title: Radiographic progression of knee osteoarthritis is associated with MRI abnormalities in both the patellofemoral and tibiofemoral joint.
abstract: OBJECTIVE
  To investigate patterns of MRI abnormalities in the patellofemoral (PFJ) and tibiofemoral joint (TFJ) and their association with radiographic progression, using hypothesis free analyses.
  
  
  METHODS
  205 patients from the GARP study with symptomatic OA at multiple sites (mean age 60 years, 80% woman, median BMI 26 kg/m(2)), underwent knee MRI at baseline. Cartilage damage, osteophytes, cysts, bone marrow lesions (BMLs) and effusion/synovitis were scored according to a validated scoring method. Baseline and 6-year TFJ and PFJ radiographs were scored (0-3) for JSN and osteophytes according to OARSI and Burnett atlases, respectively; progression was defined as ≥1 point increase. Baseline patterns of MRI abnormalities derived from principal component analysis (PCA) were associated with progression using adjusted generalized estimating equations (GEE).
  
  
  RESULTS
  PCA resulted in extraction of six components, explaining 69% of variance. In 29% and 29% of 133 patients with follow-up the TFJ progressed, whereas in 15% and 9% the PFJ progressed for osteophytes and JSN, respectively. Component 1 (cartilage damage of the PFJ and osteophytes of both joints) was statistically significant associated with TFJ JSN progression and PFJ osteophyte progression. Component 2 (all lateral PFJ abnormalities except osteophytes) was associated with JSN/osteophyte progression in the PFJ alone, whereas component 3 (all medial TFJ abnormalities except osteophytes) was associated with JSN and osteophyte progression in both PFJ and TFJ.
  
  
  CONCLUSIONS
  Baseline structural damage and bone turnover activity, as reflected by BMLs, seem to be involved in knee OA progression. Moreover, progression in PFJ and TFJ seems to be related.
authors.affiliation: Department of Rheumatology, Leiden University Medical Centre, Leiden, The Netherlands. Electronic address: b.j.e.de_lange@lumc.nl.
authors.forename: B J E
authors.initials: BJ
authors.lastname: de Lange-Brokaar
authors.affiliation: Department of Rheumatology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Bijsterbosch
authors.affiliation: Department of Radiology, Bronovo Hospital, The Hague, The Netherlands.
authors.forename: P R
authors.initials: PR
authors.lastname: Kornaat
authors.affiliation: Department of Rheumatology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Yusuf
authors.affiliation: Department of Rheumatology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Ioan-Facsinay
authors.affiliation: TNO, Leiden, The Netherlands.
authors.forename: A-M
authors.initials: AM
authors.lastname: Zuurmond
authors.affiliation: Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: H M
authors.initials: HM
authors.lastname: Kroon
authors.affiliation: Department of Molecular Epidemiology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: I
authors.initials: I
authors.lastname: Meulenbelt
authors.affiliation: Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: J L
authors.initials: JL
authors.lastname: Bloem
authors.affiliation: Department of Rheumatology, Leiden University Medical Centre, Leiden, The Netherlands; Department of Clinical Epidemiology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Kloppenburg
mesh_terms: D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000473:pathology; D054850:Osteophyte / Q000473:pathology; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging / Q000473:pathology; D011859:Radiography / Q000379:methods; D012720:Severity of Illness Index; D013585:Synovitis / Q000000981:diagnostic imaging
keywords: Osteoarthritis; Radiographic progression; Synovitis