WO2022027085A1

WO2022027085A1 - An orthopaedic compression and distraction device and method

Info

Publication number: WO2022027085A1
Application number: PCT/AU2021/050777
Authority: WO
Inventors: Bradley Ryan
Original assignee: Bradley Ryan
Priority date: 2020-08-05
Filing date: 2021-07-19
Publication date: 2022-02-10

Abstract

The invention relates to an orthopaedic distraction and compression device for positioning bones or bone fragments relative to each other. The device includes a pair of arms that are movable relative to each other wherein each arm includes a wire holder at a distal end thereof. The wire holder includes an opening for receiving a wire axially therethrough and a wire engaging member for limiting axial movement of the wire relative to the holder. The holder is pivotally coupled to the arm for allowing the wire to pivot relative to the arm.

Description

AN ORTHOPAEDIC COMPRESSION AND DISTRACTION DEVICE AND METHOD

TECHNICAL FIELD

[001 ] The present disclosure relates to a device and method for the positioning of bones or bone fragments relative to each other in orthopaedic surgery procedure. The device and method are particularly suitable for use in orthopaedic procedures involving the positioning of bone fragments relative to each other such as in reconstructive surgery, fracture reduction or in an osteotomy procedure. However, it is to be appreciated that the present invention may have broader application.

BACKGROUND

[002] Various orthopaedic surgical procedures require a surgeon to freely mobilise a bone fragment in any direction or orientation relative to another bone fragment or other tissue and once a desired position is obtained to be able to hold the bone fragment in place.

[003] One such procedure is reduction, which is a surgical procedure to repair a fracture or dislocation of a bone or joint to the correct alignment. When a bone fractures, the fragments lose their alignment in the form of displacement or angulation. For the fractured bone to heal without any deformity the bony fragments must be re-aligned to their normal anatomical position. Orthopedic surgery attempts to recreate the normal anatomy of the fractured bone by reduction of the displacement.

[004] Reduction may be employed in an osteotomy which is a surgical operation whereby a bone is cut to shorten or lengthen it or to change its alignment. It is sometimes performed to correct a hallux valgus, or to straighten a bone that has healed crookedly following a fracture.

[005] It is often desired to achieve reduction of a fracture or an osteotomy prior to insertion of an implant into the fracture or osteotomy location. It is difficult to obtain an accurate reduction after an implant has been inserted.

Further, it is difficult to accurately reduce a fracture with an implant.

[006] Surgical distraction and compression devices are used by surgeons to position bone fragments relative to each other. A distraction device is one that forces apart two bone surfaces to thereby stabilise the bones prior to definitive surgical fixation. A compression device is one that forces two bone surfaces together. Such extraction and compression devices can be comprised of an external frame for holding the bones or bone fragments in position. Metal pins or screws are placed into the bone through incisions in the skin and muscle.

[007] With most fusions and deformity corrections performed in orthopaedic surgery such as hallux valgus and fracture repairs the location of bone fragments often need to be corrected in more than one plane, namely sagittal, coronal and frontal, with this instrument surgeons will be able to do that with one instrument in a controlled manner.

[008] However, existing distraction and compression devices are limited in the range of positions in which they can hold bones or bone fragments relative to each other. In particular, existing distraction and compression devices typically allow for relative positioning of bone fragments in one plane. Accordingly, there exists a need for a distraction and/or compression device capable of relative positioning of bones or bone fragments relative to each other in different planes.

[009] Any discussion of background art throughout the specification should in no way be considered as an admission that any of the documents or other material referred to was published, known or forms part of the common general knowledge.

SUMMARY OF THE INVENTION

[0010] In one aspect, the present invention provides an orthopaedic distraction and compression device for positioning bones or bone fragments relative to each other, the device including: a pair of arms being movable relative to each other; each arm including a wire holder at a distal end thereof; the wire holder including an opening for receiving a wire axially therethrough; a wire engaging member for limiting axial movement of the wire relative to the holder; and the holder being pivotally coupled to the arm for allowing the wire to pivot relative to the arm.

