[Modern viewpoints of hip joint dysplasia, clinical and radiologic. III. Radiologic follow-up].

Dysplasia of the hip-joint can unequivocally be recognized at the age of 7 weeks as proved by further developments. Defects in the acetabular angle remain in spite of abductionsplints which may have to be continued until the acetabular roof including its angle have become normal. It must not be abandoned when the PDW has returned to normal. One ought to demand that treatment should be started before this stage has been reached i.e. before the 7th week of life. 1. Clinical and radiologic observations in the first 3 months prove that dysplasia of the hip-joint can be well recognized at this early stage. A diagnosis beyond the 3rd month is a late diagnosis. 2. Essential radiologic signs are: wedge-segments, delayed ossification of the acetabular angel, "Tailliation" at the angle, subchondral sclerosis of the acetabular roof, double contour of the angle in radiographs and, in severe cases, steep PDW. 3. The averages and standard deviations of the Tonnis statistics have proved too large for the radiographs of the first 2 months of life and useless as shown in follow-up. 4. The dysplastic acetabulum is not immature but pathologic. 5. The common mild dysplasias cannot be recognized with PDW but only when searching for structural and contour changes at the acetabular roof.