초록

A bone cement comprising an acrylic polymer mixture which is formulated to have a relatively high viscosity for a relatively long window, due to distributions of molecular weights and/or sizes of acrylic beads.

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1. A cement kit, comprising: (a) a liquid component including a monomer; and(b) a powder component including polymeric beads,in which the distribution of the molecular weight of the powder component is non-normal so that it is skewed to a higher molecular weight by introduction of higher molecular w

1. A cement kit, comprising: (a) a liquid component including a monomer; and(b) a powder component including polymeric beads,in which the distribution of the molecular weight of the powder component is non-normal so that it is skewed to a higher molecular weight by introduction of higher molecular weight beads, the non-normal distribution of the molecular weight of the powder component causing (a) an increase in the immediate viscosity of a mixture of the liquid and powder components and compared with a cement having a substantially normal distribution, and (b) an increase in the length of the working window period in which the viscosity of the cement does not exceed 500 Pa.s compared with a cement having a substantially normal distribution. 2. A cement kit according to claim 1, in which the higher molecular weight beads have an average molecular weight of at least a factor of 2 of an average molecular weight of the polymeric beads. 3. A cement kit according to claim 2, in which the factor is at least 3. 4. A cement kit according to claim 3, in which the factor is at least 5. 5. A cement kit according to claim 1, further comprising a relatively small component including smaller sized beads. 6. A cement kit according to claim 1, wherein the polymeric beads comprise PMMA. 7. A cement kit according to claim 1, wherein the higher molecular weight beads have a molecular weight of about 600,000 Dalton to about 5,000,000 Dalton. 8. A cement kit according to claim 1, wherein the higher molecular weight beads have a molecular weight of about 3,000,000 to 4,000,000 Dalton. 9. A cement kit according to claim 1, wherein the higher molecular weight beads have a molecular weight of about 3,500,000 to 3,900,000 Dalton. 10. A cement kit according to claim 1, wherein an average molecular weight of the polymeric beads is about 130,000 to 170,000 Dalton. 11. A cement kit according to claim 1, wherein an average molecular weight of the polymeric beads is about 375,000 Dalton.