hip dysplasia

About Hip Dysplasia

Hip dysplasia is a condition where the hip joint socket (acetabulum) is too shallow. Hip dysplasia causes abnormal loading of the cartilage and labrum (soft tissue socket) and can lead to early arthritis.

Some mild dysplasia problems may be treated arthroscopically, while others are more suitable for open procedure surgery (periacetabular osteotomy).

Somtimes Called Developmental Dysplasia of the Hip

Hip dysplasia, sometimes called DDH (developmental dysplasia of the hip), is a relatively common abnormality in the shape of the hip joint. This abnormality originates at birth or in early childhood. DDH is the most common developmental hip deformity causing symptoms in adults and is also the most common single cause of osteoarthritis in the hip.

Most frequently hip dysplasia is in a hip socket (acetabulum). The shallowness of the acetabulum causes the head of the femur to exert excessive pressure on the rim of the acetabulum.

Individuals with acetabular dysplasia often go through childhood and adolescence without symptoms or knowledge of their condition. However, when they reach young adulthood, they may experience hip pain. At that time an X-ray will reveal the acetabular dysplasia.

Classic Dysplasia vs. Retroversion

Classic dysplasia is demonstrated in figure A where the socket (acetabulum) is facing forward and the lines representing the front wall (anterior) of the socket and the back (posterior) wall of the socket are not overlapping. In classic dysplasia there is not enough coverage of the outside of the femoral head.

Retroversion, figure B, is when the opening of the socket is facing to the side or backwards causing the femur to contact the front of the socket when it rotates. This can cause femoroacetabular impingement and can damage the cartilage inside the socket (articular cartilage) and the rim of the socket (bone or labrum).

The arrow shows the part of the anatomy (ischial spine) that should not usually be visible unless this whole region of the pelvis is twisted backwards. There is often enough or too much lateral coverage of the head, but there may not be enough coverage of the back of the head.

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Frequently Asked Questions and Answers about Hip Dysplasia

What is hip dysplasia?

Dysplasia can also be referred to as developmental dysplasia of the hip (DDH); it is a condition through a child’s early development where the hip socket (acetabulum) doesn’t form normally. The socket is usually too shallow and the femoral head (ball) is partially uncovered; sometimes it can be facing more backward than forward (retroversion).

What are common symptoms with dysplasia?

Many people, especially women, have dysplasia and don’t know it until their mid to late twenties or thirties. Most of the time, individuals will start to feel pain in the front of their hip (groin) after prolonged sitting or walking, such as a dull ache in the groin or catching or popping. Walking up or downhill can also be difficult.

What happens inside a dysplastic hip?

Since the weight-bearing surface of the acetabulum (socket) is smaller or more shallow, it has to withstand more force and tends to wear out faster than if it shared the forces with more of the acetabulum. The cartilage and labrum are the cushion between the ball and socket (clear space on X-rays), and this can get damaged and start to degenerate (develop small tears and arthritis).

If left untreated the majority of dysplastic hips need hip replacement (total hip arthroplasty) at some time in their life.

How do I know if I need surgery?

You may want to consider surgery if you have a pain that is in the front groin (anterior) that affects daily activities and prevents you from doing the things you want to. Also if X-rays show dysplasia with early degenerative changes (mild arthritis), but still evidence of good cartilage, you may be a candidate for an osteotomy.

Does pain correlate with dysplasia?

Not necessarily. Sometimes people have significant dysplasia without significant symptoms to warrant a big surgery. In those patients we observe the hips over time with X-rays and re-evaluate their symptoms every year or two.

Frequently Asked Questions and Answers about Periacetabular Osteotomy

What does “periacetabular osteotomy” mean?

“Peri” means around, “acetabular” means the hip socket and “osteotomy” means to cut bone. Thus the surgery involves cutting out or carving around the hip socket to move it to a new and better location.

What is involved in a periacetabular osteotomy (PAO)?

The surgeon goes through an incision over the front of the hip about 6-8 inches long, separating muscles to get to the pelvis, then with X-ray guidance (fluoroscopy) carefully cuts through the three pelvic bones (ischium, pubis, ilium) around the acetabulum to free it from its original position. Next the acetabulum is fixed in its new location with screws (usually three to six); a bone graft is used if needed.

What other surgical options are there?

Sometimes if the angle made by the femur and head is too low (varus) or too high (valgus), then an osteotomy of the femur may be needed. This helps the femoral head to be in a more normal position to preserve it from wearing out. This surgery is called a proximal femoral osteotomy.

Will I need a blood transfusion?

You may. We recycle the blood you lose at surgery and give it back to you if there is enough. But sometimes you will need a transfusion of 1–2 units after surgery. We usually like you to donate your own blood if you are able, but if not, the blood bank is very safe and we can use that.

How long will I be in the hospital?

Usually, the hospital stay is two to three days after surgery.

What physical therapy do I have to do?

