The mechanical response of a polyetheretherketone femoral knee implant under a deep squatting loading condition

Lennert de Ruiter* (Corresponding Author), Dennis Janssen, Adam Briscoe, Nico Verdonschot

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    8 Citations (Scopus)
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    Abstract

    The current study was designed to investigate the mechanical response of a polyetheretherketone-on-polyethylene total knee replacement device during a deep squat. Application of this high-demand loading condition can identify weaknesses of the polyetheretherketone relative to cobalt-chromium. This study investigated whether the implant is strong enough for this type of loading, whether cement stresses are considerably changed and whether a polyetheretherketone femoral component is likely to lead to reduced periprosthetic bone loss as compared to a cobalt-chromium component. A finite element model of a total knee arthroplasty subjected to a deep squat loading condition, which was previously published, was adapted with an alternative total knee arthroplasty design made of either polyetheretherketone or cobalt-chromium. The maximum tensile and compressive stresses within the implant and cement mantle were analysed against their yield and fatigue stress levels. The amount of stress shielding within the bone was compared between the polyetheretherketone and cobalt-chromium cases. Relative to its material strength, tensile peak stresses were higher in the cobalt-chromium implant; compressive peak stresses were higher in the polyetheretherketone implant. The stress patterns differed substantially between polyetheretherketone and cobalt-chromium. The tensile stresses in the cement mantle supporting the polyetheretherketone implant were up to 33% lower than with the cobalt-chromium component, but twice as high for compression. Stress shielding was reduced to a median of 1% for the polyetheretherketone implant versus 56% for the cobalt-chromium implant. Both the polyetheretherketone implant and the underlying cement mantle should be able to cope with the stress levels present during a deep squat. Relative to the cobalt-chromium component, stress shielding of the periprosthetic femur was substantially less with a polyetheretherketone femoral component.

    Original languageEnglish
    Pages (from-to)1204-1212
    Number of pages9
    JournalProceedings of the Institution of Mechanical Engineers. Part H: Journal of engineering in medicine
    Volume231
    Issue number12
    DOIs
    Publication statusPublished - 1 Dec 2017

    Keywords

    • biomaterials stress analysis
    • bone remodelling
    • finite element modelling/analysis
    • knee biomechanics
    • knee prostheses
    • polyetheretherketone
    • stress analysis/testing
    • stress shielding
    • Total knee arthroplasty

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