title: Bakers' cyst and tibiofemoral abnormalities are more distinctive MRI features of symptomatic osteoarthritis than patellofemoral abnormalities.
abstract: OBJECTIVE
  To investigate which structural MR abnormalities discriminate symptomatic knee osteoarthritis (OA), taking co-occurrence of abnormalities in all compartments into account.
  
  
  METHODS
  The Netherlands Epidemiology of Obesity (NEO) study is a population-based cohort aged 45-65 years. In 1285 participants (median age 56 years, 55% women, median body mass index (BMI) 30 kg/m(2)), MRI of the right knee were obtained. Structural abnormalities (osteophytes, cartilage loss, bone marrow lesions (BMLs), subchondral cysts, meniscal abnormalities, effusion, Baker's cyst) at 9 patellofemoral and tibiofemoral locations were scored following the knee OA scoring system. Symptomatic OA in the imaged knee was defined following the American College of Rheumatology criteria. Logistic ridge regression analyses were used to investigate which structural abnormalities discriminate best between individuals with and without symptomatic OA, crude and adjusted for age, sex and BMI.
  
  
  RESULTS
  Symptomatic knee OA was present in 177 individuals. Structural MR abnormalities were highly frequent both in individuals with OA and in those without. Baker's cysts showed the highest adjusted regression coefficient (0.293) for presence of symptomatic OA, followed by osteophytes and BMLs in the medial tibiofemoral compartment (0.185-0.279), osteophytes in the medial trochlear facet (0.262) and effusion (0.197).
  
  
  CONCLUSIONS
  Baker's cysts discriminate best between individuals with and without symptomatic knee OA. Structural MR abnormalities, especially in the medial side of the tibiofemoral joint and effusion, add further in discriminating symptomatic OA. Baker's cysts may present as a target for treatment.
authors.affiliation: Department of Rheumatology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: A W
authors.initials: AW
authors.lastname: Visser
authors.affiliation: Department of Medical Statistics and Bio-informatics, Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Mertens
authors.affiliation: Department of Radiology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Reijnierse
authors.affiliation: Department of Radiology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: J L
authors.initials: JL
authors.lastname: Bloem
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: de Mutsert
authors.affiliation: Department of Medical Statistics and Bio-informatics,Leiden University Medical Center, Leiden, The Netherlands; Department of Clinical Epidemiology,Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: le Cessie
authors.affiliation: Department of Clinical Epidemiology,Leiden University Medical Center, Leiden, The Netherlands; Department of Thrombosis and Homeostasis, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: F R
authors.initials: FR
authors.lastname: Rosendaal
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands; Department of Clinical Epidemiology,Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Kloppenburg
keywords: Epidemiology; Knee Osteoarthritis; Magnetic Resonance Imaging