title: The relationship between quadriceps muscle weakness and worsening of knee pain in the MOST cohort: a 5-year longitudinal study.
abstract: OBJECTIVE
  To determine whether quadriceps weakness is associated with elevated risk of worsening knee pain over 5 years.
  
  
  METHODS
  The Multicenter Osteoarthritis Study (MOST) is a longitudinal study of 50-79-year-old adults with knee osteoarthritis (OA) or known risk factors for knee OA. The predictor variable was baseline isokinetic quadriceps strength. Covariates included baseline body mass index (BMI), physical activity level, and history of knee surgery. The outcome was worsening pain reported on the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index pain subscale or knee replacement surgery between baseline and 5-year follow-up. Analyses were knee-based and used generalized estimating equations, stratified by sex to assess whether the lowest compared with the highest tertile of baseline quadriceps strength was associated with an increased risk of worsening knee pain at 5-year follow-up, controlling for age, BMI, history of knee surgery, and physical activity level as well as correlation between knees within participants.
  
  
  RESULTS
  Analyses of worsening knee pain included 4,648 knees from 2,404 participants (61% female). Men with lower quadriceps strength did not have a higher risk of worsening knee pain (RR {95% CI} = 1.01 {0.78-1.32}, P = 0.9183). However, women in the lowest compared with the highest strength tertile had a 28% increased risk of worsening knee pain (RR {95% CI} = 1.28 {1.08-1.52}, P = 0.0052).
  
  
  CONCLUSIONS
  Quadriceps weakness was associated with an increased risk of worsening of knee pain over 5 years in women, but not in men.
authors: Department of Orthopaedics and Rehabilitation, The University of Iowa, Iowa City, IA 52242-1088, USA.
authors: N A
authors: NA
authors: Glass
authors: J C
authors: JC
authors: Torner
authors: L A
authors: LA
authors: Frey Law
authors: K
authors: K
authors: Wang
authors: T
authors: T
authors: Yang
authors: M C
authors: MC
authors: Nevitt
authors: D T
authors: DT
authors: Felson
authors: C E
authors: CE
authors: Lewis
authors: N A
authors: NA
authors: Segal
mesh_terms: D000368:Aged; D018771:Arthralgia / Q000453:epidemiology* / Q000503:physiopathology* / Q000601:surgery; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D053580:Muscle Strength / Q000502:physiology; D018908:Muscle Weakness / Q000453:epidemiology* / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000453:epidemiology* / Q000503:physiopathology* / Q000601:surgery; D052097:Quadriceps Muscle / Q000503:physiopathology; D012307:Risk Factors
keywords: Knee osteoarthritis; Knee pain; Quadriceps weakness
references: Arthritis Rheum. 2009 Jan;60(1):189-98
references: 19116936
references: Osteoarthritis Cartilage. 2010 Jun;18(6):769-75
references: 20188686
references: J Clin Epidemiol. 2010 May;63(5):524-34
references: 19926446
references: Ann Rheum Dis. 2006 Jul;65(7):865-70
references: 16308342
references: J Clin Epidemiol. 1993 Feb;46(2):153-62
references: 8437031
references: Arthritis Rheum. 2009 Sep 15;61(9):1210-7
references: 19714608
references: Ann Rheum Dis. 1998 Oct;57(10):588-94
references: 9893569
references: J Rheumatol. 2002 Jan;29(1):131-8
references: 11824949
references: Rheumatology (Oxford). 2000 May;39(5):490-6
references: 10852978
references: Ann Intern Med. 2011 Dec 6;155(11):725-32
references: 22147711
references: Arthritis Rheum. 2001 Aug;45(4):384-91
references: 11501727
references: J Pain. 2009 May;10(5):447-85
references: 19411059
references: J Orthop Res. 2009 Dec;27(12):1562-8
references: 19533741
references: Arthritis Rheum. 2007 Sep;56(9):2986-92
references: 17763427
references: Osteoarthritis Cartilage. 2005 Dec;13(12):1076-83
references: 16154777
references: J Pain. 2012 Mar;13(3):228-34
references: 22245360
references: Arch Phys Med Rehabil. 2009 Jun;90(6):897-904
references: 19480863
references: J Rheumatol. 2000 Jun;27(6):1513-7
references: 10852280
references: J Sports Med Phys Fitness. 2004 Jun;44(2):186-92
references: 15470317
references: Med Sci Sports Exerc. 1999 May;31(5):627-33
references: 10331879
references: J Rheumatol. 1999 Nov;26(11):2431-7
references: 10555906
references: J Gerontol A Biol Sci Med Sci. 2002 Apr;57(4):B144-52
references: 11909879
references: Arch Phys Med Rehabil. 2007 Aug;88(8):988-92
references: 17678660
references: Med Care. 1999 May;37(5):469-78
references: 10335749
references: PM R. 2009 May;1(5):459-65
references: 19627933
references: Clin Rheumatol. 1995 May;14(3):308-14
references: 7641507
references: BMJ. 2002 Oct 5;325(7367):752
references: 12364304
references: Curr Opin Rheumatol. 2000 Sep;12(5):456-63
references: 10990187
references: Osteoarthritis Cartilage. 2007 Mar;15(3):273-80
references: 17052924
references: Osteoarthritis Cartilage. 1997 Mar;5(2):87-97
references: 9135820
references: Arthritis Rheum. 2006 Oct 15;55(5):779-85
references: 17013827
references: Ann Rheum Dis. 2005 Jan;64(1):29-33
references: 15208174
references: Ann Intern Med. 2001 Apr 3;134(7):541-9
references: 11281736
references: Ann Rheum Dis. 2008 Jan;67(1):43-7
references: 19623678