title: Joint space width of the tibiotalar joint in the healthy foot.
abstract: BACKGROUND
  It is important to evaluate dynamic changes in the joint space width of the ankle mortise in detail in order to better understand the pathology of foot and ankle disorders. However, there are few reports on changes in the joint space width of the foot and ankle assessed using 3D images. The purpose of this study was to determine the changes in the joint space width of the ankle (tibiotalar joint) in association with dorsiflexion and plantar flexion of the ankle joint in healthy feet.
  
  
  METHODS
  Computed tomography (CT) images of 10 healthy feet were obtained in the neutral, plantarflexed and dorsiflexed positions of the ankle joint, from which 3D virtual models were fabricated of the tibia, fibula and talus. The 3D joint space width in these models was calculated using a custom made software program.
  
  
  RESULTS
  The joint space width increased in the order of dorsiflexion, neutral position and plantar flexion. Regarding the amount of change in dorsiflexion and plantar flexion relative to the neutral position, there were no significant differences in the middle-middle position. On the other hand, there were highly significant differences in the medial-anterior, medial-middle and medial-posterior positions.
  
  
  CONCLUSIONS
  The joint space width of the ankle joint can be calculated accurately using 3D reconstruction images. Our findings should assist in clarifying pathology associated with movement of the ankle during the gait cycle based on changes in the joint space width in feet exhibiting disorders.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Kan
authors.initials: K
authors.lastname: Imai
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ikoma
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Kido
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Maki
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Arai
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Oda
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Daisaku
authors.initials: D
authors.lastname: Tokunaga
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Nozomu
authors.initials: N
authors.lastname: Inoue
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
keywords: Ankle joint; Computed tomography; X-ray