Final answer:
The newborn should be checked for hip dislocation and dysplasia using Ortolani's maneuver.
Step-by-step explanation:
To check for hip dislocation and dysplasia in newborns, the technique that would be used is Ortolani's maneuver. This technique involves manually moving the hips in order to feel for any clicking or clunking sensations, which could indicate a problem with the hip joint.