Fixation pin for small-bone fragments

Claim 2

An elongate compression wire for fixating a fragment of a fractured bone to remainder structure of the same fractured bone in an osteosynthesis procedure, said wire having a shoulder between proximal and distal ends, said wire having a central axis and comprising a smooth-walled cylindrical shank portion extending from said shoulder to said proximal end and adapted for selective chuck engagement to a rotary power tool, said shank portion having a diameter in the range 1.5 to 3.0-mm and having a self-tapping threaded portion of lesser diameter than that of said shank, and said threaded portion having an advance per turn in the range 0.2 to 0.5-mm, wherein said threaded portion extends distally of said shoulder, whereby said wire may be power-driven for self-tapping threading advance through the bone fragment and into implantation in remainder bone structure to an extent of shoulder contact with cortex tissue of the bone fragment and bone-fragment retention against remainder bone structure.

Claim 3

A compression wire according to claim 1, wherein the diameter of said threaded portion is in the range of approximately 70 to 80 percent of the diameter of said shank portion.

Claim 4

A compression wire according to claim 1, wherein said shoulder is in substantially a radial plane normal to said axis.

Claim 5

A compression wire according to claim 1, wherein said shoulder is a frusto-conical reduction from said shank portion to said threaded portion.

Claim 6

A compression wire according to claim 4, in which said frusto-conical reduction has a half angle of convergence of about 30 degrees.

Claim 7

A compression wire according to claim 1, in which the wire is of a material that may be cut by a suitable nipper tool after implantation of said threaded portion.

Claim 8

A compression wire according to claim 6, in which said material is stainless steel.

Claim 9

A compression wire according to claim 1, in which said threaded portion has a cutting distal-tip end which is characterized by at least three angularly spaced ground surfaces which converge distally from distal threads of said threaded portion.

Claim 10

A compression wire according to claim 8, in which said angularly spaced surfaces are flat, adjacent flat surfaces intersecting to define bone-cutting edges which converge to a distal point on said central axis.

Claim 11

A compression wire according to claim 9, in which the number of said flat surfaces is three.

Claim 12

A compression wire according to claim 9, in which each of said surfaces converges with respect to said central axis at an angle in the range 12° to 18°.

Claim 13

A compression wire according to claim 9, in which each of said surfaces converges with respect to said central axis at an angle in the range 15° to 16°.

Claim 14

An elongate compression wire for fixating a fragment of a fractured bone to remainder structure of the same fractured bone or for fixating a bone graft or supporting plate to existing bone structure, said wire having a shoulder between proximal and distal ends, said wire having a central axis and comprising a smooth-walled cylindrical shank portion extending from said shoulder to said proximal end and adapted for selectively chucked engagement to a rotary power tool, said shank portion having a diameter in the range 1.5 to 3.0-mm and having a self-tapping threaded portion of a diameter in the range 1.2 to 2.2-mm, wherein the threaded portion extends distally from said shoulder and has a bone-cutting distal-tip end, and wherein the threaded portion has an advance per turn that is about one fifth of the thread diameter.

Claim 15

An elongate compression wire for fixating a fragment of a fractured bone to remainder structure of the same fractured bone or for fixating a bone graft or supporting plate to existing bone structure, said wire having a shoulder between proximal and distal ends, said wire having a central axis and comprising a smooth-walled cylindrical shank portion extending from said shoulder to said proximal end and adapted for selectively chucked engagement to a rotary power tool, said shank portion having a diameter in the range 1.5 to 3.0-mm and having a self-tapping threaded portion of a diameter in the range 1.2 to 2.2-mm, wherein the threaded portion extends distally from said shoulder and has a bone-cutting distal-tip end, and wherein the threaded portion has an advance per turn that is about one fifth of the thread diameter.

Claim 16

A compression wire according to claim 13, in which the thread diameter is about 1.2-mm, and the advance per turn is about 0.25-mm.

Claim 17

A compression wire according to claim 13, in which the thread diameter is about 1.6-mm, and the advance per turn is about 0.35-mm.

Claim 18

A compression wire according to claim 13, in which the thread diameter is about 2.2-mm, and the advance per turn is about 0.45-mm.

Claim 19

A kit comprising an elongate compression wire for fixating a fragment of a fractured bone to remainder structure of the same fractured bone or for fixating a bone graft or supporting plate to existing bone structure, said wire having a shoulder between proximal and distal ends, said wire having a central axis and comprising a smooth-walled cylindrical shank portion extending from said shoulder to said proximal end and adapted for selectively chucked engagement to a rotary power tool, said shank portion having a diameter in the range 1.5 to 3.0-mm and having a self-tapping threaded portion of a diameter in the range 1.2 to 2.2-mm wherein the threaded portion extends distally from said shoulder and has a bone-cutting distal-tip end, and wherein the threaded portion has an advance per turn that is about one fifth of the thread diameter; and a flat washer having a bore of diameter which exceeds the diameter of the threaded portion and which is less than the diameter of the shank portion, said washer having like chamfers at the respective ends of the bore, and the washer having an outer diameter which exceeds the diameter of the shank portion.

