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 (P = 0.023). Independent variables that were associated with fixation failure were poor reduction according to the modified Baumgaertner classification (OR 7.81; P = 0.0001), the difference in neck shaft angle on AP pelvis radiograph between injured and uninjured hips (OR 1.22; P = 0.0003), malreduction on the lateral hip radiograph >10 degrees (OR 4.45; P = 0.003), fracture displacement in any direction >4 mm (OR 3.8; P = 0.006), a tip to apex distance (TAD) > 21 mm (OR 3.30; P = 0.019), and TAD >21 mm plus >10 degrees malreduction in the lateral plane (OR 4.70; P = 0.009).

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.