Developmental Dysplasia of the Hip

Abstract

Developmental dysplasia of the hip (DDH) is a common condition seen in children worldwide, with incidence ranging from 1-34/1000 live births. Although universal ultrasound screening programs are used in some countries, selective ultrasound screening based on physical examination and risk factors is endorsed by American medical societies. Two ultrasound methods have been well described, the static Graf method focused on acetabular morphology and measurements, and the dynamic Harcke method which also incorporates femoral head position and stability assessed in orthogonal planes. Ultrasound of the hip is the preferred imaging method in infants up to age 4-6 months, with radiographs recommended thereafter. Treatment in Pavlik harness is highly effective in infants less than 6 months old, and ultrasound can be used to follow progress during treatment. Fast, non-sedated MRI of the hips is employed after surgical reduction and spica casting. Hip dysplasia may also be diagnosed in adolescence and young adulthood, either related to infant DDH or later onset. Early detection and intervention in adolescence provides a window of opportunity to realign the joint prior to the onset of osteoarthritis. Acetabular dysplasia is most commonly defined as a lateral center edge angle less than 20° on pelvic radiographs, with multiple other measurements also described. CT can be useful in further defining the 3-dimensional morphology of the acetabulum, while MRI can show concomitant labral hypertrophy and degeneration. Periacetabular osteotomy is the mainstay of surgical treatment for symptomatic hip dysplasia in adolescents and young adults.