Transient mixed lubrication model of the human knee implant

Hamza Butt, Lee Nissim, Leiming Gao, Connor Myant, Greg de Boer, Rob Hewson

Research output: Contribution to journalArticlepeer-review

4 Citations (SciVal)


The human knee implant is computationally modelled in the mixed lubrication regime to investigate the tribological performance of the implant. This model includes the complex geometry of the implant components, unlike elliptical contact models that approximate this geometry. Film thickness and pressure results are presented for an ISO gait cycle to determine the lubrication regime present within the implant during its operation. It was found that it was possible for the lubrication regime to span between elastohydrodynamic, mixed and boundary lubrication depending on the operating conditions of the implant. It was observed that the tribological conditions present in one condyle were not necessarily representative of the other. Multiple points of contact were found within the same condyle, which cannot be computed by the elliptical contact solvers. This model can be used to balance forces in all directions, instead of only the normal loads, as often done in elliptical contact models. This work is an initial step towards understanding the role of the complex geometry in the tribological characteristics of the human knee implant when operating in physiological conditions.
Original languageEnglish
Pages (from-to)206 - 218
JournalBiosurface and Biotribology
Issue number4
Early online date12 Nov 2021
Publication statusPublished - 31 Dec 2021

Bibliographical note

This research was funded by EPSRC DTP studentship (EP/N509486/1) and Imperial College Research Fellowship.


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