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.
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 anti-inflammatory 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.
Sourced from the International Hip Dysplasia Institute (hipdysplasia.org)
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