[0011 ] Embodiments of the invention are advantageous as they provide for adjustment of a distance between a pair of bones or bone fragments in a direction perpendicular to a plane of an interface between the bones or bone fragments (i.e. compression and distraction). The invention also permits adjustment of the positions of the bones or bone fragments relative to each other in the sagittal, coronal and frontal planes. In embodiments, when a desired relative position of the bones or bone fragments is achieved the device is adapted to fix the respective positions thereof so that the bones or bone fragments may be fixed relative to each other such as by way of screws and/or plates or a combination thereof.

[0012] In embodiments, at least one of the holders is pivotal multi-directionally relative to one of the arms for allowing the wire located within the holder to pivot multi-directionally relative to the arm.

[0013] In embodiments, at least one of the holders and the wire positioned therethrough is rotatable about a central pivot point relative to one of the arms up to about 10 degrees or up to about 20 degrees or up to about 30 degrees, or any increment between 0 and 30 degrees from a central axis passing through the central pivot point.

[0014] In embodiments, at least one of the holders includes a body comprising a rounded exterior surface and at least one of the arms includes a rounded interior surface defining a recess shaped at least in part complementarily with the rounded exterior surface of the holder, wherein the rounded exterior surface of the holder is receivable within the recess. [0015] In embodiments, a small tolerance exists between a dimension of the rounded exterior surface of the holder and a dimension of the rounded interior surface of the arm whereby the holder is received within the recess in a tight fit.

[0016] In embodiments, the rounded exterior surface is at least in part substantially spherical and the rounded interior surface is at least in part substantially spherical.

[0017] In embodiments, a restraining mechanism is provided for selectively maintaining at least one of the holders and the wire positioned therethrough at a desired rotational position about the central pivot point relative to one of the arms.

[0018] In embodiments, the restraining mechanism includes a manually rotatable threaded shaft received within a threaded opening within the arm, wherein manually tightening the threaded shaft causes the threaded shaft to engage the holder to prevent movement of the holder relative to the arm.

[0019] In embodiments, the overall length of at least one of the arms is adjustable.

[0020] In embodiments, at least one of the arms includes a proximal portion and a distal portion, wherein the proximal and distal portions are movably coupled to be extendable and retractable relative to each other.

[0021 ] In embodiments, the device includes an actuator mechanism for progressively extending and retracting the proximal and distal portions relative to each other to thereby adjust the overall length of the arm.

[0022] In embodiments, the actuator mechanism includes a rotatable threaded shaft located within a threaded opening whereby rotation of the shaft causes the shaft to translate axially within the opening to thereby extend and retract the distal portion relative to the proximal portion. [0023] In embodiments, at least one of the arms includes a pivoting portion at the distal end at which the holder is coupled, wherein the pivoting portion is pivotally coupled at an elbow joint with the remainder of the arm for permitting the pivoting portion and the holder to pivot about a transverse axis relative to the remainder of the arm.

[0024] In embodiments, the arms are movably coupled together to be movable relative to each other in a plane.

[0025] In embodiments, the arms are movable so that a distance between the arms is adjustable whilst the arms are maintained parallel to each other.

[0026] In embodiments, a transverse bar extends between and links proximal ends of the arms, wherein the length of the bar between the proximal ends of the arms is adjustable to thereby adjust the distance between the arms.

[0027] In embodiments, the bar is fixed to the proximal end of one of the arms and is moveable relative to the proximal end of the other one of the arms.

[0028] In embodiments, the proximal end of the other one of the arms includes an opening for slidably receiving the rod therewithin and a rack and pinion gear mechanism for driving linear movement of the rod within the opening.

[0029] In embodiments, the device further includes a ratchet for allowing linear movement of the rod in only one direction while preventing motion in the opposite direction.

[0030] In embodiments, the wire engaging member includes a mechanism for selectively clamping the wire within the opening of the wire holder and limiting axial movement of the wire relative to the holder.

