title: Prevalence of abnormalities in knees detected by MRI in adults without knee osteoarthritis: population based observational study (Framingham Osteoarthritis Study).
abstract: OBJECTIVE
  To examine use of magnetic resonance imaging (MRI) of knees with no radiographic evidence of osteoarthritis to determine the prevalence of structural lesions associated with osteoarthritis and their relation to age, sex, and obesity.
  
  
  METHODS
  Population based observational study.
  
  
  METHODS
  Community cohort in Framingham, MA, United States (Framingham osteoarthritis study).
  
  
  METHODS
  710 people aged >50 who had no radiographic evidence of knee osteoarthritis (Kellgren-Lawrence grade 0) and who underwent MRI of the knee.
  
  
  METHODS
  Prevalence of MRI findings that are suggestive of knee osteoarthritis (osteophytes, cartilage damage, bone marrow lesions, subchondral cysts, meniscal lesions, synovitis, attrition, and ligamentous lesions) in all participants and after stratification by age, sex, body mass index (BMI), and the presence or absence of knee pain. Pain was assessed by three different questions and also by WOMAC questionnaire.
  
  
  RESULTS
  Of the 710 participants, 393 (55%) were women, 660 (93%) were white, and 206 (29%) had knee pain in the past month. The mean age was 62.3 years and mean BMI was 27.9. Prevalence of "any abnormality" was 89% (631/710) overall. Osteophytes were the most common abnormality among all participants (74%, 524/710), followed by cartilage damage (69%, 492/710) and bone marrow lesions (52%, 371/710). The higher the age, the higher the prevalence of all types of abnormalities detectable by MRI. There were no significant differences in the prevalence of any of the features between BMI groups. The prevalence of at least one type of pathology ("any abnormality") was high in both painful (90-97%, depending on pain definition) and painless (86-88%) knees.
  
  
  CONCLUSIONS
  MRI shows lesions in the tibiofemoral joint in most middle aged and elderly people in whom knee radiographs do not show any features of osteoarthritis, regardless of pain.
authors.affiliation: Department of Radiology, Boston University School of Medicine, FGH Building, 820 Harrison Avenue, Boston, MA 02118, USA. guermazi@bu.edu
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
authors.forename: Jingbo
authors.initials: J
authors.lastname: Niu
authors.forename: Daichi
authors.initials: D
authors.lastname: Hayashi
authors.forename: Frank W
authors.initials: FW
authors.lastname: Roemer
authors.forename: Martin
authors.initials: M
authors.lastname: Englund
authors.forename: Tuhina
authors.initials: T
authors.lastname: Neogi
authors.forename: Piran
authors.initials: P
authors.lastname: Aliabadi
authors.forename: Christine E
authors.initials: CE
authors.lastname: McLennan
authors.forename: David T
authors.initials: DT
authors.lastname: Felson
mesh_terms: D017677:Age Distribution; D015992:Body Mass Index; D001845:Bone Cysts / Q000473:pathology*; D001853:Bone Marrow / Q000002:abnormalities; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007717:Knee / Q000002:abnormalities*; D008023:Ligaments, Articular / Q000002:abnormalities; D008279:Magnetic Resonance Imaging; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008592:Menisci, Tibial / Q000002:abnormalities; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D020370:Osteoarthritis, Knee / Q000175:diagnosis; D054850:Osteophyte / Q000473:pathology; D010147:Pain Measurement; D010329:Patella / Q000002:abnormalities*; D011237:Predictive Value of Tests; D015995:Prevalence; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D013585:Synovitis / Q000473:pathology