The hip is considered a “ball-and-socket” joint. Normally, the ball at the upper end of the femur fits firmly into the socket of the large pelvis bone. In all forms of hip dysplasia, this causes the ball of the hip to sit loosely in the socket, making it easy to dislocate.
Hip dysplasia is characterized by pain in the groin region that extends to the outer thigh. An affected individual may experience weakness in legs, difficult walking, loss of mobility, limping or waddling. Some cases of hip dysplasia in adults are subtle and may not be recognized until symptoms are prevalent.
A joint that is out of place or too shallow will wear out faster than a normal hip. Non-operative methods may be chosen in mild cases and are designed to decrease pain but may only provide temporary relief, which is why most people with hip dysplasia need surgery at some point or another.
Developmental Dysplasia of the Hip or DDH is a particular type of hip dysplasia present at birth or in the first year of a child’s life. Improper swaddling of infants may lead to problems like DDH. In individuals with DDH, the socket is too shallow to let the ball of the femur to fit firmly. The ligaments that help hold the joint in place may also be stretched.
The severity of hip looseness varies among those with DDH. Nonsurgical treatments include placing the baby in a soft positioning device for 1 to 2 months to keep the femur in the socket. These methods are usually successfully for babies younger than 6 months old. Surgical treatments are most often performed on children 6 months and older.
Reference: International Hip Dysplasia Institute, “Adult Treatments for Hip Dysplasia”. http://hipdysplasia.org/adult-hip-dysplasia/adult-treatments/
Reference: American Academy of Orthopaedic Surgeons, “Developmental Dislocation (Dysplasia) of the Hip (DDH),” October 2013. http://orthoinfo.aaos.org/topic.cfm?topic=a00347