Clinical meaning
Developmental dysplasia of the hip (DDH) occurs when the femoral head is not properly seated within the acetabulum (hip socket), ranging from instability to subluxation to complete dislocation. The Pavlik harness is the primary treatment for DDH diagnosed before 6 months of age. It holds the infant's hips in flexion and abduction to keep the femoral head centered in the hip socket, allowing the acetabulum to develop and deepen normally around the femoral head over 6-12 weeks of continuous wear.
Exam relevance
Risk factors: - Breech presentation at birth (strongest risk factor) - Female infant (4-8 times more common than males) - First-born child - Family history of hip dysplasia - Oligohydramnios (low amniotic fluid) - Left hip more commonly affected - Cultural swaddling with legs straight and together
Diagnostics: - Ortolani test (hip abduction produces a clunk = femoral head going back in) - Barlow test (hip adduction produces a clunk = femoral head sliding out) - Hip ultrasound for infants under 6 months - Asymmetric thigh or gluteal skin folds - Limited hip abduction on one side - Unequal knee heights when hips flexed (Galeazzi sign)