Femoral fixation
Various methods and devices are provided for a graft fixation device for fixing a graft member within a bone tunnel. In one embodiment, a graft fixation device is provided having a radially expandable sheath adapted to be disposed within a bone tunnel, and a sheath expander adapted to be received within the radially expandable sheath to expand the sheath and thereby anchor a graft between the sheath and the bone tunnel. In an exemplary embodiment, the graft fixation device is particularly useful to affix a graft within a femoral tunnel.
1. A graft fixation device for fixing a graft member within a bone tunnel, the device comprising:
a radially expandable sheath having proximal and distal ends with first, second, and third sidewalls extending therebetween and defining a central lumen, the first, second, and third sidewalls being separated by longitudinal slots extending between proximal and distal attachment points, wherein the first sidewall has a substantially concave outer surface adapted to seat a graft member, and wherein the first and second sidewalls include surface features formed thereon and extending in an opposite direction to surface features formed on the third sidewall, the sheath having a substantially triangular cross-sectional shape; and
a sheath expander adapted to be disposed in the central lumen of the radially expandable sheath and configured to flex the three sidewalls to radially expand the sheath so as to fix the graft member within a bone tunnel.
2. The graft fixation device of claim 1 , wherein the second sidewall has a substantially concave outer surface adapted to seat a graft member, and the third sidewall has a substantially convex outer surface adapted to engage a bone tunnel.
3. The graft fixation device of claim 2 , wherein the first and second sidewalls include surface features formed within the concave outer surface thereof and adapted to engage the graft member, and the third sidewall includes surface features formed on the convex outer surface thereof and adapted to engage bone within the bone tunnel.
4. The graft fixation device of claim 3 , wherein the surface features on the first, second, and third sidewalls extend in a radial direction.
5. The graft fixation device of claim 1 , wherein a proximal-most end of the radially expandable sheath is angled relative to a longitudinal axis of the radially expandable sheath.
6. The graft fixation device of claim 1 , wherein the sheath expander and a distal-most end of the radially expandable sheath each include a lumen extending longitudinally therethrough for receiving a guide wire.
7. The graft fixation device of claim 1 , wherein the radially expandable sheath includes a stop member formed on a proximal end thereof and adapted to prevent over-insertion of the radially expandable sheath into a bone tunnel.
8. The graft fixation device of claim 1 , wherein the sheath expander comprises a tapered screw.
9. The graft fixation device of claim 8 , wherein the sheath expander has a maximum outer diameter that is greater than a maximum inner diameter of the radially expandable sheath in an unexpanded state.
10. The graft fixation device of claim 1 , wherein the sheath expander and the radially expandable sheath are formed from a bioabsorbable material.
11. The graft fixation device of claim 1 , wherein the distal end of the radially expandable sheath includes a cradle for seating a graft therein.
12. The graft fixation device of claim 1 , wherein at least one sidewall of the radially expandable sheath includes a conical taper formed on an inner surface of a proximal end thereof to align the sheath expander with the radially expandable sheath.
13. A graft fixation device, comprising:
an elongate expandable sheath having three sidewalls extending between proximal and distal ends, the sidewalls comprising first, second, and third sidewalls, and wherein the first and second sidewalls have a substantially concave outer surface adapted to seat a graft member and having surface features formed thereon, and the third sidewall has a substantially convex outer surface having surface features formed thereon and extending in an opposite direction to the surface features of the first and second sidewalls, the outer surface of the third sidewall being adapted to engage a bone tunnel, the three sidewalls being attached to one another at a proximal attachment point and a distal attachment point, and being separated from one another by three longitudinal slots extending between the proximal and distal attachment points; and
an expander disposable within the expandable sheath and adapted to expand the sheath such that the proximal attachment points break to separate the sidewalls at the proximal end of the sheath.
14. A graft fixation device of claim 13 , further comprising radially oriented ridges formed on the three sidewalls.
15. A graft fixation device of claim 13 , wherein a proximal-most end of the elongate expandable sheath is angled relative to a longitudinal axis of the elongate expandable sheath.
