RESUMEN
Vitamin E (VE) blended ultra-high molecular weight polyethylene (UHMWPE) has been developed in Japan as a material for use in total knee replacement (TKR). Various results have demonstrated that VE blended UHMWPE reduces the incidence of delamination failure and lowers the amount of wear produced during knee simulator testing. It was also found that wear particles from VE blended UHMWPE elicited a reduced biological response compared to conventional UHMWPE. A great deal of research concerning vitamin E (VE) stabilized ultrahigh molecular weight polyethylene (UHMWPE) has focused on VE's effects as an antioxidant and its ability to prevent the oxidative degradation of UHMWPE chains. However, other chemical and mechanical changes have been observed in VE blended UHMWPE that are unrelated to the oxidative protection that VE provides. This paper provides a general review of VE blended UHMWPE, with a particular focus on the non-antioxidant effects of VE. The potential application of VE blended UHMWPE in total hip replacement (THR), along with the differences in loading conditions between the knee and the hip are also discussed.
Asunto(s)
Materiales Biocompatibles/síntesis química , Prótesis de la Rodilla/efectos adversos , Polietilenos/química , Infecciones Relacionadas con Prótesis/inmunología , Infecciones Relacionadas con Prótesis/prevención & control , Vitamina E/administración & dosificación , Animales , Antioxidantes/química , Antioxidantes/metabolismo , Artroplastia de Reemplazo de Rodilla/efectos adversos , Artroplastia de Reemplazo de Rodilla/instrumentación , Materiales Biocompatibles/farmacología , Implantes de Medicamentos/administración & dosificación , Implantes de Medicamentos/síntesis química , Humanos , Ensayo de Materiales , Oxidantes/química , Oxidantes/inmunología , Polietilenos/farmacología , Diseño de Prótesis , Infecciones Relacionadas con Prótesis/etiología , Vitamina E/inmunologíaRESUMEN
The effects of vitamin E addition on the strain-induced crystallization and molecular chain orientation of ultrahigh molecular weight polyethylene (UHMWPE) were examined in order to clarify the wear mechanism of vitamin E-blended UHMWPE in knee prostheses. The structure changes of vitamin E-blended UHMWPE before and after tensile strain were analyzed by X-ray diffraction, Raman spectroscopy and image correlation method. The vitamin E-blended UHMWPE exhibited lower strain-induced crystallization than virgin UHMWPE but a higher Ic value in Raman spectroscopic analysis. The vitamin E-blended UHMWPE also exhibited a larger percentage of negative areal dilatation under tensile strain. These results suggest that the addition of vitamin E to UHMWPE decreases the strain-induced crystallization and increases the strain-induced orientation of the molecular chains present in the amorphous phase.