HIPPO artificial intelligence: Correlating automated radiographic femoroacetabular measurements with patient-reported outcomes in developmental hip dysplasia

Table 2 HIPPO radiographic hip measurements and landmarks

Measurement	Description
CCD	The CCD angle was measured as the angle between the femur neck and shaft axis[23]
Pelvic obliquity	The pelvic obliquity was measured with a tangential line from the apex of the femoral heads and a line parallel to the horizontal plane as in Figure 1
Sharps angle	Sharp’s angle was measured with a line connecting the inferior ischial tuberosities and a line connecting the lower medial edge of the acetabular teardrop and the lateral edge of acetabular sourcil[23]
LCEA	The LCEA was measured as a perpendicular line through the center of the femoral head perpendicular to the acetabular tuberosities and the angle between a line from the center of the femoral head to the lateral acetabular sourcil[24]
Extrusion index	The extrusion index was measured by the difference of medial and lateral femoral head and the lateral edge sourcil with three vertical lines at edge aspect. The femoral head coverage was represented by the percentage of femoral head covered: Lateral femoral head to lateral edge sourcil distance minus the total horizontal head diameter[23]
Tönnis angle	The Tönnis angle was measured as the angle between a line connecting the inferior and lateral aspects of the acetabular sourcil and a line connecting the inferior portion of the ischial tuberosities[12]

CCD: Caput-Collum-Diaphyseal; LCEA: Lateral center edge angle.