VITAL-E & VITAL-XE\u00ae<\/sup><\/h4><\/div>Vitamin E cross-linked polyethylene<\/h5>\n
VITAL-XE\u00ae<\/sup> is a polyethylene (UHMWPE) fortified with 0.1 percent by weight of Vitamin E<\/strong> (alpha-tocopherol) used to make joint inserts.
\nThe Vitamin E is mixed with the polyethylene powder from the outset before the raw material rods are formed.<\/p>\nVITAL-XE\u00ae<\/sup> is cross-linked polyethylene<\/strong> as it is irradiated with beta rays by a dose of 60 kGy and then sterilized in ethylene oxide.
\nVITAL-XE\u00ae<\/sup> is used to make joint inserts used in total hip arthroplasty<\/strong>.<\/p>\nVITAL-E\u00ae<\/sup> is the non-irradiated, thus non-cross-linked version<\/strong> of Vitamin E-supplemented polyethylene, sterilized by ethylene oxide.
\nVITAL-E\u00ae<\/sup> is used to make non-cross-linked joint inserts of knee prostheses as well as humeral and glenosphere heads for shoulder prostheses<\/strong>.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>OXIDATION.<\/h4><\/div>The degradation of UHMWPE and polymers in general is that process such that there is an alteration of the chemical structure of the material with a decrease in molecular weight. Degradation decreases the mechanical properties of polyethylene and, therefore, causes premature wear.<\/strong><\/p>\nThe degradation of a polymer occurs with the breaking of certain chemical bonds and the creation of new free radicals when, for example, the material is exposed to more energy than the chemical bonds themselves of which the molecular chains of the polymer are made. This process in the presence of oxygen is called oxidative degeneration or more simply oxidation. <\/p>\n
Once triggered, the oxidative process is irreversible. As new radicals are formed and react with oxygen, they trigger breaks in other chemical bonds that generate other radicals and so on, creating a chain reaction that is self-perpetuating at increasing speed. The rate of oxidation depends on the number of radicals present and the amount of oxygen that may be present in the atmosphere during polyethylene processing and sterilization processes into which it may penetrate by diffusion during product storage or once implanted in the patient. <\/p>\n
Polyethylenes used in arthroplasty are typically subjected to high doses of energy in the form of gamma or beta irradiation to sterilize or to increase the degree of cross-linking of the polyethylene. Such irradiation produces the formation of active free radicals within the material. Most free radicals recombine to form new cross-links in the amorphous phase of polyethylene, cross-linking precisely. Instead, free radicals that have formed within the crystalline phase of polyethylene remain trapped for a long time without recombining into new bonds. Such radicals in the presence of oxygen are responsible for the progressive breakdown of polymer chains through oxidation cascade reactions and consequently, are responsible for the reduction of the mechanical properties of polyethylene. <\/p>\n
Oxidation results in the degradation of the molecular structure of polyethylene and thus over time causes its mechanical and tribological properties to progressively decay.<\/strong><\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>VITAMIN “E” AS A STABILIZING ADDITIVE<\/h4><\/div>Polymer stabilization is mainly based on reducing the oxygen concentration or reducing the number of free radicals or their reactivity to reduce or theoretically eliminate the problem of polyethylene oxidation. In the case of polyethylene (UHMWPE), sterilizing in vacuum or modified atmosphere brings advantages, but oxygen is still present within the material by penetrating through diffusion during the production process; therefore, it is materially impossible to completely eliminate oxygen from polyethylene. <\/p>\n
There are many additives on the market that can limit radical reactivity; unfortunately, almost all of them have problems with biocompatibility, which is absolutely necessary for a product to be implanted in the human body.<\/p>\n
One biocompatible dopant that has long been studied in the literature for medical polyethylene stabilization is vitamin E<\/strong> (alpha-tocopherol). Vitamin E is present in many vegetables and is an essential vitamin nutrient for metabolism in humans. <\/p>\nStabilization of UHMWPE by vitamin E was introduced as an alternative method to provide oxidation resistance without sacrificing the mechanical properties of UHMWPE.<\/strong> There are two methods to introduce low concentrations (0.05%-1%) of vitamin E within UHMWPE. The first consists of mixing vitamin E in liquid form to UHMWPE powder before the rod extrusion process and irradiation for cross-linking. The second method, on the other hand, involves diffusing vitamin E within the already consolidated and cross-linked UHMWPE. <\/p>\nThe addition of minute concentrations of vitamin E in polyethylene eliminates the problem of oxidation and consequently increases its longevity.<\/strong><\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div>BIBLIOGRAPHY<\/h4><\/div>Torre M, Brach Del Prever E, Costa L, Romanini E, Masciocchi M, Manno V. Innovative materials in orthopedics: cross-linked polyethylene.
