title: In Vivo Talocrural Joint Contact Mechanics With Functional Ankle Instability.
abstract: BACKGROUND
  Functional ankle instability (FAI) may involve abnormal kinematics and contact mechanics during ankle internal rotation. Understanding of these abnormalities is important to prevent secondary problems in patients with FAI. However, there are no in vivo studies that have investigated talocrural joint contact mechanics during weightbearing ankle internal rotation. The objective of this study to determine talocrural contact mechanics during weightbearing ankle internal rotation in patients with FAI.
  
  
  METHODS
  Twelve male subjects with unilateral FAI (age range, 18-26 years) were enrolled. Computed tomography and fluoroscopic imaging of both lower extremities were obtained during weightbearing passive ankle joint complex rotation. Three-dimensional bone models created from the computed tomographic images were matched to the fluoroscopic images to compute 6 degrees of freedom for talocrural joint kinematics. The closest contact area in the talocrural joint in ankle neutral rotation and maximum internal rotation during either dorsiflexion or plantar flexion was determined using geometric bone models and talocrural joint kinematics data.
  
  
  RESULTS
  The closest contact area in the talus shifted anteromedially during ankle dorsiflexion-internal rotation, whereas it shifted posteromedially during ankle plantar flexion-internal rotation. The closest contact area in FAI joints was significantly more medial than that in healthy joints during maximum ankle internal rotation and was associated with excessive talocrural internal rotation or inversion.
  
  
  CONCLUSIONS
  This study demonstrated abnormal talocrural kinematics and contact mechanics in FAI subjects. Such abnormal kinematics may contribute to abnormal contact mechanics and may increase cartilage stress in FAI joints.
  
  
  METHODS
  Therapeutic, Level IV: cross-sectional case-control study.
authors.affiliation: Department of Physical Therapy, Hokkaido Chitose Institute of Rehabilitation Technology, Hokkaido, Japan (TK)Department of Orthopaedics, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (ES)Department of Medical Radiation, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (NY)Department of Rehabilitation, Yokohama Sports Medical Center, Kanagawa, Japan (MS)Department of Orthopaedics, Yokohama Sports Medical Center, Kanagawa, Japan (AA, KS)Department of Rehabilitation, Hiroshima International University, Hiroshima, Japan (KG).
authors.forename: Takumi
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Department of Physical Therapy, Hokkaido Chitose Institute of Rehabilitation Technology, Hokkaido, Japan (TK)Department of Orthopaedics, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (ES)Department of Medical Radiation, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (NY)Department of Rehabilitation, Yokohama Sports Medical Center, Kanagawa, Japan (MS)Department of Orthopaedics, Yokohama Sports Medical Center, Kanagawa, Japan (AA, KS)Department of Rehabilitation, Hiroshima International University, Hiroshima, Japan (KG).
authors.forename: Eiichi
authors.initials: E
authors.lastname: Suzuki
authors.affiliation: Department of Physical Therapy, Hokkaido Chitose Institute of Rehabilitation Technology, Hokkaido, Japan (TK)Department of Orthopaedics, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (ES)Department of Medical Radiation, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (NY)Department of Rehabilitation, Yokohama Sports Medical Center, Kanagawa, Japan (MS)Department of Orthopaedics, Yokohama Sports Medical Center, Kanagawa, Japan (AA, KS)Department of Rehabilitation, Hiroshima International University, Hiroshima, Japan (KG).
authors.forename: Naohito
authors.initials: N
authors.lastname: Yamazaki
authors.affiliation: Department of Physical Therapy, Hokkaido Chitose Institute of Rehabilitation Technology, Hokkaido, Japan (TK)Department of Orthopaedics, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (ES)Department of Medical Radiation, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (NY)Department of Rehabilitation, Yokohama Sports Medical Center, Kanagawa, Japan (MS)Department of Orthopaedics, Yokohama Sports Medical Center, Kanagawa, Japan (AA, KS)Department of Rehabilitation, Hiroshima International University, Hiroshima, Japan (KG).
authors.forename: Makoto
authors.initials: M
authors.lastname: Suzukawa
authors.affiliation: Department of Physical Therapy, Hokkaido Chitose Institute of Rehabilitation Technology, Hokkaido, Japan (TK)Department of Orthopaedics, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (ES)Department of Medical Radiation, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (NY)Department of Rehabilitation, Yokohama Sports Medical Center, Kanagawa, Japan (MS)Department of Orthopaedics, Yokohama Sports Medical Center, Kanagawa, Japan (AA, KS)Department of Rehabilitation, Hiroshima International University, Hiroshima, Japan (KG).
authors.forename: Atsushi
authors.initials: A
authors.lastname: Akaike
authors.affiliation: Department of Physical Therapy, Hokkaido Chitose Institute of Rehabilitation Technology, Hokkaido, Japan (TK)Department of Orthopaedics, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (ES)Department of Medical Radiation, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (NY)Department of Rehabilitation, Yokohama Sports Medical Center, Kanagawa, Japan (MS)Department of Orthopaedics, Yokohama Sports Medical Center, Kanagawa, Japan (AA, KS)Department of Rehabilitation, Hiroshima International University, Hiroshima, Japan (KG).
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Department of Physical Therapy, Hokkaido Chitose Institute of Rehabilitation Technology, Hokkaido, Japan (TK)Department of Orthopaedics, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (ES)Department of Medical Radiation, Kanagawa Prefectural Shiomidai Hospital, Kanagawa, Japan (NY)Department of Rehabilitation, Yokohama Sports Medical Center, Kanagawa, Japan (MS)Department of Orthopaedics, Yokohama Sports Medical Center, Kanagawa, Japan (AA, KS)Department of Rehabilitation, Hiroshima International University, Hiroshima, Japan (KG) kazgamada@ortho-pt.com.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Gamada
mesh_terms: D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D003198:Computer Simulation; D003430:Cross-Sectional Studies; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D012399:Rotation; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: cartilage contact mechanics; functional ankle instability; internal rotation; talocrural joint kinematics; weightbearing