Micro-wear features on unique 100-Mrad cupsTwo retrieved cups compared to hip simulator wear study

Yamamoto, Kenjiro; Masaoka, Toshinori; Manaka, M.; Oonishi, Hironobu; Clarke, Ian C.; Shoji, Hiroto; Kawanabe, Keiichi; Imakiire, Atsuhiro

doi:10.1080/00016470412331294375

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…We found the wear rates of 100-Mrad PE cups that had been shelf-aged for 30 years were very low and consistent with the excellent clinical results observed with 100-Mrad PE implanted for more than 30 years [9,27]. However, the initial wear rate of 187.9 mg/10 6 cycles in unpackaged 100-Mrad PE was extremely high as compared with that of packaged 100-Mrad PE.…”

Section: Discussionsupporting

confidence: 79%

“…These cups were withdrawn from the market in 1978 owing to the bankruptcy of the company providing the special irradiation treatment. However, over the last 30 years, excellent clinical results have been observed with 100-Mrad PE [9,18,27]. Several studies suggest the linear wear rate in vivo of acetabular cups made from conventional PE (gamma-sterilized in air or inert gas) is as high as 0.1 to 0.2 mm per year [6,7].…”

Section: Introductionmentioning

confidence: 99%

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Oxidation and Wear of 100-Mrad Cross-linked Polyethylene Shelf-aged for 30 Years

Kim

Oonishi

Kyomoto

et al. 2008

Clinical Orthopaedics &Amp; Related Research

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Some previous studies suggest that aging influences wear and oxidatively degraded nonsterilized ultra-high-molecular-weight polyethylene (UHMWPE) exhibits decreased wear resistance. We therefore asked whether shelf-aging storage conditions influenced degradation and wear resistance of gamma-irradiated UHMWPE. We examined oxidation and wear of 100-Mrad gamma-irradiated UHMWPE (100-Mrad polyethylene) cups shelf-aged for 30 years without (n = 2) or with (n = 2) packages. The oxidation index of the unpackaged 100-Mrad polyethylene surface (4) was higher than that of the packaged one (2.7). The packaged 100-Mrad polyethylene cup exhibited a high wear resistance with a steady wear rate of 0.5 mg/10 6 cycles. In contrast, the unpackaged 100-Mrad polyethylene exhibited an extremely high initial wear rate of 187.9 mg/10 6 cycles over the first 0.25 · 10 6 cycles with a subsequently reduced wear rate of 5 mg/10 6 cycles after 5 · 10 6 cycles. Packaging over long periods inhibits surface oxidation and maintains the wear resistance of gamma-irradiated UHMWPE cups.

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Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Oxidation and Wear of 100-Mrad Cross-linked Polyethylene Shelf-aged for 30 Years

Kim

Oonishi

Kyomoto

et al. 2008

Clinical Orthopaedics &Amp; Related Research

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“…However, wear of ceramic retrievals was only mapped in its entirety by our previous SEM studies 12, 13. Unlike the soft polyethylene cup that shows a large region of wear over its superior hemisphere,20, 21 the rigidity of ceramic bearings clearly allows the formation of a main wear region, a transition wear region and also the stripe wear. Our SEM description of five progressive grades of wear in alumina ceramic made such mapping of wear possible 13.…”

Section: Discussionmentioning

confidence: 99%

Surface micro‐analyses of long‐term worn retrieved “Osteal™” alumina ceramic total hip replacement

et al. 2007

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We analyzed wear pattern of long-term retrieved alumina-alumina hip prostheses from Osteal, which were implanted for 15-19 years. A comparison was carried out with our previous study of 17-year Biolox alumina-on-alumina hip prostheses, (Shishido et al., J Biomed Mater Res B 2003;67:638-647) and all-alumina total hip replacement run under microseparation simulator tests. Of particular interest was the occurrence of stripe wear in these first generation alumina ceramic bearings. Two balls of Osteal revealed only one stripe wear as did the respective liners on their rim areas. In these latter balls, the stripes were shallower than those previously observed in Biolox implants. A microscopic analysis of the bearing surface was carried out using scanning electron microscopy and fluorescence microprobe spectroscopy. On average, the Osteal retrievals had one grade lower wear than Biolox retrievals. Fluorescence microprobe maps showed that Biolox ball surfaces had higher compressive stress than the Osteal likely due to severe impingement and microseparation promoted by the bulky implant design.

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“…1 Several studies have been concerned with UHMWPE improving the properties of UHMWPE by using irradiation processes. [2][3][4][5][6] Irradiation effects induced on UHMWPE are difficult to predict and very complex, despite the simple polymeric structure.…”

Section: Introductionmentioning

confidence: 99%

Mechanical performance of electron‐beam‐irradiated UHMWPE in vacuum and in air

et al. 2008

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Ultrahigh molecular weight polyethylene (UHMWPE) was modified by a 5-MeV energy electron beam at different temperatures before, during, and after irradiation, both in air and in high vacuum. Wear resistance, hardness, and tensile strength of irradiated polyethylene were compared with those of untreated one. Physical analyses (like infrared spectroscopy and calorimetric analysis) were carried out to investigate about the changes in the material induced by irradiation. Experimental results suggested that structural changes (double bonds, crosslinks, and oxidized species formation) occur in the polymer depending on the environmental conditions of the irradiation. Mechanical behavior is related to the structural modifications. A temperature of 110 degrees C before, during, and after the in vacuum irradiation of UHMWPE produces a high amount of crosslinks and improves polymeric tensile and wear resistance, compared to that of the untreated material.

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Micro-wear features on unique 100-Mrad cupsTwo retrieved cups compared to hip simulator wear study

Cited by 11 publications

References 15 publications

Oxidation and Wear of 100-Mrad Cross-linked Polyethylene Shelf-aged for 30 Years

Oxidation and Wear of 100-Mrad Cross-linked Polyethylene Shelf-aged for 30 Years

Surface micro‐analyses of long‐term worn retrieved “Osteal™” alumina ceramic total hip replacement

Mechanical performance of electron‐beam‐irradiated UHMWPE in vacuum and in air

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