Method of and prosthesis for restoring ligaments of a joint

Claim 3

A prosthesis for restoring ligaments of a joint, comprising at least one artificial ligament constituted, by at least one pair of strands of thread forming, at one of their ends, a loop and covered by a sheath and by two attachment plates comprising a part in the shape of a bridge and each of which is able to be fixed by screws to one of the bones corresponding to an end of a tunnel traversing the respective bone, the bridge-shaped part of one of the plates being previously engaged in the loop-shaped end of the artificial ligament whereas the bridge-shaped part of the other plate is provided with means capable of ensuring the retention of the free end of the artificial ligament.

Claim 4

A prosthesis for restoring ligaments of a joint, comprising at least one artificial ligament constituted, by at least one pair of strands of thread forming, at one of their ends, a loop and covered by a sheath and by two attachment plates comprising a part in the shape of a bridge and each of which is able to be fixed by screws to one of the bones corresponding to an end of a tunnel traversing the respective bone, the bridge-shaped part of one of the plates being previously engaged in the loop-shaped end of the artificial ligament whereas the bridge-shaped part of the other plate is provided with means capable of ensuring the retention of the free end of the artificial ligament.

Claim 5

The prosthesis according to claim 2, wherein said means capable of ensuring the retention of the free end of the ligament on the bridge-shaped part of the plate intended for anchoring it is constituted by teeth cut out from the part of the plate which surrounds the said bridge-shaped part, these teeth being directed so that they allow sliding of the artificial ligament only in a direction increasing its tension.

Claim 6

The prosthesis according to claim 2, wherein said means capable of ensuring the retention of the free end of the artificial ligament is constituted by an auxiliary plate capable of being pressed against said other plate in order to compress said free end of the artificial ligament.

Claim 7

The prosthesis according to claim 4, wherein the means for pressing the auxiliary plate against said other plate is constituted by screws.

Claim 8

The prosthesis according to claim 4 wherein at least two corresponding parts of the opposed sides of said other and auxiliary plates, located in the region for positioning the free end of the artificial ligament, are provided with ridges.

Claim 9

The prosthesis according to claim 2 wherein the sheath of said artificial ligament is made from a material which does not cause any rejection reaction of the organism receiving the prosthesis.

Claim 10

The prosthesis according to claim 7 wherein said material of the sheath is a synthetic polymer material.

Claim 11

The prosthesis according to claim 2 wherein the strands of said artificial ligament are made from a product of the polyamide family of medical quality.

Claim 12

The prosthesis according to claim 9 wherein the strands of said artificial ligament have a diameter between 1 and 5mm.

Claim 13

The prosthesis according to claim 2, wherein the strands and the sheath of said ligament are connected.

Claim 14

The prosthesis according to claim 11 wherein the strands and the sheath of said ligament are connected by stitching.

Claim 15

The prosthesis according to claim 11 wherein the strands and the sheath of said ligament are connected by means of an adhesive of medical quality.

Claim 16

The prosthesis according to claim 2 wherein, in the case of its application to the restoration of the front ligament of the knee, the strands and the sheath of the artificial ligament are twisted such that the twisting angle of the part of this ligament to be located in the inter-articular gap is comprised between 45* and 90* and preferably equal to 60*, this twisting being fixed and the pitch of the helix being right or left-handed depending on whether the knee is a right or left knee.

Claim 17

The prosthesis according to claim 2 wherein, in the case of its application to the restoration of the rear ligament of the knee, the strands and the sheath of the artificial ligament are twisted such that the twisting angle of the part of this ligament to be located in the inter-articular gap is comprised between 10* and 30*, this twisting being fixed and the pitch of the helix being right or left-handed depending on whether the knee is a right or left knee.

Claim 18

The prosthesis according to claim 2 wherein, in the case of its application to the restoration of both front and rear crossed ligaments of a knee, the two artificial ligaments are integral one with the other at one of their ends forming a common loop and engaged on the bridge-shaped part of one of said plates for attachment to the tibia, one of the strands of this loop intended to constitute the front ligament being twisted such that the twisting angle of its part to be located in the inter-articular gap is comprised between 45* and 90* with a right-handed or left-handed pitch of the helix depending on whether the knee is a right or left knee, whereas the other strand, intended to constitute the rear ligament is twisted such that the twisting angle of its part to be located in the inter-articular gap is comprised between 10* and 30*, with a right or left-handed pitch of the helix depending on whether the knee is a right or left knee.