Surface Texture Analysis of Artificial Disks Wear-Tested under Different Conditions and Comparison to a Retrieved Implant

    Volume 3, Issue 4 (April 2006)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Page Count: 8


    Pare, PE
    Research Engineer, Medtronic Sofamor Danek, Memphis, TN

    Chan, FW
    Director of Research, Medtronic Sofamor DanekMemphis, TN

    Buchholz, P
    Research Engineer, Medtronic Sofamor Danek, Memphis, TN

    Kurtz, S
    Principal Engineer and Office Director, Exponent, Philadelphia, PA

    McCombe, P
    Orthopaedic Surgeon, Watkins Medical Centre, Brisbane,

    (Received 30 September 2005; accepted 24 February 2006)

    Abstract

    Total disk arthroplasty is growing in popularity and becoming an alternative to fusion for the treatment of some degenerative disk diseases. To date, there is little consensus regarding the appropriate in vitro techniques with which to evaluate the biotribological properties of these devices. The current study evaluated the surface texture and topography of lumbar metal-on-metal artificial disks tested in a spine wear simulator compared to an explanted device after twelve months in situ. Six implants were tested under a constant load and unidirectional flexion-extension motion as defined by the ASTM standard guide. One implant was tested under a variable load using a combination of flexion-extension, lateral bending, and axial rotation as specified by the ISO standard. While the retrieved disk retained its initial mirror-like surface finish, implants tested under unidirectional motion were severely damaged by abrasive wear resulting in a significant increase in roughness. The implant tested under combined motions exhibited a multi-directional wear scar with limited surface damage. Although only a single retrieved implant was characterized, the current study suggests that wear testing under unidirectional motion may not produce clinically-relevant surface morphology of metal-on-metal artificial disks.


    Paper ID: JAI14173

    DOI: 10.1520/JAI14173

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    Author
    Title Surface Texture Analysis of Artificial Disks Wear-Tested under Different Conditions and Comparison to a Retrieved Implant
    Symposium Wear of Articulating Surfaces, 2005-11-10
    Committee F04