Expandable bone anchor and method of anchoring a suture to a bone

A kit for securing a suture in a borehole in a bone, comprising:

• a bone anchor including an expandable body having a distal tip for insertion distally in a borehole, and an open proximal end, the body defining an expansion chamber that communicates proximally with the open end and defines a seat, the body further defining a means for carrying a suture therein;
• an expansion slot extending through the body that allows a proximal portion of the body to expand in response to outwardly directed force applied to the body from within the expansion chamber;
• and
• an expansion instrument that is insertable through the proximal end into the expansion chamber.

A kit for securing a suture in a bone borehole, the anchor comprising:

• a bone anchor including an expandable anchor body having a solid distal tip and an open proximal end, the body tapering in the direction of the distal tip and defining an expansion chamber that communicates proximally with the open end and distally with a guide seat, the expansion chamber having an oblong ovoid cross-section with walls that form a pair of opposing arcuate guide surfaces;
• a pair of opposing expansion slots extending through the walls and the proximal end, and separating the opposing arcuate guide surfaces along a portion of the body such that a proximal portion of the body is expandable;
• a retention member on the exterior of the body that inhibits extraction of the anchor from the borehole after the anchor has been expanded;
• an elongated expansion instrument that is insertable into the expansion chamber, the instrument having an oblong ovoid shape with a greater and lesser diameter that are respectively less than a greater and lesser diameter of the chamber;
• and
• a rotary guide member on the instrument that cooperates with the guide seat of the chamber to seat the instrument in the chamber and provide an axis of rotation of the instrument relative to the body.

A method of anchoring a suture to a bone, comprising:

• drilling a borehole in a bone;
• inserting a bone anchor, carrying a portion of a suture, into the borehole with the distal tip positioned distally in the hole;
• and
• placing an expansion instrument into the expansion chamber through the proximal end of the anchor and expanding the proximal end of the bone anchor by rotating the instrument.