[0031 ] In embodiments, wherein the mechanism for selectively clamping the wire includes a collar threadably coupled to a set of jaws wherein rotating the collar causes the jaws to tighten or loosen from engagement with the wire. [0032] In another aspect, the invention provides a surgical method for positioning bones or bone fragments relative to each other using an orthopaedic distraction and compression device, the method including: driving the ends of a two of wires into respective bones or bone fragments; positioning the wires axially within openings of a pair of wire holders pivotally coupled at distal ends of a pair of arms, operating wire engaging members to limit axial movement of the wires relative to the holders, moving the arms relative to each other; and pivoting the wire holders relative to the arms to thereby position the bones or bone fragments relative to each other.

[0033] In embodiments, the method includes multi-directionally pivoting the wire holders relative to the arms to thereby multi-directionally pivot the wires positioned within the holders relative to the arms to thereby adjust the positions of the bones or bone fragments, in which the other ends of the wires are embedded, relative to each other in the sagittal, coronal and frontal planes.

[0034] In embodiments, the method includes manually rotating a threaded shaft within a threaded opening in the arm to bring the threaded shaft into engagement with the holder to prevent movement of the holder relative to the arm.

[0035] In embodiments, the method includes operating an actuator mechanism for progressively extending or retracting proximal and distal portions of arms relative to each other to thereby adjust the relative position of the bones or bone fragments in a direction parallel to a plane of an interface between the bones or bone fragments.

[0036] In embodiments, the method includes manually rotating a pinion gear in meshing engagement with a linear gear provided on a transverse bar extending between the arms to progressively adjust a distance between the arms while maintaining the arms parallel and in a single plane to thereby compress or distract the bones or bone fragments. BRIEF DESCRIPTION OF THE FIGURES

[0037] The invention will now be described in more detail with reference to embodiments of the invention illustrated in the accompanying drawings, wherein:

[0038] Figure 1 illustrates a perspective view of an orthopaedic distraction and compression device in accordance with an embodiment of the invention including a pair of arms that each include a wire holder at a distal end thereof;

[0039] Figure 2 illustrates an exploded view of the orthopaedic distraction and compression device of Figure 1 ;

[0040] Figure 3 illustrates a cross section view of a wire holder of the device of Figure 1 ;

[0041 ] Figure 4 illustrates a perspective view of the device of Figure 1 including a pair of wires driven into respective bone fragments and received within the wire holders of the device to thereby hold the bone fragments in position relative to each other;

DETAILED DESCRIPTION

[0042] Figures 1 to 4 illustrate embodiments of the invention including an orthopaedic distraction and compression device 10 for positioning bones or bone fragments relative to each other. The device 10 includes a pair of arms 20, 30. The arms 20, 30 are movable relative to each other in a manner that will be described in further detail below. In embodiments, the arms 20, 30 are movable relative to each other in a plane. Each one of the arms 20, 30 includes a wire holder 60, 70. In embodiments, the wire holders 60, 70 are located at distal ends 25, 35 of the arms 20, 30. Each one of the wire holders 60, 70 includes an opening 65, 75 for receiving a respective wire 2, 4 axially therethrough. Associated with each holder 60, 70 is a respective wire engaging member 80, 90 for limiting axial movement of the wire 2, 4 relative to the holder 60, 70. Each one of the holders 60, 70 are being pivotally coupled to one of the arms 20, 30 for allowing the wire 2, 4 to pivot relative to the arm 20, 30. The Arms

[0043] The arms 20, 30 are movably coupled together to be movable relative to each other in a plane. Each one of the arms 20, 30 are comprised of a proximal part 22, 32 and a distal part 24, 34. The proximal part 22, 32 includes a hollow longitudinal internal passage 23, 33 that is open at a distal end 26, 36 and is closed at an opposite proximal end 21 , 31. The distal part 24, 34 of each arm 20, 30 has a proximal end 28, 38 that is received within the hollow longitudinal internal passage 23, 33 so as to be longitudinally moveable therewithin. The proximal parts 22, 32 and distal parts 24, 34 are thus extendable and retractable relative to each other. The overall length of the arms 20, 30 are thereby extendable and retractable.

