of physical therapy and rehabilitative exercises can help you get your life back. However, on rare occasions, the pain may be a sign of something more serious, like a misshapen or shallow hip socket known as hip dysplasia. In these cases, periacetabular osteotomy surgery (PAO) may be recommended. PAO surgery treats painful hip instability resulting from an abnormally shallow or dysplastic hip joint by realigning the socket to better stabilize the ball.

Many patients opt for PAO surgery because it prolongs the life of the natural hip, enabling an active lifestyle for years to come. While effective, not all patients with hip dysplasia are good candidates for PAO. Find out if you’re an ideal candidate for PAO surgery, what the procedure involves, and potential alternatives to this treatment.

What is PAO surgery?

PAO surgery is a way to manage hip dysplasia, a hip joint abnormality where the hip socket is too shallow, causing the hip ball to slip out. It’s considered preventive because PAO decreases the likelihood of premature osteoarthritis and the need for hip replacement surgery.

Potential candidates for PAO are those born with shallow hip sockets that cause pain or instability, says Tigran Garabekyan, M.D., an orthopedic surgeon at Commons Clinic. 

Garabekyan says the surgery cannot make the socket less shallow, but it can realign the socket so the ball sits directly under it. By realigning the socket, PAO restores hip stability, prevents overcompensation from nearby muscles, and reduces mechanical stress on the hip cartilage.

Hip Joint Anatomy and Function

Before we cover how PAO surgery works, let’s dive into the anatomy of a hip joint (very briefly, we promise). The joint connects the thigh (femur bone) to the pelvis (innominate bone). It is made up of two main parts: a ball and socket. This joint provides stability and supports the weight of the upper body when someone is standing, running, walking, or doing something active, such as home repairs or mowing the lawn.

A well-functioning, stable hip requires a socket that has good depth and sits on top of the ball to contain and support the ball during weight-bearing activities. A shallow hip joint makes it harder for the ball to stay in the socket, making the ball unstable. A shallow socket is both genetic and developmental. For most patients with dysplasia, the condition is mild and only becomes a problem if they engage in an activity that puts extreme pressure on the hip, like training for a marathon. The combination of a naturally shallow hip socket and intense activity increases the likelihood of hip injuries and conditions like labral tears and premature arthritis. 

Importance of Proper Hip Alignment

If you were writing a job description for the hip joint, maintaining proper hip alignment would be one of its most important tasks. Vikram A. Rao, M.D., a musculoskeletal radiologist at the West County Radiology Group in St. Louis, outlines three reasons why hip alignment matters:

• Posture: Properly aligned hips help you maintain a natural posture and normal walking pattern, Dr. Rao says.
• Muscle balance: “When the hips are not aligned, some muscles around the hip are overworked, while others are not used enough,” explains Dr. Rao. “This imbalance can lead to muscle strain or weakness in surrounding areas.”
• Preventing wear and tear: A misaligned hip leads to extra stress on the hip joint. Over time, this leads to narrowing joint space or arthritis, resulting in pain when moving around and a lack of mobility.

While socket depth is pretty much established by the time you’re in grade school, you can improve hip alignment by stretching out the hip flexors regularly. A kneeling lunge hip flexor stretch and lying-down hip flexor stretch are great additions to a morning or evening stretching routine. 

Many physical therapists also recommend strengthening the muscles around the hip. A 2024 study suggests strengthening the gluteus maximus — the largest muscle in the buttock and hip area — may have the biggest impact on hip alignment. Potential exercises to strengthen the gluteus maximus include Bulgarian squats, step-ups, and lunges.

What is Hip Dysplasia?

Remember how the hip joint is made up of a ball and socket? Sometimes the socket doesn’t fully align with the ball, resulting in hip dysplasia. 

“Hip dysplasia is a condition where the hip socket doesn’t fully cover the ball portion of the upper thigh bone, which can lead to partial or complete dislocation of the hip joint,” says William Ashford, M.D., an orthopedic surgeon at AICA Orthopedics in Atlanta.

To better understand this condition and why PAO surgery can correct wear and tear caused by hip dysplasia, let’s explore the condition’s causes and symptoms. 

Causes of hip dysplasia 

Hip dysplasia has genetic and developmental components, with firstborn females born in breech presentation having a higher risk of being born with a shallow hip socket. It begins at birth and solidifies at skeletal maturity, an age that differs for everyone but is usually between ages 11 and 18. However, it often isn’t diagnosed until later because symptoms are not usually present until young adulthood. 

