title: Posterior translation of the fibula may indicate malreduction: CT study of normal variation in uninjured ankles.
abstract: OBJECTIVE
  The aim of our study was to assess the intersubject and intrasubject variations of distal tibiofibular syndesmosis on computed tomography (CT) scans and to define standardized measures to verify syndesmosis reduction.
  
  
  METHODS
  A retrospective study of 107 CT scans of ankles with normal tibiofibular syndesmosis.
  
  
  METHODS
  Main trauma center, university teaching hospital.
  
  
  METHODS
  The CT scans of 64 patients were reviewed by 2 musculoskeletal radiologists.
  
  
  METHODS
  Bilateral variation was estimated. The intra- and interobserver reliabilities were calculated using standardized measurement points. CT measurements included the length of the tibial incisura (LI), A width and P width of the incisura (PW), depth of the incisura, narrowest part of the incisura, and sagittal translation of the fibula.
  
  
  RESULTS
  In 97% of normal cases, the fibula is situated either centrally or anteriorly in the tibial incisura. There were significant differences in PW and LI between genders, and the difference between the PW and A width was significantly larger in males (2.7 mm, SD 2.1) than in females (1.9 mm, SD 1.6, P = 0.023, t test). Significant asymmetry was not detected between ankles in single subjects. All CT measurements demonstrated good inter- and intraobserver reliabilities.
  
  
  CONCLUSIONS
  If P translation of the fibula is present, malreduction should be considered. Sagittal translation measurements are not affected by the size of the joint or the gender of the patient, in contrast to traditionally used cross-sectional measurement methods.
authors.affiliation: *Department of Diagnostic Radiology; and †Division of Orthopaedic and Trauma Surgery, Department of Surgery, Oulu University Hospital, Oulu, Finland.
authors.forename: Sannamari
authors.initials: S
authors.lastname: Lepojärvi
authors.forename: Harri
authors.initials: H
authors.lastname: Pakarinen
authors.forename: Olli
authors.initials: O
authors.lastname: Savola
authors.forename: Marianne
authors.initials: M
authors.lastname: Haapea
authors.forename: Roberto B
authors.initials: RB
authors.lastname: Sequeiros
authors.forename: Jaakko
authors.initials: J
authors.lastname: Niinimäki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019412:Anatomy, Cross-Sectional; D000843:Ankle Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D005260:Female; D005360:Fibula / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012016:Reference Values; D012189:Retrospective Studies; D013977:Tibia / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D014102:Torsion Abnormality / Q000000981:diagnostic imaging*; D055815:Young Adult