title: Frequency of bone marrow lesions and association with pain severity: results from a population-based symptomatic knee cohort.
abstract: OBJECTIVE
  To evaluate the prevalence of bone marrow lesions (BML) and their association with pain severity in a population-based cohort of symptomatic early knee osteoarthritis (OA).
  
  
  METHODS
  Subjects with knee pain (n = 255), age 40-79 years, were evaluated by radiograph and magnetic resonance imaging (MRI) and classified into OA stages: no OA (NOA), preradiographic OA (PROA), and radiographic OA (ROA). BML were graded 0-3 (none, mild, moderate, severe) in 6 regions and defined as (1) BMLsum = the sum of 6 scores; and (2) BMLmax = the worst score at any region. Pain was assessed by the Western Ontario and McMaster Universities OA Index (WOMAC). Linear regression analysis was completed to assess the association of Total WOMAC Pain (primary outcome) versus BMLsum or BMLmax. Secondary outcomes were WOMAC Pain on Walking and WOMAC Pain on Climbing Stairs. All analyses were adjusted for age, sex, body mass index, OA stage, joint effusion, and meniscal damage.
  
  
  RESULTS
  BML were present in 11% of NOA, 38% of PROA, and 71% of ROA subjects (p < 0.001). No association was seen for BMLsum or BMLmax versus Total WOMAC Pain or Pain on Walking. However, BMLsum was associated with Pain on Climbing Stairs [regression coefficients (RC) = 0.09, 95% CI 0.00-0.18]. BMLmax was associated with Pain on Climbing Stairs, with the strongest association for severe BML (RC 0.60, 95% CI 0.04-1.17).
  
  
  CONCLUSIONS
  BML were present in 38% of PROA and 71% of ROA subjects in this symptomatic knee cohort. BML were significantly associated with Pain on Climbing Stairs but not Total WOMAC or Pain on Walking.
authors.affiliation: Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Stephen
authors.initials: S
authors.lastname: Ip
authors.forename: Eric C
authors.initials: EC
authors.lastname: Sayre
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
authors.forename: Savvakis
authors.initials: S
authors.lastname: Nicolaou
authors.forename: Hubert
authors.initials: H
authors.lastname: Wong
authors.forename: Anona
authors.initials: A
authors.lastname: Thorne
authors.forename: Joel
authors.initials: J
authors.lastname: Singer
authors.forename: Jacek A
authors.initials: JA
authors.lastname: Kopec
authors.forename: John M
authors.initials: JM
authors.lastname: Esdaile
authors.forename: Jolanda
authors.initials: J
authors.lastname: Cibere
mesh_terms: D000328:Adult; D000368:Aged; D018771:Arthralgia / Q000453:epidemiology* / Q000209:etiology; D001853:Bone Marrow / Q000000981:diagnostic imaging* / Q000473:pathology*; D001855:Bone Marrow Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009864:Ontario; D020370:Osteoarthritis, Knee / Q000150:complications / Q000453:epidemiology*; D015995:Prevalence; D011859:Radiography; D012720:Severity of Illness Index