Measurement of acetabular angle using ultrasound.

We have developed a method of measuring the acetabular angle by using ultrasound. Normal acetabular roofs are delineated as curvilinial hyperechoic lines on the screen, whereas in displastic hips the outlines of the acetabular roofs are shallower and more vertical. The values of 150 acetabular angles of 75 babies measured by ultrasound were in reasonably good agreement with those derived from roentgenography. This is a safe, handy, and effective for measuring the acetabular angle.