The hip joint consists of a femoral head which is part of the femur (thigh bone) and the acetabulum of the pelvis which form a ball and socket joint. The femoral head fits into the acetabulum and is held together by surrounding ligaments and a joint capsule.
Hip dysplasia also known as developmental dysplasia of the hip (DDH), is when the hip joint is displaced. The ball and socket joint do not fit together in the ‘ideal’ ‘normal’ position.
There are different severities of hip dysplasia, from subluxation where the femoral head is no longer in the socket of the joint or worse the hip can be slightly or completely dislocated.
There are no known causes of DDH as it can develop during birth, after birth and even in childhood but some possible causes include;
Reference:
http://hipdysplasia.org/developmental-dysplasia-of-the-hip/causes-of-ddh/
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