title: Cartilage repair of the knee with Hyalograft C:® magnetic resonance imaging assessment of the glycosaminoglycan content at midterm.
abstract: OBJECTIVE
  The aim of this study was to assess the stability of the glycosaminoglycan (GAG) content in the long term after matrix-associated autologous chondrocyte transplantation (MACT) with Hyalograft C in the knee over a follow-up period of one year.
  
  
  METHODS
  In this cross-sectional evaluation, 11 patients after MACT of the knee consented to delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) measurements. The mean post-operative interval before the first MR examination was 40.6 ± 22.0 months, and the second MR examination was carried out after another 12 months. The Lysholm score was assessed for clinical evaluation. Quantitative T1 measurements after intravenous negatively charged MR contrast agent administration were performed. Global post-contrast T1 of the reference cartilage and the repair tissue and a relative post-contrast T1 value were calculated.
  
  
  RESULTS
  The Lysholm score improved significantly from 59.8 ± 12.9 at baseline to 86.1 ± 15.7 at the second visit (p < 0.01). The mean global T1 of the repair tissue (1st visit 581.3 ± 126.4 ms; 2nd visit 684.1 ± 169.9 ms; p = 0.104) and the mean relative T1 value showed stable results over one year (1st visit 0.81 ± 0.28; 2nd visit 0.76 ± 0.32; p = 0.4).
  
  
  CONCLUSIONS
  The study demonstrated stable glycosaminoglycan content of the repair tissue after MACT at midterm.
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Vienna, Austria.
authors.forename: Martin O
authors.initials: MO
authors.lastname: Brix
authors.forename: David
authors.initials: D
authors.lastname: Stelzeneder
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
authors.forename: Reinhard
authors.initials: R
authors.lastname: Windhager
authors.forename: Stephan E
authors.initials: SE
authors.lastname: Domayer
mesh_terms: D000328:Adult; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000293:injuries / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D003287:Contrast Media; D003430:Cross-Sectional Studies; D005260:Female; D005682:Gadolinium; D006025:Glycosaminoglycans / Q000032:analysis*; D006801:Humans; D006820:Hyaluronic Acid / Q000627:therapeutic use*; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D014182:Transplantation, Autologous; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D006025:Glycosaminoglycans; D006820:Hyaluronic Acid; D005682:Gadolinium