I think what you are referring to is the Barlow and/or Ortolani tests, which are used by most physcians and paediatricians, when checking for congenital disclocation of the hip in the newborn, and upto and including babies of 4-6 months of age.
Despite what has been suggested , nobody is 'listening ' for a 'click' or indeed to hear bones cracking, (ouch) the dislocated hip can quite easily moved in and out of the joint due to instability and lax hip ligaments.
Just to reassure, this is only done by proffessionals trained to use these techniques as part of an overall diagnostic process.
It is considered best practice in this country, to screen every newborn infant, and again at the six week check., because it may not present at birth.
A family history of CDH, a breech presentation, will automatically be referred for ultrasound .
Carpenter, only a tiny minority of those referred need any surgical intervention, and most babies are being detected early these days, and will only need the double nappy job, or the soft harness.
good luck!