Interfragmentary gap is a risk factor for nonunion after intramedullary nailing for femoral shaft fractures. About 190 cases.

INTRODUCTION

Intramedullary nailing (IMN) is the standard treatment for femoral shaft fractures (FSF). Complications include nonunion and rotational malunions, the contributing factors of which remain less clearly defined. The aim of this study was to find the relevant risk factors for complications after IMN for FSF.

HYPOTHESIS: Complications after IMN for FSF are related to several risk factors.

MATERIALS AND

METHODS

All patients who underwent surgery for open or closed FSF, performed as a first-line treatment or after temporary external fixation, between 2014 and 2020 were included. The potential risk factors for complications studied were smoking, BMI, bone comminution, Damage Control Orthopedics, night surgery, an open fracture, and persistence of an interfragmentary gap (IFG) after reduction. Complications, their time of onset, and their management were recorded.

RESULTS

A total of 190 IMNs were performed during the study period. Forty complications were found in 35 patients (18%), including 10 nonunions (5.2%) and 10 rotational malunions (5.2%). The only proven risk factor for complications was IFG (OR 1.10 [1.05-1.14], p < 0.0001), which was also found to be a risk factor for nonunion (OR 1.08 [1.02-1.14], p = 0.001). ROC analysis identified an IFG threshold of 12 mm for any complication and 13 mm for nonunion in this cohort. No risk factors for rotational malunions were found.

CONCLUSION

In this cohort, a postoperative IFG around 12-13 mm was associated with an increased risk of complications, particularly nonunion. IFG is easy to measure and allows the identification of patients requiring closer follow-up.

LEVEL OF EVIDENCE: IV; Single-centre retrospective cohort study.