title: Lack of quadriceps dysfunction in women with early knee osteoarthritis.
abstract: Quadriceps dysfunction, specifically weakness and central activation failure (CAF), has been implicated in the development and progression of knee osteoarthritis (OA), though few data are available to confirm its presence in early OA. The purpose of this study was to determine the presence and magnitude of quadriceps dysfunction in those with and without early knee OA. Thirty-five female volunteers were classified into two groups, OA (n=22) and control (n=13), based on the presence [Kellgren-Lawrence (K-L) grade 2] or absence (K-L grade 0-1) of mild OA, respectively. Isometric quadriceps strength and central activation ratio (CAR) were assessed and compared between groups utilizing a one-way ANOVA. Frequency statistics and Fisher's exact test were used to compare the percentage of women with and without CAF between groups. Quadriceps strength (control: 1.47+/-0.62 Nm/kg; OA: 1.30+/-0.62 Nm/kg; p=0.45) was not significantly different for women with and without mild OA. Further, the CAR (control: 0.91+/-0.07; OA: 0.87+/-0.12; p=0.19) did not differ between groups; however, women in both groups presented with CAF (control: 54%; OA: 73%; p=0.29). Our results suggest that the women with mild osteoarthritis do not present with quadriceps dysfunction.
authors.affiliation: School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, Michigan 48109-2214, USA. abbeyt@umich.edu
authors.forename: Abbey C
authors.initials: AC
authors.lastname: Thomas
authors.forename: Maryfran
authors.initials: M
authors.lastname: Sowers
authors.forename: Carrie
authors.initials: C
authors.lastname: Karvonen-Gutierrez
authors.forename: Riann M
authors.initials: RM
authors.lastname: Palmieri-Smith
mesh_terms: D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008875:Middle Aged; D008954:Models, Biological; D053580:Muscle Strength / Q000502:physiology; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging / Q000502:physiology*; D011859:Radiography; D012720:Severity of Illness Index; D019415:Torque; D016474:Weight-Bearing / Q000502:physiology