A one-month-old girl had a physical examination suggesting developmental dysplasia of the hip (DDH). A coronal sonographic image through the right hip in neutral position, performed at one month of age, demonstrated an abnormal alpha angle of 47 degrees and less than 50% coverage of the femoral head under the acetabular roof (Fig. 83.1a). Pelvic AP radiograph at three months of age demonstrated a steep right acetabular roof with asymmetrically delayed ossification of the right femoral head (Fig. 83.1b).
A three-year-old girl with a chromosomal deletion syndrome presented with bilateral hip pain and difficulty with abduction. Pelvic AP radiograph demonstrated dysplastic acetabulae with bilateral femoral head dislocation, pseudoacetabula formation, and valgus deformity (Fig. 83.2a). Frog leg view demonstrated that the hips did not relocate with abduction (Fig. 83.2b). This appearance is typical of secondary neurogenic hip dislocation related to muscle imbalance and overactive hip adductors.