16. A graft fixation device of claim 13 , wherein the distal end of the radially expandable sheath includes a cradle for seating a graft therein.
17. A method for fixing a ligament graft in a bone tunnel comprising the steps of:
positioning a leading end of a graft within a femoral tunnel, the graft having a trailing end that extends through a tibial tunnel;
inserting a flexible sheath into the femoral tunnel, the flexible sheath having first, second, and third sidewalls at least partially separated from one another by three longitudinal slots extending between proximal and distal attachment points, wherein surface features formed on the first and second sidewalls extend in an opposite direction to surface features formed on the third sidewall, the flexible sheath having a substantially triangular cross-sectional shape such that the flexible sheath positions the graft on a posterior side of the femoral tunnel;
inserting an expansion plug into the flexible sheath to break the proximal attachment points and expand the flexible sheath such that the first and second sidewalls engage the graft and the third sidewall engages the femoral tunnel to thereby fix the leading end of the graft within the femoral tunnel.
18. The method of claim 17 , further comprising inserting a graft fixation device into the tibial tunnel to fix the trailing end of the graft within the tibial tunnel.
19. The method of claim 17 , wherein the graft includes two strands, each strand being looped at the leading end of the graft around a distal end of the flexible sheath.
20. The method of claim 19 , wherein the flexible sheath includes a cradle disposed on a distal end thereof for securing the strands at the leading end of the graft.
21. The method of claim 17 , wherein positioning comprises looping the leading end of the graft around a length of suture, and pulling the suture through the tibial and femoral tunnels to pull the leading end of the graft into the femoral tunnel.
22. The method of claim 17 , wherein the first and second sidewalls have substantially concave outer surfaces that seat the graft, and the third sidewall has a substantially convex surface that engages the femoral tunnel.
23. The method of claim 17 , wherein a proximal most end of the flexible sheath extends at an angle other than 90° relative to a longitudinal axis of the sheath such that the proximal-most end of the flexible sheath is aligned with an opening of the femoral tunnel.
24. The method of claim 17 , wherein inserting the expansion plug into the flexible sheath expands the sheath such that proximal attachment points connecting sidewalls of the flexible sheath break to separate the sidewalls at the proximal end of the sheath.
25. A method for fixing a ligament graft in a bone tunnel comprising the steps of
positioning a leading end of a graft within a femoral tunnel, the graft having anteromedial and posterolateral bundles with trailing ends that extend through a tibial tunnel;
inserting a flexible sheath into the femoral tunnel, the flexible sheath having first, second, and third sidewalls separated by longitudinal slots that extend between proximal and distal attachment points that connect the sidewalls, wherein surface features formed on the first and second sidewalls extend in an opposite direction to surface features formed on the third sidewall, the flexible sheath having a configuration that positions the anteromedial and posterolateral graft bundles on a posterior side of the femoral tunnel and in an anatomic position that mimics a position of native anteromedial and posterolateral ligament bundles;
inserting an expansion plug into the flexible sheath to expand the flexible sheath such that the proximal attachment points connecting the sidewalls of the flexible sheath break to separate the sidewalls at the proximal end of the sheath and thereby fix the leading end of the graft within the femoral tunnel, wherein the first and second sidewalls engage the graft and the third sidewall engages the femoral tunnel.
26. The method of claim 25 , wherein each graft bundle comprises a strand that is looped at the leading end of the graft around a distal end of the flexible sheath and that has two trailing ends.
27. The method of claim 25 , wherein the first and second sidewalls have substantially concave outer surfaces that seat the bundles, and the third sidewall has a substantially convex surface that engages the femoral tunnel.
28. The method of claim 25 , wherein a proximal most end of the flexible sheath extends at an angle other than 90° relative to a longitudinal axis of the sheath such that the proximal-most end of the flexible sheath is aligned with an opening of the femoral tunnel.