title: Evaluation of malrotation following intramedullary nailing in a femoral shaft fracture model: Can a 3D c-arm improve accuracy?
abstract: BACKGROUND
  Difficulty determining anatomic rotation following intramedullary (IM) nailing of the femur continues to be problematic for surgeons. Clinical exam and fluoroscopic imaging of the hip and knee have been used to estimate femoral version, but are inaccurate. We hypothesize that 3D c-arm imaging can be used to accurately measure femoral version following IM nailing of femur fractures to prevent rotational malreduction.
  
  
  METHODS
  A midshaft osteotomy was created in a femur Sawbone to simulate a transverse diaphyseal fracture. An intramedullary (IM) nail was inserted into the Sawbone femur without locking screws or cephalomedullary fixation. A goniometer was used to simulate four femoral version situations after IM nailing: 20° retroversion, 0° version, 15° anteversion, and 30° anteversion. In each simulated position, 3D c-arm imaging and, for comparison purposes, perfect lateral radiographs of the knee and hip were performed. The femoral version of each simulated 3D and fluoroscopic case was measured and the results were tabulated.
  
  
  RESULTS
  The measured version from the 3D c-arm images was 22.25° retroversion, 0.66° anteversion, 19.53° anteversion, and 25.15° anteversion for the simulated cases of 20° retroversion, 0° version, 15° anteversion, and 30° anteversion, respectively. The lateral fluoroscopic views were measured to be 9.66° retroversion, 12.12° anteversion, 20.91° anteversion, and 18.77° anteversion for the simulated cases, respectively.
  
  
  CONCLUSIONS
  This study demonstrates the utility of a novel intraoperative method to evaluate femur rotational malreduction following IM nailing. The use of 3D c-arm imaging to measure femoral version offers accuracy and reproducibility.
authors.affiliation: Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, 301 E 17th Street, New York, NY, USA.
authors.forename: Austin J
authors.initials: AJ
authors.lastname: Ramme
authors.affiliation: Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, 301 E 17th Street, New York, NY, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Egol
authors.affiliation: Department of Radiology, Center for Musculoskeletal Care, NYU Langone Medical Center, 550 First Ave, New York, NY, 10016, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Chang
authors.affiliation: Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, 301 E 17th Street, New York, NY, USA.
authors.forename: Roy I
authors.initials: RI
authors.lastname: Davidovitch
authors.affiliation: Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, 301 E 17th Street, New York, NY, USA. Electronic address: Sanjit.konda@nyumc.org.
authors.forename: Sanjit
authors.initials: S
authors.lastname: Konda
mesh_terms: D001187:Artificial Organs; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000601:surgery*; D005264:Femoral Fractures / Q000601:surgery*; D005269:Femur; D005471:Fluoroscopy; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation* / Q000592:standards*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008422:Materials Testing; D010027:Osteotomy / Q000379:methods; D015203:Reproducibility of Results; D012399:Rotation; D000066908:Simulation Training
keywords: 3D; Femoral version; Intramedullary nail; Malunion; c-arm