Biomedical Engineering Reference
In-Depth Information
10
Biomechanical Properties of Synovial
Fluid in/Between Peripheral Zones
of Articular Cartilage
Miroslav Petrtyl, Jaroslav Lisal and Jana Danesova
Laboratory of Biomechanics and Biomaterial Engineering, Faculty of Civ. Engineering,
Czech Technical University in Prague
Czech
Republic
1. Introduction
The properties and behaviour of articular cartilage (
AC
) have been studied from numerous
aspects. A number of biomechanical models of the properties and behaviour of AC are
available today. The traditional model presents cartilage as homogeneous, isotropic and
biphase material (Armstrong et al., 1984). There also exist models of transversally isotropic
biphase cartilage material (Cohen et al., 1992; Cohen et al., 1993), non-linear poroelastic
cartilage material (Li et al., 1999), models of poroviscoelastic (Wilson et al., 2005) and
hyperelastic cartilage material (Garcia & Cortes, 2006), models of triphase cartilage material
(Lai et al., 1991; Ateshian et al., 2004), and other models (Wilson et al., 2004; Jurvelin et al.,
1990). The published models differ, more or less, by the angle of their authors' view of the
properties and behaviour of articular cartilage during its loading.
The authors base their theories on various assumptions concerning the mutual links
between the structural components of the cartilage matrix and their interactions on the
molecular level.
The system behaviour of AC very depend on nonlinear properties of synovial fluid (
SF
).
Certain volumes of SF are moveable components during the mechanical loading in the
peripheral zone of AC. Biomechanical properties of peripheral zone of AC are significantly
influenced by change of SF viscosity due to mechanical loading.
The hydrodynamic lubrication systems and influences of residual strains on the initial
presupplementation of articular plateaus by synovial fluid were not sufficiently analyzed up
to now.
Our research has been focused on analyses of residual strains arising in AC at cyclic loading
and on the viscous properties of SF. Residual strains in articular cartilage contribute the
preaccumulation of articular surfaces by synovial fluid.
SF reacts very sensitively to the magnitude of shear stress and to the velocity of the rotation
of the femoral and tibial part of the knee joint round their relative centre of rotation when
the limb shifts from flexion to extension and vice versa. Shear stresses decrease aggregations
of macromolecules of hyaluronic acid in SF.
Articular cartilage (AC) is a viscohyperelastic composite biomaterial whose biomechanical
functions consist
