title: Anteroposterior and varus-valgus laxity of the knee increase after stair climbing in patients with mild osteoarthritis.
abstract: The aim of this study was to measure exercise-induced changes in knee joint laxity in patients with knee osteoarthritis (OA). The study subjects were 46 female patients with OA and 22 age- and sex-matched normal controls. Radiographs of the knee were taken in all subjects, and the disease severity was graded according to the Kellgren and Lawrence (K-L) grading system. The K-L grade of the control subjects (non-OA group) was 0-1. The OA patients were divided into those with mild OA (K-L grade 2, n = 20) and advanced OA (K-L grade 3-4, n = 26). The subject climbed up and down 8 steps on a staircase apparatus over a period of 10 min. The anteroposterior (A-P) translation was measured with KT2000 arthrometer, and varus-valgus (V-V) rotation was measured on stress radiographs before and after the stair climbing. The Δchange in A-P translation after the exercise was significantly larger in mild OA group than other groups (P < 0.005). The Δchange in V-V rotation after exercise was significantly larger in mild and advanced OA groups than the control (P < 0.003). There were no significant differences in A-P laxity and V-V laxity before exercise among the non-OA, mild OA and advanced OA groups. Exercise resulted in significant changes in A-P knee joint laxity in patients with mild OA relative to the control. The results suggest that daily physical activities (e.g., knee bending or squatting) play a role in the development of knee laxity, particularly in patients with mild OA, and that progression of knee OA seems to correlate with increments of A-P knee joint laxity.
authors.affiliation: Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, The University of Fukui, Fukui, Japan. mtuyo@u-fukui.ac.jp
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Kenzo
authors.initials: K
authors.lastname: Uchida
authors.forename: Makoto
authors.initials: M
authors.lastname: Wada
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Sato
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sugita
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Shimada
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Baba
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D016059:Range of Motion, Articular / Q000502:physiology; D012399:Rotation; D012720:Severity of Illness Index; D013997:Time Factors