[Difficulties in the treatment of congenital instability of the hip].

The method of early diagnosis of congenital dislocation of the hip and the results of immediate treatment are described. X-rays are only useful to prove an instability if the hip is dislocated at the moment the X-ray is taken. If the unstable hips are reduced and redislocation is prevented by means of a splint the great majority of the hips show a normal developement. A primarily unstable hip which was stabilised spontaneously or by using a splint for a short time may become unstable again. Nevertheless splinting in the stable positon should not last longer than 1-2 months. The development of a coxa vara in three children rises the question whether the fixation of the hips in a frog position combined with the presence of a contraction of the adductors may impede the blood supply to the epiphysis and metaphysis. Early diagnosis of congenital dislocation of the hip means demonstration of instability of the neontal hip and not diagnosis of "dysplasia" during the first year of life. "Dysplasia" without instability does not mean predislocation. It is either a stable dysplasia or a residual sign of neonatal instability which became stable with or without treatement. Difficulties in diagnosis of neonatal instability are discussed. Etiology, pathogenesis and genetics of congenital dislocation of the hip are mentioned.