RIBEIRO, M. C. M. R.; RIBEIRO, Márcia Cristina de Moraes Reis.
Résumé:
The polyethylene, ultra high molecular weight (UHMWPE) is a polymer with
excellent physical and mechanical properties with the most notable its chemical
inertness, lubricity, impact resistance and abrasion resistance. Displays a
relevant role in the successful Total Knee Arthroplasty (TKA) and Total Hip
Arthroplasty (THA). The arthroplasty is characterized by replacement of the
natural joint with an artificial joint. Artificial joints are formed by a set of
components, being manufactured from metal or ceramic raw material and a
component normally done in UHMWPE, which is interposed between the metal
components. Some factors contribute to increased wear of the polyethylene
component. Components manufactured in polyethylene UHMWPE not have
photostabilizers. And inspections on manufacturers and distributors of these
products was observed that during its industrial processing and marketing they
are not adequately protected from direct light. Characteristics considered
important for the in vitro performance of these devices are set in technical
standards, but many of these standards only recommend certain requirements
considered important from a technical standpoint. Currently the area of
materials for use in healthcare working on regulations that seek to establish the
minimum requirements for registration of orthopedic implants. Thus, this study
aimed to evaluate the possible changes of components manufactured in
polyethylene, ultra high molecular weight used in surgical procedures and knee
arthroplasty and hip, exposed to ultraviolet radiation. The work was divided into
4 groups: group 1 (material not exposed to UV); group 2 (material exposed to
UV for 1 h); group 3 (material exposed to UV for 24 h) and group 4 (material
exposed to UV for 48 h). All samples were characterized by X-Ray Diffraction
(XRD), Absorption Spectroscopy Fourier Transform Infrared (FTIR), optical
microscopy (OM), scanning electron microscopy (SEM) with EDS mapping and
Atomic Force Microscopy (AFM) in order to evaluate the possible degradation of
UHMWPE subjected to UV radiation. The results showed that exposure of the
polymer to UV radiation at all times tested in this study modified the samples, it
was observed mainly in the experimental XRD and EDS which occurred
respectively a slight increase in crystallinity and decrease in the percentage
oxygen. Thus, it can be concluded that the increase in crystallinity can by the
action of UV radiation, affect the material properties contributing to increased
wear and reduced useful life of the implant.
