LAUSR

OBJECTIVES To determine if the Radiographic Union Score for Hip (RUSH) measured at 3 and 6 months post-femoral neck fracture were predictive of re-operation for infection, non-union, delayed union, avascular necrosis, or implant failure within 24 months of initial surgery. DESIGN Secondary analysis of a randomized controlled trial. Logistic regression was performed to investigate associations between lower RUSH and re-operation. Results were reported as odds ratios (OR), 95% Confidence Intervals (CIs), and associated p-values. All tests were 2-tailed with alpha=0.05. SETTING 81 clinical sites across eight countries. PATIENTS/PARTICIPANTS Data from 734 of the clinical trial participants with radiographs at 3- and 6-months post-fracture fixation were included. INTERVENTION A reviewer blinded to patients' outcomes independently assigned a RUSH at each follow-up time point. MAIN OUTCOME MEASUREMENTS Revision surgery rate related to intervention. RESULTS Lower RUSH at 3 and 6 months were associated with increased odds of re-operation within 24 months of fracture fixation. For every 2-point decrease in RUSH at 3 months, there was a 16% increase in the odds of a patient experiencing a re- operation (OR 1.16, 95% CI 1.10-1.22; p<0.0001). A similar association was observed at the 6-month assessment for every 2-point decrease (OR=1.05, 95% CI 1.01-1.09; p=0.005). CONCLUSIONS Decreased radiographic healing as early as 3-months post-fracture fixation is associated with developing patient important femoral neck fracture re-operations. This relationship may guide early treatment decisions, suggesting that 3- and 6-month RUSH are a useful surrogate measure of re-operations within 24 months of fracture fixation. LEVEL OF EVIDENCE II.