Fixation method, not vascular injury, is the primary determinant of union in gunshot-related femoral fractures: a retrospective cohort analysis

BACKGROUND: Gunshot-related femoral fractures pose significant challenges due to periosteal disruption, contamination, and potential vascular injury. The impact of fixation method and vascular status on union time and functional outcomes remains incompletely defined. OBJECTIVES: To evaluate the influence of vascular injury and fixation technique on fracture union and clinical outcomes in gunshot-induced femoral fractures. We hypothesized that intramedullary nailing (IMN) would demonstrate faster union than external fixation (EF), and that vascular injury would prolonged healing. METHODS: A retrospective cohort of 74 patients treated between 2015 and 2024 was analyzed. Group 1 consisted of EF with vascular injury (n = 19), Group 2 of EF without vascular injury (n = 19), and Group 3 of IMN without vascular injury (n = 36). Clinical variables, fracture characteristics, operative details, and radiographic outcomes were recorded. Delayed union was defined as union time > 6 months. Statistical analyses included ANOVA, Tukey tests, Fisher's exact tests, and multivariate regression. RESULTS: The mean age was 32.1 ± 9.7 years, and 98.6% were male. Most fractures occurred in zone 2 (85.1%). The mean operative time was longest in Group 1 (319 ± 61.3 min) compared with Groups 2 and 3. Overall mean union time was 7.4 ± 3.7 months; Group 3 demonstrated significantly shorter time for union (5.6 ± 3.2 months) than Group 1 (9.5 ± 2.9 months) and 2 (8.7 ± 3.6 months) (p < 0.001). Knee ROM was greatest in Group 3 (125.1° ± 7.5°, p = 0.001). Delayed union occurred in 34/38 EF patients (89.5%) and 11/36 IMN patients (30.6%). EF was associated with a substantially higher risk of delayed union than IMN (OR 19.3, 95% CI 5.5-67.8; p < 0.001). Vascular injury also increased delayed union risk, occurring in 18/19 patients with vascular trauma versus 27/55 without (OR 18.7, 95% CI 2.3-149.7; p = 0.0003). Fixation method was the only independent predictor of union time in multivariate analysis (p < 0.001). CONCLUSION: IMN results in faster union, better alignment, and superior knee motion compared with EF in gunshot-related femoral fractures. Although vascular injury contributed to prolonged healing, fixation method had the dominant influence on outcomes. Prospective studies with larger cohorts are needed.