Effects of proximal smooth pegs on surgical outcomes of plate fixation for proximal humeral fractures

Background Plate fixation yields satisfactory functional outcomes in proximal humeral fractures; nonetheless, a relatively high complication rate has been reported. Smooth pegs were introduced to reduce proximal screw cut-out. However, no direct comparison has been performed between proximal pegs and screws within the same plate system. This study aimed to compare the surgical outcomes of osteosynthesis with ALPS plates featuring proximal pegs and screws. Methods Fifty-four patients who had undergone plate fixation for proximal humeral fractures were retrospectively identified. All operations were performed by the same surgeon using a deltopectoral approach. Whereas ALPS plates fixed exclusively with proximal pegs were used prior to January 2024 (peg group, 26 patients), those with exclusive proximal screw fixation were used after February 2024 (screw group, 28 patients). As an outcome measure, we assessed postoperative shoulder functional scores and compared the two groups regarding the respective rates of complication. Results At 1 year postoperatively, no significant between-group differences were observed in the adjusted Constant and American Shoulder and Elbow Surgeons scores. Nonetheless, the incidence of loss of greater tuberosity reduction was significantly higher in the peg group than in the screw group (23.1% vs. 3.6%, P = 0.047). Conversely, three patients required revision surgery because of symptomatic proximal implant penetration or varus progression in the screw group, whereas no patients required reoperation in the peg group. Conclusions The use of proximal pegs rather than screws did not significantly affect postoperative functional outcomes, although reoperation was not required in the peg group. Nevertheless, proximal threaded screws are recommended for three-part fractures to reduce the risk of secondary displacement of the greater tuberosity. Trial registration: Not applicable.