Low viscosity bone cement
First Claim
1. An acrylic bone cement composition comprising:
- a liquid monomer component and a polymer powder component in the form of beads wherein the liquid component to powder component ratio is 1 to 2 (volume weight) there the liquid component is measured in milliliters and the powder component is measured in grams and wherein said liquid monomer component is comprised of methylmethacrylate monomer and said polymer powder component is comprised at least 80% by weight of polymethylmethacrylate polymer powder in which at least 85-95% by weight of the polymethylmethacrylate polymer powder beads are regular beads which fall through a #40 mesh (425 micron openings) screen and a #100 mesh screen (150 micron openings) and which have a maximum average size of about 25 microns and a minimum average size of about 13 microns, and about 5-15% by weight of polymethylmethacrylate polymer powder beads which fall through a #40 mesh (425 micron openings) screen, but not through a #100 mesh screen, (150 micron openings) and are subsequently milled to roughen and break up the surface of the bead, and whereby when the liquid monomer component is mixed with said polymer powder component, the resulting cement has a viscosity of less than 1500 poise at approximately 20 degrees C. (68 degrees F.) for at least six minutes after the components are initially mixed, and such that the resulting bone cement becomes completely hard in not more than ten to eleven minutes from the time the components were initially mixed.
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Accused Products
Abstract
An acrylic cement-like substance which permits seating and securing of a prosthesis into living bone which comprises a mixture of a liquid monomer component and a polymer powder component such that upon mixing the two components, a cement which maintains a low viscosity for a longer period of time is formed. The low viscosity bone cement is intended for syringe or injector gun use only as it is to be used before the cement becomes doughy. This low viscosity bone cement has a viscosity of approximately 20 degrees C. (68 degrees F.), of less than 1500 poise, and preferably less than 1000 poise up to the sixth or seventh minute after the two components are mixed. The cement used in the lower viscosity state is more capable of penetrating the trabeculae of bones when used to secure a prosthesis, than when the cement is applied in the doughy state.
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Citations
21 Claims
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1. An acrylic bone cement composition comprising:
- a liquid monomer component and a polymer powder component in the form of beads wherein the liquid component to powder component ratio is 1 to 2 (volume weight) there the liquid component is measured in milliliters and the powder component is measured in grams and wherein said liquid monomer component is comprised of methylmethacrylate monomer and said polymer powder component is comprised at least 80% by weight of polymethylmethacrylate polymer powder in which at least 85-95% by weight of the polymethylmethacrylate polymer powder beads are regular beads which fall through a #40 mesh (425 micron openings) screen and a #100 mesh screen (150 micron openings) and which have a maximum average size of about 25 microns and a minimum average size of about 13 microns, and about 5-15% by weight of polymethylmethacrylate polymer powder beads which fall through a #40 mesh (425 micron openings) screen, but not through a #100 mesh screen, (150 micron openings) and are subsequently milled to roughen and break up the surface of the bead, and whereby when the liquid monomer component is mixed with said polymer powder component, the resulting cement has a viscosity of less than 1500 poise at approximately 20 degrees C. (68 degrees F.) for at least six minutes after the components are initially mixed, and such that the resulting bone cement becomes completely hard in not more than ten to eleven minutes from the time the components were initially mixed.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 21)
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11. An acyrlic bone cement composition comprising:
- a liquid monomer component and a polymer powder component in the form of beads wherein the liquid component to powder component ratio is 1 to 2 (volume/weight) where the liquid component is measured in milliliters and the powder component is measured in grams and wherein said liquid monomer component is comprised of methylmethacrylate monomer and said polymer powder component is comprised at least 80% by weight of poly methylmethacrylate polymer powder in which at least 85-95% by weight of the poly methylmethacrylate polymer powder beads are regular beads which fall through a #40 mesh (425 micron openings) screen and a #100 mesh screen (150 micron openings) and which have a maximum average size of about 25 microns and a minimum average size of about 13 microns, and about 5-15% by weight of poly methylmethacrylate polymer powder beads which are less than 13 to 17 microns in diameter, and whereby when the liquid monomer component is mixed with said polymer powder component, the resulting cement has a viscosity of less than 1500 poise at approximately 20 degrees C. (68 degrees F.) for at least six minutes after the components are initially mixed, and such that the resulting bone cement becomes completely hard in not more than ten to eleven minutes from the time the components were initially mixed.
- View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
Specification