Surgical Outcomes of Internal Fixation Using Multiple Screws in Femoral Neck Fractures with Valgus Impaction: When Should We Consider Hip Arthroplasty? A Retrospective, Multicenter Study

PURPOSE: We analyzed the surgical outcomes at two institutions after internal fixation using multiple screws in femoral neck fractures with valgus impaction to determine independent predictors and their cut-off values for nonunion and reoperation. MATERIALS AND METHODS: Between January 2006 and December 2016, 104 femoral neck fractures with valgus impaction that underwent internal fixation using multiple screws from two institutions were enrolled. The multiple logistic regression model and receiver operating characteristics analysis were used to determine the independent predictors and cut-off values for nonunion and reoperation. RESULTS: There were 20 reoperations (19.2%) due to 11 nonunions (10.6%) and nine cases of femoral head osteonecrosis (8.7%). Multiple logistic regression analysis revealed that independent predictors of nonunion and reoperation were age and posterior tilt angle (P<0.05). The cut-off value for age and the posterior tilt angle for reoperation were 72.5 years and 12.2°, respectively. The patients with a posterior tilt angle of greater than 13° had poorer radiological and clinical outcomes compared with those with a posterior tilt angle of less than 13°, even though they did achieve bone union. CONCLUSION: Primary hip arthroplasty should be considered in patients older than 73 years of age with a posterior tilt angle greater than 13°.