The AASA (anterior acetabular sector angle) is the most reliable measure of acetabular insufficiency in the adult, since the coverage deficit tends to affect the anterior acetabulum. Measurements vary slightly from males to females; however, the cut-off point of 60 degrees is valid for both genders.

The AASA is measured by tracing a line uniting the centers of the femoral heads. From that line, the AASA is calculated by measuring the angle formed with a second line that intersects the anterior rim of the acetabulum.

The PASA (posterior acetabular sector angle) may be important to determine pre-operatively. Normally, it measures above 105 degrees.

The sum of AASA + PASA detemines the HASA (horizontal acetabular sector angle).

The FAV or femoral anteversion angle shows a good inverse relationship with the AASA: the greater the degree of femoral anteversion, the less acetabular coverage there is.

FAV is calculated as the angle between the posterior intecondylar line in the knee and a line along the femoral neck.