Neonatal Hip Dysplasia

Make the Diagnosis: Dislocated Hip in Infants

Prior Probability of Development of Hip Dysplasia in Infants

Developmental hip dysplasia ranges in severity from instability of the hip to frank dislocation. It occurs in 4 to 23 infants of 1000 live births. Among infants screened with a clinical examination and a diagnostic ultrasound, the prevalence of a dislocated hip is 0.94% (95% CI, 0.28%-2.0%).¹

Population Who Should Be Screened for Hip Dysplasia

The rationale for screening is that a delayed diagnosis (eg, after 4 months of age) may result in the need for surgery to restore the position of the hip. This may require immobilization of the hip and thigh for up to 6 months using a spica cast.

There are different approaches to population screening for hip dysplasia. Some countries (such as Austria²) recommend hip ultrasounds at 3 to 5 days for all newborns and again at 6 to 8 weeks of age for all infants, whereas other countries such as the UK³ and the US⁴ selectively perform ultrasound screening after an abnormal clinical examination or in the presence of risk factors (eg, female sex, positive family history of developmental dysplasia of the hip).

Assessing the Likelihood of a Dislocated Hip

The clinical examination involves first looking for asymmetry between the hips, though one-third of affected children have bilateral dislocation that appears symmetric. The examiner assesses the range of motion during gentle abduction (>20° difference between the hips is abnormal), or if the examiner thinks there is restriction, in the instance that bilateral disease is suspected (Table 114-1). Next, the Barlow procedure is done, in which the infant lies supine with the hip and knee flexed to a 90° angle (watch the video at https://edhub.ama-assn.org/jn-learning/video-player/18867177). While the infant lies supine with the hip and knee flexed to a 90° angle, the examiner places their index and middle fingers laterally over the infant’s greater trochanter and their thumb medially along inner thigh. Each hip is separately examined with gentle adduction while the opposite hip is stabilized; downward force is applied to the adducted hip. A positive result is when the downward force dislocates the hip. The Ortolani procedure then immediately follows, in which the examiner gently abducts the hip (from the final Barlow position) while an upward anterior force is applied to the greater trochanter. A positive result occurs when a “clunk” is felt as the hip relocates into its proper position. A positive Barlow and Ortolani maneuver are the most useful findings for dislocation (Table 114-1). Clicking sounds can be heard by the examiner or reported by the parents or caretaker, but the sounds are of little diagnostic value (Table 114-1).