[0044] Each one of the arms 20, 30 includes an actuator mechanism 40, 50 for progressively extending and retracting the proximal parts 22, 32 and distal parts 24, 34 relative to each other. The actuator mechanism 40, 50 includes a rotatable threaded shaft 42, 52 located within an opening 45, 55 extending through the closed ends 21 , 31 of the proximal parts 22, 32 of the arms 20, 30. A knurled knob 41 , 51 is fixed to an end of each of the threaded shafts 42, 52 that protrudes from the opening 45, 55. A threaded part 44, 54 is provided at an opposite end of each of the threaded shafts 42, 52. The threaded part 44, 54 is located inside the hollow longitudinal internal passage 23, 33 of the proximal parts 22, 32 of each of the arms 20, 30. The thread 44, 54 of each of the threaded shafts 42, 52 is received within a threaded passage 46, 56 of a respective one of the distal parts 24, 34 located within the longitudinal internal passage 23, 33.

[0045] Each threaded shaft 42, 52 is captured by the opening 45, 55 through the closed ends 21 , 31 of the proximal parts 22, 32 of the arms 20, 30 such that the threaded shaft does cannot move axially relative to the proximal parts 22, 32. The hollow longitudinal internal passage 23, 33 of the proximal parts 22, 32 are configured to receive the distal parts 24, 34 in a manner that permits relative longitudinal movement but to prevent relation rotational movement. In the illustrated embodiment, this is achieved by the exterior shape of the distal parts 24, 34 having a substantially polygonal (e.g. square) cross section and the interior shape of the longitudinal internal passage 23, 33 having a complementary shaped cross-section.

[0046] Rotation of each knurled knob 41 , 51 thereby rotates each threaded shaft 42, 52 which in turn causes relative axial movement of the threaded shaft 42, 52 and the distal part 24, 34 threadably coupled therewith. As the distal parts 24, 34 are prevented from rotation relative to the proximal parts 22, 32 and because the threaded shafts 42, 52 are prevented from axial movement relative to the proximal potions 22, 32, the distal parts 34, 44 are thereby translated longitudinally within the hollow longitudinal internal passages 23, 33 of the proximal parts 22, 32. Rotation of the knurled knob 41 , 51 in opposite directions respectively causes translation of the distal parts 34, 44 in opposite directions and thereby extends and retracts the proximal parts 22, 32 and distal parts 24, 34 relative to each other.

[0047] In embodiments, rotation of the knurled knobs 41 , 51 adjusts the overall length of the arms 20, 30. Embodiments of the actuator mechanism 40, 50 that include a threaded mechanism permit progressive, that is infinite adjustment, of the overall length of the arms 20, 30 as opposed to incremental adjustment. Furthermore, embodiments permit such adjustment to occur without any removal of support or force maintaining the relative position of the proximal parts 22, 32 and distal parts 24, 34. The knurled knobs 41 , 51 each include a hexagonal recess 41 a, 51 a that is adapted to receive a hex key driver to rotate the knurled knobs 41 , 51 and the threaded shafts 42, 52 to thereby adjust the overall length of the arms 20, 30.

Distraction-Compression - Distance between the Arms

[0048] The proximal part 22 of one of the arms 20 is connected at the proximal end 21 thereof to a transverse elongated bar 120. In the illustrated embodiment, the proximal part 22 and the transverse bar 120 are integrally formed such as by being moulded as a single component. The proximal part 32 of the other one of the arms 30 includes an opening 130 extending transversely to a longitudinal axis of the proximal part 32. The opening 130 is adapted to receive the transverse bar 120. In embodiments, the opening 130 is configured to slidably receive the transverse bar 120 therethrough.

