title: In vivo tibiofemoral cartilage-to-cartilage contact area of females with medial osteoarthritis under acute loading using MRI.
abstract: OBJECTIVE
  To investigate the effect of acute loading on in vivo tibiofemoral contact area changes in both compartments, and to determine whether in vivo tibiofemoral contact area differs between subjects with medial knee osteoarthritis (OA) and healthy controls.
  
  
  METHODS
  Ten subjects with medial knee OA (KL3) and 11 control subjects (KL0) were tested. Coronal three-dimensional spoiled gradient-recalled (3D-SPGR) and T(2) -weighted fast spin-echo FSE magnetic resonance imaging (MRI) of the knee were acquired under both unloaded and loaded conditions. Tibiofemoral cartilage contact areas were measured using image-based 3D models.
  
  
  RESULTS
  Tibiofemoral contact areas in both compartments significantly increased under loading (P < 0.001) and the increased contact area in the medial compartment was significantly larger than in the lateral compartment (P < 0.05). Medial compartment contact area was significantly larger in KL3 subjects than KL0 subjects, both at unloaded and loaded conditions (P < 0.05). Contact areas measured from 3D-SPGR and T(2) -weighted FSE images were strongly correlated (r = 0.904).
  
  
  CONCLUSIONS
  Females with medial OA increased tibiofemoral contact area in the medial compartment compared to healthy subjects under both unloaded and loaded conditions. The contact area data presented in this study may provide a quantitative reference for further cartilage contact biomechanics such as contact stress analysis and cartilage biomechanical function difference between osteoarthritic and healthy knees.
authors.affiliation: Department of Mechanical Engineering, Sogang University, Seoul, Korea. cshin@sogang.ac.kr
authors.forename: Choongsoo S
authors.initials: CS
authors.lastname: Shin
authors.forename: Richard B
authors.initials: RB
authors.lastname: Souza
authors.forename: Deepak
authors.initials: D
authors.lastname: Kumar
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Wyman
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
mesh_terms: D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D005269:Femur / Q000473:pathology*; D006801:Humans; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000503:physiopathology; D015203:Reproducibility of Results; D013977:Tibia / Q000473:pathology*; D016474:Weight-Bearing / Q000502:physiology*