Bone fixation system including K-wire compression
View Patent ↗A bone fixation system includes a bone plate, bone anchors, temporary fixation members, and forceps. The temporary fixation members are configured to be inserted through apertures in the bone plate and into underlying bone segments that are separated by a bone gap. The forceps are configured to apply a force to the temporary fixation members that causes at least one of the underlying bone segments to translate with respect to the other bone segment, thereby reducing or distracting the bone segments without interfering with final fixation by screws of bone segments.
1. A forceps configured to apply a biasing force to a pair of temporary fixation members, each temporary fixation member having a distal portion and an engagement member disposed proximal of the distal portion, the engagement member defining a dimension greater than that of the distal portion, the forceps comprising:
a pair of arms, each arm having:
a proximal end and an opposed distal end;
an arm engagement member defining a first pocket that extends into the distal end such that the first pocket defines a channel that extends through the distal end along a vertical direction, the first pocket further defining an engagement surface that defines a horizontal radius of curvature swept along a horizontal direction and a vertical radius of curvature swept along the vertical direction, the horizontal radius of curvature being equal to or greater than the vertical radius of curvature;
wherein relative movement of the arms causes the distal ends to correspondingly move, such that each first pocket at least partially receives a respective one of the temporary fixation members and each engagement surface applies a biasing force against the engagement member of respective one of the temporary fixation members.
2. The forceps as recited in claim 1 , wherein the first pockets of each arm face each other, such that the engagement surfaces are configured to apply a compressive force to the engagement members of the respective temporary fixation members when the distal ends are brought together.
3. The forceps as recited in claim 2 , wherein each arm further comprises a second pocket at the distal end such that the first and second pockets of each arm face away from each other, each second pocket defining an engagement surface having a shape corresponding to that of the engagement member of the temporary fixation member such that the engagement surfaces are configured to apply a distractive force to the engagement members of the respective temporary fixation members when the distal ends are brought apart.
4. The forceps as recited in claim 3 , wherein the second pocket of each arm is aligned with the first pocket along a direction that is perpendicular to the vertical direction.
5. The forceps as recited in claim 3 , wherein the second pocket of each arm is offset with respect to the first pocket.
6. The forceps as recited in claim 3 , wherein each arm engagement member of the forceps is forked and comprises first and second arms that define a gap therebetween, the gap sized to receive the engagement member of the temporary fixation member.
7. The forceps as recited in claim 1 , wherein the first pockets face toward each other, such that the engagement surfaces are configured to apply a compressive force to the engagement members of the respective temporary fixation members when the distal ends are brought together.
8. The forceps as recited in claim 1 , wherein the handles are pivotally coupled.
9. The forceps as recited in claim 8 , wherein the distal ends are moved closer together as the handles are moved closer together.
10. The forceps as recited in claim 8 , wherein the distal ends are moved farther apart as the handles are moved farther apart.
11. The forceps as recited in claim 1 , further comprising a ratchet connected between the arms and configured to incrementally move the arms when a force is applied to the arms.
12. The forceps as recited in claim 1 , wherein the engagement surface conforms to the engagement member of the temporary fixation member along at least one direction.
13. The forceps as recited in claim 12 , wherein the engagement surface is circular in the direction.
14. The forceps as recited in claim 1 , wherein the each temporary fixation member is a K-wire configured to engage one of the bone segments.
15. The forceps as recited in claim 1 , wherein one of the temporary fixation members is a K-wire configured to engage one of the bone segments, and the other one of the temporary fixation members is a post configured to engage a bone plate.
16. The forceps as recited in claim 3 , wherein the second pockets each define a second engagement surface having a horizontal radius of curvature and a vertical radius of curvature.
17. A forceps configured to apply a biasing force to a pair of temporary fixation members, each temporary fixation member having a distal portion and an engagement member disposed proximal of the distal portion, the engagement member defining a dimension greater than that of the distal portion, the forceps comprising:
a pair of arms, each arm having:
a proximal end and an opposed distal end;
an arm engagement member defining a first pocket that extends into the distal end and a second pocket that extends into the distal end such that the first and second pockets face away from each other, the first and second pockets each defining a respective engagement surface that defines a horizontal radius of curvature and a vertical radius of curvature;
wherein (i) a first relative movement of the arms causes the distal ends to correspondingly move, such that each first pocket at least partially receives a respective one of the temporary fixation members such that the engagement surfaces of the first pockets apply a compressive force to the engagement members of the temporary fixation members, and (ii) a second relative movement of the arms causes the distal ends to correspondingly move, such that each second pocket at least partially receives a respective one of the temporary fixation members such that the engagement surfaces of the second pockets apply a distractive force to the engagement members of the temporary fixation members.
18. The forceps as recited in claim 17 , wherein the temporary fixation members are configured to extend through the distal ends along a first direction and wherein the second pocket of each arm is aligned with the first pocket along a direction that is perpendicular to the first direction.
19. The forceps as recited in claim 17 , wherein the second pocket of each arm is offset with respect to the first pocket.
20. The forceps as recited in claim 17 , wherein the horizontal radius of curvature is swept along a horizontal direction and the vertical radius of curvature is swept along a vertical direction.