Positioning the Infant for a Pelvic Radiograph

Abstract

It can be difficult to take reproducible radiographs of infants’ hips. We have compared antero-posterior pelvic radiographs when the infant's hips are held in flexion or extension. One hundred and fifty radiographs of infants aged 3 to 12 months have been analysed. Radiographic indicators for the diagnosis of developmental dysplasia of the hip and alignment pelvic indicators have been assessed. There were significant differences using the Student t-test analysis for the symphysis-os ischium angle (p<0.0001) and the pelvic tilt index (p=0.0017) between the positions of the infants’ hips on the x-ray table. Twenty degrees of hip flexion increases the pelvic tilt backward (decreased lumbar lordosis). When positioning infants over 3 months old on the x-ray table the neutral antero posterior position is preferable. The pelvic position is more neutral when the hips are extended.