Tissue digestion for wear debris particle isolation

Campbell, Pat; Ma, S.; Schmalzried, Thomas P.; Amstutz, Harlan C.

doi:10.1002/jbm.820280415

Cited by 68 publications

(51 citation statements)

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“…Also, Firkins et al used a strong alkaline solution (12N of KOH) in the isolation proto-col, which was demonstrated to induce a partial dissolution of the metal particles, 17 a change in particle composition, 18 and particle agglomeration. 17,18,38,39 Finally, Firkins et al used SEM whereas TEM was used in the present study.…”

Section: Comparison With Other Investigationsmentioning

confidence: 99%

Size, shape, and composition of wear particles from metal–metal hip simulator testing: Effects of alloy and number of loading cycles

Catelas

Bobyn

Medley

et al. 2003

J Biomedical Materials Res

108

106

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There has been a revived interest in metal-metal total hip replacements because of their potential for improved wear performance compared with conventional metal-polyethylene implants. The aim of the present study was to characterize metal wear particles isolated from metal-metal hip simulator testing of various clinically relevant alloys and to analyze the effects of these alloys and the number of loading cycles on wear particle characteristics. Implants were manufactured using medical-grade cobalt-chromium-molybdenum (CoCrMo) alloys that were high-carbon wrought, low-carbon wrought, or cast (with solution annealing). Testing was performed in a MATCO orbital bearing hip simulator in 95% bovine calf serum. The wear particles were isolated from the serum at test periods of 0-0.25 million cycles (Mc) (run-in wear) and 1.75-2 Mc (steady-state wear) using an enzymatic protocol previously optimized to minimize particle changes due to reagents. Isolated particles embedded in epoxy resin were characterized by transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDXA). The EDXA results revealed the predominance of "lighter" particles containing Cr and O (most likely chromium oxide particles from the passivation layer) and fewer darker CoCrMo particles, with varying ratios of Co and Cr (possibly from carbides and from implant matrix material). More CoCrMo particles were observed with the low-carbon wrought alloy, but the majority of the particles for all three alloys was chromium oxides, especially for the 1.75-2 Mc test period. Image analysis of TEM micrographs revealed that for 0-0.25 Mc, there was up to 21% needle-shaped particles but that the majority remained round to oval in shape, reflecting the predominance of chromium oxide particles. Particle length averaged about 52 +/- 4 nm, with only small differences due to the alloy. For 1.75-2 Mc, most particles were round to oval in shape. They were even less needle-shaped than at 0.25 Mc, and they had a slightly smaller length, averaging 46 +/- 3 nm. In addition to characterizing the size and shape of particles from a MATCO simulator, this study is the first to demonstrate that particles that do not contain Co (presumably chromium oxides) can be predominant in the wear of metal-metal hip implants. It is therefore recommended that future in vitro and in vivo studies include the effects of these particles rather than just the effects of CoCrMo particles on the overall tissue response.

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Section: Comparison With Other Investigationsmentioning

confidence: 99%

Size, shape, and composition of wear particles from metal–metal hip simulator testing: Effects of alloy and number of loading cycles

Catelas

Bobyn

Medley

et al. 2003

J Biomedical Materials Res

108

106

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“…Indeed, the protocol used by Firkins et al involved a strong alkaline solution that has been demonstrated to induce a partial dissolution of the metal particles, 27 a change in particle composition, 28 as well as particle agglomeration. 27,28,43,44 The characterization protocol used by these authors also involved filtration of the particles for SEM analysis, which most likely led to the loss of some particles. The protocol used by Firkins et al may not have been optimal for precise characterization of metal particles.…”

Section: Particles From the Simulatormentioning

confidence: 99%

Comparison of in vitro with in vivo characteristics of wear particles from metal–metal hip implants

et al. 2004

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The purpose of the present study was to compare wear particles isolated from metal-metal (MM) hip implants worn in an orbital bearing simulator with particles from similar MM total hip replacement (THR) implants worn in vivo. Comparison of these particles is important because it will help to assess the overall suitability of this type of hip simulator for reproducing in vivo wear and for producing physiological wear particles suitable for biological studies of in vitro cellular response. Commercial grade components made of ASTM F75 (cast) alloy were evaluated. Simulator tests were performed in 95% bovine calf serum with a 28-mm-diameter implant. Wear particles were collected from 0 to 0.25 million cycles (run-in wear period) and 1.75 to 2 million cycles (steady-state wear period). Tissues from seven patients with MM implants (surface replacement or stem type) were harvested at revision surgeries (after 1-43 months). Metal wear particles were isolated from serum lubricant or tissues using an enzymatic protocol that was previously optimized to minimize particle changes due to reagents. After isolation, particles were centrifuged, embedded in epoxy resin, and characterized by transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDXA). Results of EDXA on particles from the hip simulator primarily indicated a predominance of particles containing Cr and O but no Co (most likely chromium oxide particles), and fewer CoCrMo particles presenting varying ratios of Co and Cr. Image analysis of TEM micrographs demonstrated that the majority of the particles from the simulator were round to oval, but a substantial number of needle-shaped particles were also found, especially from 0 to 0.25 Mc. The particles generated from 0 to 0.25 Mc had an average length of 53 nm, whereas those generated from 1.75 to 2 Mc had an average length of 43 nm. In vivo, EDXA and TEM analysis of particles that were retrieved from two patients at 23 and 43 months respectively, revealed that they were the most comparable in composition, average length (57 nm), and shape to particles generated in the hip simulator during the run-in wear period. Because a large clinical retrieval study in the literature suggested that a run-in wear regime might occur in vivo for some 6-36 months, the fidelity of the simulator of the present study was strongly supported. However, some uncertainties existed, including the finding that the particles isolated from the other five patients generated from 1 month up to 15 months (shorter implantation times than the other two patients) were smaller and mostly contained only Cr and O (no Co). In the opinion of the authors, this particular very short term patient group was somewhat atypical. Therefore, despite these uncertainties, the present study was deemed to support the ability of the orbital bearing hip simulator to produce physiological wear particles.

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“…Joint type and retrieval site information can be seen in Table I. The debris retrieval protocol of Campbell et al [5,7] was used because it produced wear debris particles of a high purity and at high concentrations within a colorless medium. To complement this work, samples of alkali digested and ®ltration retrieved ex vivo wear debris were also examined by SEM.…”

Section: Methodsmentioning

confidence: 99%

Untitled

Elfick

Green

Pinder

et al. 2000

Journal of Materials Science: Materials in Medicine

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The accurate and detailed characterization of arti®cial joint wear debris is important in determining both the wear rate of prostheses and understanding the role that the debris plays in the development and progression of aseptic loosening. The novel application of low angle laser light scattering (LALLS) to the particle size characterization of ultra high molecular weight polyethylene (UHMWPE) wear debris is described. The results demonstrate that both ex vivo and in vitro origin wear debris samples, at concentrations typical of those produced via an alkali-digestion retrieval route, can be reproducibly analyzed via LALLS. Because the LALLS route enables particle size analysis of the entire debris sample to be acquired non-destructively and whilst in suspension, artefacts associated with ®ltering, drying and agglomeration of debris are avoided, in contrast to currently used techniques such as ®ltration and scanning electron microscopy (SEM) observation.

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Tissue digestion for wear debris particle isolation

Cited by 68 publications

References 1 publication

Size, shape, and composition of wear particles from metal–metal hip simulator testing: Effects of alloy and number of loading cycles

Size, shape, and composition of wear particles from metal–metal hip simulator testing: Effects of alloy and number of loading cycles

Comparison of in vitro with in vivo characteristics of wear particles from metal–metal hip implants

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