writer：Jie Shen, Guorong Gao, Xincai Liu, Jun Fu
keywords：UHMWPE
source：期刊
specific source：Clinical Orthopaedics and Related Research, 2015, 473, 760-766.
Issue time：2015年
該論文榮獲CORR雜志首屆最佳中國(guó)論文獎(jiǎng)，雜志主編專門撰寫(xiě)了Editor''s Spotlight文章介紹本論文工作（見(jiàn)附件）。
Abstract
Background Radiation-crosslinked UHMWPE has been
used for joint implants since the 1990s. Postirradiation
remelting enhances oxidative stability, but with some loss
in strength and toughness. Vitamin E-stabilized crosslinked
UHMWPE has shown improved strength and stability as
compared with irradiated and remelted UHMWPE. With
more active phenolic hydroxyl groups, natural polyphenols
are widely used in the food and pharmaceutical industries
as potent stabilizers and could be useful for oxidative stability
in crosslinked UHMWPE.
Questions/purposes We asked whether UHMWPE blended
with polyphenols would (1) show higher oxidation
resistance after radiation crosslinking; (2) preserve the
mechanical properties of UHMWPE after accelerated
aging; and (3) alter the wear resistance of radiation-crosslinked
UHMWPE.
Methods The polyphenols, gallic acid and dodecyl gallate,
were blended with medical-grade UHMWPE followed
by consolidation and electron beam irradiation at 100 kGy.
Radiation-crosslinked virgin and vitamin E-blended
UHMWPEs were used as reference materials. The
UHMWPEs were aged at 120 C in air with oxidation
levels analyzed by infrared spectroscopy. Tensile (n = 5
per group) and impact (n = 3 per group) properties before
and after aging as per ASTM F2003 were evaluated. The
wear rates were examined by pin-on-disc testing (n = 3
per group). The data were reported as mean ± SDs. Statistical
analysis was performed by using Student’s t-test for
a two-tailed distribution with unequal variance for tensile
and impact data obtained with n C 3. A significant difference
is defined with p \0.05.
Results The oxidation induction time of 100 kGy
UHMWPE was prolonged to 144 hours with 0.05 wt%
dodecyl gallate and 192 hours with 0.05 wt% gallic acid
compared with 48 hours for 0.05 wt% vitamin E-blended
UHMWPE. Accelerated aging of these polyphenol-blended
UHMWPEs resulted in ultimate tensile strength of
50.4 ± 1.4 MPa and impact strength of 53 ± 5 kJ/m2 for
100 kGy-irradiated UHMWPE with 0.05 wt% dodecyl
gallate, for example, in comparison to 51.2 ± 0.7 MPa
(p = 0.75) and 58 ± 5 kJ/m2 (p = 0.29) before aging. The
pin-on-disc wear rates of 100 kGy-irradiated UHMWPE
with 0.05 wt% dodecyl gallate and 0.05 wt% gallic acid were 2.29 ± 0.31 and 1.65 ± 0.32 mg/million cycles,
comparable to 1.68 ± 0.25 and 2.05 ± 0.22 mg/million
cycles for 100 kGy-irradiated virgin and 0.05 wt% vitamin
E-blended UHMWPE.
Conclusions Based on the sample numbers tested in this
study, polyphenols appear to effectively enhance the oxidation
stability without altering the mechanical properties
or pin-on-disc wear rate of radiation-crosslinked
UHMWPE.
Clinical Relevance Crosslinked UHMWPE with natural
polyphenols with improved oxidative stability and low
wear may find clinical application in joint implants.