title: Application of a customized 3D printed reduction aid after external fixation of the femur and tibia: Technical note.
abstract: BACKGROUND
  To construct a fracture-specific reduction aid by means of virtual reduction technology and 3D printing to reduce malreduced, externally fixed, long bone fractures.
  
  
  METHODS
  Following application of an external fixator to a malreduced long bone fracture, we performed postoperative computed tomography to visualise the fragments and their position relative to Schanz screws. DICOM data were transferred to 3D planning software, and the fracture was then virtually reduced. Subsequently, a reduction aid was designed to cover the Schanz screws in such a way that it would maintain the position of the new fragments. Following 3D printing, the solid reduction aid could be applied onto the Schanz screws. The reduction aid fit only in the reduced position of the fracture, thus maintaining correct bone alignment.
  
  
  CONCLUSIONS
  Our reduction technique can be applied during the temporary external fixation period on the preexisting external fixator or as a reduction aid during definitive treatment.
authors.affiliation: Trauma Department, Hannover Medical School, Hannover, Germany.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Omar
authors.affiliation: Department of Craniomaxillofacial Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Alexander-Nicolai
authors.initials: AN
authors.lastname: Zeller
authors.affiliation: Department of Craniomaxillofacial Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Nils-Claudius
authors.initials: NC
authors.lastname: Gellrich
authors.affiliation: Department of Craniomaxillofacial Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Majeed
authors.initials: M
authors.lastname: Rana
authors.affiliation: Trauma Department, Hannover Medical School, Hannover, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Krettek
authors.affiliation: Trauma Department, Hannover Medical School, Hannover, Germany.
authors.forename: Emannouil
authors.initials: E
authors.lastname: Liodakis
mesh_terms: D000465:Algorithms; D016267:External Fixators; D005264:Femoral Fractures / Q000601:surgery*; D005269:Femur / Q000601:surgery*; D005592:Fracture Fixation / Q000295:instrumentation* / Q000379:methods; D017102:Fracture Healing; D006801:Humans; D066330:Printing, Three-Dimensional; D012984:Software; D013977:Tibia / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: 3D printing; external fixation; long bone fracture; secondary intramedullary nailing; virtual reduction