title: High-field magnetic resonance imaging assessment of articular cartilage before and after marathon running: does long-distance running lead to cartilage damage?
abstract: BACKGROUND
  There is continuing controversy whether long-distance running results in irreversible articular cartilage damage. New quantitative magnetic resonance imaging (MRI) techniques used at 3.0 T have been developed including T1rho (T1ρ) and T2 relaxation time measurements that detect early cartilage proteoglycan and collagen breakdown.
  
  
  OBJECTIVE
  Marathon runners will demonstrate T1ρ and T2 changes in articular cartilage on MRI after a marathon, which are not seen in nonrunners. These changes are reversible.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  Ten asymptomatic marathon runners had 3-T knee MRI scans 2 weeks before, within 48 hours after, and 10 to 12 weeks after running a marathon. The T1ρ and T2 MRI sequences in runners were compared with those of 10 age- and gender-matched controls who had MRI performed at baseline and 10 to 12 weeks.
  
  
  RESULTS
  Runners did not demonstrate any gross morphologic MRI changes after running a marathon. Postmarathon studies, however, revealed significantly higher T2 and T1ρ values in all articular cartilage areas of the knee (P < .01) except the lateral compartment. The T2 values recovered to baseline except in the medial femoral condyle after 3 months. Average T1ρ values increased after the marathon from 37.0 to 38.9 (P < .001) and remained increased at 3 months.
  
  
  CONCLUSIONS
  Runners showed elevated T1ρ and T2 values after a marathon, suggesting biochemical changes in articular cartilage, T1ρ values remain elevated after 3 months of reduced activity. The patellofemoral joint and medial compartment of the knee show the highest signal changes, suggesting they are at higher risk for degeneration.
authors.affiliation: Anthony C. Luke, University of California, San Francisco, Department of Orthopaedics, 500 Parnassus Ave, MU-320W, San Francisco, CA 94143-0728, USA. lukea@orthosurg.ucsf.edu
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Luke
authors.forename: Christoph
authors.initials: C
authors.lastname: Stehling
authors.forename: Robert
authors.initials: R
authors.lastname: Stahl
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
authors.forename: Terry
authors.initials: T
authors.lastname: Kay
authors.forename: Stephen
authors.initials: S
authors.lastname: Takamoto
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ma
authors.forename: Sharmilla
authors.initials: S
authors.lastname: Majumdar
authors.forename: Thomas
authors.initials: T
authors.lastname: Link
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000209:etiology*; D002358:Cartilage, Articular / Q000293:injuries*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008297:Male; D012307:Risk Factors; D012420:Running / Q000293:injuries* / Q000502:physiology; D013312:Stress, Physiological; D013997:Time Factors; D055815:Young Adult