Smoking, medial comminution, and single fixation as predictors of failure in the fixation of native distal femur fractures: a multicenter retrospective study over 109 fractures.

INTRODUCTION

Native distal femur fractures (DFF) pose a significant challenge. The rates of fixation failure and nonunion range from 10 to 50%. This study aims to identify patient characteristics, injury types, or treatment factors that may predict failures in the surgical management of native distal femur fractures.

METHODS

This retrospective study was conducted by reviewing all distal femur fractures treated consecutively from January 2015 to December 2022 at three orthopedic trauma referral centers. Adult patients with acute 33 A2–A3, and 33 C distal femur fractures who were treated with internal fixation and had available clinical and radiological follow-up for analysis were included. Periprosthetic or peri-implant fractures, those resulting from pathological fractures, and cases with follow-up of less than 12 months were excluded. We analyzed patient demographics, injury characteristics, and treatment details. We performed both univariate and multivariate analyses between patients who achieved bone union following a single procedure (Group A) with those who experienced delayed nonunion, nonunion, or fixation failure (Group B).

RESULTS

We included 109 fractures, with a median follow-up of 38 (12–90) months. Group A comprised 86 (78.9%) patients, while Group B had 23 (21.1%). Univariate analysis revealed significant differences in smoking habits, medial comminution, nail-plate combination, and the use of one or two implants for fixation. In the multivariate analysis, we identified smoking habit (OR 3.98; 95% Confidence Interval CI 1.16–12.63; p = 0.0019) and medial comminution (OR 5.09; 95% CI 1.53–16.05; p = 0.008) as predictors of failure, while fixation with combined implants (double plate or nail plus plate) showed a protective effect against failure (OR 0.14; 95% CI 0.01–0.98; p = 0.043).

CONCLUSION

Given its predictive power for failure, we must emphasize to the patients the importance of smoking cessation in treating DFF. The presence of medial comminution should alert the surgeon to the potential risk of fixation failure. Combined implants, mainly nail plus plate, have shown a protective effect against failure. Future studies are needed to identify the best fixation strategies for native DFF.