title: Relation of synovitis to knee pain using contrast-enhanced MRIs.
abstract: BACKGROUND
  It has been suggested that synovitis causes joint pain. On non-contrast-enhanced MRIs synovial thickening cannot be assessed and on these images synovitis has been inconsistently associated with pain.
  
  
  OBJECTIVE
  To assess synovial thickening in relation to knee pain severity among subjects in the Multicenter Osteoarthritis Study (MOST) using contrast-enhanced (CE) MRI.
  
  
  METHODS
  MOST is a cohort study of people who have, or are at high risk of, knee osteoarthritis (OA). An unselected subset of 535 participants who volunteered underwent CE 1.5 T MRI of one knee. Synovitis was scored in six compartments and a summary score was created. Knee pain severity was assessed using the maximum item score on the Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain scale. The association between synovitis and pain severity was examined using a logistic regression model adjusting for age, sex, body mass index (BMI), MRI bone marrow lesions and effusions in the whole sample and in a subgroup without radiographic OA.
  
  
  RESULTS
  454 of the 535 subjects undergoing CE MRI had complete data on synovitis and WOMAC pain. Mean age was 59 years, mean BMI 30 and 48% were women. In knees with moderate pain, 80% had synovitis. For knee pain, synovitis conferred a 9.2-fold increased odds compared with those without synovitis. In knees without radiographic OA (n=329), there was also an association of synovitis with an increased prevalence of pain.
  
  
  CONCLUSIONS
  Synovitis has a strong relation with knee pain severity, an association detected more clearly with CE MRI than suggested by previous studies using non-CE MRI measures of synovitis.
authors.affiliation: Clinical Epidemiology Research and Training Unit, Boston University Medical Center, 650 Albany Street, Suite X200, Boston, MA 02118, USA. krbaker@bu.edu
authors.forename: K
authors.initials: K
authors.lastname: Baker
authors.forename: A
authors.initials: A
authors.lastname: Grainger
authors.forename: J
authors.initials: J
authors.lastname: Niu
authors.forename: M
authors.initials: M
authors.lastname: Clancy
authors.forename: A
authors.initials: A
authors.lastname: Guermazi
authors.forename: M
authors.initials: M
authors.lastname: Crema
authors.forename: L
authors.initials: L
authors.lastname: Hughes
authors.forename: J
authors.initials: J
authors.lastname: Buckwalter
authors.forename: A
authors.initials: A
authors.lastname: Wooley
authors.forename: M
authors.initials: M
authors.lastname: Nevitt
authors.forename: D T
authors.initials: DT
authors.lastname: Felson
mesh_terms: D000368:Aged; D000407:Alabama / Q000453:epidemiology; D018771:Arthralgia / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology; D015992:Body Mass Index; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007484:Iowa / Q000453:epidemiology; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D013585:Synovitis / Q000150:complications* / Q000453:epidemiology / Q000473:pathology
references.citation: J Rheumatol. 1996 Jul;23(7):1151-61
references.pmid: 8823685
references.citation: Osteoarthritis Cartilage. 2004 Mar;12(3):177-90
references.pmid: 14972335
references.citation: Rheumatology (Oxford). 2005 Dec;44(12):1569-73
references.pmid: 16188949
references.citation: Rheumatology (Oxford). 2006 Nov;45(11):1389-94
references.pmid: 16606655
references.citation: Osteoarthritis Cartilage. 2009 Sep;17(9):1186-92
references.pmid: 19332177
references.citation: J Rheumatol. 2001 Jun;28(6):1330-7
references.pmid: 11409127
references.citation: Ann Rheum Dis. 2007 Dec;66(12):1599-603
references.pmid: 17491096
references.citation: Osteoarthritis Cartilage. 2006 Oct;14(10):1033-40
references.pmid: 16713310
references.citation: Ann Intern Med. 1992 Apr 1;116(7):598-9
references.pmid: 1543316
references.citation: Arthritis Rheum. 2007 Sep;56(9):2986-92
references.pmid: 17763427
references.citation: Rheum Dis Clin North Am. 2004 Nov;30(4):783-97, vii
references.pmid: 15488693
references.citation: Ann Rheum Dis. 2008 Jan;67(1):43-7
references.pmid: 19623678