title: Multi-joint postural behavior in patients with knee osteoarthritis.
abstract: BACKGROUND
  Previous studies have demonstrated balance impairment in patients with knee osteoarthritis (OA). Although it is currently accepted that postural control depends on multi-joint coordination, no study has previously considered this postural strategy in patients suffering from knee OA. The objectives of this study were to investigate the multi-joint postural behavior in patients with knee OA and to evaluate the association with clinical outcomes.
  
  
  METHODS
  Eighty-seven patients with knee OA and twenty-five healthy elderly were recruited to the study. A motion analysis system and two force plates were used to investigate the joint kinematics (trunk and lower body segments), the lower body joint moments, the vertical ground reaction force ratio and the center of pressure (COP) during a quiet standing task. Pain, functional capacity and quality of life status were also recorded.
  
  
  RESULTS
  Patients with symptomatic and severe knee OA adopt a more flexed posture at all joint levels in comparison with the control group. A significant difference in the mean ratio was found between groups, showing an asymmetric weight distribution in patients with knee OA. A significant decrease in the COP range in the anterior-posterior direction was also observed in the group of patients. Only small associations were observed between postural impairments and clinical outcomes.
  
  
  CONCLUSIONS
  This study brings new insights regarding the postural behavior of patients with severe knee OA during a quiet standing task. The results confirm the multi-joint asymmetric posture adopted by this population.
authors.affiliation: Willy Taillard Laboratory of Kinesiology, Geneva University Hospitals and Geneva University, Geneva, Switzerland; Center for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Université Laval, Quebec City, Quebec, Canada. Electronic address: kturcot@gmail.com.
authors.forename: Katia
authors.initials: K
authors.lastname: Turcot
authors.affiliation: Willy Taillard Laboratory of Kinesiology, Geneva University Hospitals and Geneva University, Geneva, Switzerland; Orthopaedic Surgery Service, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Sagawa
authors.affiliation: Orthopaedic Surgery Service, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Pierre
authors.initials: P
authors.lastname: Hoffmeyer
authors.affiliation: Orthopaedic Surgery Service, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Domizio
authors.initials: D
authors.lastname: Suvà
authors.affiliation: Willy Taillard Laboratory of Kinesiology, Geneva University Hospitals and Geneva University, Geneva, Switzerland; Orthopaedic Surgery Service, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Armand
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology*; D011312:Pressure; D011788:Quality of Life; D016059:Range of Motion, Articular / Q000502:physiology*; D012189:Retrospective Studies
keywords: Balance; Body sway; Knee osteoarthritis (OA); Multi-joint coordination; Posture