Fig. 2.

Schematic diagram showing the definition of the screw-apex distance (SAD) and the tip-apex distance (TAD). The SAD was measured as the distance between the apex of the weight-bearing area and the end of each screw on anteroposterior (AP) and conventional lateral radiographs of the hip (A and B). The TAD was measured as the distance between the apex of the medial femoral head and the tip of each screw on AP and lateral radiographs of the hip (C and B). All images were calibrated using the known diameter of the screw