title: Material properties of the human posterior knee capsule.
abstract: BACKGROUND
  There is considerable interest to develop accurate subject-specific biomechanical models of the knee. Most of the existing models currently do not include a representation of the posterior knee capsule. In order to incorporate the posterior capsule in knee models, data is needed on its mechanical properties.
  
  
  OBJECTIVE
  To quantify the mechanical properties of the human posterior knee capsule through semi-static tensile tests.
  
  
  METHODS
  Fifteen posterior knee capsule specimens (5 knees, 3 male, 2 female; age 79.2±7.9 years) were used to perform tensile tests. A medial, central and lateral specimen was taken from each knee. The cross-sectional area was measured, after which semi-static tensile tests were performed to quantify the material properties.
  
  
  RESULTS
  The stiffness of the capsule was randomly distributed over the regions. The global Young's modulus and yield strength was 8.58±10.77 MPa and 1.75±1.89 MPa, respectively. A strong correlation (ρ=0.900) was found between Young's modulus and yield strength. The location of failure was not associated with smallest cross-sectional area or highest strain.
  
  
  CONCLUSIONS
  The results suggest that the posterior knee capsule does not have a systematic (medial-central-lateral) distribution of material properties. The posterior capsule may play an important role in knee joint mechanics, particularly when in hyper extension.
authors: Department of Biomedical Engineering, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands Department of Electrical Engineering, Institut Teknologi Nasional (ITENAS) Bandung, West Java, Indonesia.
authors: H H
authors: HH
authors: Rachmat
authors: Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors: D
authors: D
authors: Janssen
authors: Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands Department of Rehabilitation Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: G J
authors: GJ
authors: Verkerke
authors: Department of Orthopaedics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: R L
authors: RL
authors: Diercks
authors: Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands.
authors: N
authors: N
authors: Verdonschot
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D055119:Elastic Modulus / Q000187:drug effects; D005260:Female; D006801:Humans; D017746:Joint Capsule / Q000187:drug effects* / Q000503:physiopathology*; D007717:Knee / Q000033:anatomy & histology; D007719:Knee Joint / Q000187:drug effects*; D008297:Male; D008954:Models, Biological; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000187:drug effects
keywords: Cross sectional area; material properties; posterior knee capsule; tensile test; three-dimensional knee model