Modifying the reduction quality criteria of the Baumgaertner classification may increase its performance in predicting mechanical failure after intertrochanteric nailing.

Objectives: The main objective of this study was to assess whether modifying the lateral plane alignment criterion of the original Baumgaertner classification from <20 to <10 degrees improved its performance in predicting failure after nailing of an intertrochanteric fracture (ITF). Methods: Patients operated consecutively between January 2016 and January 2021 with a cephalomedullary nail for an ITF, with a minimum follow-up of 12 months, were retrospectively analyzed. The postoperative reduction was classified according to the original Baumgaertner classification and using the modified classification. The performance of the original and modified classifications was analyzed by a comparative analysis of receiver operating characteristic (ROC) curves. Univariate and multivariate analysis was performed to identify variables associated with failure. Results: A total of 282 patients were included. The failure rate was 10.63%. The area under the ROC curve of the original classification was 0.66 and of the modified classification 0.78 ( Conclusion: Modification of the lateral plane alignment component of the criteria used to grade the quality of intertrochanteric fracture reduction as originally proposed by Baumgaertner, from <20 degrees to <10 degrees significantly improved the classification's ability to predict fixation failure. Level of evidence: IV.