The exact genetic component is not yet understood by researchers, but there are some established risk factors, including:

• Being born female
• Being born in a breech position, where the baby’s bottom is down, during pregnancy
• Being the first child
• A heavier birth weight
• A family history of hip dysplasia 

Hip Dysplasia Symptoms

Sometimes, hip dysplasia doesn’t present symptoms. In these scenarios, PAO likely isn’t required. When symptoms are present, the most common include:

• Pain in the hip
• A clicking sound or sensation when the hip moves 
• A catching sensation, which can feel like the hip locking up or tensing
• A lack of stability and balance in the hips
• Reduced hip mobility, in later stages of the disease when arthritis sets in
• Pain in adjacent areas, like the sacroiliac joint or lower back, due to overcompensation

These symptoms can be similar to a muscle strain or other hip injuries, though there are two key differentiators. If the legs give out when you move incorrectly and there’s a constant ache, it may be hip dysplasia. 

Hip dysplasia ranges in severity from mild to severe. Mild cases may be stable for years, but symptoms associated with severe dysplasia tend to progress. “Eventually, you get to the point where it’s hard to go through an entire day without feeling and thinking about your hip to some extent,” Dr. Garabekyan says .

Diagnosing Hip Dysplasia

If you are experiencing persistent pain in the hips, Dr. Garabekyan recommends seeing an orthopedic surgeon or other specialist trained in treating hip dysplasia. For insurance to cover appointments, you will most likely have to see a primary care doctor first, who will order scans of the hips. 

Once those hip scans come back with a potential diagnosis of hip dysplasia, a primary care doctor will refer you to a specialist (no referral equals no guarantee insurance will cover treatment). One of those specialists could be Commons Clinic which provides a more advanced diagnosis and any necessary treatment in a one-price, comprehensive care model.

Once a specialist confirms if your symptoms are due to hip dysplasia or something else, they will create a treatment plan. For hip dysplasia, treatment often starts with physical therapy and lifestyle adjustments, such as avoiding high-intensity exercise like running or HIIT, and then progresses to PAO surgery if these options don’t work.

Questions to ask about hip dysplasia

If you suspect you have hip dysplasia, make an appointment with a physician. During that appointment, you can ask questions, such as:

• What symptoms or signs indicate hip dysplasia?
• How is hip dysplasia diagnosed?
• What are the different stages or severities of hip dysplasia?
• What are the potential long-term effects of untreated hip dysplasia?

Benefits of PAO Surgery

PAO surgery treats hip dysplasia, leading to some significant benefits for the hip joint and nearby muscles. Those benefits include: 

• Treating hip pain
• Realigning the hip ball and socket
• Preventing nearby muscles from overcompensating for the hip’s weaknesses
• Reducing undue stress on the hip
• Providing hip stability
• Reducing the likelihood of premature arthritis of the hip

Because PAO reduces undue stress and realigns the hip socket and ball, it is considered a prevention tactic against premature osteoarthritis caused by hip dysplasia. 

PAO preserves and realigns your own hip joint for a more natural and durable solution compared with the alternative, hip replacement surgery. With PAO, patients typically spend three nights in the hospital, go through intensive rehabilitative physical therapy, and when fully recovered, have no restrictions on activities. By contrast, hip replacement surgery typically requires lifelong restrictions of avoiding high-impact activities, such as running, so as not to cause premature wear of the prosthesis. Additionally, a prosthetic joint is often not ideal for patients younger than 40, who typically aspire to live a more active life than the older population. 

When you should get PAO surgery

PAO surgery is predominantly diagnosed for patients who suffer from instability due to significant underlying hip dysplasia. For an orthopedic surgeon to consider this surgery, you must meet the PAO trifecta: painful instability, failure to improve with conservative treatment, and healthy cartilage in the hip without significant arthritis.

Age is just a number, but it’s one of the best indicators of hip cartilage health and longevity following PAO surgery. Typically, surgeons recommend PAO for adults between 20 and 55. In fact, a 2022 study suggests the surgery may be more effective for patients under 40. That’s because there’s a smaller chance of osteoarthritis being present. 

The second prong is twofold: there must be a hip dysplasia diagnosis and other treatment options have been explored, such as physical therapy and guided training to strengthen muscles around the hip. 

Getting the right diagnosis, however, is easier said than done. “The majority of patients don’t know that they have dysplasia until they have symptoms,” Dr. Garabekyan says. He adds that even after experiencing symptoms, patients often bounce around from doctor to doctor until someone diagnoses them with hip dysplasia. The condition can be even harder to diagnose in children, unless severe, because children are still developing, and growing pains could be responsible for hip symptoms, too.

After diagnosis, someone will start with more conservative treatments, usually conducted under the supervision of a physical therapist. These PT appointments focus on strengthening the muscles around the hip so they can compensate for any hip instability. If conservative treatments don’t work, then it’s time to discuss surgical options.

The third prong makes someone a Goldilocks candidate: arthritis hasn’t developed in the hip. Once osteoarthritis has developed, PAO isn’t as effective, and other measures, such as hip replacement surgery or medications for osteoarthritis, may be a better option.

