SYMPOSIA PAPER Published: 01 January 2004
STP11921S

Assessment of Surface Roughness and Waviness Using White Light Interferometry for Short-Term Implanted, Highly Crosslinked Acetabular Components

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The reduction of volumetric wear continues to be one of the imminent challenges for the orthopaedic research community in the area of ultra-high molecular weight polyethylene (UHMWPE) joint replacement components. Retrieval analyses are necessary to determine the relationship between in vitro hip simulator predictions and actual wear performance in vivo. To quantify short term wear in retrieved highly crosslinked acetabular components it is necessary to differentiate between the initial surface morphology (dominated by manufacturer's machining marks) and the smaller scale surface features associated with in vivo adhesive/abrasive wear mechanisms. We have developed and validated a technique for deconvolution of as-manufactured versus in vivo generated surface topology from retrieved, highly crosslinked polyethylene acetabular inserts. Surface topology was characterized by white light interferometry with advanced texture analysis software. A Fourier transform algorithm was used to deconvolve the low-frequency features (i.e., waviness) such as machining marks, from the high-frequency features (i.e., roughness). Twenty-one (21) short-term (less than 24 months) conventional and highly crosslinked retrievals from different manufacturers were evaluated in this study. The wear surfaces in the short-term retrievals were deconvolved using the cut-off frequencies from the new inserts. The frequency distribution and magnitude of the machining marks were found to be material and manufacturer specific. This study highlights the importance of quantitative techniques, such as white light interferometry for distinguishing between initial and in vivo generated surface morphology. The topology observed in the crosslinked retrievals was consistent with the surface damage mechanisms previously observed in conventional UHMWPE components, namely macroscopic and microscopic adhesive/abrasive wear.

Author Information

Kurtz, SM
Exponent, Inc., Philadelphia, PA School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA
Turner, J
School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA
Herr, M
Exponent, Inc., Philadelphia, PA
Edidin, AA
School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA
Rimnac, CM
Case Western Reserve University, Cleveland, OH
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Details
Developed by Committee: F04
Pages: 41–56
DOI: 10.1520/STP11921S
ISBN-EB: 978-0-8031-5492-6
ISBN-13: 978-0-8031-3474-4