The role of interstitial fluid pressurization in articular cartilage lubrication

Abstract

Over the last two decades, considerable progress has been reported in the field of cartilage mechanics that impacts our understanding of the role of interstitial fluid pressurization on cartilage lubrication. Theoretical and experimental studies have demonstrated that the interstitial fluid of cartilage pressurizes considerably under loading, potentially supporting most of the applied load under various transient or steady-state conditions. The fraction of the total load supported by fluid pressurization has been called the fluid load support. Experimental studies have demonstrated that the friction coefficient of cartilage correlates negatively with this variable, achieving remarkably low values when the fluid load support is greatest. A theoretical framework that embodies this relationship has been validated against experiments, predicting and explaining various outcomes, and demonstrating that a low friction coefficient can be maintained for prolonged loading durations under normal physiological function. This paper reviews salient aspects of this topic, as well as its implications for improving our understanding of boundary lubrication by molecular species in synovial fluid and the cartilage superficial zone. Effects of cartilage degeneration on its frictional response are also reviewed.

Influence of synovia constituents on tribological behaviors of articular cartilage

“…Since an experimental finding [17] and a proposal of boundary friction model based on biphasic lubrication by Ateshian [18], the important phenomena on the effectiveness of biphasic lubrication with interstitial fluid pressurization have been demonstrated on the basis of the biphasic finite element (FE) analyses and experimental observations [19,20]. The articular cartilage has high water content from 70% to 80% in tissue as porous media composed of type II collagen, proteoglycan and chondrocytes, and thus exhibits a time-dependent biphasic behavior due to the simultaneous coexistence of solid and liquid phases [21].…”

An integrated microfluidic device for characterizing chondrocyte metabolism in response to distinct levels of fluid flow stimulus

“…In addition, fluid flow-induced shear stress is closely relevant with the regulation of articular cartilage metabolism and the pathophysiologic process of articular cartilage (Das et al 1997). Therefore, different levels of hydrodynamic shear stresses may affect cellular signaling pathways in mechanotransduction in chondrocytes, thereby further regulating cell metabolism (Ateshian 2009). It is of great significant to investigate the influence of fluid flow stimuli on the chondrocyte metabolism.…”

A pendulum test as a tool to evaluate viscous friction parameters in the equine fetlock joint

“…Frictional forces would be significant only over the portion of the load transferred across the solid matrices of the opposing articular layers; thus, as long as the interstitial fluid pressure remains elevated, supporting most of the load, the friction should remain low (Ateshian, 2009). This mechanism, called biphasic boundary lubrication or self-pressurised hydrostatic lubrication, is related to cartilage composition.…”

“…Due to the negative polarity of proteoglycans, which attracts more cations than anions into the tissue to maintain electroneutrality, a net electrolytic imbalance is created between the cartilage interstitial fluid and the surrounding tissue bath. This phenomenon produces a difference in osmotic pressure whereby the interstitial fluid exhibits a higher pressure than the external solution (Ateshian, 2009). A complementary approach, called boundary lubrication, has however been proposed, which describes the lubricating ability of the components of synovial fluid (SF).…”