EP0106501A1 — A synthetic prosthesis for replacement or repair …

Claim 1

Independent Claim 81 words

An article of manufacture for use as a tensile load-bearing tissue prosthesis for connection between tensile force-applying tissues, characterised by, in the portion wherein attachment to the tensile force-applying tissue is required, a plurality of longitudinally adjacent parallel non-adhering strands of microporous polytetrafluoroethylene material having interconnecting voids defined by nodes and fibrils, the thickness of each of said strands being chosen in relation to the microstructure of said material such that tissue ingrowth can occur across substantially the entire strand thickness.

Claim 2

Dependent Claim 81 words

An article of manufacture for use as a tensile load-bearing tissue prosthesis for connection between tensile force-applying tissues, characterised by, in the portion wherein attachment to the tensile force-applying tissue is required, a plurality of longitudinally adjacent parallel non-adhering strands of microporous polytetrafluoroethylene material having interconnecting voids defined by nodes and fibrils, the thickness of each of said strands being chosen in relation to the microstructure of said material such that tissue ingrowth can occur across substantially the entire strand thickness.

Claim 3

Dependent Claim 89 words

An article according to claim 1 characterised in that the characteristic interstitial dimension of the material is greater than about 7 microns and the strand thickness is determined from the following relationships: ln (strand diameter) ≤ 2.28 x 10- 2 (C ID ) - 4.3 6 for CID > 7 microns, ≤ 120 microns ln (strand diameter) ≤ 6.98 x 10- 2 (CID) - 9.94 for CID ≤ 120 microns where: C I D = characteristic interstitial dimension (microns) ln = natural logarithm strand diameter is expressed in inches

Claim 4

Dependent Claim 19 words

An article according to claim 1 or claim 2 characterised in that the porosity is greater than about 30%.

Claim 5

Dependent Claim 24 words

An article according to claim 3 characterised in that the matrix tensile strength of the material is greater than about 20,000 psi (138 MPa)..

Claim 6

Dependent Claim 24 words

An article according to claim 3 characterised in that the matrix tensile strength of said material is greater than about 40,000 psi (276 MPa).

Claim 7

Dependent Claim 52 words

An article according to claim 4 or claim 5 characterised in that the strand thickness is less than 0.08 inch (0.2 cm), the characteristic interstitial dimension is about 74 microns, the matrix tensile strength of the material is about 74,000 psi (511 MPa), and the porosity of the material is about 81%.

Claim 8

Dependent Claim 17 words

An article according to claim 6 characterised in that the strand thickness is about 0.026 inch (0.066cm).

Claim 9

Dependent Claim 31 words

An article according to claim 1 further characterised by means for distributing the tensile load among the individual strands when the prosthesis 15 is intended to be passed over a radius.

Claim 10

Dependent Claim 26 words

An article according to claim 8 characterised in that said load distributing means comprises said plurality of strands being twisted about the tensile 20 load direction.

Claim 11

Dependent Claim 16 words

An article according to claim 9 characterised in that the angle of twist is about 180°.

Claim 12

Dependent Claim 20 words

ll. An article according to claim 8 characterised in that said load distributing means comprises the strands being loosely braided.

Claim 13

Dependent Claim 75 words

An article according to claim 1 characterised in that said parallel strands are formed from a plurality of elongated concentric loops, said loops being formed from a continuous filament of said material, wherein said strands are gathered at least at one elongate area end to form at least one eyelet for initially attaching the article to tensile force-applying bone tissue, and wherein the article further includes means for restraining the gathered loop ends against ungathering.

Claim 14

Dependent Claim 19 words

An article according to claim 12 characterised in that two opposing eyelets are formed by the gathered loop ends.

Claim 15

Dependent Claim 28 words

An article according to claim 12 or 13 characterised in that each of said eyelets are the strand portions adhered to one another to provide uniform load sharing.

Claim 16

Independent Claim 128 words

A method for making a tensile load-bearing tissue prosthesis having a plurality of parallel longitudinally adjacent strands positioned between and connected to at least one eyelet for initially attaching the prosthesis to tensile force-applying bone tissue, the method characterised by the steps of: a. arranging and spacing a plurality of pin means to define an elongate area in accordance with the desired size of the prosthesis; b. forming a plurality of elongate loops around the plurality of pin means from a continuous filament of the desired strand material until the desired number of parallel strands is obtained; and c. gathering the loop ends at one end of the elongate area to form the eyelet, said gathering step including the step of securing the gathered loop ends against ungathering.

Claim 17

Independent Claim 128 words

A method for making a tensile load-bearing tissue prosthesis having a plurality of parallel longitudinally adjacent strands positioned between and connected to at least one eyelet for initially attaching the prosthesis to tensile force-applying bone tissue, the method characterised by the steps of: a. arranging and spacing a plurality of pin means to define an elongate area in accordance with the desired size of the prosthesis; b. forming a plurality of elongate loops around the plurality of pin means from a continuous filament of the desired strand material until the desired number of parallel strands is obtained; and c. gathering the loop ends at one end of the elongate area to form the eyelet, said gathering step including the step of securing the gathered loop ends against ungathering.

Claim 18

Dependent Claim 43 words

A method according to claim 15 characterised by the additional steps of imparting a twist to the loop strands about the longitudinal axis of the prosthesis to provide more even load distribution when the prosthesis is intended to be passed over a radius.

Claim 19

Dependent Claim 16 words

A method according to claim 16 charcterised in that the loop strands are twisted about 180°.

Claim 20

Dependent Claim 33 words

A method according to claim 15 characterised by the further step of loosely braiding the loop-strands to provide more even load distribution when the prosthesis is intended to be passed over a radius.

Claim 21

Dependent Claim 37 words

A method according to claim 15 characterised in that the securing against ungathering step includes the step of compressing and heating the gathered ends at a temperature and for a time sufficient to coalesce the loop ends.

Claim 22

Dependent Claim 49 words

A method according to claim 15 or claim 19 characterised in that the securing against ungathering step also includes the preliminary step of wrapping strands of a high strength material about the gathered ends in a direction tangential to the prosthesis axis at a position adjacent to the eyelet.

Claim 23

Dependent Claim 27 words

A method according to claim 9 characterised in that the high strength material is expanded PTFE having a matrix tensile strength of about 70,000 psi (483 MPa).

Claim 24

Dependent Claim 26 words

A method according to claim 19 characterised in that the gathered ends are compressed and heated in a die having the desired eyelet shape and dimensions.

A synthetic prosthesis for replacement or repair of ligaments or tendons

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