Claim 20

A kit comprising an elongate compression wire for fixating a fragment of a fractured bone to remainder structure of the same fractured bone or for fixating a bone graft or supporting plate to existing bone structure, said wire having a shoulder between proximal and distal ends, said wire having a central axis and comprising a smooth-walled cylindrical shank portion extending from said shoulder to said proximal end and adapted for selectively chucked engagement to a rotary power tool, said shank portion having a diameter in the range 1.5 to 3.0-mm and having a self-tapping threaded portion of a diameter in the range 1.2 to 2.2-mm wherein the threaded portion extends distally from said shoulder and has a bone-cutting distal-tip end, and wherein the threaded portion has an advance per turn that is about one fifth of the thread diameter; and a flat washer having a bore of diameter which exceeds the diameter of the threaded portion and which is less than the diameter of the shank portion, said washer having like chamfers at the respective ends of the bore, and the washer having an outer diameter which exceeds the diameter of the shank portion.

Claim 21

A kit according to claim 17, in which the shoulder of said compression wire is a frusto-conical transition from the smooth shank diameter to the diameter of the threaded portion, said frusto-conical transition having a first slope with respect to the central axis, and each of the chamfers having a second slope with respect to the washer-bore axis, said first slope being at a lesser angle than said second slope.

Claim 22

A kit according to claim 18, in which said first slope is in the range of 12 to 18 degrees, and in which said second slope is in the range of 40 to 50 degrees.

Claim 23

A kit according to claim 17, in which said compression wire is one of a plurality of compression wires of equal overall length, and in which the longitudinal position of said shoulder of one of said wires is different from the longitudinal position of said shoulder of another of said wires, whereby the longitudinal extent of the threaded portion of said one wire is different from the longitudinal extent of the threaded portion of said other wire.

Claim 24

A kit according to claim 17, in which said compression wire is one of a plurality of compression wires of equal overall length, and in which the longitudinal extent of the threaded portions of different compression wires of said plurality differ by successive integer multiples of a single increment of length.

Claim 25

A kit according to claim 21, in which the diameter of said threaded portion is in the range 1.2 to 1.6-mm, and in which the single increment of length is 2-mm.

Claim 26

A kit according to claim 21, in which the diameter of said threaded portion is in the range of 2.0 to 2.5-mm, and in which the single increment of length is 5-mm.

Claim 27

An elongate compression wire for fixating a fragment of a fractured bone to remainder structure of the same fractured bone in an osteosynthesis procedure, said wire having a shoulder between proximal and distal ends, said wire having a central axis and comprising a smooth-walled cylindrical shank portion extending from said shoulder to said proximal end and adapted for selective chuck engagement to a rotary power tool, said wire having a self-tapping threaded portion of lesser diameter than that of said shank, wherein said threaded portion extends distally of said shoulder and is characterized by a thread advance per turn in the range 0.2 to 0.5-mm, whereby said wire may be power-driven for self-tapping threading advance through the bone fragment and into implantation in remainder bone structure to an extent of shoulder contact with cortex tissue of the bone fragment and bone-fragment retention against remainder bone structure.

Claim 28

An elongate compression wire for fixating a fragment of a fractured bone to remainder structure of the same fractured bone in an osteosynthesis procedure, said wire having a shoulder between proximal and distal ends, said wire having a central axis and comprising a smooth-walled cylindrical shank portion extending from said shoulder to said proximal end and adapted for selective chuck engagement to a rotary power tool, said wire having a self-tapping threaded portion of lesser diameter than that of said shank, wherein said threaded portion extends distally of said shoulder and is characterized by a thread advance per turn in the range 0.2 to 0.5-mm, whereby said wire may be power-driven for self-tapping threading advance through the bone fragment and into implantation in remainder bone structure to an extent of shoulder contact with cortex tissue of the bone fragment and bone-fragment retention against remainder bone structure.

Claim 29

A compression wire according to claim 24, wherein the diameter of said threaded portion is in the range of approximately 70 to 80 percent of the diameter of said Shank portion.

Claim 30

A compression wire according to claim 24, wherein said shoulder is in substantially a radial plane normal to said axis.

Claim 31

A compression wire according to claim 24, wherein said shoulder is a frusto-conical reduction from said shank portion to said threaded portion.

Claim 32

A compression wire according to claim 27, in which said frusto-conical reduction has a half angle of convergence of about 30 degrees.

Claim 33

A compression wire according to claim 24, in which the wire is of a material that may be cut by a suitable nipper tool after implantation of said threaded portion.

Claim 34

A compression wire according to claim 29, in which said material is stainless steel.

Claim 35

A compression wire according to claim 24, in which said threaded portion has a cutting distal-tip end which is characterized by at least three angularly spaced ground surfaces which converge distally from distal threads of said threaded portion.

Claim 36

A compression wire according to claim 31, in which said angularly spaced surfaces are flat, adjacent flat surfaces intersecting to define bone-cutting edges which converge to a distal point on said central axis.

Claim 37

A compression wire according to claim 32, in which the number of said flat surfaces is three.

Claim 38

A compression wire according to claim 32, in which each of said surfaces converges with respect to said central axis at an angle in the range 12° to 18°.

Claim 39

A compression wire according to claim 31, in which each of said surfaces converges with respect to said central axis at an angle in the range 15° to 16°.