Photoelastic measurements of polymer insert stress in the knee prostheses designed for high/deep flexion

A. Lawi, J. Takiguchi, M. Hasegawa, S. Hirokawa, M. Todo, T. Hotokebuchi

    Research output: Contribution to journalArticlepeer-review


    This paper presents the experimental results of photoelasticity for determining the magnitude and distribution of stresses on the polyethylene insert of the knee prostheses designed for high/deep knee flexion. The prostheses used in our experiment were a conventional posterior stabiliser knee, Scorpio NRG (Non-Restricted Geometry, Stryker Co., USA) and CFK (Complete Flexion Knee, Japan Medical Material Co., Japan), which we have developed to enable the patient to make a complete knee flexion (i.e. seiza in Japanese). Prior to the photoelastic experiment, we had introduced the forces exerted on the knee joint during ascending from deep knee flexion. Here we took squatting as an example of deep knee flexion instead of seiza because ascending from seiza contains complex modalities. The introduced data in terms of knee angles and joint forces were applied to the photoelastic models. The results demonstrated that after the knee angle became larger than 90°, the shear stresses on the post and cam of NRG were higher than those on the ball and socket of CFK. We conclude that the design and the configuration of CFK is acceptable at deep knee flexion from a load-bearing viewpoint.

    Original languageEnglish
    Pages (from-to)177-186
    Number of pages10
    JournalApplied Bionics and Biomechanics
    Issue number3
    Publication statusPublished - 2010

    All Science Journal Classification (ASJC) codes

    • Biotechnology
    • Medicine (miscellaneous)
    • Bioengineering
    • Biomedical Engineering


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