title: Physical function and properties of quadriceps femoris muscle in men with knee osteoarthritis.
abstract: OBJECTIVE
  To examine the objective physical function of the lower extremities, to measure the properties of quadriceps femoris muscle (QFM), and to assess subjective disabilities in men with knee osteoarthritis (OA) and to compare the results with those obtained from age- and sex-matched control subjects.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Rehabilitation clinic in a university hospital.
  
  
  METHODS
  Male volunteers (n=54) (age range, 50-69y) with knee OA and randomly selected healthy, age- and sex-matched control subjects (n=53).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Physical function evaluated with a test battery including the QFM composition measurement, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the RAND 36-Item Short-Form Health Survey, version 1.0.
  
  
  RESULTS
  Knee OA patients had 13% to 26% poorer (P range, .050-.001) physical function and muscle strength compared with the controls. There were also significant differences in QFM composition. WOMAC (P range, .050-.001) and muscle strength (P<.001) associated with physical function tests, but subjective pain correlated with neither physical function nor muscle strength in knee OA patients. The radiographic knee OA grade did not have any significant effect on physical function, but passive knee motion, knee extension strength, and WOMAC were related to the severity of the disease (P<.05).
  
  
  CONCLUSIONS
  The patients with knee OA exhibited impaired physical function and muscle strength and QFM composition compared with healthy controls. The severity of radiographic knee OA clearly had adverse effects on functional ability at the later stages of the disease. The results highlight the effect of QFM strength on physical function as well as the importance of patient's subjective and objective physical function when deciding on knee OA treatment policy.
authors.affiliation: Department of Physical and Rehabilitation Medicine, Kuopio University Hospital, Kuopio, Finland; Kolari Health Centre, Kolari, Finland. liikavai@hytti.uku.fi
authors.forename: Tuomas
authors.initials: T
authors.lastname: Liikavainio
authors.forename: Tarja
authors.initials: T
authors.lastname: Lyytinen
authors.forename: Erja
authors.initials: E
authors.lastname: Tyrväinen
authors.forename: Sarianna
authors.initials: S
authors.lastname: Sipilä
authors.forename: Jari P
authors.initials: JP
authors.lastname: Arokoski
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D053580:Muscle Strength; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000534:rehabilitation*; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011788:Quality of Life; D016059:Range of Motion, Articular; D012720:Severity of Illness Index; D014463:Ultrasonography