title: Fibrous cartilage of human menisci is less shock-absorbing and energy-dissipating than hyaline cartilage.
abstract: OBJECTIVE
  To test meniscal mechanical properties such as the dynamic modulus of elasticity E* and the loss angle δ at two loading frequencies ω at different locations of the menisci and compare it to E* and δ of hyaline cartilage in indentation mode with spherical indenters.
  
  
  METHODS
  On nine pairs of human menisci, the dynamic E*-modulus and loss angle δ (as a measure of the energy dissipation) were determined. The measurements were performed at two different strain rates (slow sinusoidal and fast single impact) to show the strain rate dependence of the material. The measurements were compared to previous similar measurements with the same equipment on human hyaline cartilage.
  
  
  RESULTS
  The resultant E* at fast indentation (median 1.16 MPa) was significantly higher, and the loss angle was significantly lower (median 10.2°) compared to slow-loading mode's E* and δ (median 0.18 MPa and 16.9°, respectively). Further, significant differences for different locations are shown. On the medial meniscus, the anterior horn shows the highest resultant dynamic modulus.
  
  
  CONCLUSIONS
  In dynamic measurements with a spherical indenter, the menisci are much softer and less energy-dissipating than hyaline cartilage. Further, the menisci are stiffer and less energy-dissipating in the middle, intermediate part compared to the meniscal base. In compression, the energy dissipation of meniscus cartilage plays a minor role compared to hyaline cartilage. At high impacts, energy dissipation is less than on low impacts, similar to cartilage.
authors.affiliation: Center of Biomechanics and Calorimetry Basel, University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland.
authors.forename: Mario
authors.initials: M
authors.lastname: Gaugler
authors.forename: Dieter
authors.initials: D
authors.lastname: Wirz
authors.forename: Sarah
authors.initials: S
authors.lastname: Ronken
authors.forename: Mirjam
authors.initials: M
authors.lastname: Hafner
authors.forename: Beat
authors.initials: B
authors.lastname: Göpfert
authors.forename: Niklaus F
authors.initials: NF
authors.lastname: Friederich
authors.forename: Reinhard
authors.initials: R
authors.lastname: Elke
mesh_terms: D000368:Aged; D002102:Cadaver; D004548:Elasticity; D005260:Female; D006801:Humans; D051457:Hyaline Cartilage / Q000502:physiology*; D008297:Male; D008592:Menisci, Tibial / Q000502:physiology*; D008875:Middle Aged; D013314:Stress, Mechanical