EOS stereographic assessment of femoral shaft malunion after intramedullary nailing. A prospective series of 48 patients at 9 months' follow-up

Introduction: The aim of the present study was to assess femoral shaft malunion following anterograde intramedullary nailing, using low-dose EOS stereoradiography. The study hypothesis was that our surgical technique is associated with radiological rotation disorder rates equivalent to those reported in the literature.

Methods: All patients with unilateral femoral shaft fracture treated by anterograde nailing between January 2014 and December 2016 and followed up in our structure were included in a single-center prospective study. The main endpoint was≥15° transverse malrotation compared to the contralateral side as measured on EOS stereoradiography. Correlations between malrotation and Harris Hip and SF12 functional scores were assessed, as were risk factors for onset of shaft malunion in rotation. Forty-eight patients with a mean age of 31.4 years were analyzed at a mean 9.3 months' follow-up.

Results: Stereoradiographic malrotation was found in 29.2% of patients. Mean anteversion was 18.5±13.8°. In 2.1% of patients, symptomatic rotation disorder required revision surgery. No correlations emerged between transverse malrotation and functional scores (p>0.05). Risk factors for malrotation comprised multi-site fracture (p=0.04), surgeon's inexperience (p=0.04), and open reduction (p=0.01).

Conclusion: The present radiologic malrotation rate was comparable to those reported in the literature, using the EOS stereoradiographic system, which provides precise assessment of rotation disorder following closed nailing of femoral shaft fracture.

Level of evidence: III; prospective study without control group.