Tissue Engineering of the Anterior Cruciate Ligament Using a Braid-Twist Scaffold Design

Interfibrillar shear stress is the loading mechanism of collagen fibrils in tendon.

http://www.mate.tue.nl/mate/pdfs/6777.pdf

Bone regeneration during distraction osteogenesis: Mechano-regulation by shear strain and fluid velocity

The viscoelastic properties of human ligament potentially guard against structural failure, yet the microstructural origins of these transient behaviors are unknown. Glycosaminoglycans (GAGs) are widely suspected to affect ligament viscoelasticity by forming molecular bridges between neighboring collagen fibrils. This study investigated whether GAGs directly affect viscoelastic material behavior in human medial collateral ligament (MCL) by using nondestructive tensile tests before and after degradation of GAGs with chondroitinase ABC (ChABC). Control and ChABC treatment (83% GAG removal) produced similar alterations to ligament viscoelasticity. This finding was consistent at different levels of collagen fiber stretch and tissue hydration. On average, stress relaxation increased after incubation by 2.2% (control) and 2.1% (ChABC), dynamic modulus increased after incubation by 3.6% (control) and 3.8% (ChABC), and phase shift increased after incubation by 8.5% (control) and 8.4% (ChABC). The changes in viscoelastic behavior after treatment were significantly more pronounced at lower clamp-to-clamp strain levels. A 10% difference in the water content of tested specimens had minor influence on ligament viscoelastic properties. The major finding of this study is that mechanical interactions between collagen fibrils and GAGs are unrelated to tissue-level viscoelastic mechanics in mature human MCL. These findings narrow the possible number of extracellular matrix molecules that have a direct contribution to ligament viscoelasticity.

https://mrl.sci.utah.edu/papers/lujan_jap_2009.pdf

Contribution of glycosaminoglycans to viscoelastic tensile behavior of human ligament

https://www.sci.utah.edu/publications/weiss05/weiss_med_eng_phys_2005.pdf

Three-dimensional finite element modeling of ligaments: technical aspects.

https://mrl.sci.utah.edu/papers/bonifasi_jor_2005.pdf

Viscoelastic properties of the human medial collateral ligament under longitudinal, transverse and shear loading.

Ligament viscoelasticity is an important determinant of tissue response to rapid loading and potential for injury, and may also play a role in tissue nutrition via fluid movement during loading/unloading. Because ligaments are anisotropic multiphase structures, it is likely that their viscoelastic response is direction-dependent. Previous efforts to describe ligament viscoelasticity have either reported experimental data without theoretical interpretation (e.g., [1]), or assumed a particular form for the viscoelastic response a priori [2–4]. Small sinusoidal perturbations about an equilibrium strain value allow application of linear viscoelasticity theory for determination of storage modulus (dynamic stiffness) and loss modulus (phase, or damping) as a function of frequency and equilibrium strain level. With these data, one can assess the appropriateness of different viscoelastic and/or poroelastic models to describe time- and rate-dependent constitutive behavior.Copyright © 2002 by ASME

https://mi-as.com/wp-content/uploads/datasheets/viscoelastic-properties-of-human-mcl-in-the-transverse-direction.pdf

Michael S. Small

Papers

Viscoelastic properties of the human medial collateral ligament under longitudinal, transverse and shear loading.

Viscoelastic Properties of Human MCL in the Transverse Direction