[Appearance of the femur head epiphysis in healthy children and in children with hip dysplasia].

In a retrospective study we evaluated 4341 sonographic examinations of 1160 healthy children and 209 children with congenital hip dysplasia with special reference to the appearance of the femoral head epiphysis. In healthy children the epiphysis appeared between the first and seventh month. In more than 95% of the children, the epiphysis was sonographically present after the seventh month. In children with congenital hip dysplasia the first appearance of the femoral hip epiphysis had a retardation of one to two months. In most of the healthy children the epiphysis appeared in the fourth month, and after the ninth month in almost all of the normal hip joints the epiphysis is present. In children with normal hip joint configuration and missing femoral head epiphysis at three months, the final ultrasound examination should not be done before the seventh month. Thus, clinically unnecessary ultrasound examination in 6-week intervals can be reduced.