ORTHOPAEDIC DEVICE

Abstract

The present invention relates to an orthopaedic device for fixation of bones and a method for the use 5 of the orthopaedic device. The orthopaedic device finds utility for fixation of bones such as fractures of the femur or tibia, although it may be used in any suitable bone.

Claims

1. An orthopaedic device comprising: connecting means comprising at least one pair of threaded portions; at least two expandable sections, each expandable section displaceable between a contracted position and an expanded position; and expanding means in operable association with the connecting means and the expandable sections, wherein rotation of the connecting means causes the expanding means to apply a force to the respective ends of the expandable sections, thereby causing displacement of the expandable sections between the contracted position and the expanded position.

2. The orthopaedic device according to claim 1 further comprising limiting means, wherein the limiting means limits displacement of at least one expandable section between the contracted position and the expanded position by preventing the respective ends of the expandable sections from moving sequentially into closer proximity relative to one another.

3. The orthopaedic device according to claim 1, wherein the connecting means comprise a shaft comprising at least a first threaded portion and a second threaded portion, wherein the threads of the first threaded portion are of reverse orientation to the threads of the second threaded portion.

4. The orthopaedic device according to claim 1, comprising a first expandable section and a second expandable section, the first expandable section comprising a first end and a second end, the second expandable section comprising a third end and a fourth end.

5. The orthopaedic device according to claim 4, wherein the first and second expandable sections are arranged contiguously and/or are reversibly expandable.

6. The orthopaedic device according to claim 3, wherein the first threaded portion and the second threaded portion are located at or adjacent respective opposing ends of the shaft.

7. The orthopaedic device according to claim 4, wherein the expanding means comprises a first body threadably mountable to the first threaded portion and a second body threadably mountable to the second threaded portion of the shaft to allow for simultaneous movement of the first threaded body and the second threaded body in opposite directions relative to each other.

8. The orthopaedic device according to claim 7, wherein rotation of the shaft causes the first threadable body to advance along the first threaded portion of the shaft and the second threadable body to advance, in the opposite direction, along the second threaded portion of the shaft, thereby applying mechanical pressure to the first end of the first expandable section and fourth end of the second expandable section, wherein the first end of the first expandable section and fourth end of the second expandable section are bought sequentially into closer proximity relative to one another thereby displacing the first and second expandable sections between the contracted position and the expanded position.

9. The orthopaedic device according to claim 1, wherein the shaft comprises two pairs of threaded portions, a first pair comprising the first threaded portion and second threaded portion; and a second pair comprising a third threaded portion and a fourth threaded portion.

10. The orthopaedic device according to claim 9, wherein the threads of the first threaded portion are in reverse orientation to the threads of the second threaded portion, the threads of the third threaded portion are in reverse orientation to the threads of the fourth threaded portion, the threads of the first threaded portion are in reverse orientation to the threads of the third threaded portion and the threads of the second threaded portion are in reverse orientation to the threads of the fourth threaded portion.

11. The orthopaedic device according to claim 1, wherein at least one end of the shaft is dimensioned and arranged to receive a torque delivery device.

12. An orthopaedic system comprising: the orthopaedic device according to claim 1; and an orthopaedic implant.

13. The orthopaedic system according to claim 12, wherein the orthopaedic device has a substantially non-circular cross-section comprising at least one linear section and at least one curved section.

14. The orthopaedic system according to claim 13, wherein the outer surface the orthopaedic device comprises at least one planar section and at least one curved section.

15. The orthopaedic system according to claim 14, wherein the orthopaedic device has a substantially non-circular cross-section comprising at least one linear section and at least one curved section, wherein the least one linear cross-section section corresponds to the at least one planar section on the outer surface of the orthopaedic device, and the at least one curved cross-section corresponds to the at least one curved section on the outer surface of the orthopaedic device.

16. The orthopaedic system according to claim 12, wherein the orthopaedic implant further comprises at least one transverse aperture which bisects the longitudinal axis relative to the orthopaedic implant.