Starting the day after surgery you will have physical therapy twice a day that includes gentle exercises, learning to sit, stand, and walk with partial weight-bearing and crutches. You may take a few steps the first day around your room, and the second day out into the hallway and so on. After you leave the hospital, the only important therapy you have to do is walk, rest, and let your surgery heal. We do not want formal physical therapy for the first six weeks; after that we evaluate your needs on an individual basis.

What are the major risks to the surgery?

The major risks include the following:

  • Blood clot We reduce risk of this by using a blood thinner, TED hose (compressive stockings) and compression boots on your feet to increase circulation.
  • Infection You are given IV antibiotics before surgery, which is continued for 24 hours after; then keep a close watch of the incision for redness or drainage, especially in the groin.
  • Nerve palsy A sensory nerve called the lateral femoral cutaneous nerve is right where we do surgery. We do our best to identify it and protect it but there is a 50 percent chance you will have some numbness over the front of your thigh; over time sensation usually returns. There are also bigger nerves, the femoral and sciatic nerves, which are deeper and can get stretched with a big correction/surgery, but this is very rare (less than one percent).
  • Failure to heal This is also uncommon but always a concern, especially if you smoke. If the bone doesn’t heal, the screws can break and the socket can move. An additional surgery to increase bone healing could be needed, but very rarely.

What happens when I leave the hospital?

Usually, you will need 24 hour help for a week. Or if you don't have adequate help at home, you could consider a rehabilitation center. The final plans will be made while you are recovering in the hospital.

What do I do at home while recovering?

Recovery involves the following:

First six weeks: Finish taking blood thinners (aspirin for six weeks), wear TED hose, walk with crutches (partial weight bearing), keep wound clean.

Next six weeks: Transition to one cane or crutch as instructed by your physician until three months after surgery; may start gentle stretching or strengthening exercises; walk.

After three months: Return to work part time or full time as tolerated (two to three months from surgery); continue to walk and return to gentle exercise.

After six months: You may return to full activity (when the bone cuts are completely healed) except for running/jumping activities.

The best lifelong activities are walking, swimming, biking to preserve your hip’s health.

How long do I take narcotics?

Only as long as you need to, about seven to 21 days from surgery. Be aware that sometimes anti-inflammatories (NSAIDS) can slow down bone healing, but Tylenol is not a problem.

When can I drive?

Usually three to four weeks after surgery (when you’re safe enough to not be at fault if you get in an accident and off narcotics).

When do I see my doctor after surgery?

You will probably have staples and should see your doctor in two weeks, then again six weeks after surgery for x-rays, then three months, six months, one year, and every year or two so we can see how the hip progresses.

Who do I call if I'm having problems after surgery?

You can call the orthopedic clinic and ask for the nurse/MA who works with your surgeon; she will get back to you within a business day; otherwise, call the orthopedic resident on-call.

How long will it take to fully recover from this surgery?

You will be walking within a couple days of surgery, but on one to two crutches for three months, and it usually takes 9–12 months to feel fully recovered.

How long will the PAO last? Will I need another surgery?

We hope to prolong the time between now and when you need a hip replacement (total hip arthroplasty). But the exact time in years is unknown and based on the amount of arthritis in your hip already.

What lifelong activities can I do or not do?

We advise patients to resume what they can tolerate, especially walking, swimming, and bicycle riding. We discourage repetitive jumping, running, and heavy manual labor and lifting. These activities tend to wear out your hip faster.

Stephen K. Aoki, MD

Patient Rating:


4.8 out of 5

Dr. Stephen K. Aoki, Associate Professor, specializes in hip and knee sports medicine. His clinical practice and research focus on both adult and pediatric sports injuries. Current interests include hip preservation/femoroacetabular impingement in the young adult, hip arthroscopy, the pediatric and adolescent athlete, ACL tears in children, patella... Read More

Jill A. Erickson, PA-C

Jill Erickson has worked with our Adult Reconstruction Surgeons since 1999, and with Christopher Peters, M.D. exclusively since 2003, with Joint Replacements as well as Hip Preservation procedures. She is an integral member of our University of Utah Center for Hip & Knee Reconstruction team and coordinates our research, surgical and clinical ou... Read More

Travis G. Maak, MD

Patient Rating:


4.8 out of 5

Dr. Travis Maak’s practice is focused on sports medicine and arthroscopic treatment of the hip, knee and shoulder. He is the Head Orthopaedic Team Physician for the Utah Jazz and Assistant Professor in the Department of Orthopaedics at the University of Utah. Dr. Maak is originally from Salt Lake City and a graduate from Stanford University. He co... Read More

Christopher L. Peters, MD

Patient Rating:


4.7 out of 5

Dr. Chris Peters, Professor, specializes in adult reconstructive orthopaedic surgery of the hip and knee. He performs routine and complex joint replacements and bioregenerative hip preserving operations. One of his specialties includes the treatment of hip pain in young adults from acetabular dysplasia and/or femoro-acetabular impingement with pelv... Read More

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