Risk factors of fixation failure in basicervical femoral neck fracture: Which device is optimal for fixation?

Background: Basicervical femur neck fracture (FNF) is a rare type of fracture, and is associated with increased risk of fixation failure due to its inherent instability. The purpose of this study was (1) to investigate the incidence of fixation failure and (2) to determine risk factors for fixation failure in basicervical FNF after internal fixation. Methods: To identify basicervical FNF with a minimum of 12 months follow-up, we retrospectively reviewed records of 3217 patients who underwent hip fracture surgery from May 2003 to March 2016. Among the identified 77 patients with basicervical FNF, 69 patients were followed up for at least 12 months. We evaluated the rate of collapse of fracture site and reoperation due to fixation failure. We performed a multivariable analysis to determine risk factors associated with fracture site collapse and fixation failure. Results: Among the 69 patients with basicervical FNF, 17 (24.6%) showed collapse of fracture site, and 6 (8.6%) underwent conversion to arthroplasty because of fixation failure. In the multivariable analysis, use of extramedullary plating with a sliding hip screw was an independent significant risk factor for both collapse of fracture site (odds ratio 6.84; 95% confidence interval 1.91–24.5, p = 0.003) and fixation failure (odds ratio 12.2; 95% confidence interval 1.08–137.7, p = 0.042). Conclusions: Basicervical FNF treated with extramedullary plate with a sliding hip screw is more likely to fail than that treated with intramedullary nail with a helical blade. Our results suggested that intramedullary nail with a helical blade is more recommended for basicervical FNF compared with extramedullary plate with a sliding hip screw. Level of evidence: III, Retrospective cohort study.