Due to abnormal relationship of femoral head to acetabulum, usually in otherwise healthy infants prior to or shortly after birth
Rare: <2% incidence
4-6X more common in females
Developmental dysplasia of hip
Acute rheumatic fever
Avascular necrosis of hip
Ankle dislocation
Femur fracture
Hip bursitis
Juvenile idiopathic arthritis
Elbow dislocation