BACKGROUND: The purpose of our study was to evaluate the functional and radiologic outcomes of additive augmentation sutures through rotator cuff for proximal humeral fractures stabilized locking plate in elderly patients. METHODS: We enrolled 74 patients over the age of 60 years who received internal fixation using locking plates for proximal humeral fractures. Of these, 50 patients had additive augmentation sutures through rotator cuff. The mean age at the time of surgery was 72.1 years (range, 60-89 years), and the mean follow-up period was 17.5 months (range, 12-62 months). The humeral neck-shaft angle and humeral head height were used as radiological markers to assess the effect of additive augmentation sutures through rotator cuff. We allocated the patients who received additive augmentation sutures into group A and those who did not into group B. RESULTS: At the final follow-up, the mean Korean Showlder Society score and Constant scores were 88.96 +/- 12.1 and 86.6 +/- 11.9, respectively, in group A and 86.21 +/- 11.8 and 85.3 +/- 11.7, respectively, in group B (p=0.368, 0.271). At the final follow-up, the mean loss in humeral neck-shaft angle from the time of immediate postoperative measurement was 1.6degrees in group A and 4.8degrees in group B, whereas the mean loss in humeral head height was 0.82 mm in group A and 0.52 mm in group B (p=0.029, 0.178). CONCLUSIONS: The surgical outcomes of internal fixation using locking plates for proximal humeral fractures were clinically and radiologically good in elderly patients over the age of 60 years without any observable complications. Further, the loss of humeral head shaft angle at the final follow-up from its initial postoperative measurement was significantly smaller in patients who received an additive augmentation suture than in those who did not. Thus, we conclude that augmentation sutures are a beneficial option for elderly patients that clinicians can consider at the time of surgical decision making.