[0049] The bar 120 includes a linear array of transverse teeth 122 along at least a part of the length thereof. A pinion gear 132 is mounted immediately adjacent to the opening 130 at the proximal part 32 of the arm 30. The pinion gear 132 is connected via a shaft 133 to a butterfly shaped knob 134 to provide a grip for a thumb and finger of a user. The butterfly shaped knob 134 includes a hexagonal recess 135 that is adapted to receive a hex key driver to rotate the shaft 133 and pinion gear 132. The pinion gear 132 includes a set of teeth disposed about a circumference thereof that mesh with the linear array of transverse teeth 122 of the bar 120. Manual rotation of the butterfly shaped knob 134 causes the pinion gear 132 to rotate which in turn causes the bar 120 to translate and thereby drive linear movement of the bar 120 within the opening 130 in the manner of a rack and pinion gear mechanism. Rotation of the butterfly shaped knob 134 in opposite directions likewise causes linear translation of the bar 120 in opposite directions.

[0050] In embodiments, the transverse bar 120 is oriented perpendicular to the longitudinal axis of the proximal part 20 of its respective arm 20. The opening 130 is also oriented perpendicular to the longitudinal axis of the proximal part 30 of its respective arm 20. In the illustrated embodiment, the exterior shape of the transverse bar 120 has a substantially polygonal (e.g. square) cross section and the interior shape of the transverse opening 130 has a complementary shaped cross-section. Further, the dimensions of the cross sections of the transverse bar 120 and of the opening 130 are within a small tolerance of each other so as to slidably receive the transverse bar 120 within the opening 130 in a near tight fit and to effectively prevent relative axial rotation therebetween.

[0051 ] The linear translation of the bar 120 within the opening 130 caused by rotation of the pinion gear 132 causes a length of the transverse bar 120 between the proximal parts 22, 32 of the arms 20, 30 to extend and retract. The proximal parts 22, 32 of the arms 20, 30 are maintained parallel to each other by virtue of the perpendicular orientations of the transverse bar 120 and the opening 130 relative to their respect proximal parts 22, 32 of the arms 20, 30. The proximal parts 22, 32 of the arms 20, 30 are also maintained in a single plane by virtue of the complementary shaped polygonal cross sections of the transverse opening 130 and the transverse bar 120 and the small tolerance within which the transverse opening 130 receives the transverse bar 120 which effectively prevents relative axial rotation.

[0052] Accordingly, embodiments of the device 10 permit selective and progressive adjustment of a distance between the arms 20, 30 while maintaining the arms parallel and in a single plane (e.g. a horizontal plane) relative to each other.

[0053] The device 10 further includes a ratchet 140 for allowing linear movement of the transverse bar 120 in only one direction and preventing movement in the opposite direction. The ratchet 140 includes a lever 142 that is pivotally coupled to the proximal part 32 of the arm 30 comprising the transverse opening 130. The lever 142 is coupled to a pawl that engages the linear array of transverse teeth 122 or the pinion gear.

[0054] The ratchet 140 is configured to provide at least two settings, namely a setting that permits manual rotation of the butterfly shaped knob 134 in one direction to extend the length of the transverse bar 120 between the proximal parts 22, 32 and another setting that permits manual rotation of the butterfly shaped knob 134 in the opposite direction to retract the length of the transverse bar 120 between the proximal parts 22, 32.

[0055] In an embodiment, the ratchet 140 has a third setting to selectively prevent linear movement of the transverse bar 120 relative to the transverse opening 130. The third setting thereby locks the length of the transverse bar 120 between the proximal parts 22, 32 to thereby lock the arms 20, 30 at a desired distance apart relative to each other. Wire Holders

[0056] As illustrated in Figures 1 to 4, the distal ends 25, 35 of each one of the arms 20, 30 includes a recess 140, 150 at its distal end 25, 35 that is configured to receive a respective one of the wire holders 60, 70 therewithin.