17. The orthopaedic system according to claim 16, wherein the transverse aperture comprises a first part and a second part, wherein the first part is circular to receive a curved outer section of the orthopaedic device, and the second part is non-circular to receive a flat outer section of the orthopaedic device.

18. The orthopaedic system according to claim 12, wherein the orthopaedic implant further comprises a longitudinal aperture, wherein the longitudinal aperture is coaxial with the longitudinal axis, and the longitudinal aperture comprises an inner threaded surface which is in mechanical communication with the transverse aperture.

19. The orthopaedic system according to claim 12, further comprising locking means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0286] Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

[0287] FIG. 1 is a perspective view of an orthopaedic device in an assembled contracted position according to a first aspect of the present invention;

[0288] FIG. 2 is an exploded perspective view of the orthopaedic device of FIG. 1 according to the first embodiment of the present invention;

[0289] FIG. 3 is an exploded perspective view an orthopaedic device according to the second embodiment of the first aspect of the present invention;

[0290] FIG. 4 is a perspective view the orthopaedic device of FIG. 1 in an assembled expanded position;

[0291] FIG. 5 is a plan view of an orthopaedic device with a set screw;

[0292] FIG. 6 is a perspective view the orthopaedic device of FIG. 5 in an assembled contracted position;

[0293] FIG. 7 is a perspective view the orthopaedic device of FIG. 5 in an assembled expanded position; and

[0294] FIG. 8 is a perspective view of the orthopaedic device further comprising limiting means.

DETAILED DESCRIPTION OF THE INVENTION

[0295] Referring to FIG. 1 and FIG. 2 of the drawings, there is provided an orthopaedic device 10 according to a first embodiment of the present invention. The orthopaedic device 10 comprises connecting means, which in this embodiment is a shaft 12; a first pair of threaded portions 14 comprising first 18a and second 18b threaded portions wherein the threads of the first threaded portion 18a are of reverse orientation to the threads of the second threaded portion 18b; two expandable sections—a first expandable section 20 and a second expandable section 22—the first 20 and second 22 expandable sections displaceable between a contracted position and an expanded position; and expanding means, which in this embodiment is a first threadable body 28 and second threadable body 30, which are in operable association with the shaft 12 and the expandable sections 20, 22.

[0296] The shaft 12 allows reciprocal movement of the threadably mountable bodies 28, 30 relative to the shaft 12. The threaded portions 18a, 18b on the shaft 12 are each helically threaded portions. The threads of the first helical screw threaded portion 18a are in reverse orientation to the threads of the second helical screw threaded portion 18b. The two helical screw threaded portions 18a, 18b are provided adjacent each terminal end of the shaft 12.

[0297] The shaft 12 is generally cylindrical in shape and each terminal end of the shaft 12 comprises a recess to actuate the shaft 12. One end of the shaft 12 is dimensioned and arranged to provide means for actuating the shaft 12, for example by providing means for delivering torque to the shaft. The terminal ends of the shaft 12 can be dimensioned and arranged to receive a torque delivery device such as a screwdriver, hex key, or similar device. A hexagonal socket (not shown) can be provided at the terminal ends of the shaft 12, and can be shaped and adapted to receive a hex key or similar torque delivery device.

[0298] In an embodiment, the threaded portions 18a, 18b are spaced apart at the terminal ends of the shaft 12. In use, the orthopaedic device 10 comprising the shaft 12 crosses an intramedullary nail 60, so that the first threaded portion 18a is one side of the intramedullary nail 60 and the second threaded portion 18b is on the other side of the intramedullary nail 60.

[0299] The threadably mountable bodies 28, 30 are annular in shape having an internal threaded surface and are open at both ends. The inner shape of the threadably mountable bodies 28, 30 are shaped and dimensioned to engage with the threaded shaft of an orthopaedic device.

[0300] A helical screw thread can be provided on the inner surface of each threadably mountable body 28, 30. The internal diameter of each threadably mountable body 28, 30 is generally of similar length to the external diameter of the shaft 12, whereby the screw thread of each threadably mountable body 28, 30 can engage with the respective screw threaded portions 18a, 18b of the shaft 12.

