Experimental investigations of lubrication mechanisms in total knee replacements

Nečas D, Vrbka M, Marian M, Wartzack S, Galandáková A, Gallo J, Wimmer MA, Hartl M (2021)

Publication Language: German

Publication Type: Conference contribution, Conference Contribution

Publication year: 2021

Event location: Online

Abstract

Introduction: Total knee arthroplasty (TKA) has become a routine procedure for patients suffering from knee osteoarthritis. Since tribological processes influence the service-life of implants, the present study is targeted to identify lubrication mechanisms occurring in the knee replacement, focusing on the role of specific synovial fluid constituents under application of realistic operating conditions.

 

Methods: The contact of a femoral knee component articulating on a tibial plateau made of transparent polymer was observed using fluorescent microscopy. A knee simulator was used for contact analysis, while the joint was lubricated by various model synovial fluids. Prior to the main phase of testing, the contact zone was lubricated by a mineral oil, while the data were compared to those obtained by the numerical model presented in another contribution.

 

Results: The contact zone showed considerable changes in terms of size and shape of the contact throughout the cycle. The experiments with oil showed very satisfactory agreement with numerical prediction. Subsequent tests performed with model synovial fluid enabled to design a lubrication model of TKA focusing on the role of specific synovial fluid constituents. In particular, it was found that hyaluronic acid together with phospholipids support formation of thin stable boundary layer of γ-globulin. Further enhancement of the lubricating film is attributed to increasing thickness of albumin layer being adsorbed on γ-globulin base.

 

Discussion: The present study employed a unique experimental set-up enabling direct in-situ observation of knee replacement components allowing the actual geometry of the rubbing surfaces together with the application of transient operating conditions. Results revealed that formation of the lubricating film is substantially influenced by the applied testing fluid. Moreover, time test showed that the film exhibits decreasing tendency under continuous loading; thus, rest periods enabling film recovery are recommended in order to enhance implant longevity.

Authors with CRIS profile

Max Marian Chair of Engineering Design Sandro Wartzack Chair of Engineering Design

Involved external institutions

Palacky University Olomouc / Univerzita Palackého v Olomouci CZ Czech Republic (CZ) Brno University of Technology (BUT) / Vysoké učení technické v Brně (VUT) CZ Czech Republic (CZ) Rush University US United States (USA) (US)

How to cite

APA:

Nečas, D., Vrbka, M., Marian, M., Wartzack, S., Galandáková, A., Gallo, J.,... Hartl, M. (2021). Experimental investigations of lubrication mechanisms in total knee replacements. In Tagungsband 5th International Conference on BioTribology. Online.

MLA:

Nečas, David, et al. "Experimental investigations of lubrication mechanisms in total knee replacements." Tagungsband 5th International Conference on BioTribology, Online 2021.

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