Developmental Dysplasia of the Hip

Developmental Dysplasia of the Hip (DDH) is a malformation of the hip characterized by a shallow acetabulum and undercovered femoral head. The condition presents in ~1% of infants as a spectrum of pathology from physiologic immaturity of the hip to a frank dislocation. Risk factors for DDH include female sex, first born, family history of hip dysplasia, and breech presentation. Physical exam may yield findings of DDH including asymmetric thigh folds, limited hip abduction, positive Galeazzi sign, Ortolani maneuver, or Barlow maneuver. Regardless of clinical findings, diagnosis is confirmed with ultrasound in infants as an alpha angle <60° and/or femoral head coverage <50%. In toddlers through adolescents, plain radiography is used to evaluate the shape of the hip through the acetabular index, lateral center edge angle, and anterior center edge angle. Conservative treatment of infantile DDH with the Pavlik harness is successful in treating even severe dysplasia or dislocations in patients under 6 months of age. Abduction orthoses may be successful as a second-line treatment, particularly in Ortolani-positive hips under 6 months of age. Closed or open reductions may be performed for dislocations refractory to conservative treatment or in those hips detected after 6 months of age. With increasing age at time of reduction, concurrent femoral and/or pelvic osteotomy may be needed to obtain stable reduction. Following reduction, the two most common sequelae include residual dysplasia and avascular necrosis of the femoral head. Consequently, surveillance for these sequelae is essential as residual dysplasia is common with frequent need for secondary reconstructive surgery.