title: Change in joint space width: hyaline articular cartilage loss or alteration in meniscus?
abstract: OBJECTIVE
  To explore the relative contribution of hyaline cartilage morphologic features and the meniscus to the radiographic joint space.
  
  
  METHODS
  The Boston Osteoarthritis of the Knee Study is a natural history study of symptomatic knee osteoarthritis (OA). Baseline and 30-month followup assessments included knee magnetic resonance imaging (MRI) and fluoroscopically positioned weight-bearing knee radiographs. Cartilage and meniscal degeneration were scored on MRI in the medial and lateral tibiofemoral joints using a semiquantitative grading system. Meniscal position was measured to the nearest millimeter. The dependent variable was joint space narrowing (JSN) on the plain radiograph (possible range 0-3). The predictor variables were MRI cartilage score, meniscal degeneration, and meniscal position measures. We first conducted a cross-sectional analysis using multivariate regression to determine the relative contribution of meniscal factors and cartilage morphologic features to JSN, adjusting for body mass index (BMI), age, and sex. The same approach was used for change in JSN and change in predictor variables.
  
  
  RESULTS
  We evaluated 264 study participants with knee OA (mean age 66.7 years, 59% men, mean BMI 31.4 kg/m(2)). The results from the models demonstrated that meniscal position and meniscal degeneration each contributed to prediction of JSN, in addition to the contribution by cartilage morphologic features. For change in medial joint space, both change in meniscal position and change in articular cartilage score contributed substantially to narrowing of the joint space.
  
  
  CONCLUSIONS
  The meniscus (both its position and degeneration) accounts for a substantial proportion of the variance explained in JSN, and the change in meniscal position accounts for a substantial proportion of change in JSN.
authors.affiliation: Boston University Clinical Epidemiology Research and Training Unit, Arthritis Center, and Boston Medical Center, Boston, Massachusetts 02118, USA. djhunter@bu.edu
authors.forename: D J
authors.initials: DJ
authors.lastname: Hunter
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Tu
authors.forename: M
authors.initials: M
authors.lastname: Lavalley
authors.forename: J B
authors.initials: JB
authors.lastname: Niu
authors.forename: S
authors.initials: S
authors.lastname: Amin
authors.forename: A
authors.initials: A
authors.lastname: Guermazi
authors.forename: H
authors.initials: H
authors.lastname: Genant
authors.forename: D
authors.initials: D
authors.lastname: Gale
authors.forename: D T
authors.initials: DT
authors.lastname: Felson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002358:Cartilage, Articular / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D031221:Knee Dislocation / Q000000981:diagnostic imaging / Q000473:pathology; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000502:physiology; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000473:pathology*; D011859:Radiography; D016474:Weight-Bearing