Coronal shear fractures of the femoral neck: a comparison with basicervical fractures.

Abstract

We propose coronal shear fracture of the femoral neck (CSFF) as a new type of fracture that differs from a basicervical fracture. This study aimed to present the incidence of CSFF and compare its clinical characteristics and outcomes with those of basicervical fractures. In this multicenter retrospective cohort study, 2207 patients with hip fractures were identified using computed tomography (CT), 17 and 27 patients were diagnosed with CSFF (CSFF group) and basicervical fractures (basicervical fracture group), respectively. The primary outcome was reoperation, while the secondary outcomes were postoperative radiographic findings, ambulatory ability, and 1-year mortality rate. These outcomes were compared between the two groups. We also conducted diagnostic reliability tests for these fractures using the Cohen's kappa coefficient. The incidence of CSFF and basicervical fractures in the 2207 patients were 0.77% and 1.22%, respectively. The inter-and intra-observer agreements for the diagnosis were almost perfect. The comorbidity score was significantly higher in the CSFF group than in the basicervical fracture group. No reoperations occurred in both groups. There were no significant intergroup differences in the postoperative radiographic findings. The 1-year mortality rate was higher in the CSFF group than in the basicervical fracture group (38.5% vs. 5.3%; odds ratio: 11.9, 95% CI: 1.2-118.5; p = 0.025). This study presents the definition and incidence of CSFF with a high diagnostic reliability. Patients with CSFF had similar reoperation rate postoperative radiographic outcomes to basicervical fractures, while 1-year mortality rate was high.