title: The in situ force in the calcaneofibular ligament and the contribution of this ligament to ankle joint stability.
abstract: BACKGROUND
  Numerous biomechanical studies of the lateral ankle ligaments have been reported; however, the isolated function of the calcaneofibular ligament has not been clarified. We hypothesize that the calcaneofibular ligament would stabilize the ankle joint complex under multidirectional loading, and that the in situ force in the calcaneofibular ligament would change in each flexed position.
  
  
  METHODS
  Using seven fresh frozen cadaveric lower extremities, the motions and forces of the intact ankle under multidirectional loading were recorded using a 6-degree-of-freedom robotic system. On repeating these intact ankle joint complex motions after the calcaneofibular ligament transection, the in situ force in the calcaneofibular ligament and the contribution of the calcaneofibular ligament to ankle joint complex stability were calculated. Finally, the motions of the calcaneofibular ligament-transected ankle joint complex were recorded.
  
  
  RESULTS
  Under an inversion load, significant increases of inversion angle were observed in all the flexed positions following calcaneofibular ligament transection, and the calcaneofibular ligament accounted for 50%-70% of ankle joint complex stability during inversion. The in situ forces in the calcaneofibular ligament under an anterior force, inversion moment, and external rotation moment were larger in the dorsiflexed position than in the plantarflexed position.
  
  
  CONCLUSIONS
  The calcaneofibular ligament plays a role in stabilizing the ankle joint complex to multidirectional loads and the role differs with load directions. The in situ force of the calcaneofibular ligament is larger at the dorsiflexed position. This ligament provides the primary restraint to the inversion ankle stability.
authors: Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1 West-16 Chuo-ku, Sapporo, Hokkaido 060-8543, Japan. Electronic address: a98m040@yahoo.co.jp.
authors: Takuma
authors: T
authors: Kobayashi
authors: Biomechanics Laboratory, Faculty of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino-shi, Tokyo 191-0065, Japan.
authors: Satoshi
authors: S
authors: Yamakawa
authors: Department of Physical Therapy, Sapporo Medical University School of Health Sciences, South-1, West-17, Chuo-ku, Sapporo, Hokkaido 060-8556, Japan.
authors: Kota
authors: K
authors: Watanabe
authors: Biomechanics Laboratory, Faculty of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino-shi, Tokyo 191-0065, Japan.
authors: Kei
authors: K
authors: Kimura
authors: Department of Musculoskeletal Biomechanics and Surgical Development, Sapporo Medical University, South-1 West-16 Chuo-ku, Sapporo, Hokkaido 060-8543, Japan.
authors: Daisuke
authors: D
authors: Suzuki
authors: Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1 West-16 Chuo-ku, Sapporo, Hokkaido 060-8543, Japan.
authors: Hidenori
authors: H
authors: Otsubo
authors: Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1 West-16 Chuo-ku, Sapporo, Hokkaido 060-8543, Japan.
authors: Atsushi
authors: A
authors: Teramoto
authors: Department of Anatomy, Sapporo Medical University School of Medicine, South-1 West-16 Chuo-ku, Sapporo, Hokkaido 060-8543, Japan.
authors: Mineko
authors: M
authors: Fujimiya
authors: Biomechanics Laboratory, Faculty of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino-shi, Tokyo 191-0065, Japan.
authors: Hiromichi
authors: H
authors: Fujie
authors: Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1 West-16 Chuo-ku, Sapporo, Hokkaido 060-8543, Japan.
authors: Toshihiko
authors: T
authors: Yamashita
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016512:Ankle Injuries / Q000503:physiopathology; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D017844:Lateral Ligament, Ankle / Q000502:physiology*; D008297:Male; D016059:Range of Motion, Articular; D012399:Rotation
keywords: Ankle joint; Biomechanics; Calcaneofibular ligament; In situ force; Robotic system