[0301] Each expandable section 20, 22 comprise a generally cylindrically shaped tube, which is open at both ends. The first expandable section 20 and the second expandable section 22 are located coaxially. The first expandable section 20 comprises deformable arms 52, the second expandable section 22 also comprises deformable arms 54, such that the expandable sections 20, 22 comprises a plurality of arms 52, 54 that extend from the longitudinal axis of the orthopaedic device 10 under mechanical pressure. A point of weakness 56 is provided at the first end 44 and second end 46 of the first expandable section of the deformable arm 52, and generally at the centre point of the length of the deformable arm 52. A point of weakness 58 is also provided at the third end 48 and fourth end 50 of the second expandable section of the deformable arm 54, and generally at the centre point of the length of the deformable arm 54. Each deformable arm 52, 54 have at least one point of folding 56, 58 along each deformable arm 52, 54. Each of the points of folding 56, 58 comprises a point of weakness, a hinge mechanism, or any such mechanism that will facilitate the folding of the deformable arm at a desired location.

[0302] The first 20 and second 22 expandable sections can be reversibly expandable. The first 20 and second 22 expandable sections are collapsible along their longitudinal axis, such that the first 20 and second 22 expandable sections are radially inwardly collapsible.

[0303] Rotation of the shaft 12 in the opposite direction can ultimately cause the deformable arms 52, 54 to retract toward the longitudinal axis of the orthopaedic device 10, 36, thereby facilitating the removal of the device, if required.

[0304] To assemble the orthopaedic device 10, the second threadable body 30 is engaged with the second threaded portion 18b of the shaft 12. The shaft 12 is then inserted coaxially into the expandable sections 20, 22, and the first threadable body 28 is engaged with the first threaded portion 18a the shaft 12. Once assembled, each of the threadably mountable bodies 28, 30 is located on one of the threaded portions 18a, 18b of the shaft 12. Each of the mountable bodies 28, 30 can be attached to each respective end 44, 50 of the expandable sections 20, 22 by an adherent means, such as an adhesive.

[0305] In use, the shaft 12 is rotated using a hex key or similar torque delivery device, inserted into the hexagonal socket is provided at the terminal ends of the shaft 12. Rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12 and the second threadable body 30 to advance, in the opposite direction, along the second threaded portion 18b of the shaft 12. This applies mechanical pressure to the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22, wherein the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22 are bought sequentially into closer proximity relative to one another, causing the deformable arms 52, 54 to deform at each of the points of weakness 56, 58, and to expand radially from the longitudinal axis of the orthopaedic device 10.

[0306] Referring to FIG. 3 of the drawings, there is provided an orthopaedic device 36 according to a second embodiment of the present, comprising a connecting means, which in this embodiment is a shaft 12; two pairs of threaded portions wherein a first threaded pair 14 comprises a first threaded portion 18a and a second threaded portion 18b, a second threaded pair 16 comprises a third threaded portion 40a and a fourth threaded portion 40b, wherein the threads of the first threaded pair comprising the first threaded portion 18a and second threaded portion 18b are of reverse orientation to each other and the threads of the second threaded pair comprising the third threaded portion 40a and the fourth threaded portion 40b are of reverse orientation to each other, additionally, the first threaded portion 18a and third threaded portion 40a are of reverse orientation to each other and the second threaded portion 18b and the fourth threaded portion 40b are of reverse orientation to each other; two expandable sections—a first expandable section 20 and a second expandable section 22—the first 20 and second 22 expandable sections displaceable between a contracted position and an expanded position; and expanding means, which in this embodiment is a first threadable body 28, a second threadable body 30, a third threadable body 32 and fourth threadable body 34, in operable association with the shaft 12 and the expandable sections 20, 22. It will be understood that FIG. 1, FIG. 4 and FIG. 5 showing orthopaedic device 10 can also equally be orthopaedic device 36.

