title: Quantitative MR imaging evaluation of the cartilage thickness and subchondral bone area in patients with ACL-reconstructions 7 years after surgery.
abstract: OBJECTIVE
  To evaluate the cartilage thickness (ThC) and subchondral bone area (tAB) of the operated and contra-lateral non-operated (healthy) knees in patients with anterior cruciate ligament (ACL)-reconstruction 7 years after surgery using a quantitative and regional cartilage MR imaging (qMRI) technique.
  
  
  METHODS
  Charts of 410 patients with ACL-reconstructions were retrospectively reviewed. Fifty-two patients (male/female, 28/24; mean age, 33.3 years) were included. Patients underwent KT-1000 testing and qMRI of both knees using coronal fat-saturated 3D spoiled gradient-recalled echo (SPGR) sequences (TR/TE, 44/4 ms) at 1.5 T. Quantitative analyses of ThC and tAB in the femoro-tibial cartilage plates were performed using a subregional approach. In addition, qualitative and quantitative assessment of femoral condyle shapes was performed. t tests with Bonferroni corrections were used for statistical analysis of side-to-side differences between the operated and non-operated knees.
  
  
  RESULTS
  KT-1000 testing was abnormal in 3/52 patients (6%). Lateral femoral tAB was significantly lower (-9.2%), and medial tibial tAB was significantly larger (+2%) in the operated vs non-operated knee (P<0.001). Regional and subregional ThC side-to-side differences were less than 0.1mm and, except for the external lateral femoral subregion, they were not statistically significant. Flattened and broader shapes of medial femoral condyles (P<0.001) were found in operated knees. No significant association of presence of cartilage or meniscus lesions at surgery with ThC 7 years post-operatively was found (P=0.06-0.98).
  
  
  CONCLUSIONS
  There is evidence for changes in the tAB and femoral shape 7 years post-ACL-reconstruction, but no side-to-side differences in subregional ThC were found between the operated and contra-lateral non-operated knees.
authors.affiliation: Division of Musculoskeletal Imaging, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, Toronto, ON, Canada. gustav@andreisek.de
authors.forename: G
authors.initials: G
authors.lastname: Andreisek
authors.forename: L M
authors.initials: LM
authors.lastname: White
authors.forename: M S
authors.initials: MS
authors.lastname: Sussman
authors.forename: M
authors.initials: M
authors.lastname: Kunz
authors.forename: M
authors.initials: M
authors.lastname: Hurtig
authors.forename: I
authors.initials: I
authors.lastname: Weller
authors.forename: J
authors.initials: J
authors.lastname: Essue
authors.forename: P
authors.initials: P
authors.lastname: Marks
authors.forename: F
authors.initials: F
authors.lastname: Eckstein
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000473:pathology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D002358:Cartilage, Articular / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D020370:Osteoarthritis, Knee / Q000473:pathology*; D011183:Postoperative Complications / Q000473:pathology*; D012189:Retrospective Studies; D013977:Tibia / Q000473:pathology*; D055815:Young Adult