Femoral neck fractures: a cohort comparison of nonunion and complication rates after ballistic versus blunt mechanism fractures.

Purpose: This study aims to review complications and union rates of ballistic femoral neck fractures when compared to their blunt counterparts. We hypothesize that gunshot injuries to the femoral neck may have higher rates of complications (nonunion, avascular necrosis [AVN], and implant failure) as a result of increasing comminution and disruption to the already tenuous blood supply through the femoral neck.

Methods: Following the Institutional Review Board approval, a retrospective chart review was performed identifying femoral neck fractures at a single level 1 trauma center from 2018 to 2023. Inclusion criteria were age 16-45 years old with intracapsular femoral neck fractures. Exclusion criteria were absence of radiographic and clinical follow-up beyond 6 weeks, prior femur fractures, pathologic fractures, or primary surgery of total hip arthroplasty. Garden classification and Pauwels angle were reported. Clinical union was defined as the absence of pain with ambulation in the absence of radiographic changes. Radiographic union was defined using the validated Radiographic Union Score for Hip (RUSH) scoring system. Complication rates (deep and superficial infection, failure of fixation, and AVN) and subsequent surgery were recorded.

Results: After exclusion, 12 ballistic and 16 blunt femoral neck fractures met inclusion criteria and were reviewed. The ballistic cohort had significant more Garden I fractures than the blunt cohort (4 [33%] vs. 0 [0%]), and significantly fewer Garden IV fractures than the blunt cohort (2 [17%] vs. 9 [56%]). Despite different Garden classification types of fracture patterns, the Pauwels angle between the two cohorts was similar (51° ballistic vs. 60° blunt, p = 0.16). The overall nonunion rate was 24.1%. Nonunion rates were similar between the two cohorts (3, 25% ballistic vs. 4, 25% blunt, p = 0.99). The mean final RUSH score between the two cohorts was similar (20.1 ballistic vs. 23.4 blunt [p = 0.05]). The total complication rate was 31% (9/28) consisting of 7 nonunions and 2 malunions across both cohorts.

Conclusion: The current study found no difference in the union rates between blunt and ballistic femoral neck fractures. Although comparing these fractures using traditional classification systems (Garden and Pauwels) are difficult due to the inherent differences in mechanism and the applicability of these tools, both groups presented with high rates of nonunion and complications. We believe the similar RUSH scores and complication rates in both cohorts show these fractures fundamentally behave similarly and remain challenging injuries to manage with ORIF.