title: Gait characteristics and lower limb muscle strength in women with early and established knee osteoarthritis.
abstract: BACKGROUND
  Based on novel classification criteria using magnetic resonance imaging, a subpopulation of "early knee osteoarthritis patients" was clearly defined recently. This study assessed whether these early osteoarthritis patients already exhibit gait adaptations (knee joint loading in particular) and changes in muscle strength compared to control subjects and established knee osteoarthritis patients.
  
  
  METHODS
  Fourteen female patients with early knee joint degeneration, defined by magnetic resonance imaging (early osteoarthritis), 12 female patients with established osteoarthritis and 14 female control subjects participated. Specific gait parameters and lower limb muscle strength were analyzed and compared between groups. Within the osteoarthritis groups, association between muscle strength and dynamic knee joint loading was also evaluated.
  
  
  RESULTS
  Early osteoarthritis patients presented no altered gait pattern, no significant increase in knee joint loading and no significant decrease in hamstring muscle strength compared to controls, while established osteoarthritis patients did. In contrast, early osteoarthritis patients experienced significant quadriceps weakness, comparable to established osteoarthritis patients. Within the osteoarthritis groups, muscle strength was not correlated with knee joint loading during gait.
  
  
  CONCLUSIONS
  The results suggest that gait changes reflect mechanical overload and are most likely the consequence of structural degeneration in knee osteoarthritis. Quadriceps weakness might however contribute to the onset and progression of the disease. This study supports the relevance of classification of early osteoarthritis patients and assists in identifying their functional characteristics. This helps to understand the trajectory of disease onset and progression and further develop more targeted strategies for prevention and treatment of knee osteoarthritis.
authors.affiliation: Department of Rehabilitation Sciences, Faculty of Kinesiology and Rehabilitation Sciences, KU Leuven, Tervuursevest 101, Heverlee, Belgium.
authors.forename: Isabel A C
authors.initials: IA
authors.lastname: Baert
authors.forename: Ilse
authors.initials: I
authors.lastname: Jonkers
authors.forename: Filip
authors.initials: F
authors.lastname: Staes
authors.forename: Frank P
authors.initials: FP
authors.lastname: Luyten
authors.forename: Steven
authors.initials: S
authors.lastname: Truijen
authors.forename: Sabine M P
authors.initials: SM
authors.lastname: Verschueren
mesh_terms: D000368:Aged; D005260:Female; D005684:Gait; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000503:physiopathology*; D018570:Risk Assessment; D013848:Thigh / Q000503:physiopathology; D016474:Weight-Bearing