Fixation failure following femoral neck system fixation for intracapsular femoral neck fractures: Association with fracture orientation.

Abstract

To evaluate fixation failure following femoral neck system fixation (FNS) for intracapsular femoral neck fractures (FNF) and to determine whether fracture characteristics, particularly fracture orientation, were associated with fixation failure. A retrospective cohort study was performed at a Level I trauma center. 82 patients with intracapsular femoral neck fractures treated with FNS fixation were included. Fixation failure was defined as implant cut-out, loss of fixation, nonunion, or revision surgery. Associations between fracture characteristics and fixation failure were evaluated. The mean age was 70.1 ± 12.7 years, with a mean follow-up of 22.2 ± 10.2 months. Eight fixation failures occurred (9.8%). Pauwels classification was significantly associated with fixation failure (p < 0.001), with higher-angle fractures demonstrating increased risk of failure. No failures occurred in Pauwels type I fractures, whereas failures occurred in Pauwels type II and III fractures. Fracture morphology (subcapital, including valgus impacted vs transcervical) and Garden classification were not associated with fixation failure (p = 1.000 and p = 1.000, respectively). One case of distal locking screw breakage was observed; however, most fixation failures were associated with fracture orientation rather than implant-related mechanical failure. Fixation failure following femoral neck system fixation appears to be primarily associated with fracture orientation rather than implant-related mechanical failure. The low rate of implant-related mechanical complications suggests that the FNS provides adequate biomechanical stability for intracapsular femoral neck fracture fixation, whereas vertical fracture patterns remain a major determinant of fixation failure.