[0057] Each recess 140, 150 is defined by a curved inwardly facing surface 142, 152 formed within the distal end 25, 35 of each arm 20, 30. In the illustrated embodiment, the curved surfaces 142, 152 are at least in part spherical. Each recess 140, 150 includes a top opening 143, 153 and a bottom opening 144, 154. Each holder 60, 70 is comprised of a body 61 , 71 having a curved shaped exterior surface 62, 72, or in the illustrated embodiment a spherically shaped exterior surface 62, 72. The exterior surface 62, 72 of each body 61 , 71 is dimensioned and shaped complementarily with the curved inwardly facing surface 142, 152 formed within the distal end 25, 35 of each arm 20, 30. Further, a diameter of the cross section of the spherical exterior surface 62, 72 of each body 61 , 71 and of the curved inwardly facing surface 142, 152 are within a small tolerance of each other so as to permit each body 61 , 71 to pivot in any direction about a single point as in the manner of a ball and socket mechanical arrangement.

[0058] As illustrated in Figure 4 in particular, the top opening 143, 153 of each recess 140, 150 is sized to permit the body 61 , 71 of each holder 60, 70 to be inserted therethrough and to thereby be positioned within the recesses 140, 150. The bottom opening 144, 154 of each recess 140, 150 is smaller than the diameter of the body 61 , 71 of each holder 60, 70 to prevent the holders 60, 70 from passing therethrough. In the illustrated embodiment, each recess 140, 150 is comprised of a hemispherical part 145, 155 immediately adjacent to the bottom opening 144, 154 that merges into a cylindrical and threaded part 146, 156 between the hemispherical part 145, 155 and the top opening 143, 153.

[0059] The spherical exterior surface 62, 72 of each body 61 , 71 includes a radial thread 141 , 151 around a narrow band. The radial thread 141 , 151 is adapted to be threadably received by the threaded cylindrical part 146, 156 of the recesses 140, 150. When the holders 60, 70 are received sufficiently within the recesses 140, 150 the radial thread 141 , 151 reaches the hemispherical part 145, 155.

[0060] Thus, the body 61 , 71 of each holder 60, 70 is supported by the hemispherical part 145, 155 of the inwardly facing surface 142, 152 of the recess 140, 150 whereby the body 61 , 71 of each holder can pivot multi- directionally about a single point at or near the centre of the hemispherical part 145, 155 of the recess 140, 150. The holders 60, 70 are pivotable about a central pivot point relative to the recesses 140, 150 up to about 20 degrees from a central axis Y1-Y1, Y2- Y2 passing through the central pivot point represented by the angle 61, 62. In alternative embodiments, the angle 61, 62 may be about 10 degrees or about 20 degrees or about 30 degrees, or any increment between 0 and 30 degrees.

[0061 ] The openings 65, 75 within each of the wire holders 60, 70 are comprised of a longitudinal passage 62, 72 extending axially through the respective bodies 61 , 71 of the wire holders 60, 70. An interior diameter of the longitudinal passage 62, 72 is marginally larger than the exterior diameter of a wire 2, 4.