[0307] The shaft 12 allows reciprocal movement of the threadably mountable bodies 28, 30, 32, 34 relative to the shaft 12. The threaded portions 18a, 18b, 40a, 40b on the shaft 12 are each helically threaded portions. The threads of the first helically threaded portion 18a are in reverse orientation to the threads of the second helically threaded portion 18b. The threads of the third helically threaded portion 40a are in reverse orientation to the threads of the fourth helically threaded portion 40b. The threads of the first helically threaded portion 18a are in reverse orientation to the threads of the third helically threaded portion 40a. The threads of the second helically threaded portion 18b are in reverse orientation to the threads of the fourth helically threaded portion 40b. The two helical screw threaded portions 18a, 18b are provided adjacent each terminal end of the shaft 12. The two helical screw threaded portions 40a, 40b are each provided in between the first helical screw threaded 18a and second helical screw threaded 18b, wherein helical screw threaded portion 40a is positioned between helical screw threaded portion 18a and helical screw threaded portion 40b; and helical screw threaded portion 40b is positioned between helical screw threaded portion 40a and helical screw threaded portion 18b.

[0308] The shaft 12 is generally cylindrical in shape and each terminal end of the shaft 12 comprises a recess to actuate the shaft 12. One end of the shaft 12 is dimensioned and arranged to provide means for actuating the shaft 12, for example by providing means for delivering torque to the shaft. The terminal ends of the shaft 12 can be dimensioned and arranged to receive a torque delivery device such as a screwdriver, hex key, or similar device. A hexagonal socket (not shown) can be provided at the terminal ends of the shaft 12, and can be shaped and adapted to receive a hex key or similar torque delivery device.

[0309] In an embodiment, the threaded portions 18a, 18b, 40a, 40b are equally spaced apart on the shaft 12. In use, the orthopaedic device 36 comprising the shaft 12 crosses the fracture site so that the first threaded pair 14 comprising the first threaded portion 18a and third threaded portion are on one side of the fracture site and the second threaded pair 16 comprising the fourth threaded portion 40b and the second threaded portion 18b is on the other side of the fracture site.

[0310] The threadably mountable bodies 28, 30, 32, 34 are annular in shape having an internal threaded surface and open at both ends. The inner shape of the threadably mountable bodies 28, 30, 32, 34 are shaped and dimensioned to engage with the threaded shaft of an orthopaedic device.

[0311] A helical screw thread can be provided on the inner surface of each threadably mountable body 28, 30, 32, 34. The internal diameter of each threadably mountable body 28, 30, 32, 34 is generally of similar length to the external diameter of the shaft 12, whereby the screw thread of each threadably mountable body 28, 30, 32, 34 can engage with the respective screw threaded portions 18a, 18b, 40a, 40b of the shaft 12.

[0312] Each expandable section 20, 22 comprise a generally cylindrically shaped tube, which is open at both ends. The first expandable section 20 and the second expandable section 22 are located coaxially. The first expandable section 20 comprises deformable arms 52, the second expandable section 22 also comprises deformable arms 54, such that the expandable sections 20, 22 comprises a plurality of arms 52, 54 that extend from the longitudinal axis of the orthopaedic devices 10, 36 under mechanical pressure. A point of weakness 56 is provided at the first end 44 and second end 46 of the first expandable section of the deformable arm 52, and the centre point of the length of the deformable arm 52. A point of weakness 58 is also provided at the third end 48 and fourth end 50 of the second expandable section of the deformable arm 54, and the centre point of the length of the deformable arm 54. Each deformable arm 52, 54 have at least one point of folding 56, 58 along each deformable arm 52, 54. Each of the points of folding 56, 58 comprises a point of weakness, a hinge mechanism, or any such mechanism that will facilitate the folding of the deformable arm at a desired location.

[0313] The first 20 and second 22 expandable sections can be reversibly expandable. The first 20 and second 22 expandable sections are collapsible along their longitudinal axis, such that the first 20 and second 22 expandable sections are radially inwardly collapsible.

