Measurement of filling ratio and alpha angle [27]. Anteroposterior radiograph of a left shoulder. The alpha angle (α) was measured between the shaft axis (blue line) and the stem axis (red line). Filling ration at the level of the metaphysis (FRmet) is a line perpendicular to the shaft axis, intersecting at the distal–medial border of the humeral platform. Filling ratio at the level of the diaphysis (FRdia) is a line perpendicular to the shaft axis, intersecting at the distal third of the prosthesis. The filling ratio is the quotient of the orange and green lines at the metaphysis (FRmet) and at the diaphysis (FRdia). Distances were calibrated based on the size of the glenosphere.