system
Given the following post, respond as if you're commenting on Reddit:
human
Why is the type of hip deformation I see in the developing world so uncommon in the developed world?

After years living in the Middle East, South Asia, and North and Subsaharan Africa, I've noticed that a very common physical deformity in the legs/pelvis leaves people able to walk, but with a characteristic uneven, staggered gait.  While I'm sure this is not always caused by the same sort of condition, it's something I never see in the United States or Western Europe, where people seem to have it treated at a very young age.  I know this question is vague, but do any doctors out there know what I'm talking about and can explain why and how this is treated in richer countries?
gpt
What it sounds like you are describing is called developmental dysplasia of the hip. This is a condition where the acetabulum (cup) of the hip joint is shallow, and the head of the femur is not properly secured within the bony architecture. The femoral head needs this contact to develop properly, and without intervention this disease will lead to problems with gait later in life. There are simple physical tests (Barlow and Ortolani tests) that most pediatricians can do to catch DDH, and treatment requires several months in a Pavlik harness. Surgery may also correct the defect, but it is used as a last resort option following failure of non-invasive methods. 

The Pavlik harness is cumbersome, and delays the child's walking by the amount of time he or she is in it. Some cultures may not see the long term benefit of this, and only worry about their child's 'delay'. Additionally, some cultures have a fear/rejection of invalids and having a child in a very publicly obvious harness might also not agree with them. Diagnosing the disease early is simple, it only requires the doctor to look for it (which is standard practice until a child begins to walk).