[0314] Rotation of the shaft 12 in the opposite direction can ultimately cause the deformable arms 52, 54 to retract toward the longitudinal axis of the orthopaedic device 10, 36, thereby facilitating the removal of the device, if required.

[0315] To assemble the orthopaedic device 36, the second threadable body 30 is engaged with the second threaded portion 18b of the shaft 12, the fourth threadable body 34 is engaged with the fourth threaded portion 40b of the shaft 12 and the third threadable body 32 is engaged with the third threaded portion 40a of the shaft 12. The shaft 12 is then inserted coaxially into the expandable sections 20, 22, and the first threadable body 28 is engaged with the first threaded portion 18a the shaft 12. Once assembled, each of the threadably mountable bodies 28, 30, 32, 34 is located on one of the threaded portions 18a, 18b, 40a, 40b of the shaft 12. Each of the mountable bodies 28, 30, 32, 34 can be attached to each respective end 44, 46, 48, 50 of the expandable sections 20, 22 by an adherent means, such as an adhesive.

[0316] In an alternative assembly of the orthopaedic device 36, the second threadable body 30 is engaged with the second threaded portion 18b of the shaft 12. The shaft 12 is then inserted coaxially into the second expandable section 22 and the fourth threadable body 34 is engaged with the fourth threaded portion 40b the shaft 12. Separately, the third threadable body 32 is engaged with the third threaded portion 40a of the shaft 12. The shaft 12 is then inserted coaxially into the second first section 20 and the first threadable body 28 is engaged with the first threaded portion 18a the shaft 12. Once assembled, each of the threadably mountable bodies 28, 30, 32, 34 is located on one of the threaded portions 18a, 18b, 40a, 40b of the shaft 12. Each of the mountable bodies 28, 30, 32, 34 can be attached to each respective end 44, 46, 48, 50 of the expandable sections 20, 22 by an adherent means, such as an adhesive.

[0317] In use, the shaft 12 is rotated using a hex key or similar torque delivery device, inserted into the hexagonal socket is provided at the terminal ends of the shaft 12. Rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12; and the second threadable body 30 to advance, in the opposite direction, along the second threaded portion 18b of the shaft 12, the third threadable body 32 body to advance along the third threaded portion 40a of the shaft 12 and the fourth threadable body 34 to advance, in the opposite direction, along the second threaded portion 40b of the shaft 12. Additionally and simultaneously, rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12 and the third threadable body 32 to advance, in the opposite direction, along the third threaded portion 40a of the shaft 12, the second threadable body 30 body to advance along the second threaded portion 18b of the shaft 12 and the fourth threadable body 34 to advance, in the opposite direction, along the second threaded portion 40b of the shaft 12. This applies mechanical pressure to the first end 44 and second end 46 of the first expandable section 20, and the third end 48 and fourth end 50 of the second expandable section 22, wherein the first end 44 and second end 46 of the first expandable section 20, and the third end 48 and fourth end 50 of the second expandable section 22 are bought sequentially into closer proximity relative to one another, causing the deformable arms 52, 54 to deform at each of the points of weakness 56, 58, and to expand radially from the longitudinal axis of the orthopaedic device 36.

[0318] Referring to FIG. 5, FIG. 6 and FIG. 7, there is provided an orthopaedic system comprising an orthopaedic device 10, 36 according to a first aspect of the present invention; and an orthopaedic implant, which in this embodiment, is an intramedullary nail 60.

[0319] The intramedullary nail 60 comprises an aperture comprising a first part 62 and a second part 64, wherein the first part 62 is circular and can receive the curved section 66 of the orthopaedic device 10, 36, and the second part 64 is non-circular and can receive the planar section 68 of the orthopaedic device 10, 36.

