Open Versus Closed Reduction in Subtrochanteric Femur Fractures: The Critical Role of Acceptable Reduction in Healing Outcomes

Introduction Subtrochanteric femur fractures are challenging injuries due to high mechanical stress and compromised vascularization, resulting in higher complication rates compared with other proximal femur fractures. While intramedullary nailing is the treatment of choice, controversy persists regarding whether open or closed reduction provides superior outcomes. Some evidence suggests that open reduction may achieve better alignment, whereas others highlight risks of impaired biology, blood loss, and infection. This study aimed to compare open versus closed reduction in subtrochanteric fractures treated with intramedullary nailing and to assess the influence of reduction quality on bone healing outcomes. Methods We performed a retrospective cohort study including 190 patients with subtrochanteric fractures treated surgically between 2017 and 2024. After exclusions, 114 patients met the inclusion criteria (minimum six months of follow-up with complete clinical and radiographic data). Open reduction was defined as requiring an incision ≥3cm and the use of reduction instruments, with or without cerclage augmentation. Reduction quality was classified as acceptable or non-acceptable according to modified Baumgaertner criteria. Outcomes included delayed union (more than six months) and nonunion (more than nine months without progression). Statistical analyses included t tests, chi-square/Fisher's exact tests, and Kaplan-Meier survival analysis, with significance set at p<0.05. Results Of the 114 patients, 39 (34.2%) underwent open reduction and 75 (65.8%) closed reduction. Acceptable reduction was achieved in 88 patients (77.2%), significantly more often in the open group (94.9% vs. 68.0%; p=0.001). The mean time to union was shorter in the open reduction group (18.2 ± 7.5 vs. 21.2 ± 7.9 weeks), but this difference did not reach significance (p=0.055). Delayed union occurred in 22 patients (19.3%), without significant group differences (12.8% open vs. 22.7% closed; p=0.21). Nonunion was observed only in the closed reduction group (5.3%; p=0.14). Reduction quality was a strong predictor of outcomes: the group with acceptable reduction had a faster union (18.1 ± 6.5 vs. 28.3 ± 7.6 weeks, p<0.001), lower delayed union (10.2% vs. 50.0%; p<0.001), and absence of nonunion (0% vs. 15.4%; p=0.002) in comparison with the non-acceptable reduction group. Discussion Although open reduction achieved acceptable alignment more frequently, clinical outcomes such as delayed union and nonunion did not significantly differ between open and closed approaches. Instead, reduction quality emerged as the most decisive factor, strongly associated with faster healing and fewer complications. These findings suggest that achieving an acceptable reduction outweighs the influence of the chosen surgical approach. Conclusion In subtrochanteric femur fractures treated with intramedullary nailing, reduction quality is the key determinant of healing outcomes. Acceptable reductions, whether achieved through open or closed techniques, significantly reduce delayed union and nonunion. Surgeons should prioritize achieving acceptable alignment.