In the clinical report, the AAP recommends against routine use of ultrasound as a screening modality for DDH and suggests that imaging with ultrasonography or radiography, depending on the child’s age, be used as an adjunctive screening tool in selected situations that take into account risk factors or suspicious physical examination.
The report states that hip ultrasonography can be considered between the ages of 6 weeks and 6 months for “high-risk” infants who lack physical findings of DDH (see Table 2 and section on risk factors).
For accurate interpretation, the hip ultrasonogram should be reviewed by an experienced, trained examiner per American Institute of Ultrasound in Medicine and the American College of Radiology guidelines. The clinical report notes that regional variability of ultrasonographic imaging quality can be a factor in undertreatment or overtreatment of DDH.2
Using ultrasound as a diagnostic tool prior to age 6 weeks is not recommended because it has a high false-positive rate and may detect abnormalities that spontaneously resolve. The clinical report notes, however, that ultrasound may be used earlier to guide treatment of an Ortolani-positive hip.
As explained in the clinical report, use of radiography as an imaging tool should be deferred until children are aged at least 4 months when the femoral is ossified. Then, radiography (anteroposterior and frog pelvis views) can be considered for high-risk infants without physical findings or for children with positive clinical findings.
Although ultrasound can also be used for imaging children aged 4 to 6 months, radiography has advantages of wider access, a lower false-positive rate, and lower cost. The drawback of radiography versus ultrasonography is exposure to a very low dose of radiation. In the absence of evidence favoring one imaging modality over the other, the clinical report recommends choice be based on local conditions and the availability of experienced, trained pediatric hip sonographers.