System and method for attaching soft tissue to bone
Disclosed herein are methods and devices for securing soft tissue to a rigid material such as bone. A bone anchor is described that comprises an anchor body with expandable tines and a spreader that expands the tines into bone. Also disclosed is a bone anchor that comprises a base and a top such that suture material may be attached to apertures in the anchor top or else compressed between surfaces on the base and top to secure the suture to the anchor. Also described is an inserter that can be used to insert the bone anchor into bone and move the spreader relative to the anchor body attach suture material. Also described is an inserter that can be used to insert the bone anchor into bone and move the anchor top relative to the anchor body or anchor base to attach to or clamp suture material there between. Methods are described that allow use of single bone anchor to secure tissue to bone or also to use more than one bone anchor to provide multiple lengths of suture material to compress a large area of soft tissue against bone.
1. An anchor for attaching tissue to bone, comprising:
an anchor body comprising an axial bore and a plurality of bone-engaging tines extending in a distal direction from the anchor body;
a spreader comprising a proximal base comprising at least one axial bore positioned internally therewithin, and a first channel opening to the at least one spreader axial bore, wherein the first channel is elongated in a direction perpendicular to a central axis of the at least one spreader axial bore; and
a first suture extending through the at least one spreader axial bore and the first channel and forming a loop distal to a distal-most end of the spreader,
wherein the proximal base of the spreader is positioned between the bone-engaging tines, and
wherein a distal portion of the spreader is configured to expand the tines outward upon proximal movement of the spreader relative to the anchor body.
2. The anchor of claim 1 , wherein the spreader further comprises a second channel opening to the axial bore.
3. The anchor of claim 2 , further comprising a second suture extending through the at least one spreader axial bore and the second channel.
4. The anchor of claim 1 , wherein the proximal base is cylindrically shaped.
5. The anchor of claim 4 , wherein the distal portion is conically shaped and comprises a distally located base, wherein the distally located base has a larger diameter than the cylindrically shaped proximal base.
6. The anchor of claim 1 , wherein the anchor body is cylindrical in shape.
7. The anchor of claim 1 , wherein the bone-engaging tines comprise teeth adapted to resist removal of the anchor from the bone.
8. The anchor of claim 1 , wherein the bone-engaging tines extend from a distal end of the anchor body.
9. The anchor of claim 1 , wherein the at least one spreader axial bore is configured to couple to an inserter tool.
10. The anchor of claim 1 , wherein the spreader comprises at least a portion that tapers proximally.
11. The anchor of claim 1 , wherein the anchor body comprises a groove on an inside surface of at least one bone-engaging tine.
12. The anchor of claim 11 , wherein the spreader comprises a ridge configured to engage with the groove.
13. The anchor of claim 1 , wherein the anchor body has a substantially constant diameter.