Questions to ask your physician

If you’re wondering if you’re a good candidate for PAO, a physician can help determine if the three prongs are met or can recommend an alternative treatment. To clarify if PAO is right for you, ask a physician: 

• What specific hip condition do I have, and how severe is it?
• Is PAO surgery the best option for my condition?
• Are there alternative treatments or surgeries that I should consider first?
• What are the criteria for being a good candidate for PAO surgery? How do I meet or not meet these criteria?
• What are the next steps if I decide to proceed with PAO surgery?

How PAO works

If an orthopedic surgeon determines that you are a good candidate for PAO, it’s time to prepare for your surgery. Fortunately, your surgeon is responsible for the surgery prep, but understanding your role and a play-by-play of what PAO surgery entails can ease any worries.

Preparing for Surgery

An orthopedic surgeon will usually recommend prehab so you can bounce back as quickly as possible after PAO surgery. Prehab is the same as rehab (a mix of physical therapy and at-home exercises and stretches), but, as the name suggests, it happens before an operation. At Commons Clinic, prehab is handled in-house so you don’t have to find another specialist or practice. 

Dr. Garabekyan also recommends a few logistical steps to prepare for PAO. These include:

• Removing throw rugs from the home or anything you may trip over after the surgery
• Installing a higher toilet seat for the first few days after PAO, since it can be hard to sit down low after PAO surgery
• Talking to a patient who has undergone the surgery to alleviate any apprehension or anxiety you may have related to the procedure

“At Commons, we typically match every prospective PAO patient with somebody who’s similar in age and activity level,” Dr. Garabekyan explains. “They spend time on the phone talking, and can get feedback from somebody who’s actually been through it.”

The PAO Surgery Procedure

PAO surgery isn’t a lone wolf. It’s preceded by hip arthroscopy surgery, which fixes torn structures in the hip, assesses the hip cartilage, and shaves abnormal bones. You can think of hip arthroscopy as the site cleanup before starting a home renovation project; it ensures the ball and socket are prepared for the more intensive PAO surgery.

Hip arthroscopy is an outpatient surgery, meaning patients don’t stay overnight in a hospital and can recover at home. About a week later, a patient undergoes PAO. Beforehand, patients are given anesthesia, meaning they shouldn’t feel anything during the surgery.

During PAO, your surgeon will cut around the hip socket until it’s free. Then, the surgeon will reposition the hip socket and reattach it to the pelvis with screws.  

While it sounds straightforward, there are two possible methods for PAO surgery: the traditional Bernese osteotomy and a modified technique called the CU PAO. Dr. Garabekyan prefers the latter technique as it enables safer bony cuts near the sciatic nerve, as well as more stable realignment enabling patients to bear 50 percent of their weight on the operative leg immediately after surgery.

“No matter how good you get, the conventional technique always carries with it a risk that once in a blue moon, you might have a patient suffer a sciatic nerve laceration or transection, which is a devastating complication. The CU PAO technique essentially eliminates that risk,” Dr. Garabekyan says.

The CU PAO technique includes two main changes:

1. Rather than making blind bony cuts near the sciatic nerve by feel, the surgeon uses a small second incision to directly visualize and protect the sciatic nerve.
2. In traditional PAO surgery, the surgeon cuts the bone from front to back and then top to bottom. With the CU PAO approach, they make three shorter cuts from front to back in the shape of a hexagon. This improves the stability of the cuts around the hip socket, making it easier to bear weight immediately after surgery.

Afterward, a patient stays in the hospital for four days to recover. There is often a PAO surgery scar, which should heal with time (about six weeks for most individuals). Patients are allowed to bear 50 percent of their body weight on the operative leg immediately after surgery, though it takes a week or two for the muscles to activate properly. 

Recovery and Outcomes

Dr. Garabekyan, who uses the CU PAO technique, outlines a typical recovery process for his patients:

• Immediately after surgery: Patients can usually bear 50 percent of their weight with the use of crutches.
• Three weeks after: Patients are allowed to gradually advance their weight bearing by 25 percent of their weight every two to three days until they are walking without crutches.
• Five to six weeks after: Patients in their 20s can walk around the house without crutches. Older patients may still need to use crutches for an additional 2 to 3 weeks.
• Nine weeks after: Patients should be able to bear 100 percent of their weight on their hip for normal everyday activity. “If you were to meet a friend for coffee at nine weeks post-op, they wouldn’t know you had anything done,” Dr. Garabekyan says.

Post-treatment

For the first three weeks, a patient should focus on rest and recovery. They’ll usually have follow-up appointments with their orthopedic surgeon one week and three weeks post operation. During the latter, the surgeon ensures you are ready for post-treatment. 

Post-treatment involves physical therapy and rehabilitation exercises at home (specific exercises are assigned by your physical therapist). These programs are often structured and tailored to your desired activity level.

