Comparison of audible sound transmission with ultrasound in screening for congenital dislocation of the hip.

In a comparative study ultrasound and the sound transmission test were used to seek congenital dislocation of the hip in 102 babies referred to a paediatric orthopaedic clinic. The sound transmission test correctly identified all those hips considered normal or dislocated on ultrasound. 17 babies underwent repeated ultrasound examination for hips considered abnormal but not dislocated. 12 improved and 5 required treatment. With a cut-off decibel difference between the hips of 5.8 dB the sound transmission test correctly identified the dislocated hips but did not detect some of the hips that needed treatment. A cut-off of 5.6 dB reduced the likelihood of a false-negative result while maintaining the sensitivity of the test.