Clinical Utility and Safety of Bone Cement Augmentation in Intramedullary Nailing for Proximal Femur Fractures: A Multicenter Prospective Observational Study.

Introduction: Proximal femur fractures are common in older adults and are associated with high morbidity and mortality. Bone cement augmentation during intramedullary nailing has been reported to improve implant stability; however, its clinical utility and safety in Japan remain unclear. Materials and Methods: This multicenter prospective observational study included patients aged ≥45 years who underwent intramedullary nailing for trochanteric or basicervical femoral fractures between May 1, 2021, and July 31, 2023. Cement augmentation was applied exclusively to patients aged ≥60 years. Femoral neck fractures were excluded. Patients were treated with cement augmentation (CA group) or without augmentation (N group). The primary outcome was screw cut-out within 6 months postoperatively. Secondary outcomes included sliding distance (>5 mm), reoperation, nonunion, postoperative infection, and other complications. Group comparisons were performed using two-sided statistical tests with p < 0.05 considered significant. Results: A total of 300 patients were analyzed (CA, n=97; N, n=203; mean age 86.8 years). No cut-out occurred in the CA group, whereas four cases (1.9%) occurred in the N group (p = 0.12). Sliding distance >5 mm was observed in 2 patients (2.0%) in the CA group and 12 patients (5.9%) in the N group (p = 0.108). Postoperative complications occurred in 2 patients (2.1%) in the CA group and 12 patients (5.9%) in the N group (p = 0.12). No cement-related adverse events were observed. Conclusions: Cement augmentation during intramedullary nailing was safe and showed numerically lower rates of cut-out and excessive sliding compared with non-augmented fixation. Although statistical significance was not reached, these findings suggest a potential clinical role in elderly patients at high risk of fixation failure. Randomized controlled trials are warranted.