At Commons, for example, a patient sees a physical therapist a couple of times per week until they are three months post-op, when the frequency of appointments is reevaluated. They also have appointments with the orthopedic surgeon six weeks, nine weeks, three months, 4 ½ months, six months, nine months, and one year post-op. Follow-up appointments may involve taking hip X-rays and ensuring the screws and hip joint are well placed.

Outside of PT, you should avoid sports and vigorous physical movement in the first few months of treatment, advises Dr. Garabekyan. As post-treatment progresses, a PT will help you decide on a healthy activity level. 

Post-treatment lasts anywhere from four months to one year, depending on a patient’s desired lifestyle. A competitive runner at UCLA, for example, will require a longer period of dedicated physical therapy than a person in their late 40s who bikes and walks for recreational exercise. 

Alternatives to PAO 

“When hip dysplasia is really severe, it’s hard to get around PAO surgery,” Dr. Garabekyan says. For milder cases, there are alternatives. Almost all should be explored whether an orthopedic surgeon recommends PAO or not.

The first avenue to explore is maintaining a healthier weight. Extra pounds place undue pressure on the hip. Losing weight or not gaining it in the first place can reduce the weight the hip must bear. Maintaining a healthier weight often boils down to diet (eating more fruits, vegetables, and lean protein) and exercise. 

While exercise is beneficial, consider low-impact options. Dr. Garabekyan recommends biking, swimming, walking, and hiking over activities with explosive movements, such as running, CrossFit, or sports with jumps or explosive movements.

When at the gym, consider breaking out some weights. Strengthening muscles in the glute and hip can help stabilize the region, reducing the likelihood of PAO.

The final measure to take before considering PAO, or as an alternative, is to work with a physical therapist. They can introduce hip mobility exercises and other rehabilitation techniques that may be able to compensate for hip dysplasia without surgery.

Knowing if PAO is right for you can also boil down to lifestyle. “Sometimes, the decision to proceed with PAO isn’t because you’re miserable with pain. It’s because you can’t be active and do the things you want to do,” Dr. Garabekyan says. Whether you’re interested in PAO or alternative treatments, an honest conversation with a specialist about your lifestyle and symptoms is the right place to start.

Frequently Asked Questions (FAQs)

Is PAO surgery worth it?

For many, PAO surgery is a preventive measure that increases the lifespan of the natural hip, reduces the likelihood of hip replacement surgery, and decreases hip pain and instability. That being said, it’s most effective when someone is an ideal candidate (younger than 40, already tried more conservative treatments, and doesn’t yet have arthritis). 

How much does PAO surgery cost?

A 2020 study found PAO can cost anywhere from $11,385 to $21,852. And that is just the cost for the surgery, not for rehabilitative physical therapy and follow-up appointments. Fortunately, most insurance plans cover all or part of the bill.

How long does PAO surgery take?

Arthroscopic surgery, the preliminary outpatient procedure, occurs one week before PAO. Later, PAO surgery itself takes about four to six hours to complete. However, patients have to stay overnight after the procedure, and total recovery time can range from four months to a year (though usually only the first one to two nights are spent in the hospital). 

How painful is PAO surgery?

PAO surgery should not be painful because anesthesia is administered, meaning a patient is unconscious for the surgery. Recovery can sometimes be painful, but physical therapy, pain medication, and rehabilitation exercises are often prescribed to help manage pain.

When can you drive after PAO surgery?

Since PAO surgery requires anesthesia, a patient should not drive for 48 hours after surgery (at minimum). However, driving can place undue pressure on the recovering hip and most surgeons recommend waiting four to six weeks to drive.

Are screws removed after PAO surgery?

Screws are typically removed after nine to 12 months, when the bone has fully healed.

How long does it take to recover from PAO surgery?

Recovery from PAO surgery is a gradual progress that can take anywhere from six months to a year. The exact time depends on the level of fitness you’re trying to achieve after surgery. Professional or collegiate athletes often need six months to a year of dedicated rehabilitation. Someone who wants to get back to less intense workouts or everyday tasks, like mowing the lawn or gardening, may achieve those goals sooner.

Conclusion:

So, is PAO surgery worth it? The answer may be yes, if you are diagnosed with hip dysplasia, have failed conservative treatment, and haven’t yet developed osteoarthritis. When recommended by an orthopedic surgeon, PAO often reduces hip pain and prolongs the life of the natural hip.

However, the key to finding the right treatment is to seek a professional opinion. “If it feels like something is wrong beyond just a strain, see an expert and let them take it from there,” Dr. Garabekyan says. If you have additional questions about PAO or treatment alternatives, share them with a physician who can provide the best assessment possible. 

Hip pain or weakness can negatively impact your life, but it doesn’t have to. There are effective, safe ways to increase the life of your natural hip and minimize hip pain.

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