title: MRI after patellofemoral replacement: the preserved compartments.
abstract: BACKGROUND
  The aim of this study was to assess the reproducibility of magnet resonance imaging (MRI) analysis of preserved anatomic structures of the knee after patellofemoral replacement (PFR). It was hypothesized that evaluation of cartilage, ligaments, meniscus and tendons would result in high inter-observer reliability after PFR.
  
  
  METHODS
  MRI, tailored to reduce metallic artefacts of the knee, after PFR was performed in seven patients. Two independent investigators evaluated cartilage, menisci, collateral and cruciate ligaments, the quadriceps and patellar tendons and the presence of joint effusion. The reviewers used a five-point scale to give a degree of confidence to their evaluation of each parameter. Inter-observer reliability was determined by calculation of Cohen's Kappas.
  
  
  RESULTS
  Artefact provoked by the implants was not observed. For all assessed structures, there was excellent inter-observer reliability, with high Cohen's Kappas. There were also high levels of inter-observer agreement and observer confidence in the evaluation of cartilage, meniscus, tendons, ligaments and joint effusion.
  
  
  CONCLUSIONS
  Tailored MRI allows reproducible analysis of the preserved knee joint structures after PFR. It might prove helpful in assessment of painful knee joints after PFR.
authors.affiliation: Department of Orthopedics and Rheumatology, University Hospital Marburg, Baldingerstrasse, 35043 Marburg, Germany. heyse@med.uni-marburg.de
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Heyse
authors.forename: Jens
authors.initials: J
authors.lastname: Figiel
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hähnlein
authors.forename: Nina
authors.initials: N
authors.lastname: Timmesfeld
authors.forename: Stefan
authors.initials: S
authors.lastname: Lakemeier
authors.forename: Markus D
authors.initials: MD
authors.lastname: Schofer
authors.forename: Susanne
authors.initials: S
authors.lastname: Fuchs-Winkelmann
authors.forename: Turgay
authors.initials: T
authors.lastname: Efe
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D059351:Organ Sparing Treatments / Q000295:instrumentation* / Q000379:methods*; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging* / Q000601:surgery*; D011859:Radiography; D016896:Treatment Outcome