title: Within-subregion relationship between bone marrow lesions and subsequent cartilage loss in knee osteoarthritis.
abstract: OBJECTIVE
  Bone marrow lesions are believed to increase risk of knee osteoarthritis (OA) progression. Whether their effect is local and whether it can be explained by other types of bone lesions concomitantly present in the same subregion is unclear. We evaluated bone lesion frequency in subregions without cartilage lesions and cartilage lesion frequency in subregions without bone lesions, and investigated the within-subregion bone marrow lesion/subsequent cartilage loss relationship after adjusting for other types of bone lesions at baseline.
  
  
  METHODS
  Individuals with knee OA had magnetic resonance imaging at baseline and 2 years later. Cartilage integrity and bone marrow lesions, cysts, and attrition were scored within tibiofemoral subregions. Logistic regression, with generalized estimating equations to account for correlation among multiple subregions within a knee, was used to estimate odds ratios (ORs) for cartilage loss associated with bone marrow lesions, adjusting for age, sex, body mass index, and bone attrition and cysts in the same subregion.
  
  
  RESULTS
  Analyzing 1,953 subregions among 177 knees, 90% of subregions had no bone lesions at baseline. Only 0-3% of subregions without cartilage lesions had bone lesions in the same subregion; in contrast, 5-33% of subregions without bone lesions had cartilage lesions. Bone marrow lesions at baseline were associated with cartilage loss in the same subregion at 2 years, adjusting for other types of bone lesions at baseline (adjusted OR 3.74, 95% confidence interval 1.59-8.82).
  
  
  CONCLUSIONS
  In subjects with knee OA, bone marrow lesions were rare at early disease stages but predicted subregional cartilage loss after accounting for the presence of other types of bone lesions in the same subregion.
authors.affiliation: Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Ami
authors.initials: A
authors.lastname: Kothari
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
authors.forename: Joan S
authors.initials: JS
authors.lastname: Chmiel
authors.forename: Dorothy
authors.initials: D
authors.lastname: Dunlop
authors.forename: Jing
authors.initials: J
authors.lastname: Song
authors.forename: Orit
authors.initials: O
authors.lastname: Almagor
authors.forename: Meredith
authors.initials: M
authors.lastname: Marshall
authors.forename: September
authors.initials: S
authors.lastname: Cahue
authors.forename: Pottumarthi
authors.initials: P
authors.lastname: Prasad
authors.forename: Leena
authors.initials: L
authors.lastname: Sharma
mesh_terms: D000368:Aged; D001845:Bone Cysts / Q000150:complications / Q000175:diagnosis; D001847:Bone Diseases / Q000150:complications / Q000175:diagnosis; D001855:Bone Marrow Diseases / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology; D002357:Cartilage Diseases / Q000150:complications / Q000175:diagnosis; D002358:Cartilage, Articular / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000175:diagnosis*