Hip Dysplasia-IMAGING AND OTHER DIAGNOSTIC STUDIES

 ■ Dynamic hip ultrasound can be used to detect hip dysplasia in very young infants (under 6 months of age). 

■ Plain radiographs, including an anteroposterior (AP) view of the pelvis and false profile views, typically can be used to make the diagnosis in older children.

 ■ Radiographic parameters, including the acetabular index, lateral center–edge angle, anterior center–edge angle, the position of the sourcil, and the line of Shenton, should be evaluated .

■ Dislocation is detected by lack of contact between the acetabulum and femoral head. 

■ Subluxation is detected by a break in the line of Shenton.

 ■ Acetabular dysplasia can be detected by a decrease in the lateral center–edge angle or an increased acetabular index on the AP pelvic radiograph or a decrease in the anterior center–edge angle on the false profile view.

 ■ A pelvic radiograph with the legs abducted and internally rotated can give some idea about the ability of the hip to reduce, with either increased acetabular coverage or a femoral osteotomy. 

■ A CT scan can provide a closer look at anterior and lateral coverage.