title: Computer-assisted planning and patient-specific guides for the treatment of midshaft clavicle malunions.
abstract: BACKGROUND
  The surgical treatment of malunions after midshaft clavicle fractures is associated with a number of potential complications and the surgical procedure is challenging. However, with appropriate and meticulous preoperative surgical planning, the surgical correction yields satisfactory results. The purpose of this study was to provide a guideline and detailed overview for the computer-assisted planning and 3-dimensional (3D) correction of malunions of the clavicle.
  
  
  METHODS
  The 3D bone surface models of the pathologic and contralateral sides were created on the basis of computed tomography data. The computer-assisted assessment of the deformity, the preoperative plan, and the design of patient-specific guides enabling compression plating are described.
  
  
  RESULTS
  We demonstrate the benefit and versatility of computer-assisted planning for corrective osteotomies of malunions of the midshaft clavicle. In combination with patient-specific guides and compression plating technique, the correction can be performed in a more standardized fashion. We describe the determination of the contact-optimized osteotomy plane. An osteotomy along this plane facilitates the correction and enlarges the contact between the fragments at once. We further developed a technique of a stepped osteotomy that is based on the calculation of the contact-optimized osteotomy plane. The stepped osteotomy enables the length to be restored without the need of structural bone graft. The application of the stepped osteotomy is presented for malunions of the clavicle with shortening and excessive callus formation.
  
  
  CONCLUSIONS
  The 3D preoperative planning and patient-specific guides for corrective osteotomies of the clavicle may help reduce the number of potential complications and yield results that are more predictable.
authors.affiliation: Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zürich, Zürich, Switzerland; Computer Vision Laboratory, ETH Zürich, Zürich, Switzerland. Electronic address: lazaros.vlachopoulos@balgrist.ch.
authors.forename: Lazaros
authors.initials: L
authors.lastname: Vlachopoulos
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schweizer
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Dominik C
authors.initials: DC
authors.lastname: Meyer
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Gerber
authors.affiliation: Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Fürnstahl
mesh_terms: D001860:Bone Plates; D002968:Clavicle / Q000293:injuries / Q000601:surgery*; D018483:Diaphyses / Q000293:injuries / Q000601:surgery; D005593:Fracture Fixation, Internal / Q000379:methods*; D017759:Fractures, Malunited / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D010027:Osteotomy / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed
keywords: Three-dimensional; clavicle midshaft; compression plating; corrective osteotomy; malunion; patient-specific guides; stepped osteotomy