Sagittal Angulation and the Treatment of Geriatric Femoral Neck Fractures: Time to Update our Classification Systems

Abstract

OBJECTIVES: Inconsistent outcomes have been reported for percutaneous fixation of Garden I/II femoral neck fractures in geriatric patients. It was hypothesized that accounting for variable follow-up would better estimate the failure rate of percutaneous fixation with and without significant sagittal angulation. METHODS: Design: Retrospective. Setting: Single academic healthcare system. Patient Selection Criteria: Patients ≥ 50 years old treated with percutaneous screw fixation of Garden I/II (OTA/AO B1.1/B1.2) femoral neck fractures from 2010 - 2020 were identified. Pathologic fractures and open approaches were excluded. Outcome Measures and Comparisons: Sagittal angulation was measured using a previously described method.11 Treatment failure was defined as early fixation failure (within 6 weeks), nonunion and/or avascular necrosis. Potential associations between treatment failure and patient, injury and treatment variables were assessed. Cox proportional hazard analysis accounted for variable follow-up when assessing for event-free survival. RESULTS: Of the 240 fractures that met inclusion criteria, there were 20 treatment failures (8%) and 33 fractures with sagittal angulation ≥ 20° on lateral radiographs (14%). Failure-free survival at 2 years was 91% for patients with < 20° posterior angulation and 52% for patients with ≥ 20° of posterior angulation (p < 0.0001). The hazard ratio, which incorporates variable follow-up, for failure with ≥ 20° of posterior angulation was 6.36 (p < 0.0001). No other factors were associated with treatment failure. CONCLUSIONS: Significant posterior angulation (≥ 20°) of Garden I/II femoral neck fractures is associated with a high failure rate following screw fixation. The authors suggest characterizing fractures with ≥ 20° of sagittal angulation as Garden III fractures to better support surgical decision-making.