title: Medial meniscal displacement and strain in three dimensions under compressive loads: MR assessment.
abstract: OBJECTIVE
  To investigate the 3D displacement and the local strain of the medial meniscus and its attachments under compressive loading.
  
  
  METHODS
  Magnetic resonance imaging (MRI) scans of six porcine knee joints were performed under unloaded and loaded conditions (100% and 200% body weight [BW]). Volumes were registered to obtain a 3D displacement field of the medial meniscus and its attachments, which were divided into five anatomic compartments. Finally, displacements of the center of mass of each compartment and the local strain were analyzed.
  
  
  RESULTS
  The meniscus and its attachments significantly displaced by up to 2.6 ± 1.2 mm (P < 0.01) under knee joint loads of 200% BW. An increase of 0.9 mm in the distance between posterior and anterior horn (P < 0.001) was observed. The meniscus and its attachment showed an average radial stretch of 0.6%, an average circumferential stretch of 0.9%, and an average axial compression of 11.6% at 200% BW.
  
  
  CONCLUSIONS
  High-resolution MRI was successfully combined with image registration to investigate the displacement and strain of the meniscus and its attachments under compression. The results of this study contribute to the basic understanding of meniscal movement which may impact the design of meniscal implants and the validation of finite element models in the future.
authors: Institute of Orthopaedic Research and Biomechanics, Centre of Musculoskeletal Research, Ulm, University of Ulm, Germany.
authors: Maren
authors: M
authors: Freutel
authors: Andreas M
authors: AM
authors: Seitz
authors: Fabio
authors: F
authors: Galbusera
authors: Axel
authors: A
authors: Bornstedt
authors: Volker
authors: V
authors: Rasche
authors: Melissa L
authors: ML
authors: Knothe Tate
authors: Anita
authors: A
authors: Ignatius
authors: Lutz
authors: L
authors: Dürselen
mesh_terms: D000818:Animals; D019245:Compressive Strength / Q000502:physiology*; D004548:Elasticity; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007719:Knee Joint / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008592:Menisci, Tibial / Q000502:physiology*; D019047:Phantoms, Imaging; D013552:Swine; D016474:Weight-Bearing / Q000502:physiology*
keywords: 3D displacement; MRI; image registration; local strain; meniscus