The objective of this retrospective study was to investigate the surgical outcomes of AO/OTA 31 A1-3 trochanteric fractures treated with the new-generation Gamma3 nail with U-Blade (RC) lag screw and to analyze the risk factors related to fixation failure. A total of 318 consecutive patients who underwent cephalomedullary nailing using Gamma3 nail with U-Blade lag screw for trochanteric hip fractures between September 2015 and June 2018 were enrolled. The average age was 80 years and most patients (69%) were women. The mean follow-up was 12.2 months with a minimum of 6 months. 309 (97.2%) showed bony union with a mean time to union of 13.5 ± 8.7 weeks. Cut-out occurred in 2 patients (0.6%) and 7 patients showed excessive collapse (≥15 mm) of the proximal fragment. These 9 patients were assigned to the failure group. The presence of a basicervical fracture component and comminution of the anterior cortex on preoperative 3-D CT showed a significant association with fixation failure, including cut-out, although comminution of the anterior cortex was the only independent risk factor for fixation failure on multivariate logistic regression analysis. Gamma3 nail with U-Blade lag screw showed favorable results for trochanteric hip fractures, with low cut-out rate (0.6%). However, more caution is required in treating trochanteric fractures with a basicervical fracture component and anterior cortex comminution even with this nail.