FAQ Adult Hip Dysplasia

  1. What causes Adult Hip Dysplasia?
  2. How common is Adult Hip Dysplasia?
  3. Why didn’t doctors diagnose me when I was a baby?
  4. What are some signs I can look for if I suspect I have hip dysplasia?
  5. Is it important to see a Hip Specialist vs a General Orthopedist if I have Hip Dysplasia?
  6. What happens if Adult Hip Dysplasia goes untreated?
  7. What are the advantages of a PAO over a total hip replacement?

What causes Adult Hip Dysplasia?

The cause of adolescent and adult hip dysplasia is obscure. Doctors are just becoming aware that infant screening detects only 10% of dysplasia that causes arthritis in adults. Hip instability in babies can usually be detected, but one possibility is that some babies have shallow sockets that fail to develop completely or become unstable at an older age. These would not be detected by current methods. There is increasing interest in identifying and treating babies that have shallow sockets that are currently considered borderline normal. Infant hips that are in the lowest 1% of hip development by measurement are usually treated, but perhaps that needs to be reconsidered so that babies in the lowest 5% by measurement are treated. This would require research to prove that early treatment might help prevent adult arthritis. Also simpler and cheaper methods need to be developed if widespread treatment is used for prevention. The International Hip Dysplasia Institute is on the leading edge of these concerns and is directing some of its research efforts towards discovering new methods of prevention that may be possible.

The known causes of hip dysplasia are mainly related to loose hips around the time of birth. This is often due to normal hormones that help relax ligaments to make childbirth easier. The left hip is more frequently involved than the right because of the normal baby position in the womb that stretches the left hip more than the right. Some instability has been identified in as many as 15% of newborn infants. Contributing factors for hip dysplasia are first born babies (not as much room), girls (more ligament laxity), positive family history, and breech position that stretches the hips. When one person in the family has hip dysplasia, the chance of hip dysplasia needing treatment is 5-10% for subsequent children (1-2 in 20).

How common is Adult Hip Dysplasia?

Hip dysplasia in adults is the most common cause of hip arthritis in young women. Men also have hip dysplasia and account for approximately one in five cases. Estimates of hip dysplasia as a cause of all hip arthritis range from 5% to 44%. The best guess is that 10% of all total hip replacements in the United States is because of hip dysplasia. This means that approximately 35,000 total hip replacements each year in the USA are because of hip dysplasia. Early detection can prevent some total hip replacements through modern techniques of hip preservation surgery.

Some hip instability is very common in newborn infants. The exact frequency of hip dysplasia that requires treatment in babies is variable depending on Nationality, sex, race, and other factors. Hip dysplasia that needs treatment occurs in approximately 2-3 children per thousand. However, some studies have detected mild instability in up to one infant in six (15%). Most of this mild instability resolves spontaneously. However, there is renewed interest in whether these that “resolve” are the ones that lead to adult hip dysplasia.

Why didn’t doctors diagnose me when I was a baby?

Simply put, the current methods of detection are inadequate. Norway has socialized medicine and implemented comprehensive screening over 40 years ago. Ultrasound screening was introduced about 30 years ago. In 2008, some Norwegian researchers looked at total hip replacements in young people. They found that 92% of the adult dysplasia had been “missed” in childhood. This is discouraging to doctors because their best efforts have failed to detect hip dysplasia during childhood. The problem is with the methods and not with the doctors themselves. It is becoming more and more clear that dysplasia can develop after infancy or that simple preventive methods need to be developed for more widespread use. The International Hip Dysplasia Institute is attempting to answer some of these questions.

What are some signs I can look for if I suspect I have hip dysplasia?

During adolescence or adulthood, the most common first sign is pain in the hip. Most people think of the hip as the bone that protrudes on the upper side of the thigh. However, the hip joint itself is in the middle of the crease where the thigh joins the body. That is where the hip bends and straightens. If there is pain or snapping in the front region of the hip, then the problem is more likely to be inside the joint itself. Pain in this region or in the groin that is aching and becoming worse over a period of several months raises concern about undetected hip dysplasia. Sometimes painful snapping occurs deep in the hip. This is different from snapping of the muscles on the side of the thigh where the muscles roll across the bump on the side of the upper thigh (that is outside the hip joint but is a common location for snapping bursitis). When the snapping is deep in the hip joint, then there may be something torn inside the joint itself.

Is it important to see a Hip Specialist vs a General Orthopedist if I have Hip Dysplasia?

Hip dysplasia is often misdiagnosed because the x-rays need to be taken in special positions. The average delay in proper diagnosis is 3 years because the methods of diagnosis are somewhat new to many physicians. If you suspect you have hip dysplasia, and the cause of your pain seems obscure, then a second opinion may be worthwhile. We’ve also suggested some questions to consider asking your doctor that might give you a better feeling about his or her experience with hip dysplasia.

What happens if Adult Hip Dysplasia goes untreated?

Hip dysplasia in adults that is not treated will worsen and eventually require total joint replacement. Exercises and medicines may help relieve pain temporarily, but the only true solution is to have the hip joint re-aligned so that the pressures on the joint surface are spread over a wider area. This requires surgery and the surgery must be done before the joint surface becomes too worn out to heal. Some doctors may advise putting up with the pain as long as possible but that is rarely the best advice when the cause of pain is dysplasia. Early hip preservation surgery can postpone artificial joint replacement surgery for many people younger than 50 years of age. It is advisable to avoid total hip replacement when possible because hip replacement in young people is less successful than replacement after the age of 50 years.

What are the advantages of a PAO over a total hip replacement?

That’s a common question that doesn’t always have a clear answer because each person is different. The decision whether to try to preserve the natural hip or replace the hip completely depends mainly on age, severity of dysplasia, and expected activity level after surgery. Your doctor is the best person to discuss the specifics of your particular situation. If your doctor primarily does total hips and hasn’t done any PAO surgery, then a second opinion from a qualified PAO surgeon is usually a good idea. On the other hand, if your doctor treats children and young adults but rarely does total hip replacements, then an opinion from a total hip surgeon may be worthwhile.

The PAO has the best results in people who are younger than 35 years with good congruency of the ball and socket. Congruency means that the ball has not moved out of the socket but the socket is shallow. Total hip replacements have the best results in people older than 45 years who are willing to limit their activities to make the artificial hip last as long as possible without wearing out.

Most orthopedic surgeons try to preserve the natural hip as long as there is some good joint surface remaining and the person is younger than 40 to 45 years old. When the hip is displaced and the joint surface is very thin, then total hip replacement is often recommended, especially after age 45 years. The years in between mainly depend on the amount of joint damage that already exists. Successful PAO surgery allows return to full activities for most people and postpones the need for total hip replacement more than ten years in 85% of patients and by 20 years or more in some cases.

Total hip replacements are very successful, even in young people but the younger population generally doesn’t follow their doctor’s advice after they get an artificial hip and feel good again. The hip will wear out and need replacement more often in younger people because of longer lifespan and greater activity levels. Each time the total hip is replaced, more bone is taken away and the procedure becomes more difficult with greater risk of infection and other complications. So, the problem with total hip replacement is not the first surgery but the next surgery and the one after that. Each time the artificial hip wears out there is an increasing possibility of complications. However, total hip replacement is needed regardless of age when the joint surface has completely worn out.

As a reminder, your doctor is the best person to tell you how bad your hip has deteriorated and whether your best choice is PAO surgery or total hip replacement.

This list is meant to answer the most common questions we receive about Hip Dysplasia. If you have questions that are not addressed by this list, please take a look around our website. There is much more information than we are able to list here in our FAQs. If our website is unable to answer your question(s), please Contact Us.

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