*2.4. Radiographic Evaluation*

All patients had standard preoperative and postoperative radiographs (true anteriorposterior, y view and axillary view). Radiographic assessment was performed by two independent viewers blinded to patient outcomes. Radiographic measurements were performed on standard anteroposterior (AP) view performed at the most recent preoperative and last postoperative visit. Preoperative measurements included center of rotation (COR), critical shoulder angle (CSA) acromiohumeral distance (AHD), lateral humeral offset (LHO), and glenoid inclination (GI). Postoperative measurements included AHD, LHO, baseplate inclination (BI), distalization shoulder angle (DSA), and lateralization shoulder angle (LSA) [20,21,24–26].

AHD was measured by calculating the perpendicular distance between the most lateral portion of the undersurface of the acromion and a line parallel to the superior border of the greater tuberosity [21] (Figure 1). LHO was measured by determining the distance from the AHD line to the most lateral projection of the greater tuberosity [21] (Figure 2). LSA was measured by drawing a line from the superior glenoid tubercle to the most lateral border of the acromion and a second line from the most lateral border of the acromion to the most lateral border of the greater tuberosity. The angle between these two lines formed the LSA [20] (Figure 3a). DSA was measured by drawing a line between the most lateral border of the acromion and the superior glenoid tubercle and drawing a second line to connect the superior glenoid tubercle with the most superior border of the greater tuberosity. The angle between these two lines formed the DSA [20] (Figure 3b). Glenoid and baseplate were determined as the angle between the floor of the supraspinatus fossa and the glenoid fossa [25] (Figure 4). COR was measured by determining the best fit circle flush to the articular surface, identifying the center of the circle in the humeral head, and then measuring the distance of the perpendicular line between the center of the humeral head

and the midpoint of the line connecting the superior and inferior glenoid tubercles [24] (Figure 5b). CSA was measured by a line from the superior pole to the inferior pole of the glenoid and a line from the inferior pole to the lateral edge of the acromion [26] (Figure 5a). In addition, scapular notching was graded according to the Nerot–Sirveaux classification and severity of preoperative cuff tear arthropathy was evaluated according to the Hamada classification [27,28].

**Figure 1.** (**a**) Preoperative acromiohumeral distance (AHD; green line); (**b**) postoperative acromiohumeral distance (AHD; green line).

**Figure 2.** (**a**) Preoperative lateral humeral offset (LHO; green line); (**b**) postoperative lateral humeral offset (LHO; green line).

**Figure 3.** (**a**) Lateralization shoulder angle (LSA); (**b**) distalization shoulder angle (DSA).

**Figure 4.** (**a**) Glenoid inclination (green angle); (**b**) baseplate inclination (green line).
