A fiber matrix model for interstitial fluid flow and permeability in ligaments and tendons

Chih Tung Chen, David S. Malkus, Ray Vanderby

Research output: Contribution to journalArticle

49 Scopus citations


Collagen fibrils in ligaments and tendons are highly organized into parallel arrays which influence interstitial fluid transport. Finite element (FE) models were developed analogous to the fibrillar arrays in ligaments and tendons to investigate interstitial fluid flow and tissue permeability as a function of interfibrillar spacing and fluid properties. Collagen fibrils were assumed to be a periodic Square array of impermeable cylinders. A two- dimensional FE model was used to study transverse fluid flow and a three- dimensional model was used to study flow parallel to the collagen fibrils. Parametric FE analysis provided data to formulate empirical expressions for permeability (κ) as a function of porosity (φ). Results show that longitudinal permeability (κ = 1.1 · 10-15 φ2.5 [1 - φ]- 0.333) can be up to 50 times higher than transverse permeability (κ = 1.2 · 10-15 φ0.5 [φ - φ(min)]2.5) in a compact array. Maximum fluid shear stresses occur at the narrowest zones of adjacent fibrils (1.21 Pa or 12.1 dyn/cm2 at 10 μm/s of average transverse influx). If interstitial fluid is highly non-Newtonian, the permeability should be considered as flow (shear)-dependent. The computational results suggest that tissue permeability in ligaments and tendons is highly anisotropic, porosity- dependent, and can be estimated by analytic expressions.

Original languageEnglish (US)
Pages (from-to)103-118
Number of pages16
Issue number2
StatePublished - Jan 1 1998



  • Finite element analysis
  • Interstitial fluid
  • Ligaments and tendons
  • Non-Newtonian fluid
  • Tissue permeability

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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