Bioabsorbable interference bone fixation screw

Claim 2

An interference bone fixation screw as recited in claim 1 wherein said drive recess means further includes a cylindrical cavity disposed concentrically in said body and said force receiving surfaces are positioned radially around said cavity.

Claim 3

An interference bone fixation screw as recited in claim 2 further including a longitudinal guide bore disposed concentrically in said body to extend longitudinally from said cavity to said distal end.

Claim 4

An interference bone fixation screw as recited in claim 3 further including an end wall disposed in said body perpendicular to said longitudinal axis and said drive recess means extends longitudinally in said body from said proximal end to said end wall.

Claim 5

An interference bone fixation screw as recited in any preceding claim wherein said thread means includes a helical screw thread.

Claim 6

An interference bone fixation screw as recited in claim 5 wherein said helical screw thread defines a major diameter and said body defines a minor diameter along said helical screw thread.

Claim 7

An interference bone fixation screw as recited in claim 6 wherein said minor diameter is approximately 55% to 75% said major diameter.

Claim 8

An interference bone fixation screw as recited in claim 5, 6 or 7 wherein said helical screw thread is of uniform pitch.

Claim 9

An interference bone fixation screw as recited in claim 5, 6, 7 or 8 wherein said screw thread further includes a spiral screw thread extending longitudinally from said helical screw thread to said distal end.

Claim 10

An interference bone fixation screw as recited in claim 9 wherein said spiral screw thread has a pitch and said spiral screw thread pitch is greater than said helical screw thread pitch.

Claim 11

An interference bone fixation screw as recited in any preceding claim wherein said interference bone fixation screw is made entirely of Poly (L-Lactide).

Claim 12

An interference bone fixation screw to be rotated by a driver comprising a cylindrical body having a proximal end, a distal end and a longitudinal axis; a screw thread disposed on said body to extend longitudinally therealong; and drive recess means disposed in said proximal end of said body including a plurality of equally spaced lobe openings having outer ends disposed a first radial distance from said longitudinal axis and inner ends disposed a second radial distance from said longitudinal axis less than said first radial distance, said lobe openings tapering inwardly from said outer ends to said inner ends to define planar force receiving walls between said outer ends and said inner ends for receiving concentric forces from the driver, said interference bone fixation screw being made entirely of bioabsorbable material.

Claim 13

An interference bone fixation screw as recited in claim 12 wherein said drive recess means includes a cylindrical cavity disposed concentrically in said proximal end of said body and said inner ends of said lobe openings communicate with said cylindrical cavity.

Claim 14

An interference bone fixation screw as recited in claim 13 wherein said cylindrical cavity is defined by a plurality of inner arcuate walls positioned, respectively, between said inner ends of said lobe openings.

Claim 15

An interference bone fixation screw as recited in claim 14 wherein said outer ends of said lobe openings are defined by outer arcuate walls joining said force receiving walls.

Claim 16

An interference bone fixation screw as recited in claim 15 wherein said outer arcuate walls define arcs of a circle, said inner arcuate walls define arcs of a circle and said arcs defined by said inner arcuate walls are longer than said arcs defined by said outer arcuate walls.

Claim 17

An interference bone fixation screw as recited in claim 16 wherein said screw thread defines a major diameter and said body defines a minor diameter extending longitudinally from said proximal end toward said distal end.

Claim 18

An interference bone fixation screw as recited in claim 17 wherein the diameter of said circle defined by said outer arcuate walls is approximately 78% said minor diameter.

Claim 19

An interference bone fixation screw as recited in claim 17 or 18 wherein the diameter of said circle defined by said inner arcuate walls is approximately 47% said minor diameter.

Claim 20

An interference bone fixation screw as recited in any one of claims 15-19 wherein said arcs defined by said outer arcuate walls subtend approximately 50°.

Claim 21

An interference bone fixation screw as recited in any preceding claim wherein there are three of said lobe openings.

Claim 22

An interference bone fixation screw to be rotated by a driver comprising a cylindrical body having a proximal end, a distal end and a longitudinal axis; a screw thread disposed on said body to extend longitudinally from said proximal end to said distal end; and a drive recess in said proximal end of said body for matingly receiving the driver including a plurality of equally spaced lobe chambers, each of said lobe chambers being defined by a pair of spaced side walls extending radially outwardly with respect to said longitudinal axis for receiving rotational forces from the driver applied perpendicular to said side walls, said interference bone fixation screw being made of bioabsorbable material in its entirety.

Claim 23

An interference bone fixation screw as recited in claim 22 wherein said drive recess extends longitudinally in said body from said proximal end toward said distal end.

Claim 24

An interference bone fixation screw as recited in claim 23 wherein the cross-section of said drive recess is constant through a substantial portion of said longitudinal length of said drive recess

Claim 25

An interference bone fixation screw as recited in claim 24 wherein the longitudinal length of said drive recess is approximately 48% to 95% the length of said body from said proximal end to said distal end.

Claim 26

An interference bone fixation screw in combination with a driver for rotating the screw comprising a cylindrical body having a proximal end, and a distal end and a longitudinal axis; thread means disposed on said body for engaging bone; drive recess means in said proximal end of said body for matingly receiving said driver, said drive recess means including a cylindrical cavity disposed concentrically in said body and a plurality of lobe openings disposed around said cavity in communication therewith, each of said lobe openings being defined by force receiving walls extending radially outwardly from said cavity, said interference bone fixation screw being fabricated entirely of bioabsorbable material; and a driver including shaft means for being received in said cavity and a plurality of lobe means having force transmitting walls extending radially outwardly from said shaft means for applying forces to said force receiving walls when said driver is rotated.

Claim 27

An interference bone fixation screw and driver as recited in claim 26 including an end wall disposed in said body perpendicular to said longitudinal axis and said drive recess means extends longitudinally from said proximal end to said end wall.

Claim 28

An interference bone fixation screw and driver as recited in claim 27 wherein said shaft means includes a longitudinal axis and further including an end surface on said driver disposed perpendicular to said longitudinal axis of said shaft means for engaging said end wall.

Claim 29

An interference bone fixation screw and driver as recited in claim 28 including a guide bore in said body extending longitudinally from said drive recess to said distal end and a guide passage in said shaft means alignable with said guide bore when said shaft means is received in said cavity.