From 1965 to 1974, 849 children with congenital dislocation of the hip (CDH) or congenital subdislocation of the hip (CSdH) were treated in our department, and primary reduction was achieved by conservative treatment in 685 cases. Seventy-five of them which had an unsatisfactory course as revealed by plain roentgenograms underwent arthrographic examinations under the age of 5 years. In the present study, 58 of them (69 hips) were evaluated around the age of 10 according to the system of Severin. The arthrographic findings were retrospectively analyzed to see if the arthrogram is of value in making prognoses. The results indicated that children showing an α angle greater than 28.0 degrees or a negative CE angle in plain roentgenograms require further arthrographic examination of the hip joint. Additional operations were thought to be necessary from treatment of cases in which arthrography revealed an α angle greater than 30 degrees or an α' angle greater than 11.6 degrees or interposition. The interposition disturbing the concentric reduction of the joint was demonstrated arthrographically as an arched shadow which continued from the "limbus" to the center of the cartilaginous acetabulum. Factors that indicate the probability of poor results according to Severin's evaluation are the presence of interposition and/or an abnormally thickened cartilaginous acetabulum: greater than 3.0mm at the Y cartilage, greater than 3.2mm at the pubic and ischial bones, or greater than 5.2mm at the iliac bone.
Congenital Dislocation of the Hip