title: Magnetic Resonance Imaging-Assessed Vastus Medialis Muscle Fat Content and Risk for Knee Osteoarthritis Progression: Relevance From a Clinical Trial.
abstract: OBJECTIVE
  Studies have proposed vastus medialis (VM) muscle cross-sectional area change as a variable associated with cartilage volume loss in knee osteoarthritis (OA). However, the VM also includes fat (%Fat), which may influence knee function. This study analyzed the VM area and %Fat data, separately and in combination, to predict symptoms, cartilage volume loss, and bone marrow lesion (BML) change in knee OA.
  
  
  METHODS
  This study included the according-to-protocol population (n = 143) of a 2-year knee OA randomized clinical trial having magnetic resonance imaging at baseline and 2 years. Correlations used multivariate analyses.
  
  
  RESULTS
  Greater baseline value for VM area and %Fat were significantly associated with sex (male, area; female, %Fat), higher body mass index (BMI), and Western Ontario and McMaster Universities Osteoarthritis Index stiffness, function, and total scores (better, high area; worse, high %Fat). Moreover, a VM %Fat increase of 1% at 2 years was associated with worsening of cartilage volume loss in the global knee (P = 0.015) and some subregions (P ≤ 0.030), and with an increment of BML global score change (P < 0.001). A 1% decrease in VM area at 2 years was associated with worsening of knee pain score (P = 0.048). Importantly, the concurrent presence of low VM area, high VM %Fat, and high BMI identified a subgroup of patients with greater cartilage volume loss in the medial femur (P = 0.028) than the rest of the cohort.
  
  
  CONCLUSIONS
  These data demonstrated, for the first time, that VM fat content is a strong predictor of cartilage volume loss and the occurrence and progression of BML. Importantly, the combined data of VM area, VM %Fat, and BMI identified patients at higher risk for OA progression.
authors.affiliation: University of Montreal Hospital Research Centre, Montreal, Quebec, Canada.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Raynauld
authors.affiliation: University of Montreal Hospital Research Centre, Montreal, Quebec, Canada.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Pelletier
authors.affiliation: University of Montreal Hospital Research Centre, Montreal, Quebec, Canada.
authors.forename: Camille
authors.initials: C
authors.lastname: Roubille
authors.affiliation: StatSciences, Notre-Dame de l'Île-Perrot, Quebec, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Dorais
authors.affiliation: ArthroLab, Inc., Montreal, Quebec, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Abram
authors.affiliation: ArthroLab, Inc., Montreal, Quebec, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Monash University, The Alfred Centre, Melbourne, Victoria, Australia.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Monash University, The Alfred Centre, Melbourne, Victoria, Australia.
authors.forename: Jessica
authors.initials: J
authors.lastname: Fairley
authors.affiliation: Monash University, The Alfred Centre, Melbourne, Victoria, Australia.
authors.forename: Flavia M
authors.initials: FM
authors.lastname: Cicuttini
authors.affiliation: University of Montreal Hospital Research Centre, Montreal, Quebec, Canada.
authors.forename: Johanne
authors.initials: J
authors.lastname: Martel-Pelletier
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000368:Aged; D015992:Body Mass Index; D002358:Cartilage, Articular / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000503:physiopathology; D010147:Pain Measurement; D011237:Predictive Value of Tests; D011379:Prognosis; D052097:Quadriceps Muscle / Q000473:pathology*; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors