title: Proprioception, laxity, muscle strength and activity limitations in early symptomatic knee osteoarthritis: results from the CHECK cohort.
abstract: OBJECTIVE
  To establish whether proprioception and varus-valgus laxity moderate the association between muscle strength and activity limitations in patients with early symptomatic knee osteoarthritis.
  
  
  METHODS
  A cross-sectional study.
  
  
  METHODS
  A sample of 151 participants with early symptomatic knee osteoarthritis from the Cohort Hip and Cohort Knee study.
  
  
  METHODS
  Regression analyses were performed to establish the associations between muscle strength, proprioception (knee joint motion detection threshold in the anterior--posterior direction), varus-valgus laxity and activity limitations (self-reported and performance-based). Interaction terms were used to establish whether proprioception and laxity moderated the association between muscle strength and activity limitations.
  
  
  RESULTS
  Proprioception moderated the association between muscle strength and activity limitations: the negative association between muscle strength and activity limitations was stronger in participants with poor proprioception than in participants with accurate proprioception (performance-based activity limitations p = 0.02; self-reported activity limitations p = 0.08). The interaction between muscle strength and varus-valgus laxity was not significantly associated with activity limitations.
  
  
  CONCLUSIONS
  The results of the present study support the theory that in the absence of adequate proprioceptive input, lower muscle strength affects a patient's level of activities to a greater degree than in the presence of adequate proprioceptive input.
authors.affiliation: Amsterdam Rehabilitation Research Center Reade, Amsterdam, The Netherlands. j.holla@reade.nl
authors.forename: Jasmijn F M
authors.initials: JF
authors.lastname: Holla
authors.forename: Marike
authors.initials: M
authors.lastname: van der Leeden
authors.forename: Wilfred F H
authors.initials: WF
authors.lastname: Peter
authors.forename: Leo D
authors.initials: LD
authors.lastname: Roorda
authors.forename: Martin
authors.initials: M
authors.lastname: van der Esch
authors.forename: Willem F
authors.initials: WF
authors.lastname: Lems
authors.forename: Martijn
authors.initials: M
authors.lastname: Gerritsen
authors.forename: Ramon E
authors.initials: RE
authors.lastname: Voorneman
authors.forename: Martijn P M
authors.initials: MP
authors.lastname: Steultjens
authors.forename: Joost
authors.initials: J
authors.lastname: Dekker
mesh_terms: D000203:Activities of Daily Living; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D053580:Muscle Strength / Q000502:physiology; D020370:Osteoarthritis, Knee / Q000150:complications / Q000503:physiopathology*; D011434:Proprioception / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology