Squeeze-film lubrication of the human ankle joint with synovial fluid filtrated by articular cartilage with the superficial zone worn out

2000 ◽  
Vol 33 (11) ◽  
pp. 1415-1422 ◽  
Author(s):  
M. Hlaváček
Keyword(s):  
Articular Cartilage ◽  
Synovial Fluid ◽  
Ankle Joint ◽  
Squeeze Film ◽  
Superficial Zone ◽  
Human Ankle ◽  
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.

The Effect of Permeability of Cartilage Superficial Zone on the Behavior of Stress Relaxation and Creep of Human Ankle Joint

2007 ◽  
Author(s):  
Lu Wan ◽  
Guoan Li
Keyword(s):  
Articular Cartilage ◽  
Stress Relaxation ◽  
Ankle Joint ◽  
Element Model ◽  
Close Packing ◽  
Superficial Zone ◽  
Narrow Channels ◽  
Calcified Cartilage ◽  
Human Ankle ◽  
Lower Permeability

The microstructure of articular cartilage could be divided into four distinct zones: the superficial zone, middle zone, deep zone, and calcified cartilage zone. It is believed that the superficial zone of articular cartilage has a lower permeability, which may be related to the close packing of the collagen fibrils resulting in a system of much narrow channels which offer a greater resistance to flow [1]. This parametric study investigated the influence of permeability of the superficial zone on the behavior of cartilage stress relaxation and creep of human ankle joint using a 2D biphasic poroelastic finite element model (FEM) that was created from a living human ankle joint.

An analysis of the squeeze-film lubrication mechanism for articular cartilage

1992 ◽  
Vol 25 (3) ◽  
pp. 247-259 ◽  
Author(s):  
J.S. Hou ◽  
V.C. Mow ◽  
W.M. Lai ◽  
M.H. Holmes
Keyword(s):  
Articular Cartilage ◽  
Squeeze Film ◽  
Lubrication Mechanism ◽  
Film Lubrication

Lubrication of the Human Ankle Joint in Walking

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Miroslav Hlaváček
Keyword(s):  
Hyaluronic Acid ◽  
Synovial Fluid ◽  
Ankle Joint ◽  
Fluid Pressure ◽  
Fluid Viscosity ◽  
Fluid Filtration ◽  
Sliding Motion ◽  
Gel Layer ◽  
Human Ankle ◽  
The Matrix

Human ankle joint lubrication in walking is analyzed. A biphasic mixture model is considered for articular cartilage (ideal interstitial fluid and elastic porous matrix that is transversely isotropic and inhomogeneous throughout its thickness). Synovial fluid is considered Newtonian. Its viscosity is due to the macromolecules of hyaluronic acid that are too large to enter the matrix pores. Due to the fluid pressure gradient water and small solutes pass through the matrix pores and across the articular surface in both directions. The effect of the time varying concentration of hyaluronic acid or of the synovial fluid viscosity on the synovial film thickness distribution is small and neglected in the model. Periodic sliding motion of the articular surfaces and periodic loading of the joint as encountered in walking are included in the analysis. Synovial fluid serves as a fluid lubricant. The model shows that soon after the onset of walking the normal human ankle joint works in a mixed lubrication mode (a combination of boundary and fluid-film lubrications). A protective gel layer formed in the gap due to the synovial fluid filtration by cartilage may serve as a boundary lubricant. The synovial gel layer is not guaranteed in the osteoarthritic case, and the rough sliding surfaces may get repeatedly into an intimate contact and wear off due to the reciprocating sliding motion.

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