title: Postural Sway, Balance Confidence, and Fear of Falling in Women With Knee Osteoarthritis in Comparison to Matched Controls.
abstract: BACKGROUND
  Osteoarthritis (OA) is a chronic degenerative disease that commonly affects the knee joints. Individuals older than 65 years of age with knee OA have a greater risk of falls. However, there has been limited examination of the parameters of postural sway (increased time, speed, and postural sway area [center of pressure{CoP}]), and OA of the knee.
  
  
  OBJECTIVE
  The primary objective of this study was to determine whether the CoP variables discriminate between patients with knee OA and matched healthy volunteers, and to correlate the CoP variables with the Activities-Specific Balance Confidence Scale (ABC) and Falls Self-Efficacy Scale (FES). The secondary objective was to compare the CoP of older women with OA with a control group in bipedal support condition with eyes opened and closed.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  University Biomechanics Laboratory.
  
  
  METHODS
  A total of 22 participants were divided into the following 2 groups of 11 participants each: an OA group (mean = 68 years, standard deviation = 7.4 years) and a control group (mean = 66 years, standard deviation = 4.4 years).
  
  
  METHODS
  Static postural balance was measured by a portable force platform. Data were collected in both visual conditions (eyes open and closed), in random order. Three attempts of 30 seconds were allowed for each participant on the force platform, with a 1-minute interval between attempts.
  
  
  METHODS
  Variables were the CoP total displacement of sway (TDS, in centimeters), anteroposterior amplitude displacement (APAD, in centimeters), medial-lateral amplitude displacement (MLAD, in centimeters), total mean velocity (TMV, in centimeters per second), and dispersion of the center of pressure (AREA, in centimeters squared).
  
  
  RESULTS
  The postural sway analysis found statistically significant differences in the eyes open condition for the TDS (P = .020), APAD (P = .042), TMV (P = .010), and AREA (P = .045). In the discriminant analysis, none of the CoP variables were able to classify the groups (P = .15). The correlation analysis showed that only the AREA with eyes closed was associated with the ABC Scale (rho = -0.42).
  
  
  CONCLUSIONS
  Women with knee OA had greater postural sway when compared with a control group for the eyes open condition. CoP variables could not discriminate between the groups. The AREA was negatively correlated with the ABC Scale, when the eyes were closed.
  
  
  METHODS
  III.
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(∗).
authors.forename: Marcelo
authors.initials: M
authors.lastname: Taglietti
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(†).
authors.forename: Laís Faganello
authors.initials: LF
authors.lastname: Dela Bela
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(‡).
authors.forename: Josilainne Marcelino
authors.initials: JM
authors.lastname: Dias
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(§).
authors.forename: Alexandre Roberto Marcondes
authors.initials: ARM
authors.lastname: Pelegrinelli
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(‖).
authors.forename: Jéssyca Fernandes
authors.initials: JF
authors.lastname: Nogueira
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(¶).
authors.forename: João Pedro
authors.initials: JP
authors.lastname: Batista Júnior
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(#).
authors.forename: Rodrigo Gustavo da Silva
authors.initials: RGDS
authors.lastname: Carvalho
authors.affiliation: Institute of Nursing and Health Research, School of Health Sciences, Ulster University, Jordanstown, Northern Ireland, United Kingdom(∗∗).
authors.forename: Joseph Gerard
authors.initials: JG
authors.lastname: McVeigh
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil(††).
authors.forename: Ligia Maria
authors.initials: LM
authors.lastname: Facci
authors.affiliation: Sports Science Centre, Universidade Estadual de Londrina, Londrina, PR, Brazil(‡‡).
authors.forename: Felipe Arruda
authors.initials: FA
authors.lastname: Moura
authors.affiliation: Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Av. Robert Kock, 60, Londrina, PR, Brazil 86038-440(§§). Electronic address: jeffcar@uel.br.
authors.forename: Jefferson Rosa
authors.initials: JR
authors.lastname: Cardoso
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data*; D000368:Aged; D016022:Case-Control Studies; D005239:Fear; D005260:Female; D006801:Humans; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000175:diagnosis; D004856:Postural Balance / Q000502:physiology*; D015995:Prevalence; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D064232:Visual Analog Scale