Radiographic union score for tibia fractures predicts success with operative treatment of tibial nonunion

Abstract Background The purpose of this study is to evaluate the ability of preoperative and postoperative radiographic union scores for tibia fractures (RUST) to predict treatment success of tibia fracture nonunion. Materials and methods Patients presenting for operative treatment of tibia fracture nonunion were enrolled in a prospective data registry. Enrolled patients were followed at regular intervals for 12 months. Preoperative and 12 week postoperative radiographs were reviewed and scored using the RUST criteria. Postoperative time to union was determined by clinical and radiographic measures. Multivariate regressions were conducted to predict time to union using preoperative and postoperative RUST while controlling for treatment method. Receiver operating characteristic (ROC) curve was conducted to determine the accuracy of preoperative RUST in predicting failure of treatment. Results Sixty-eight patients with aseptic tibia fracture nonunion treated operatively were identified. Sixty-one patients achieved union. Mean preoperative RUST was 7.5 (SD 1.4). Mean postoperative RUST was 9.2 (SD 1.4). Multivariate linear regressions demonstrated that preoperative (p = 0.043) and postoperative (p = 0.007) RUST are significant predictors of time to union after tibia fracture nonunion surgery. ROC curve demonstrated preoperative RUST below 7 was a good predictor of developing persistent tibia fracture nonunion (AUC = 0.83, Sensitivity = 1.000, Specificity = 0.745). Conclusions RUST preoperatively and postoperatively predicts outcome after nonunion surgery. RUST can be used as part of the complete clinical picture to shape patient expectations and guide treatment.