Size, shape, and spatial distribution analysis of sub-micron hip implant wear particles at sub-optical resolution using deconvolution methods
Year: 2011
Type: dissertation
Abstract: Total joint replacement (TJR) has long been a common and effective treatment option for individuals suffering from osteoarthritis. However, the bearing surfaces for TJR implants, generally a metal femoral head inserted into an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup, are prone to wear. UHMWPE particles generated through articulating wear can contribute to the failure of implants, and have been shown to have health risks for patients. Understanding the generation and characteristics of wear particles is crucial for learning how to reduce these health risks and assess different implant materials and designs. Using a novel elliptically polarized light imaging system we employ new techniques for image acquisition, with subsequent manipulation to enhance particle analysis. Microscopy slides containing UHMWPE wear debris were prepared and imaged using a custom designed polarizing microscope. A calibration methodology was developed to model the point spread function (PSF) artifact introduced by the optical system. Deconvolution methods, based on a PSF model developed by Gibson et al. [33], were used to remove the PSF from images captured by the optical system. Optimization of the theoretical PSF produced a model that consistently correlated above 0.85, which is a threshold determined to result in reasonable improvement in resolution of image data. Particle size, shape, and spatial distribution were quantified and used to characterize the imaged particles. Statistical comparison of particle characterization before and after deconvolution, and compared against scanning electron microscopy images of the same particles, revealed a significant improvement in particle characterization. Further refinement and work could improve the packages presented in this work dramatically, offering a robust alternative to SEM analysis of wear debris. The main advantage of this new method is the ability to image UHMWPE wear particles in-situ from histology slides of relevant tissues, allowing for distribution and location data to be collected in addition to size and shape information.
DOI: 10.17918/etd-4295
Authors: Andrew Carter Erwin, Todd C. Doehring
Institution: University of Dhaka
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Funder: Drexel University
OpenAlex ID: W4206438492