title: Magnetic resonance imaging of in vivo kinematics after total knee arthroplasty.
abstract: OBJECTIVE
  To improve the quality of magnetic resonance imaging (MRI) on knees after total knee arthroplasty (TKA) by minimizing image artifacts caused by metallic implants, and to establish a method determining in vivo kinematics of TKA knees using MRI.
  
  
  METHODS
  Two knee implants made of cobalt-chrome and oxidized zirconium were tested with different pulse sequences and imaging parameters. Then, in vivo kinematic MRI was performed on five well-functioning TKAs under simulated weight-bearing conditions. Kinematic measurements were made and a linear correlation test was run between the tibio- and patellofemoral measurements.
  
  
  RESULTS
  The best images with minimum metallic artifacts were observed using oxidized zirconium implants, a fast spin echo sequence (FSE), thin slice thickness, and high readout gradient. TKA kinematics exhibited a large deviation from the normal kinematics and considerable patient-to-patient variability. However, significant linear correlations between tibiofemoral and patellofemoral kinematics were observed (R = -0.96, 0.92, 0.88).
  
  
  CONCLUSIONS
  Metallic artifacts due to orthopedic implants can be reduced in MR images for some materials, appropriate pulse sequence, and imaging parameters selection, enabling MR quantification of knee kinematics. Tibiofemoral kinematics appears to affect patellofemoral position after total knee arthroplasty.
authors.affiliation: Department of Radiology, University of California at San Francisco, San Francisco, California 94143-0946, USA. Kehyang.Lee@mrsc.ucsf.edu
authors.forename: Keh-Yang
authors.initials: KY
authors.lastname: Lee
authors.forename: John P
authors.initials: JP
authors.lastname: Slavinsky
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ries
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Blumenkrantz
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
mesh_terms: D000368:Aged; D000497:Alloys / Q000737:chemistry; D019645:Arthroplasty, Replacement, Knee; D016477:Artifacts; D002858:Chromium Alloys / Q000737:chemistry; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007720:Knee Prosthesis; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009068:Movement; D010329:Patella / Q000033:anatomy & histology / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D013977:Tibia / Q000033:anatomy & histology / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology; D015040:Zirconium / Q000737:chemistry
chemical_list: D000497:Alloys; D002858:Chromium Alloys; D015040:Zirconium; C028541:zirconium oxide