title: Preoperative virtual reduction reduces femoral malrotation in the treatment of bilateral femoral shaft fractures.
abstract: BACKGROUND
  In bilateral femoral shaft fractures, significant malrotation (>15°) occurs in about 40 % of cases after intramedullary nailing. Most of the methods that provide rotational control during surgery are based on a comparison to the intact femur and, thus, not applicable for bilateral fractures. In this study, we evaluated if preoperative virtual reduction can help improving rotational alignment in patients with bilateral femoral shaft fractures.
  
  
  METHODS
  Seven patients with bilateral femoral shaft fractures were initially treated with external fixation of both femurs. After obtaining a CT scan of both legs, the fractures were reduced virtually using the software program VoXim®, and the amount and direction of rotational correction were calculated. Subsequently, the patients were treated by antegrade femoral nailing and rotation was corrected to the preoperatively calculated amount.
  
  
  RESULTS
  After external fixation, the mean rotational difference between both legs was 15.0° ± 10.2°. Four out of seven patients had a significant malrotation over 15°. Following virtual reduction, the mean rotational difference between both legs was 2.1° ± 1.2°. After intramedullary nailing, no case of malrotation occurred and the mean rotational difference was 6.1° ± 2.8°.
  
  
  CONCLUSIONS
  Preoperative virtual reduction allows determining the pretraumatic femoral antetorsion and provided useful information for the definitive treatment of bilateral femoral shaft fractures. We believe that this procedure is worth being implemented in the clinical workflow to avoid malrotation after intramedullary nailing.
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany. omar.mohamed@mh-hannover.de.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Omar
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Suero
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Nael
authors.initials: N
authors.lastname: Hawi
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Decker
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Krettek
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Musa
authors.initials: M
authors.lastname: Citak
mesh_terms: D000328:Adult; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000628:therapy*; D005594:Fracture Fixation, Intramedullary / Q000379:methods*; D006801:Humans; D008297:Male; D008349:Manipulation, Orthopedic / Q000379:methods*; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D012399:Rotation; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Bilateral femoral shaft fracture; Computed tomography; Femoral antetorsion; Intramedullary nailing; Malrotation; Virtual reduction