[0320] In use, the orthopaedic device 10, 36 according to a first aspect of the present invention, is inserted into the first part 62 of the aperture in the intramedullary nail 60. A set-screw 70 is threadably mountable to the longitudinal aperture 72 of the intramedullary nail 60. The outer surface 74 of the set-screw 70 is dimensioned and arranged to provide means for actuating the set screw 70, for example by providing means for delivering torque to the set-screw 70. The outer surface 74 of the set-screw 70 can be dimensioned and arranged to receive a torque delivery device such as a screwdriver, hex key, or similar device. The set-screw 70, by the application of torque, is driven through the longitudinal aperture 72 of the intramedullary nail 60 in the direction of the longitudinal axis of intramedullary nail 60 the towards the first part 62 of the aperture in the intramedullary nail 60 until the set-screw 70 engages with the curved section 62 of the orthopaedic device 10, 36. The set-screw 70, by the application of further torque, displaces the orthopaedic device 10, 36 from the first part 62 of the aperture to the second part 64 of the aperture to secure the orthopaedic device 10, 36 therein, thus preventing further rotation of the orthopaedic device 10, 36 in the intramedullary nail 60 and assuring that the expandable sections 20, 22 of the orthopaedic device 10, 36 do not collapse under external pressure from the surrounding bone, with which it is in contact.

[0321] Alternatively, there is provided an orthopaedic device according to FIG. 8, wherein the orthopaedic device further comprises limiting means.

[0322] In use, the shaft 12 is rotated using a hex key or similar torque delivery device, inserted into the hexagonal socket is provided at the terminal ends of the shaft 12. Rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12 and the second threadable body 30 to advance, in the opposite direction, along the second threaded portion 18b of the shaft 12. This applies mechanical pressure to the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22, wherein the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22 are bought sequentially into closer proximity relative to one another causing the deformable arms 52, 54 to deform at each of the points of weakness 56, 58, and to expand radially from the longitudinal axis of the orthopaedic device 10 and also closes the space 76 between the non-contiguously arranged limiting means, which in this instance is a first strut 78 and a second strut 80, until the first strut 78 and a second strut 80 meet, thereby limiting displacement between the contracted position and the expanded position.

[0323] Alternatively, in use, the shaft 12 is rotated using a hex key or similar torque delivery device, inserted into the hexagonal socket is provided at the terminal ends of the shaft 12. Rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12; and the second threadable body 30 to advance, in the opposite direction, along the second threaded portion 18b of the shaft 12, the third threadable body 32 body to advance along the third threaded portion 40a of the shaft 12 and the fourth threadable body 34 to advance, in the opposite direction, along the second threaded portion 40b of the shaft 12. Additionally and simultaneously, rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12 and the third threadable body 32 to advance, in the opposite direction, along the third threaded portion 40a of the shaft 12, the second threadable body 30 body to advance along the second threaded portion 18b of the shaft 12 and the fourth threadable body 34 to advance, in the opposite direction, along the second threaded portion 40b of the shaft 12. This applies mechanical pressure to the first end 44 and second end 46 of the first expandable section 20, and the third end 48 and fourth end 50 of the second expandable section 22, wherein the first end 44 and second end 46 of the first expandable section 20, and the third end 48 and fourth end 50 of the second expandable section 22 are bought sequentially into closer proximity relative to one another, causing the deformable arms 52, 54 to deform at each of the points of weakness 56, 58, and to expand radially from the longitudinal axis of the orthopaedic device 10 and also closes the space 76 between the non-contiguously arranged limiting means, which in this instance is a first strut 78 and a second strut 80, until the first strut 78 and a second strut 80 meet, thereby displacement between the contracted position and the expanded position.

[0324] In some embodiments, the limiting means is a stop, which radially expands from the shaft 12 thereby preventing the first end of the first expandable section 44 and/or the fourth end of the second expandable section 55 from moving sequentially into closer proximity relative to one another, thereby limiting the expansion of the at least one expandable section 20, 22.

[0325] The advantage of limiting expansion ensures uniform and reproducible expansion of the respective expandable sections and prevents preferential over-expansion of one expandable section versus the other expandable section. For example, in some embodiments, the first expandable section 20 may preferentially over-expand in comparison to the second expandable section 22 and limiting displacement of the first expandable 20 section may be preferable to ensure uniform expansion and ensure weight bearing post-operatively is consistent. In some embodiments, the second expandable section 22 may preferentially over-expand in comparison to the first expandable section 20 and limiting displacement of the second expandable section 22 may be preferable to ensure uniform expansion and ensure weight bearing post-operatively is consistent. In some embodiments, it may be preferable to limit displacement of both the first expandable section 20 and the second expandable section 22 to ensure uniform expansion and ensure weight-bearing load is consistent.

