Ultrahigh-Molecular-Weight Polyethylene
Weihong Jin, Paul K. ChuEncyclopedia of Biomedical Engineering, 2019
UHMWPEndi mzerepolyolefinndi gawo lobwereza la − CH2CH2 −.Medical-grade UHMWPE ili ndi unyolo wautali wokhala ndi amisa ya maselowa 2 × 106–6 × 106 g mol− 1 ndipo ndisemicrystalline polimandi gulu la zigawo olamulidwa ophatikizidwa mu chisokonezogawo la amorphous(Turell ndi Bellare, 2004).UHMWPE ili ndi kukangana kochepa, kukana kuvala kwakukulu, kulimba kwabwino, kukwezekamphamvu yamphamvu, kukana kwambiri kwa mankhwala owononga, biocompatibility yabwino kwambiri, komanso mtengo wotsika.
UHMWPE yakhala ikugwiritsidwa ntchito kuchipatalapamodzi implantskwa zaka zoposa 40, makamaka ngati chingwe chowongolera m'malo mwa chiuno chonse ndi tibial kuika m'malo onse a mawondo.Mu 1962, UHMWPE idagwiritsidwa ntchito koyamba ngati zigawo za acetabular ndipo yakhala yayikulu.kubala zipangizom'malo onse a chiuno kuyambira 1970s.Komabe, kuvala kwa UHMWPE pokhudzana ndi zigawo zolimba kwambiri zopangidwa ndi zitsulo kapena zoumba linali vuto lalikulu mu mafupa a m'ma 1980 makamaka chifukwa cha kukonzanso kosalekeza kwa maunyolo a polima.Zovala zoterezi zimatha kuyambitsaosteolysiskumabweretsa kumasulidwa kwa ma implants ndi kufooka kwa mafupa.
Panali kusintha kwakukulu pakupanga UHMWPE yolumikizana kwambiri kumapeto kwa zaka za m'ma 1990.Kuphatikizika kwa UHMWPE kumayendetsedwa kwambiri ndikusintha maunyolo am'mbali ndi ma radiation mongagamma ray,electron mtengo, kapena mankhwala monga peroxide kuti azitha kukana kuvala chifukwa cha kuchepa kwa unyolo wa polima pambuyo pogwirizanitsa (Lewis, 2001).Kupititsa patsogolookosijenikukana, UHMWPE yolumikizidwa ndi mtanda imathandizidwa ndi thermally.UHMWPE yolumikizidwa kwambiri yagwiritsidwa ntchito bwino ponyamula katunduzolumikizanandipo amakhala muyezo mu okwana m'malo m'chiuno.
Asanakhazikitsidwe, ma implants a mafupa nthawi zambiri amatsekeredwa ndi kuwala kwa gamma mumpweya wozungulira.Gamma ray imapangitsa kuti ma free radicals apangidwe kudzera mu chain cleavage.Pambuyo pa kuyatsa kwa gamma, ma radicals aulere amatha kukhalapobe mu polima ndikuchitapo kanthu ndi mitundu ya O yomwe ilipo panthawi yosungidwa kapena mu vivo imayambitsa kuwononga okosijeni kwa UHMWPE (Premnath et al., 1996).Ngakhale UHMWPE yolumikizidwa kwambiri yawonjezera kukana kuvala, zinthu zina monga ductility,kulimba kwa fracture, kukana kutopa, ndikulimba kwamakokedweakhoza kusokonezedwa ndi gamma irradiation (Lewis, 2001; Premnath et al., 1996).
Nonionizing njira monga kutsekereza pogwiritsa ntchito mpweya wa ethylene oxide kapenagasi plasmakutuluka, ndipo chithandizo china chokhazikika chachitikanso pambuyo polumikizana kuti athetse chikoka chomwe chatchulidwa kale (Kurtz et al., 1999).The antioxidantvitamini Eimaphatikizidwanso mu UHMWPE yolumikizidwa kuti itseke oxidation pochita ndi ma free radicals (Bracco ndi Oral, 2011).
Palibe mbiri yachipatala m'magawo olowa m'malo ngakhale vitamini E amawonetsa chitetezo ndi biocompatibility.Chifukwa chake, njira zolimbikitsira kukana kovala popanda kuwononga zina zilizonse zofunika za UHMWPE ndikugwiritsa ntchito kwanthawi yayitali kwachipatala ndizofunika UHMWPE muntchito zamafupa.
Nthawi yotumiza: Jun-26-2023
