Bone cement and method for making it

Claim 2

Bone cement composed of a mixture of particulate polyacrylate and/or polymethacrylate prepolymers, monomeric acrylic and/or methacrylic acid derivatives, a polymerisation catalyst and, optionally, a stabiliser and an activator, wherein the entire specific surface of the prepolymer particles in the bone cement is enlarged by pretreating the particles mechanically and/or chemically before mixing them.

Claim 3

Bone cement composed of a mixture of polyacrylate and/or polymethacrylate prepolymers, monomeric acrylic and/or methacrylic acid derivatives, a polymerisation catalyst and, optionally, a stabiliser and an activator, wherein the prepolymer is a mixture of 5 to 50% by weight of polyacrylate and/or polymethacrylate fibres with a length of over 2 mm and up to 40 mm and a thickness of 50 to 750 pm, and 50 to 95% by weight of polyacrylate and/or polymethacrylate bead polymers consisting of polymer bead particles.

Claim 4

Bone cement composed of a mixture of polyacrylate and/or polymethacrylate prepolymers, monomeric acrylic and/or methacrylic acid derivatives, a polymerisation catalyst and, optionally, a stabiliser and an activator, wherein the prepolymer is a mixture of 5 to 50% by weight of polyacrylate and/or polymethacrylate fibres with a length of over 2 mm and up to 40 mm and a thickness of 50 to 750 pm, and 50 to 95% by weight of polyacrylate and/or polymethacrylate bead polymers consisting of polymer bead particles.

Claim 5

The bone cement according to claim 2, characterised in that the polyacrylate and/or polymethacrylate fibres are employed in the form of monofils or woven to textiles.

Claim 6

The bone cement according to claim 2 or 3, characterised in that the surface of the polymer bead particles and/or the polyacrylate and/or polymethacrylate fibres are pretreated chemically or mechanically.

Claim 7

The bone cement according to any of claims 1 to 4, characterised in that the bead-shaped particles have been partially or fully crushed to polymorphous fragments by prior mechanical treatment.

Claim 8

The bone cement according to any of claims 2 to 5, characterised in that the morphological structure at the surface of the bead-shaped particles and/or the fibres has been changed by prior chemical treatment.

Claim 9

The bone cement according to any of claims 1 to 6, characterised in that the particle size is 1 to 140 pm, preferably 5 to 60 um, more preferably 10 to 45 pm.

Claim 10

The bone cement according to claim 7, characterised in that the particles are as uniform as possible in size, preferably about 30 to 40 pm.

Claim 11

The bone cement according to any of claims 1 and 8, characterised in that it also contains a pharmaceutical agent such as gentamycin and/or a "bone morphogenetic protein".

Claim 12

The bone cement according to claims 1 to 9, characterised in that it also contains 5 to 35% by weight, based on the prepolymer and monomer mass, of absorbable tricalcium phosphate having a particle size ranging from 50 to 300 pm and an available pore volume of less than 0.1 ml/g.

Claim 13

A process for preparing the bone cement according to claim 1, characterised in that polyacrylate and/or polymethacrylate prepolymers composed of polymer bead particles are broken down by mechanical and/or chemical treatment to yield polymorphous particles having a larger relative surface, and/or in that their surface is roughened, whereupon the monomeric acrylic and/or methacrylic acid derivatives are added, and in that the mass is homogenously mixed with a polymerisation catalyst and, optionally, with a stabiliser and an activator.

Claim 14

A process for preparing the bone cement according to claim 2, characterised in that 5 to 50% by weight of polyacrylate and/or polymethacrylate fibres having a length of over 2 mm and up to 15 mm and a thickness of 50 to 750 pm and in the form of monofils or woven to textiles are added together with 50 to 95% by weight of polyacrylate and/or polymethacrylate bead polymers consisting of polymer bead particles having a size of 1 to 140 pm and/or their chemically and/ or mechanically treated derivatives to the monomeric acrylic and/or methacrylic acid derivatives and in that the mass is homogenously mixed with a polymerisation catalyst and, optionally, a stabiliser and an activator.

Claim 15

The process according to claim 11 or 12, characterised in that the particles are first sifted out to a fraction of uniform size.

Claim 16

The use of polyacrylate and/or polymethacrylate in the form of fibres having a length of over 2 mm and up to 15 mm and a thickness of 50 to 750 µm in the form of monofils or woven to textiles in polyacrylate-based bone cement.

Claim 17

The use of polyacrylate and/or polymethacrylate in the form of fibres having a length of over 2 mm and up to 15 mm and a thickness of 50 to 750 µm in the form of monofils or woven to textiles in polyacrylate-based bone cement.

Claim 18

The use of the bone cement according to claims 1 to 10 in the treatment of bone defects.