title: Magnetic resonance imaging lesions are more severe and cartilage T2 relaxation time measurements are higher in isolated lateral compartment radiographic knee osteoarthritis than in isolated medial compartment disease - data from the Osteoarthritis Initiative.
abstract: Isolated lateral compartment tibiofemoral radiographic osteoarthritis (IL-ROA) is an understudied form of knee osteoarthritis (OA). The objective of the present study was to characterize Magnetic Resonance Imaging (MRI) abnormalities and MR-T2 relaxation time measurements associated with IL-ROA and with isolated medial compartment ROA (IM-ROA) compared with knees without OA.
  
  
  
  200 case subjects with IL-ROA (Kellgren/Lawrence (K/L) grade≥2 and joint space narrowing (JSN) > 0 in the lateral compartment but JSN = 0 in the medial compartment) were randomly selected from the Osteoarthritis Initiative baseline visit. 200 cases with IM-ROA and 200 controls were frequency matched to the IL-ROA cases. Cases and controls were analyzed for odds of having a subregion with >10% cartilage area affected, with ≥25% bone marrow lesions (BML), with meniscal tear or maceration, and for association with cartilage T2 values.
  
  
  
  IL-ROA was more strongly associated with ipsilateral MRI knee pathologies than IM-ROA (IL-ROA: OR = 135.2 for size of cartilage lesion, 95% CI 42.7-427.4; OR = 145.4 for large size BML, 95% CI 41.5-509.5; OR = 176 for meniscal tears, 95% CI 59.8-517.7; IM-ROA: OR = 28.4 for size of cartilage lesion, 95% CI 14.7-54.7; OR = 38.1 for size of BML, 95% CI 12.7-114; OR = 37.0 for meniscal tears, 95% CI 12-113.6). Cartilage T2 values were higher in both tibial and medial femoral compartments in IL-ROA, but in IM-ROA were only significantly different from controls in the medial femur.
  
  
  
  IL-ROA knees show a greater prevalence and severity of MRI lesions and higher cartilage T2 values than IM-ROA knees compared with controls.
authors.affiliation: University of California, Davis School of Medicine, Sacramento, CA, USA. Electronic address: blwise@ucdavis.edu.
authors.forename: B L
authors.initials: BL
authors.lastname: Wise
authors.affiliation: Boston University School of Medicine, Boston, MA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Niu
authors.affiliation: Boston University School of Medicine, Boston, MA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Guermazi
authors.affiliation: University of California, San Francisco School of Medicine, USA.
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.affiliation: University of California, San Francisco School of Medicine, USA.
authors.forename: U
authors.initials: U
authors.lastname: Heilmeier
authors.affiliation: University of California, San Francisco School of Medicine, USA.
authors.forename: E
authors.initials: E
authors.lastname: Ku
authors.affiliation: University of California, San Francisco School of Medicine, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Lynch
authors.affiliation: Boston University School of Medicine, Boston, MA, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Boston University School of Medicine, Boston, MA, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Felson
authors.affiliation: University of Arizona College of Medicine, Tuscon, AZ, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Kwoh
authors.affiliation: University of California, Davis School of Medicine, Sacramento, CA, USA.
authors.forename: N E
authors.initials: NE
authors.lastname: Lane
mesh_terms: D000368:Aged; D002358:Cartilage, Articular; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D012720:Severity of Illness Index
keywords: Cartilage; Knee osteoarthritis; Lateral compartment; Magnetic resonance imaging