In Vivo Oxidation in Remelted Highly Cross-Linked Retrievals

Currier, Barbara H.; Citters, Douglas W. Van; Currier, John H.; Collier, John

doi:10.2106/jbjs.i.01006

Cited by 85 publications

(73 citation statements)

References 19 publications

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“…Nonetheless, the strong correlations that have been made in retrieved implants between peak oxidation and the length of time of implantation [13,14] suggest that longer term retrievals must be analyzed to gain more clarity as to whether mechanical failure of the polymer (fracture or delamination) may become more likely with continued increases in oxidation levels at or below loaded regions of the articular 134 Liu et al Clinical Orthopaedics and Related Research 1 surface. Similarly, if crosslink density continues to decrease in the loaded regions of the tibial insert, the possibility exists for increased wear over time.…”

Section: Discussionmentioning

confidence: 99%

“…To decrease the potential for oxidative degradation, heating the polymer to above its melting point (''remelting'') or to just below that temperature (''below-melt thermal annealing'') is a step added postirradiation to reduce the free radicals. However, retrieved crosslinked PE tibial inserts demonstrate increased oxidation levels at the articular surfaces after in vivo implantation regardless of whether they were either remelted or annealed after crosslinking, a phenomenon not observed with pristine, never implanted inserts [13,14,25].…”

Section: Introductionmentioning

confidence: 88%

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Crosslink Density Is Reduced and Oxidation Is Increased in Retrieved Highly Crosslinked Polyethylene TKA Tibial Inserts

Liu

Esposito

Burket

et al. 2017

Clinical Orthopaedics &Amp; Related Research

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Background The wear resistance of highly crosslinked polyethylene depends on crosslink density, which may decrease with in vivo loading, leading to more wear and increased oxidation. The relationship among large and complex in vivo mechanical stresses, breakdown of the polyethylene crosslinks, and oxidative degradation is not fully understood in total knee arthroplasty (TKA). We wished to determine whether crosslink density is reduced at the articular surfaces of retrieved tibial inserts in contact areas exposed to in vivo mechanical stress.Questions/purposes (1) Does polyethylene crosslink density decrease preferentially in regions of the articular surface of thermally stabilized crosslinked polyethylene tibial components exposed to mechanical stress in vivo; and (2) what is the ramification of decreased crosslink density in TKA in terms of accompanying oxidation of the polyethylene? Methods From May 2011 to January 2014, 90 crosslinked polyethylene tibial components were retrieved during revision surgery as a part of a long-standing implant retrieval program. Forty highly crosslinked polyethylene tibial inserts (27 posterior-stabilized designs and 13 cruciate-retaining designs) retrieved for instability (15 cases), stiffness (11), infection (six), aseptic loosening (four), pain (two), and malposition (two) after a mean time of 18 months were inspected microscopically to identify loaded (burnished) and unloaded (unburnished) regions on the articular surfaces. Swell ratio testing was done according to ASTM F2214 to calculate crosslink density and infrared spectroscopy was used according to ASTM F2102 to measure oxidation. Results The region of the tibial insert influenced crosslink density. Loaded surface regions had a mean crosslink density of 0.19 (95% confidence interval [CI], 0.18-0.19) mol/dm 3 , lower than the other three regions (loaded subsurface, unloaded surface, and unloaded subsurface), which had crosslink densities of 0.21 (95% CI, 0.21-0.22; p \ 0.01) mol/dm 3 . Peak oxidation levels were higher in loaded regions with a mean oxidation index (OI) of 0.67 (95% CI, 0.56-0.78) versus unloaded regions with a mean OI of 0.36 (95% CI, 0.27-0.45; p \ 0.01). Peak oxidation levels were higher in annealed samples with a mean OI of 0.66 (95% CI, 0.52-0.81) versus remelted samples with a mean OI of 0.40 (95% CI, 0.34-0.47; p \ 0.01).Conclusions The results suggest that the crosslink density decreases and accompanying oxidation is driven 123Clin Orthop Relat Res (2017) 475:128-136 DOI 10.1007 Clinical Orthopaedics and Related Research ® A Publication of The Association of Bone and Joint Surgeons® predominantly by contact stress conditions. If crosslink density continues to decrease with continued loading over time, crosslinked polyethylene may not provide a clinical advantage over conventional polyethylene in the long term for TKA. Therefore, we will continue to collect longer term retrievals to evaluate mechanical property changes in crosslinked polyethylenes. Clinical Relevance Although we found a de...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

Crosslink Density Is Reduced and Oxidation Is Increased in Retrieved Highly Crosslinked Polyethylene TKA Tibial Inserts

Liu

Esposito

Burket

et al. 2017

Clinical Orthopaedics &Amp; Related Research

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“…However, head size is limited based on recommendations of minimum polyethylene thickness of 4 to 8 mm. In addition, there is some concern about long-term in vivo oxidation with degraded wear performance in the second decade [7,17]. Ceramic-on-ceramic (CoC) has the advantage of very low wear and comparatively friendly wear debris.…”

Section: Introductionmentioning

confidence: 99%

No Difference in Reoperations at 2 Years Between Ceramic-on-metal and Metal-on-metal THA: A Randomized Trial

Engh

Sritulanondha

Korczak

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background Hard-on-hard bearings for total hip arthroplasty continue to warrant analysis even though crosslinked polyethylene is performing very well. Ceramicon-metal (CoM) has low in vitro wear and did well in an early clinical trial. We report on a prospective, randomized, multicenter investigational device trial comparing CoM with metal-on-metal (MoM). Questions/purposes (1) Is there a difference in the number or type of revisions comparing CoM with MoM? (2) Are cobalt and chromium metal levels different for CoM and MoM THA? Methods Between

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“…Delamination can result from substantial oxidative degradation [8] and has been observed with XLPE tibial plateaus that were sequentially annealed (rather than remelted) [4]. The observation of no delamination by Liu et al is consistent with the low levels of oxidation measured in XLPE tibial plateaus after as long as 10 years use in vivo [2]. In fact, oxidation even of conventional polyethylene in vivo is minimal for the first few years [1].…”

mentioning

confidence: 69%

CORR Insights®: Surface Damage Is Not Reduced With Highly Crosslinked Polyethylene Tibial Inserts at Short-term

McKellop

2016

Clinical Orthopaedics &Amp; Related Research

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In Vivo Oxidation in Remelted Highly Cross-Linked Retrievals

Cited by 85 publications

References 19 publications

Crosslink Density Is Reduced and Oxidation Is Increased in Retrieved Highly Crosslinked Polyethylene TKA Tibial Inserts

Crosslink Density Is Reduced and Oxidation Is Increased in Retrieved Highly Crosslinked Polyethylene TKA Tibial Inserts

No Difference in Reoperations at 2 Years Between Ceramic-on-metal and Metal-on-metal THA: A Randomized Trial

CORR Insights®: Surface Damage Is Not Reduced With Highly Crosslinked Polyethylene Tibial Inserts at Short-term

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