BackgroundThis study aimed to compare the clinical efficacy of locking plate and intramedullary nail fixations in the treatment of patients with OTA/AO type 11C proximal humerus fractures.MethodsWe retrospectively analyzed the data of patients with OTA/AO type 11C1.1 and 11C3.1 proximal humerus fractures who underwent surgery at our institution from June 2012 to June 2017. Perioperative indicators, postoperative morphological parameters of the proximal humerus, and Constant–Murley scores were evaluated and compared.ResultsSixty-eight patients with OTA/AO type 11C1.1 and 11C3.1 proximal humerus fractures were enrolled in this study. Overall, 35 patients underwent open reduction and plate screw internal fixation, and 33 patients underwent limited open reduction and locking of the proximal humerus with intramedullary nail internal fixation. The total cohort had a mean follow-up duration of 17.8 months. The mean operation time of the locking plate group was significantly longer than that of the intramedullary nail group (P< 0.05), while the mean bleeding volume was significantly higher in the locking plate group than that in the intramedullary nail group (P< 0.05). The initial neck–shaft angles, final neck–shaft angles, forward flexion ranges, or Constant–Murley scores did not show significant differences between the two groups (P> 0.05). Complications, including screw penetrations, acromion impingement syndrome, infection, and aseptic necrosis of the humeral head, occurred in 8 patients (8/35, 22.8%) in the locking plate group and 5 patients in the intramedullary nail group (5/33, 15.1%; including malunion and acromion impingement syndrome), with no significant difference between the groups (P> 0.05).ConclusionsSimilar satisfactory functional results can be achieved with locking plates and intramedullary nailing for OTA/AO type 11C1.1 and 11C3.1 proximal humerus fractures, with no significant difference in the number of complications between these two techniques. However, intramedullary nailing has advantages over locking plates for OTA/AO type 11C1.1 and 11C3.1 proximal humerus fractures in terms of operation time and bleeding volume.