title: One- and multi-segment foot models lead to opposite results on ankle joint kinematics during gait: Implications for clinical assessment.
abstract: BACKGROUND
  Biomechanical models representing the foot as a single rigid segment are commonly used in clinical or sport evaluations. However, neglecting internal foot movements could lead to significant inaccuracies on ankle joint kinematics. The present study proposed an assessment of 3D ankle kinematic outputs using two distinct biomechanical models and their application in the clinical flat foot case.
  
  
  METHODS
  Results of the Plug in Gait (one segment foot model) and the Oxford Foot Model (multisegment foot model) were compared for normal children (9 participants) and flat feet children (9 participants). Repeated measures of Analysis of Variance have been performed to assess the Foot model and Group effects on ankle joint kinematics.
  
  
  RESULTS
  Significant differences were observed between the two models for each group all along the gait cycle. In particular for the flat feet group, opposite results between the Oxford Foot Model and the Plug in Gait were revealed at heelstrike, with the Plug in Gait showing a 4.7° ankle dorsal flexion and 2.7° varus where the Oxford Foot Model showed a 4.8° ankle plantar flexion and 1.6° valgus.
  
  
  CONCLUSIONS
  Ankle joint kinematics of the flat feet group was more affected by foot modeling than normal group. Foot modeling appeared to have a strong influence on resulting ankle kinematics. Moreover, our findings showed that this influence could vary depending on the population. Studies involving ankle joint kinematic assessment should take foot modeling with caution.
authors: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France. Electronic address: claude.pothrat@univ-amu.fr.
authors: Claude
authors: C
authors: Pothrat
authors: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France; APHM, Hopital La Timone, Service d'orthopédie pédiatrique, 13005 Marseille, France. Electronic address: guillaume.authier@hotmail.fr.
authors: Guillaume
authors: G
authors: Authier
authors: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France; APHM, Hopital La Timone, Service d'orthopédie pédiatrique, 13005 Marseille, France. Electronic address: elke.viehweger@ap-hm.fr.
authors: Elke
authors: E
authors: Viehweger
authors: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France. Electronic address: eric.berton@univ-amu.fr.
authors: Eric
authors: E
authors: Berton
authors: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France. Electronic address: guillaume.rao@univ-amu.fr.
authors: Guillaume
authors: G
authors: Rao
mesh_terms: D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D002648:Child; D003198:Computer Simulation; D005260:Female; D005413:Flatfoot / Q000503:physiopathology; D005528:Foot; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D016059:Range of Motion, Articular
keywords: Ankle; Children; Clinical gait analysis; Flat feet; OFM; Plug in Gait