[0326] In some embodiments, one expandable section, in this instance, the first expandable section 20 comprises the limiting means. Rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12 and the second threadable body 30 to advance, in the opposite direction, along the second threaded portion 18b of the shaft 12. This applies mechanical pressure to the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22, wherein the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22 are bought sequentially into closer proximity relative to one another causing the deformable arms 52, 54 to deform at each of the points of weakness 56, 58, and to expand radially from the longitudinal axis of the orthopaedic device 10. The limiting means on the first expandable section 20 limits displacement of the first expandable section 20 between the contracted position and the expanded position by preventing the first end of the first expandable section 44 from moving sequentially into closer proximity to the fourth end of the second expandable section 55, thereby limiting the displacement of the at least one expandable section 20, 22, whilst allowing the second expandable section 22 to preferentially expand and thereby causing uniform expansion.

[0327] Alternatively, the second expandable section 22 comprises the limiting means. Rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12 and the second threadable body 30 to advance, in the opposite direction, along the second threaded portion 18b of the shaft 12. This applies mechanical pressure to the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22, wherein the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22 are bought sequentially into closer proximity relative to one another causing the deformable arms 52, 54 to deform at each of the points of weakness 56, 58, and to expand radially from the longitudinal axis of the orthopaedic device 10. The limiting means on the second expandable section 22 limits expansion of the second expandable section 22 between the contracted position by preventing the fourth end of the second expandable section 55 from moving sequentially into closer proximity relative to the first end of the first expandable section 44, thereby limiting the displacement of the at least one expandable section 20, 22, whilst allowing the second expandable section 22 to preferentially expand and thereby causing uniform expansion.

[0328] Further alternatively, both the first expandable section 20 and the second expandable section 22 comprise the limiting means. Rotation of the shaft 12 causes the first threadable body 28 to advance along the first threaded portion 18a of the shaft 12 and the second threadable body 30 to advance, in the opposite direction, along the second threaded portion 18b of the shaft 12. This applies mechanical pressure to the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22, wherein the first end 44 of the first expandable section 20 and fourth end 50 of the second expandable section 22 are bought sequentially into closer proximity relative to one another causing the deformable arms 52, 54 to deform at each of the points of weakness 56, 58, and to expand radially from the longitudinal axis of the orthopaedic device 10. The limiting means on the first expandable section 20 and the second expandable section 22 limits displacement of the first expandable section 20 and the second expandable section 22 between the contracted position by preventing the first end of the first expandable section 44 and fourth end of the second expandable section 55 from moving sequentially into closer proximity relative to each other, thereby limiting the displacement of both expandable sections 20, 22.

[0329] It will be understood that FIG. 4 and FIG. 5 showing orthopaedic device 10 can also equally be orthopaedic device 36.

[0330] In an embodiment, the aperture in the intramedullary nail is circular and orthopaedic device is circular in shape.

[0331] In a further embodiment, the aperture in the intramedullary nail is substantially non-circular and orthopaedic device is substantially non-circular in shape.

[0332] In a further embodiment, the aperture in the intramedullary nail circular and orthopaedic device is substantially non-circular in shape.

[0333] In a further embodiment, the aperture in the intramedullary nail is substantially non-circular and orthopaedic device is circular in shape.

[0334] The orthopaedic devices of the present invention 10, 36 are formed of a material that is suitable for sterilisation, such as an autoclavable material, so as to be provided in a sterile packaged state for use. The material can be surgical stainless steel, but it will be seen that any material that is suitable for sterilisation and can impart the required mechanical strength may be used.

