Screw Configuration Does Not Significantly Alter Neck Shortening Following Valgus Impacted Femoral Neck Fracture (OTA Type 31B1.1)

Abstract

To compare three different cancellous screw configurations used for Garden 1 femoral neck fractures (FNF). Design: Retrospective review. A large urban academic medical center. All patients with OTA 31B1.1 FNF that underwent in situ fixation with cancellous screws between 2012 and 2021 were included. Patients were divided into three groups: two screws placed in a parallel fashion, three screws placed in an inverted triangle configuration, and three-screw fixation with placement of one “out of plane” (OOP) screw perpendicular to the long axis of the femur. Post operative femoral neck shortening (mm) was the primary outcome, which was compared amongst the three groups of different screw configurations. Sixty-one patients with a median follow-up of 1 year (IQR 0.6-1.8 years) and an average age of 72 years (IQR 65.0-83.0 years) were included. All fractures united. Overall, 68.9% of the cohort had ≤ 2 mm of femoral neck shortening. There was no difference between groups in the proportion of patients who experienced greater than 2 mm of shortening (p = 0.839) or in the amount (mm) of femoral neck shortening (Kruskal-Wallis χ2 = 0.517, p = 0.772). While most patients with valgus impacted femoral neck fractures treated with screw fixation do not experience further femoral neck shortening, some patients demonstrated continued radiographic shortening during the healing process. The development of further femoral neck shortening and the amount of shortening that occurs do not differ based on implant configuration. Multiple different screw configurations appear to be acceptable with regards to achieving healing and minimizing further femoral neck impaction. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.