title: Whole joint MRI assessment of surgical cartilage repair of the knee: cartilage repair osteoarthritis knee score (CROAKS).
abstract: OBJECTIVE
  To develop a magnetic resonance imaging (MRI) scoring system for follow-up of knee cartilage repair procedures integrating assessment of the repair site and the whole joint called Cartilage Repair OsteoArthritis Knee Score (CROAKS), and to assess its reliability.
  
  
  METHODS
  MRI examinations of 20 patients that had undergone matrix-associated autologous chondrocyte transplantation (MACT) of the knee 12 months before were semi-quantitatively assessed for the repair site using features of the magnetic resonance observation of cartilage repair tissue (MOCART) system and for the whole joint based on experiences with the MRI Osteoarthritis Knee Score (MOAKS) instrument. Intra- and inter-observer reliability was calculated using weighted (w) kappa statistics for plates (medial/lateral tibia, medial/lateral femur, trochlea, patella), compartments (medial tibio-femoral, lateral tibio-femoral, patello-femoral) and the whole joint. For certain features with low prevalence the overall percent agreement was calculated in addition.
  
  
  RESULTS
  For cartilage, reliability on a plate level ranged between 0.48 (lateral femur) and 1.00 (medial femur). BML assessment showed comparable results ranging on a plate level between 0.46 and 1.00 with overall percent agreement between 83.3% and 100%. Meniscal morphology assessment ranged between 0.62 and 0.94. For repair site assessment reliability ranged from 0.41 (signal intensity inter-observer) to 1.00 (several features). Overall percent agreement was above 80% for 17 of 22 features assessed (intra- and inter-observer results combined).
  
  
  CONCLUSIONS
  Combined scoring of the repair site and whole joint assessment for common osteoarthritis features using CROAKS, which is based on experience with two established semi-quantitative scoring tools, is feasible and may be performed with good to excellent reliability.
authors.affiliation: Department of Radiology, University of Erlangen-Nuremberg, Erlangen, Germany; Quantitative Imaging Center (QIC), Department of Radiology, Boston University School of Medicine, Boston, MA, USA. Electronic address: frank.roemer@uk-erlangen.de.
authors.forename: F W
authors.initials: FW
authors.lastname: Roemer
authors.affiliation: Quantitative Imaging Center (QIC), Department of Radiology, Boston University School of Medicine, Boston, MA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Guermazi
authors.affiliation: MR Center of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Trattnig
authors.affiliation: MR Center of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Apprich
authors.affiliation: Department of Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Marlovits
authors.affiliation: Clinical Epidemiology Training and Research Unit, Boston University School of Medicine, Boston, MA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Niu
authors.affiliation: Institute of Bone and Joint Research and Kolling Institute, University of Sydney, Sydney, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hunter
authors.affiliation: Department of Trauma Surgery, University of Erlangen-Nuremberg, Erlangen, Germany. Electronic address: welsch@bwh.harvard.edu.
authors.forename: G H
authors.initials: GH
authors.lastname: Welsch
mesh_terms: D000293:Adolescent; D000328:Adult; D002358:Cartilage, Articular / Q000473:pathology* / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D010147:Pain Measurement; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors; D014182:Transplantation, Autologous; D016896:Treatment Outcome; D055815:Young Adult
keywords: CROAKS; Cartilage repair; Magnetic resonance imaging; Osteoarthritis; Reliability; Scoring