title: Biochemical change in joint fluid after isometric quadriceps exercise for patients with osteoarthritis of the knee.
abstract: OBJECTIVE
  The purpose of this study was to analyze the biochemical changes in the joint fluid, and pain relief resulting from isometric quadriceps exercise in patients with osteoarthritis of the knee.
  
  
  METHODS
  Nineteen osteoarthritic knees in 17 patients with joint effusion were included. The patients performed isometric quadriceps exercise for 3 months. Isometric muscle torque at 30 and 60 degrees flexion, pain as measured using the visual analog scale and biochemical markers in joint fluid were evaluated before and after the exercise.
  
  
  RESULTS
  Pain score decreased from 3.9 to 2.3 after 12 weeks of exercise (P<0.001). Extension torque at 30 and 60 degrees knee flexion significantly increased from 4.7 to 6.9 kgm (47% increase, P<0.001) and from 10.8 to 12.6 kgm (17% increase, P<0.005) after 12 weeks of exercise. The molecular weight of hyaluronan increased from 2.11 to 2.40x10(6)(P<0.05) and the viscosity of joint fluid increased from 45.8 to 59.8 mPas after 12 weeks of exercise (P<0.05). Chondroitin 4-, 6-sulfate concentration in joint fluid decreased from 81.9 to 75.5 nmol/ml (P<0.05).
  
  
  CONCLUSIONS
  Isometric quadriceps exercise resulted in significant changes in joint fluid biochemical parameters, and these changes, at least in part, may explain the ameliorative effect of muscle exercise for osteoarthritis of the knee.
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Medical School, Osaka, Japan.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Miyaguchi
authors.forename: Akio
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kadoya
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ohashi
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Yamano
authors.forename: Kunio
authors.initials: K
authors.lastname: Takaoka
mesh_terms: D000368:Aged; D000418:Albumins / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D002809:Chondroitin Sulfates / Q000032:analysis; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007537:Isometric Contraction / Q000502:physiology; D007719:Knee Joint / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000378:metabolism* / Q000503:physiopathology; D010146:Pain / Q000517:prevention & control; D011506:Proteins / Q000032:analysis; D013582:Synovial Fluid / Q000378:metabolism*; D014783:Viscosity
chemical_list: D000418:Albumins; D015415:Biomarkers; D011506:Proteins; D006820:Hyaluronic Acid; D002809:Chondroitin Sulfates