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    Gruen and Modes of Failure

    en-usMarch 05, 2021
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    About this Episode

    "Modes of Failure" of Cemented Stem-type Femoral Components
    Gruen, McNeice and Amstutz
    CORR 1979

    Seven Gruen zones

    1 - proximal lateral 1/3
    2 - central lateral 1/3
    3 - distal lateral 1/3
    4 - tip
    5 - distal medial 1/3
    6 - central medial 1/3
    7 - proximal medial 1/3

    Modes of Failure

    I. Pistoning
         Ia. stem pistons in cement (punch-out crack)
         Ib. cement pistons in bone (halo)

    II. Medial Midstem Pivot - medial migration of proximal stem, lateral migration of tip

    III. Calcar Pivot - medial-lateral toggle of tip (windshield)

    IV. Cantilever Bending - loss of proximal support, tip is fixed

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