title: Is the contralateral tibia a reliable template for reconstruction: a three-dimensional anatomy cadaveric study.
abstract: OBJECTIVE
  The contralateral anatomy is regularly used as a reconstruction template for corrective osteotomies of several deformities and pathological conditions. However, there is lack of evidence that the intra-individual differences between both tibiae are sufficiently small to use the contralateral tibia as a 3D reconstruction template for complex osteotomies. The aim of this study was to evaluate the intra-individual side differences of the tibia in length, torsion, angulation, and translation using 3D measurement techniques.
  
  
  METHODS
  3D surface models of both tibiae were created from computed tomography data of 51 cadavers. The (mirrored) models of the right tibiae were divided into two halves at the centre of the shaft. Thereafter, the proximal and distal segments were aligned to the left (contralateral) tibia in an automated fashion. The relative 3D transformation between both aligned segments was measured to quantify the side difference in 6° of freedom (3D translation vector, 3 angles of rotation).
  
  
  RESULTS
  The mean side difference in tibia length was 2.1 mm (SD 1.3 mm; range 0.2-5.9 mm). The mean side difference in torsion was 4.9° (SD 4.1°; range 0.2°-17.6°). The mean side difference in the coronal and sagittal planes was 1.1° (SD 0.9°; range 0.0°-4.6°) and 1.0° (SD 0.8°; range 0.1°-2.9°), respectively.
  
  
  CONCLUSIONS
  The present study confirms small side differences in torsion between the left and right tibia, while the side differences in the coronal and sagittal plane are probably negligible. The contralateral tibia seems to be a reliable reconstruction template for the 3D preoperative planning of complex corrective osteotomies of the tibia. However, torsional differences should be interpreted with caution, as a single cut-off value of a clinically relevant torsional side difference cannot be defined. The presented results are relevant to surgeons considering the contralateral tibia as a 3D reconstruction template for corrective osteotomies of the tibia.
  
  
  METHODS
  Basic science.
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland. Pascal.Schenk@balgrist.ch.
authors.forename: Pascal
authors.identifier: http://orcid.org/0000-0002-6500-7487
authors.initials: P
authors.lastname: Schenk
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.|Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
authors.forename: Lazaros
authors.initials: L
authors.lastname: Vlachopoulos
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hingsammer
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
authors.forename: Sandro F
authors.initials: SF
authors.lastname: Fucentese
authors.affiliation: Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Fürnstahl
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy; D012399:Rotation; D013977:Tibia / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
keywords: Cadaveric study; Contralateral comparison; Three-dimensional analysis; Tibia osteotomy