title: Assessment of tibial rotation and meniscal movement using kinematic magnetic resonance imaging.
abstract: OBJECTIVE
  This work aimed to assess tibial rotations, meniscal movements, and morphological changes during knee flexion and extension using kinematic magnetic resonance imaging (MRI).
  
  
  METHODS
  Thirty volunteers with healthy knees were examined using kinematic MRI. The knees were imaged in the transverse plane with flexion and extension angles from 0° to 40° and 40° to 0°, respectively. The tibial interior and exterior rotation angles were measured, and the meniscal movement range, height change, and side movements were detected.
  
  
  RESULTS
  The tibia rotated internally (11.55° ± 3.20°) during knee flexion and rotated externally (11.40° ± 3.0°) during knee extension. No significant differences were observed between the internal and external tibial rotation angles (P > 0.05), between males and females (P > 0.05), or between the left and right knee joints (P > 0.05). The tibial rotation angle with a flexion angle of 0° to 24° differed significantly from that with a flexion angle of 24° to 40° (P < 0.01). With knee flexion, the medial and lateral menisci moved backward and the height of the meniscus increased. The movement range was greater in the anterior horn than in the posterior horn and greater in the lateral meniscus than in the medial meniscus (P < 0.01). During backward movements of the menisci, the distance between the anterior and posterior horns decreased, with the decrease more apparent in the lateral meniscus (P < 0.01). The side movements of the medial and lateral menisci were not obvious, and a smaller movement range was found than that of the forward and backward movements.
  
  
  CONCLUSIONS
  Knee flexion and extension facilitated internal and external tibial rotations, which may be related to the ligament and joint capsule structure and femoral condyle geometry.
authors.forename: Hai-Nan
authors.initials: HN
authors.lastname: Chen
authors.forename: Kan
authors.initials: K
authors.lastname: Yang
authors.affiliation: Department of Orthopaedics, Second Affiliated Hospital of Soochow University, Suzhou 215004, China. qirongdongcn@163.com.
authors.forename: Qi-Rong
authors.initials: QR
authors.lastname: Dong
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000502:physiology*; D008875:Middle Aged; D012399:Rotation; D013977:Tibia / Q000502:physiology*