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Lubrication of the human ankle joint in walking / Miroslav Hlavacek in Transactions of the ASME . Journal of tribology, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Titre : Lubrication of the human ankle joint in walking Type de document : texte imprimé Auteurs : Miroslav Hlavacek, Auteur Année de publication : 2010 Article en page(s) : 08 p. Langues : Anglais (eng) Mots-clés : Articular  cartilage  Human  ankle  joint  Lubrication  Synovial  fluid  filtration  Walking Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : 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. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013200 [...] [article] Lubrication of the human ankle joint in walking [texte imprimé] / Miroslav Hlavacek, Auteur . - 2010 . - 08 p. Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Mots-clés : Articular  cartilage  Human  ankle  joint  Lubrication  Synovial  fluid  filtration  Walking Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : 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. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013200 [...]