Ligament fixation system, implants, devices, and methods of use
Implants, devices, systems, and methods for achieving ligament fixation are disclosed. An implant is disclosed that includes a head member, a breakaway portion, and an anchor member. The anchor member may be coupled to the head member by the breakaway portion. The implant may be designed to fail in fatigue at the breakaway portion. The breakaway portion may thereby extend between a first end of the anchor member and a second end of the head member. The breakaway portion may comprise a circumferential groove. The groove may be configured to concentrate stress forces in situ such that a fatigue failure/fracture occurs at the groove. Insertion instruments for inserting an implant for ligament fixation are also disclosed. Methods of using an implant for achieving ligament fixation are also disclosed.
1. An implant, comprising:
a head member;
a breakaway portion; and
an anchor member coupled to the head member, the anchor member comprising:
a shaft portion with a first and second end;
a proximal coupling portion extending from the first end of the shaft portion of the anchor member to the breakaway portion and comprising an internal drive opening extending into a first end of the proximal coupling portion and toward a second end of the proximal coupling portion coupled to the first end of the shaft portion of the anchor member; and
a distal portion extending from the second end of the shaft portion of the anchor member;
wherein the head member is coupled to the anchor member by the breakaway portion.
2. The implant of claim 1 , wherein the breakaway portion extends between a first end of the anchor member and a second end of the head member.
3. The implant of claim 2 , wherein the breakaway portion comprises a circumferential groove that defines a first diameter that is less than a second diameter defined by a portion of the head member positioned proximate to the breakaway portion and a third diameter defined by a portion of the anchor member positioned proximate to the breakaway portion.
4. The implant of claim 3 , wherein a ratio of the first diameter to the second and/or the first diameter to the third diameter is within a range of 64% to 89%.
5. The implant of claim 1 , wherein the breakaway portion comprises a plurality of openings positioned around a circumference of the breakaway portion that extend in a radial direction from a center axis of the breakaway portion.
6. The implant of claim 1 , wherein the breakaway portion comprises at least one through hole extending through a diameter of the breakaway portion.
7. The implant of claim 1 , wherein the head member comprises:
a shaft portion with a first end and a second end extending from the breakaway portion;
a head portion extending from the first end of the shaft portion; and
a tool engagement opening extending into the head portion toward the second end of the shaft portion.
8. The implant of claim 7 , wherein a portion of the shaft portion comprises external threads, and wherein a portion of the shaft portion at the second end is void of external threads.
9. The implant of claim 1 , wherein at least a portion of the shaft portion of the anchor member comprises external threads, and wherein the proximal coupling portion is void of external threads.
10. The implant of claim 1 , wherein the proximal coupling portion comprises outer planar surfaces circumferentially arranged about the proximal coupling portion.
11. The implant of claim 1 , wherein the distal portion comprises at least one cutting flute.
12. The implant of claim 1 , wherein the distal portion comprises a plurality of circumferentially arranged longitudinally extending flutes.
13. The implant of claim 1 , wherein the head member, the breakaway portion and the anchor member are integral.
14. The implant of claim 1 , comprising a cannulated opening extending through an entire length of the implant extending from a proximal head portion of the head member defining a first end of the implant to a distal end of the anchor member defining a second end of the implant.
15. The implant of claim 1 , wherein the breakaway portion is formed of a bio-resorbable material.
16. A method for inserting an implant, comprising:
obtaining an implant, wherein the implant comprises:
a head member;
a breakaway portion; and
an anchor member coupled to the head member, wherein the head member is coupled to the anchor member by the breakaway portion and comprises an internal drive opening extending into the anchor member adjacent the breakaway portion;
engaging the head member of the implant with an insertion instrument; and
inserting the implant into a patient such that the head member is positioned within a first bone, the anchor member is positioned within a second bone, and the breakaway portion is positioned at least partially within a gap extending between the first and second bones.
17. The method of claim 16 , wherein the first bone is a fibula, the second bone is a tibia, and the gap is a tibiofibular space.
18. The method of claim 16 , wherein the breakaway portion comprises a circumferential groove that defines a first diameter that is less than a second diameter defined by a portion of the head member positioned proximate to the breakaway portion and a third diameter defined by a portion of the anchor member positioned proximate to the breakaway portion, wherein a ratio of the first diameter to the second and/or the first diameter to the third diameter is within a range of 64% to 89%, and wherein the anchor member comprises a distal end portion comprising a plurality of circumferentially arranged longitudinally extending flutes.
19. The implant of claim 1 , wherein the internal drive opening comprises a hexagonal or multi-lobed drive opening.
20. The implant of claim 1 , wherein the breakaway portion comprises at least one channel extending into the implant from an exterior surface thereof.