title: Altered gait characteristics in individuals with knee osteoarthritis and self-reported knee instability.
abstract: METHODS
  Experimental laboratory study.
  
  
  OBJECTIVE
  To characterize the differences in lower extremity gait biomechanics in individuals who have knee osteoarthritis (OA) with and without self-reported knee instability.
  
  
  BACKGROUND
  Individuals with knee OA who experience episodes of knee instability often report gait difficulties that interfere with their daily lives. A better understanding of the alterations in gait biomechanics may help to mitigate symptomatic knee instability in this patient population.
  
  
  METHODS
  Seventeen participants with knee OA and self-reported knee instability and 36 participants with knee OA and no self-reported knee instability underwent instrumented gait analysis on level ground. Knee-specific symptoms and functional limitations were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index.
  
  
  RESULTS
  Knee instability was associated with greater odds of reporting moderate to severe gait-related pain (odds ratio = 6.0; 95% confidence interval: 1.2, 28.9) and moderate to severe difficulty when walking on flat surfaces (odds ratio = 10.7; 95% confidence interval: 1.7, 69.2). During early stance, the group with self-reported knee instability walked with a greater knee flexion excursion (P = .02) and a smaller lower extremity support moment (P<.01), due to reduced contributions from the hip extensors (P<.01) and ankle plantar flexors (P = .04). The group with self-reported knee instability also walked with a greater knee extensor contribution to the lower extremity support moment (P = .04) during the initial knee extension phase of gait compared to their counterparts with good knee stability.
  
  
  CONCLUSIONS
  These findings suggest that self-reported knee instability is associated with significant alterations in hip, knee, and ankle joint function during the stance phase of gait in individuals with knee OA.
authors: Human Movement Research Laboratory, Department of Physical Therapy, University of Pittsburgh, Pittsburgh, PA.
authors: Shawn
authors: S
authors: Farrokhi
authors: Megan
authors: M
authors: O'Connell
authors: Alexandra B
authors: AB
authors: Gil
authors: Patrick J
authors: PJ
authors: Sparto
authors: G Kelley
authors: GK
authors: Fitzgerald
mesh_terms: D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D010146:Pain / Q000209:etiology; D016059:Range of Motion, Articular; D057566:Self Report
keywords: biomechanics; kinematics; kinetics; lower extremity