[0335] There is also provided a method for fixation of bones comprising the steps of reducing the fracture by utility of orthopaedic devices of the present invention 10, 36. A pathway across the fractured bone is prepared using a surgical drill, or similar device. When the pathway has been prepared, the orthopaedic device 10, 36, once assembled and with the expandable sections 20, 22 in a contracted position, the orthopaedic device 10, 36 is placed into the pathway. The deformable arms 52, 54 of the expandable sections 20, 22 are radially expanded using, for example, a screwdriver inserted into, for example, a hex socket in the terminal end of the connecting means 12, for example the shaft 12. Optionally, the method comprises providing an intramedullary nail 60 used in conjunction with the orthopaedic device 10, 36.

[0336] In an embodiment for the fixation of bones, the threaded portions 18a, 18b are spaced apart at the terminal ends of the shaft 12. In use, the orthopaedic device 10 comprising the shaft 12 crosses the fracture site so that the first threaded portion 18a is one side of the fracture site and the second threaded portion 18b is on the other side of the fracture site.

[0337] In an embodiment for the fixation of bones, the threaded portions 18a, 18b, 40a, 40b are equally spaced apart on the shaft 12. In use, the orthopaedic device 36 comprising the shaft 12 crosses the fracture site so that the first threaded pair 14 comprising the first threaded portion 18a and third threaded portion are on one side of the fracture site and the second threaded pair 16 comprising the fourth threaded portion 40b and the second threaded portion 18b is on the other side of the fracture site.

[0338] The present invention finds utility as an apparatus for fixation of bones such as fractures of the distal femur or proximal tibia.

[0339] For distal femoral fractures, the patient is anaesthetised, and positioned supine on the operating table with the affected leg flexed to about 45 degrees. A medial parapatellar incision is made, and access is made to the intercondylar notch of the femur from within the knee joint. The starting point for the nailing is confirmed by anteroposterior (AP) and lateral fluoroscopy. A guidewire is passed from the centre of the intercondylar notch, in line with the vertical axis of the femur, aiming for the mid-point of the femur along the vertical axis in both planes. The guidewire is passed across the fracture site and into the proximal fragment.

[0340] The channel for the orthopaedic implant/intramedullary nail is prepared by reaming the intramedullary cavity with appropriately sized reamers. The correct length and diameter of the orthopaedic implant/intramedullary nail are selected from x-ray templating, or using a ruler overlaying the femur and using fluoroscopy. The appropriately sized nail is mounted on the alignment jig. The orthopaedic implant/intramedullary nail is inserted over the guidewire, across the fracture site and into the proximal femur. The distal part of the orthopaedic implant/intramedullary nail should be sunk 3-5 mm within the bone at the intercondylar notch.

[0341] The correct orientation and trajectory of the orthopaedic device is identified with a guidewire trough the appropriate aperture on the alignment jig and via a stab incision over the lateral distal femur. The correct length of orthopaedic device is measured via the guidewire and sleeve, noting the distance on either side of the nail. The orthopaedic device should be similar or slightly shorter in length than the transverse width of the distal femur.

[0342] The channel for the orthopaedic device is drilled over the guidewire, both of which are then removed. The orthopaedic device is inserted via the sleeve and alignment jig and advanced into position. The rotation of the orthopaedic device is noted, so the flat aspects on the shaft are facing along the longitudinal axis of the nail.

[0343] The set-screw is now advanced via a screwdriver up from the distal end of the nail, to engage with the orthopaedic device. Further advancement of the set-screw retracts the nail downwards towards the knee, until the orthopaedic device is seated within the narrower keyed part of the nail aperture. This now secures the orthopaedic device from spinning when deployed. The orthopaedic device is deployed via clockwise rotation of the screwdriver. Expansion may continue until a stop is felt or the surgeon is satisfied with the position on fluoroscopy. The screwdriver is removed, and further locking screws may be inserted into the nail, completing the overall construct.

[0344] The alignment jig is removed, and an end cap is inserted onto the distal part of the nail to prevent bone ingrowth and to reduce blood and bone marrow from entering the knee joint.

[0345] Final construct positions are checked on fluoroscopy, wounds are closed and dressed.