The influence of the acetabular labrum seal, intact articular superficial zone and synovial fluid thixotropy on squeeze-film lubrication of a spherical synovial joint

2002 ◽  
Vol 35 (10) ◽  
pp. 1325-1335 ◽  
Author(s):  
M. Hlaváček
Keyword(s):  
Synovial Fluid ◽  
Squeeze Film ◽  
Synovial Joint ◽  
Acetabular Labrum ◽  
Superficial Zone ◽  
Film Lubrication

Squeeze-Film Lubrication of the Human Ankle Joint Subjected to the Cyclic Loading Encountered in Walking

2005 ◽  
Vol 127 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Miroslav Hlava´cˇek
Keyword(s):  
Articular Cartilage ◽  
Synovial Fluid ◽  
Ankle Joint ◽  
Interstitial Fluid ◽  
Fluid Film ◽  
Squeeze Film ◽  
Normal Cartilage ◽  
Gel Film ◽  
Human Ankle ◽  
Film Lubrication

Squeeze-film lubrication of the human ankle joint during walking is numerically analyzed, the effect of surface sliding being neglected at this stage. Biphasic mixture models are considered for synovial fluid (an ideal and viscous fluid phases) and for articular cartilage (an ideal interstitial fluid and an elastic porous matrix). In the model, the ideal fluid phase passes through the articular surface and matrix pores. The cartilage matrix is considered both normal and pathological (with primary osteoarthrosis). Calculations show that water and small solutes of synovial fluid imbibe into the articular cartilage during the stance period, while the interstitial fluid of the cartilage exudes and enriches the lubricant during the swing period in a central part of the contact at each step. Soon after the onset of walking, repeatedly near the load culmination of each step, the synovial fluid should be turned into a synovial gel and, shortly after, changed back again into a fluid there. In the pathological case, the protective synovial gel layer is quickly depleted after several steps and the surfaces may come briefly into contact in each cycle. With normal cartilage, however, the protective intermittent gel film (formed briefly at each step) maintains its thickness for a longer time. Normal cartilage also behaves more favorably, when a long walk is broken and then resumed shortly afterwards. With normal articular cartilage, maintenance of a lubricating fluid film is much aided by the cyclic nature of the loading encountered in walking, compared with the steady loading in standing where the fluid film is quickly filtered out into a protective permanent gel film.

Effect of concentration dependence of viscosity on squeeze film lubrication

2020 ◽  
Vol 75 (6) ◽  
pp. 533-542
Author(s):  
Poosan Muthu ◽  
Vanacharla Pujitha
Keyword(s):  
Carrying Capacity ◽  
Iterative Procedure ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Convection Diffusion ◽  
Load Carrying ◽  
Newtonian Viscous Fluid ◽  
Nicolson Scheme ◽  
Human Joint ◽  
Film Lubrication

AbstractThe influence of concentration of solute particles on squeeze film lubrication between two poroelastic surfaces has been analyzed using a mathematical model. Newtonian viscous fluid is considered as a lubricant whose viscosity varies linearly with concentration of suspended solute particles. Convection-diffusion model is proposed to study the concentration of solute particles and is solved using finite difference method of Crank–Nicolson scheme. An iterative procedure is used to get the solution for concentration, pressure and velocity components in film region. It has been observed that load carrying capacity decreases as the concentration of solute particles in the fluid film decreases. Further, the concentration of suspended solute particles decreases as the permeability of the poroelastic plate increases and these results may be useful in understanding the mechanism of human joint.

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