Ultrasound in the diagnosis of congenital dysplasia and dislocation of the hip joints in children older than two years.

To evaluate the use of ultrasound in the diagnosis to congenital dysplasia and dislocation of the hip (CDH) in children older than two years of age, 64 patients with normal hip joints and 47 patients with present or previous CDH were examined. Lateral and anterior ultrasound scanning was employed, and the coverage of the femoral head by the acetabular roof was assessed. The ultrasound measurements were compared with standard roentgenography, and a good accordance between the methods was found. A lateral projection of the femoral head in relation to the bony acetabular rim of more than 8 mm in children younger than ten years of age indicated subluxation and more than 15 mm at age two to four years indicated dislocation. Reliable images were obtained by ultrasound at any age between two and 18 years. Ultrasound is recommended as the primary imaging technique in the evaluation of hip joints, even in older children, and ultrasound should replace roentgenography in most of the follow-up examinations of children with previous CDH.