BackgroundThe importance of tuberosity healing in reverse total shoulder arthroplasty for proximal humeral fractures has been recognized. The turned stem tension band technique has been applied to tuberosity repair, and high bone healing and low reduction loss rates have been reported. Vertical sutures were added to the original method to reinforce fixation. We hypothesized that vertical sutures would be unnecessary in case the supraspinatus tendon was resected. This study aimed to compare the turned stem tension band technique with or without vertical suturing for proximal humeral fractures and evaluate the rates of tuberosity healing and reduction loss. Methods35 patients (vertical suture group: 18 cases, non-vertical suture group: 17 cases) who underwent reverse total shoulder arthroplasty for complex proximal humeral fractures using the turned stem tension band technique. We evaluated the postoperative range of motion, the American Shoulder and Elbow Surgeons score, tuberosity healing rates, and reduction loss. ResultsThe vertical and non-vertical suture groups showed no significant difference in flexion (119±33° vs. 124±23°, P =0.95), abduction (116±35° vs. 115±27°, P= 0.78), external rotation (27±12° vs. 21±8°, P= 0.16), internal rotation (6±4° L3 vs. 6±4°, L3 P= 0.87), the American Shoulder and Elbow Surgeons (77.3±10.7 vs. 81.6±6.3, P =0.59), Numerical Rating Scale scores (1.2±0.9 vs. 0.8±0.9, P= 0.13), and tuberosity reduction loss (P=0.34). The tuberosity healing rate in both groups was 100%. ConclusionsThe turned stem tension band technique for proximal humeral fractures provided high tuberosity healing and low reduction loss rates, regardless of vertical sutures.