Fulcrum for tarsal-metatarsal joint procedure
A technique for correcting a bone deformity, such as a bunion, may be performed using a fulcrum. In some examples, the fulcrum includes multiple members that are joined together at one end and spaced apart from each other at an opposite end. The fulcrum members can be manipulated to adjust the distance separating the fulcrum members from each other and, correspondingly, an amount of force separating the multiple members from each other. The force can be controlled to press against opposed bones, such as first and second metatarsals in an intermetatarsal space.
1. A fulcrum for use in a bone realignment procedure comprising:
a body configured to be inserted in an intermetatarsal space between adjacent metatarsals, and
a handle operatively connected to the body,
wherein the body comprises a first member having a length extending from a first end to a second end and a second member having a length extending from a first end to a second end, and
the first end of the second member is coupled to the first member to define a junction between the first member and the second member, the junction providing a spring force biasing the second end of the second member away from the first member to expand a thickness of the body between the first member and the second member, and the second end of the second member being compressible toward the first member to reduce the thickness of the body between the first member and the second member for insertion into the intermetatarsal space.
2. The fulcrum of claim 1 , wherein the first member is fixedly coupled to the second member.
3. The fulcrum of claim 1 , wherein first end of the second member is coupled to the first member at an angle such that the body defines a wedge of increasing thickness moving from the first end of the first and second members to the second end of the first and second members.
4. The fulcrum of claim 3 , wherein the angle ranges from 0 degrees to 10 degrees when the second member is moved toward the first member to greater than 10 degrees when the second member is moved away from the first member.
5. The fulcrum of claim 4 , wherein the angle is within a range from greater than 0 degrees to less than 15 degrees when the second member is moved away from the first member.
6. The fulcrum of claim 1 , wherein the first member has a first member thickness, the second member has a second member thickness, and the first member thickness is substantially the same as the second member thickness.
7. The fulcrum of claim 1 , wherein the thickness of the body is within a range from 2.5 mm to 10 mm when the second member is moved away from the first member and the thickness of the body is within a range from 1.5 mm to 3.5 mm when the second member is moved toward the first member.
8. The fulcrum of claim 1 , wherein the second end of the second member is biased away from the first member with an amount of force effective to retain the body in the intermetatarsal space, when the body is inserted between adjacent metatarsals of a human foot.
9. The fulcrum of claim 8 , wherein the second end of the second member is biased away from the first member by a spring force provided between the first end of the first member and the first end of the second member.
10. The fulcrum of claim 1 , wherein the handle comprises a first handle portion connected to the first member and a second handle portion connected to the second member.
11. The fulcrum of claim 10 , wherein the first handle portion is attached to the second end of the first member and the second handle portion is attached to the second end of the second member.
12. The fulcrum of claim 11 , wherein the first handle portion and the second handle portion are parallel to each other and project in a same direction away from the body.
13. The fulcrum of claim 1 , wherein:
the handle projects from the body to define a tissue retraction space between the handle and the body;
the body defines an axis extending along the length of the body,
the handle defines a handle axis projecting at a non-zero degree angle from the body, and
an angle between the axis of the body and the handle axis ranges from 20 degrees to 75 degrees.
14. The fulcrum of claim 13 , wherein the angle ranges from 35 degrees to 55 degrees.
15. The fulcrum of claim 1 , wherein the body and the handle are formed as a unitary structure.
16. The fulcrum of claim 1 , wherein the body is configured to be inserted between a first metatarsal and a second metatarsal.
17. The fulcrum of claim 1 , wherein
the first member has an outward face and an inward face;
the second member has an outward face and an inward face, the inward face of the second member being positioned to contact the inward face of the first member when the second member is moved toward the first member;
the outward face of the first member has surface features configured to inhibit proximal to distal movement of the outward face of the first member along a metatarsal against which the outward face of the first member is positioned, and
the outward face of the second member has surface features configured to inhibit dorsal to plantar movement of the outward face of the second member along a metatarsal against which the outward face of the second member is positioned.