title: Bilateral cartilage T2 mapping 9 years after Mega-OATS implantation at the knee: a quantitative 3T MRI study.
abstract: OBJECTIVE
  To evaluate morphological and quantitative MR findings 9 years after autograft transfer of the posterior femoral condyle (Mega-OATS) and to correlate these findings with clinical outcomes. Quantitative MR measurements were also obtained of the contralateral knee and the utility as reference standard was investigated.
  
  
  METHODS
  Both knees of 20 patients with Mega-OATS osteochondral repair at the medial femoral condyle (MFC) were studied using 3T MRI 9 years after the procedure. MR-sequences included morphological sequences and a 2D multislice multiecho (MSME) spin echo (SE) sequence for quantitative cartilage T2 mapping. Cartilage segmentation was performed at the cartilage repair site and six additional knee compartments. Semi-quantitative MR observation of cartilage repair tissue (MOCART) scores and clinical Lysholm scores were obtained. Paired t-tests and Spearman correlations were used for statistical analysis.
  
  
  RESULTS
  Global T2-values were significantly higher at ipsilateral knees compared to contralateral knees (42.1 ± 3.0 ms vs 40.4 ± 2.6 ms, P = 0.018). T2-values of the Mega-OATS site correlated significantly with MOCART scores (R = -0.64, P = 0.006). The correlations between MOCART and Lysholm scores and between absolute T2-values and Lysholm scores were not significant (P > 0.05). However, higher T2 side-to-side differences at the femoral condyles correlated significantly with more severe clinical symptoms (medial, R = -0.53, P = 0.030; lateral, R = -0.51, P = 0.038).
  
  
  CONCLUSIONS
  Despite long-term survival, 9 years after Mega-OATS procedures, T2-values of the grafts were increased compared to contralateral knees. Clinical scores correlated best with T2 side-to-side differences of the femoral condyles, indicating that intraindividual adjustment may be beneficial for outcome evaluation.
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: pia.jungmann@tum.de.
authors.forename: P M
authors.initials: PM
authors.lastname: Jungmann
authors.affiliation: Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: peter.brucker@lrz.tu-muenchen.de.
authors.forename: P U
authors.initials: PU
authors.lastname: Brucker
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: thomas.baum@tum.de.
authors.forename: T
authors.initials: T
authors.lastname: Baum
authors.affiliation: Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA. Electronic address: thomas.link@ucsf.edu.
authors.forename: T M
authors.initials: TM
authors.lastname: Link
authors.affiliation: Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: foerschnerfelix@aim.com.
authors.forename: F
authors.initials: F
authors.lastname: Foerschner
authors.affiliation: Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: philippminzlaff@gmx.de.
authors.forename: P
authors.initials: P
authors.lastname: Minzlaff
authors.affiliation: Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany; Department of Orthopaedic Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: ingo@banke.eu.
authors.forename: I J
authors.initials: IJ
authors.lastname: Banke
authors.affiliation: Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: tim.saier@me.com.
authors.forename: T
authors.initials: T
authors.lastname: Saier
authors.affiliation: Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: a.imhoff@lrz.tu-muenchen.de.
authors.forename: A B
authors.initials: AB
authors.lastname: Imhoff
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: ernst.rummeny@tum.de.
authors.forename: E J
authors.initials: EJ
authors.lastname: Rummeny
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany; Department of Neuroradiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: jsb@tum.de.
authors.forename: J S
authors.initials: JS
authors.lastname: Bauer
mesh_terms: D000293:Adolescent; D000328:Adult; D002356:Cartilage / Q000637:transplantation*; D002358:Cartilage, Articular / Q000293:injuries / Q000473:pathology* / Q000601:surgery; D005260:Female; D005269:Femur / Q000473:pathology* / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000601:surgery; D007719:Knee Joint / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D014182:Transplantation, Autologous; D055815:Young Adult
keywords: Cartilage repair; Knee; Magnetic resonance imaging; OATS; T2 measurements