New technique for early screening of developmental dysplasia of the hip: pilot study.

An acoustical technique has been developed for early screening of developmental dysplasia of the hip (DDH) in neonates by comparing the sound transmitted across the hips while a vibratory force was applied to the sacrum. The baseline for 90 normal neonates has been established and tests in the frequency bands of 200, 250, and 315 Hz were found to be most effective, achieving high coherence and smallest discrepancy. Sixteen patients with unilateral DDH were examined and the results suggested that coherence below 0.8 in at least one of these frequency bands was strongly indicative of structural asymmetry between both hips, and there was a significant difference between normal neonates and patients with unilateral DDH. By setting the cut-off discrepancy at 2.0 dB, the best sensitivity (100%) would be achieved, and this could be proposed as the threshold for wide-scale screening of DDH.