title: Computed tomography of the ankle in full plantar flexion: a reliable method for preoperative planning of arthroscopic access to osteochondral defects of the talus.
abstract: OBJECTIVE
  The purpose of this study was to determine whether preoperative computed tomography (CT) of the ankle joint in full plantar flexion is a reliable and accurate tool to determine the anterior arthroscopic accessibility of talar osteochondral defects (OCDs).
  
  
  METHODS
  Twenty consecutive patients were prospectively studied. All patients had an OCD of the talar dome and had a preoperative CT scan of the affected ankle in maximum plantar flexion. Accessibility of the OCD was defined by the distance between the anterior border of the OCD and the anterior distal tibial rim. This distance was measured on sagittal CT reconstructions by 2 investigators. The reference standard was the distance between the same landmarks measured during anterior ankle arthroscopy by an orthopaedic surgeon blinded to the CT scans. Intraobserver and interobserver reliability of CT, as well as the correlation and agreement between CT and arthroscopy, were calculated.
  
  
  RESULTS
  The measured distance between the anterior border of the OCD and the anterior distal tibial rim ranged from -3.1 to 9.1 mm on CT and from -3.0 to 8.5 mm on arthroscopy. The intraobserver and interobserver reliability of the measurements made on CT scans (intraclass correlation coefficients >0.99, P < .001), as well as the correlation between CT and arthroscopy, were excellent (r = 0.98, P < .001).
  
  
  CONCLUSIONS
  Measurements on CT scans of the ankle in full plantar flexion are a reliable and accurate preoperative method to determine the in situ arthroscopic location of talar OCDs.
authors.affiliation: Orthopedic Research Center Amsterdam, Department of Orthopedic Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. c.j.vanbergen@amc.nl
authors.forename: Christiaan J A
authors.initials: CJ
authors.lastname: van Bergen
authors.forename: Gabriëlle J M
authors.initials: GJ
authors.lastname: Tuijthof
authors.forename: Leendert
authors.initials: L
authors.lastname: Blankevoort
authors.forename: Mario
authors.initials: M
authors.lastname: Maas
authors.forename: Gino M M J
authors.initials: GM
authors.lastname: Kerkhoffs
authors.forename: C Niek
authors.initials: CN
authors.lastname: van Dijk
mesh_terms: D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D054544:Arthroplasty, Subchondral; D001182:Arthroscopy; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015588:Observer Variation; D056888:Patient Positioning; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D016037:Single-Blind Method; D013628:Talus / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D055815:Young Adult