title: Association between in vivo knee kinematics during gait and the severity of knee osteoarthritis.
abstract: BACKGROUND
  Osteoarthritis patients may exhibit different kinematics according to the disease stage. However, changes in the frontal and horizontal planes in each stage remain unclear. The purpose of this study was to investigate changes in the knee kinematic gait variables of osteoarthritis patients, including the frontal and horizontal planes, with respect to the severity of the disease.
  
  
  METHODS
  Forty-five patients with knee osteoarthritis and 13 healthy young subjects were recruited for the experiment. All subjects were examined while walking on a 10-m walkway at a self-selected speed. In each trial, we calculated the angular displacements of flexion/extension, abduction/adduction, and external/internal tibial rotation. We also measured muscle strength, range of motion (ROM), and alignment. We compared the differences in osteoarthritis severity and knee kinematic variables between osteoarthritis patients and normal subjects.
  
  
  RESULTS
  The flexion angle at the time of foot contact was significantly less in patients with severe and moderate osteoarthritis than in normal subjects (both p<0.01). The abduction angle at the 50% stance phase was significantly less in patients with severe osteoarthritis than in normal subjects (p<0.05). The excursion of axial tibial rotation was significantly less in patients with early osteoarthritis than in normal subjects (p<0.05).
  
  
  CONCLUSIONS
  Osteoarthritis patients had different knee kinematics during gait, depending on the progress of osteoarthritis. Early-stage patients exhibit decreased axial tibial rotation excursion, while severe-stage patient exhibit increased knee adduction.
authors.affiliation: Niigata University of Health and Welfare, Department of Health and Sports, Niigata, Japan. nagano@nuhw.ac.jp
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nagano
authors.forename: Kenji
authors.initials: K
authors.lastname: Naito
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Saho
authors.forename: Suguru
authors.initials: S
authors.lastname: Torii
authors.forename: Toru
authors.initials: T
authors.lastname: Ogata
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Nakazawa
authors.forename: Masami
authors.initials: M
authors.lastname: Akai
authors.forename: Toru
authors.initials: T
authors.lastname: Fukubayashi
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D005500:Follow-Up Studies; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000503:physiopathology*; D016059:Range of Motion, Articular; D012720:Severity of Illness Index; D016138:Walking / Q000502:physiology*; D055815:Young Adult