Great advances have been made in developing strategies to improve the quality of medical care in the past decade; these advances include better diagnostic technologies, such as ultrasonography (US), computed tomography, and magnetic resonance imaging. Although these tests provide new information on many conditions, such as developmental dysplasia of the hip (DDH), the differentiation of what is normal, what is abnormal, and what is disease is no longer intuitive. Historically, the diagnosis of DDH was straightforward. The diagnosis was based primarily on clinical findings, which were often confirmed with radiography. Abnormal hips were either subluxated or dislocated and, if left untreated, adverse consequences were certain in either situation. Since the introduction of hip US, however, increased diagnostic sophistication has led to uncertainty as to how to interpret the continuous spectrum of acetabular morphology. There is no consensus on the degree of acetabular dysplasia that does or does not require treatment. Because not every abnormal finding may require treatment, the terms abnormality and disease are not synonymous.
(c) RSNA, 2007.