Figure 3

The vault method as an alternative glenoid version measurement. The same cases as Figure 2 are measured with the vault method. The glenoid line is the same as that of the conventional method (blue line). The glenoid vault axis is defined as the line connecting the tip of the scapular vault and the center of the glenoid line (red solid line). Glenoid version measured with the vault method (β) is calculated as the angle between the glenoid line and the line perpendicular to the glenoid vault axis (red dashed line). (A) The vault method for measuring a normal shoulder. Glenoid vault retroversion is 9.7°. The difference between conventional glenoid version and glenoid vault version is only 3.5°. (B) The glenoid has 5.0° retroversion when measured with the vault method. The difference between conventional glenoid version and glenoid vault version amounts to 13.9°. (C) The vault method for measuring an arthritic shoulder. The glenoid vault has 34.8° retroversion. The difference between conventional glenoid version and glenoid vault version is 6.5°.