\nAnn Ig 2011;23:81-90.<\/p>\n<\/div><\/div><\/div>
<\/div><\/div><\/div>![](\"data:image\/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20width%3D%271024%27%20height%3D%27930%27%20viewBox%3D%270%200%201024%20930%27%3E%3Crect%20width%3D%271024%27%20height%3D%27930%27%20fill-opacity%3D%220%22%2F%3E%3C%2Fsvg%3E\")
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Vitamin E cross-linked polyethylene<\/h5>\n
VITAL-XE\u00ae<\/sup> is a polyethylene (UHMWPE) fortified with 0.1 percent by weight of Vitamin E<\/strong> (alpha-tocopherol) used to make joint inserts. VITAL-XE\u00ae<\/sup> is cross-linked polyethylene<\/strong> as it is irradiated with beta rays by a dose of 60 kGy and then sterilized in ethylene oxide. VITAL-E\u00ae<\/sup> is the non-irradiated, thus non-cross-linked version<\/strong> of Vitamin E-supplemented polyethylene, sterilized by ethylene oxide. The degradation of UHMWPE and polymers in general is that process such that there is an alteration of the chemical structure of the material with a decrease in molecular weight. Degradation decreases the mechanical properties of polyethylene and, therefore, causes premature wear.<\/strong><\/p>\n The degradation of a polymer occurs with the breaking of certain chemical bonds and the creation of new free radicals when, for example, the material is exposed to more energy than the chemical bonds themselves of which the molecular chains of the polymer are made. This process in the presence of oxygen is called oxidative degeneration or more simply oxidation. <\/p>\n Once triggered, the oxidative process is irreversible. As new radicals are formed and react with oxygen, they trigger breaks in other chemical bonds that generate other radicals and so on, creating a chain reaction that is self-perpetuating at increasing speed. The rate of oxidation depends on the number of radicals present and the amount of oxygen that may be present in the atmosphere during polyethylene processing and sterilization processes into which it may penetrate by diffusion during product storage or once implanted in the patient. <\/p>\n Polyethylenes used in arthroplasty are typically subjected to high doses of energy in the form of gamma or beta irradiation to sterilize or to increase the degree of cross-linking of the polyethylene. Such irradiation produces the formation of active free radicals within the material. Most free radicals recombine to form new cross-links in the amorphous phase of polyethylene, cross-linking precisely. Instead, free radicals that have formed within the crystalline phase of polyethylene remain trapped for a long time without recombining into new bonds. Such radicals in the presence of oxygen are responsible for the progressive breakdown of polymer chains through oxidation cascade reactions and consequently, are responsible for the reduction of the mechanical properties of polyethylene. <\/p>\n Oxidation results in the degradation of the molecular structure of polyethylene and thus over time causes its mechanical and tribological properties to progressively decay.<\/strong><\/p>\n<\/div><\/div><\/div> Polymer stabilization is mainly based on reducing the oxygen concentration or reducing the number of free radicals or their reactivity to reduce or theoretically eliminate the problem of polyethylene oxidation. In the case of polyethylene (UHMWPE), sterilizing in vacuum or modified atmosphere brings advantages, but oxygen is still present within the material by penetrating through diffusion during the production process; therefore, it is materially impossible to completely eliminate oxygen from polyethylene. <\/p>\n There are many additives on the market that can limit radical reactivity; unfortunately, almost all of them have problems with biocompatibility, which is absolutely necessary for a product to be implanted in the human body.<\/p>\n One biocompatible dopant that has long been studied in the literature for medical polyethylene stabilization is vitamin E<\/strong> (alpha-tocopherol). Vitamin E is present in many vegetables and is an essential vitamin nutrient for metabolism in humans. <\/p>\n Stabilization of UHMWPE by vitamin E was introduced as an alternative method to provide oxidation resistance without sacrificing the mechanical properties of UHMWPE.<\/strong> There are two methods to introduce low concentrations (0.05%-1%) of vitamin E within UHMWPE. The first consists of mixing vitamin E in liquid form to UHMWPE powder before the rod extrusion process and irradiation for cross-linking. The second method, on the other hand, involves diffusing vitamin E within the already consolidated and cross-linked UHMWPE. <\/p>\n The addition of minute concentrations of vitamin E in polyethylene eliminates the problem of oxidation and consequently increases its longevity.<\/strong><\/p>\n<\/div><\/div><\/div> Torre M, Brach Del Prever E, Costa L, Romanini E, Masciocchi M, Manno V. Innovative materials in orthopedics: cross-linked polyethylene.
\nThe Vitamin E is mixed with the polyethylene powder from the outset before the raw material rods are formed.<\/p>\n
\nVITAL-XE\u00ae<\/sup> is used to make joint inserts used in total hip arthroplasty<\/strong>.<\/p>\n
\nVITAL-E\u00ae<\/sup> is used to make non-cross-linked joint inserts of knee prostheses as well as humeral and glenosphere heads for shoulder prostheses<\/strong>.<\/p>\n<\/div>OXIDATION.<\/h4><\/div>
VITAMIN “E” AS A STABILIZING ADDITIVE<\/h4><\/div>
BIBLIOGRAPHY<\/h4><\/div>
\nAnn Ig 2011;23:81-90.<\/p>\n<\/div><\/div><\/div>