[Radiologic detection of congenital hip dislocation at the 4th month].

For the systematic detection of the congenital dislocation of the hip the roentgen examination must be performed at the beginning of the fourth month. At birth, only are X rayed the dislocations clinically detected in order to have a picture for the follow-up and to check the beneficial effect of the treatment by an abduction device. At the fourth month, for radiological detection, an ordinary frontal film of the pelvis is performed with a strict technique. The criteria of a well performed radiograph are given. For the diagnosis of dislocation the roentgen signs are quite precise. Among them, the high-value of the acetabular angles is not longer considered as a good criterion for detection at this age. It has been shown that radiological mass screening is beneficial from the socio-economic and radiation risk point of view. Nevertheless such a mass screening, in our opinion, is not advisable. Radiological screening must be restricted to infants at risk (infant born after breech presentation, infant with pes talus, genu recurvatum, torticollis, infant with other cases in the family, first born in a family, mainly if of important birthweight).