[0062] A collet 64, 74 is provided at one end of the longitudinal passage 62, 72 that comprises an inner collar comprised of a set of jaws 64a, 74a, 64b, 74b defining a part of the longitudinal passage 62, 72. The jaws 64a, 74a, 64b, 74b include a radially outer thread 64c, 74c. The collet 64, 74 further includes an outer collar 66, 76 comprising a radially inner thread 66a, 76a. The outer collar 66, 76 and the jaws 64a, 74a, 64b, 74b are threadably coupled. Either the outer collar 66, 76 and the jaws 64a, 74a, 64b, 74b are tapered such that rotating the outer collar 66, 76 relative to the jaws 64a, 74a, 64b, 74b in opposite directions respectively tightens or releases the jaws 64a, 74a, 64b, 74b around the wire 2, 4 positioning therewithin. The outer collar 66, 76 includes a knurled outer surface 67, 77 to provide a grip for a thumb and finger of a user to manually tighten and release the wire 2,4. [0063] The device 10 includes a mechanism for restraining the position of the body 61 , 71 of each holder 60, 70 relative to the recess 140, 150. A knurled knob 147, 157 and lug 148, 158 are threadably coupled within a threaded opening 149, 159 that is oriented obliquely through the distal ends 25, 35 of each one of the arms 20, 30. The threaded opening 149, 159 passes through the curved inwardly facing surface 142, 152 such that an end of the lug 148, 158 is in communication with the recess 140, 150. In use, the position of the body 61 , 71 of each holder 60, 70 relative to the recess 140, 150 can be fixed by rotating the knurled knob 147, 157 to thereby tighten the lug 148, 158 against the exterior surface 62, 72 of the body 61 , 71 of the holder 60, 70. The knurled knobs 147, 157 each include a hexagonal recess 147a, 157a that is adapted to receive a hex key driver to rotate the knobs 147, 157 and thereby tighten or release the lugs 148, 158.

Elbow

[0064] The distal parts 24, 34 of the arms 20, 30 each include an intermediate pivot joint 29, 39. The pivot joint 29, 39 divides the distal parts 24, 34 into a stationary part 100, 110 and a pivoting part 105, 115. The stationary parts 100, 110 comprise the proximal ends 28, 38 of the distal parts 24, 34 of each arm 20, 30. The pivoting parts 105, 115 comprise the distal ends 25, 35 of each arm 20, 30 and also incorporate the recesses 140, 150 containing the wire holders 60, 70.

[0065] The pivot joints 29, 39 are each comprised of an elbow joint enabling the pivoting part 105, 115 to pivot about respective transverse axes X¹-X¹, X²- X² relative to the stationary parts 100, 110. Thus, the pivot joints 29, 39 permit the wire holders 60, 70 to pivot about the transverse axes X¹-X¹, X²-X² relative to the proximal parts of the arms 20, 30. The pivot joints 29, 39 provide for adjustment of the holders 60, 70 and the wires 2, 4 held thereby in a plane transverse to the plane in which the distance between the arms 20, 30 is adjustable as described above. For example, if the arms 20, 30 are movable relative to each other in a horizontal plane then the pivot joints 29, 39 provide for adjustment of the holders 60, 70 relative to the remainder of the arms 20, 30 in a sagittal plane.

Method

[0066] As illustrated in Figure 4, in use a wire 2, 4 is inserted through each one of the longitudinal passages 62, 72 extending axially through the respective bodies 61 , 71 of the wire holders 60, 70. An end of each of the wires 2, 4 is driven into a respective bone or bone fragment. A user grips the knurled outer surface 67, 77 of the outer collar 66, 76 to thereby rotate the outer collar 66, 76. Rotating the outer collars 66, 76 manually tightens the jaws 64a, 74a, 64b, 74b around the wires 2,4 so that the axial positions of the wires 2, 4 are fixed relative to the longitudinal passages 62, 72 of the wire holders 60, 70. The device 10 is then operable to adjust the positions of the bones or bone fragments relative to each other in different planes as described below.

[0067] The butterfly shaped knob 134 is rotated to selectively and progressively adjust the distance between the arms 20, 30 while maintaining the arms parallel and in a single plane (e.g. a horizontal plane) relative to each other. The user operates the lever 142 to select a setting of the ratchet 140 permitting manual rotation of the butterfly shaped knob 134 in one direction to increase the distance between the arms 20, 30. The bones or bone fragments in which the wires 2, 4 are embedded are thereby forced apart from each other (i.e. distraction).

[0068] The user can operate the lever 142 to select another setting of the ratchet 140 permitting manual rotation of the butterfly shaped knob 134 in the opposite direction to reduce the distance between the arms 20, 30. The bones or bone fragments in which the wires 2, 4 are embedded are thereby forced towards each other (i.e. compression).

[0069] The user can operate the lever 142 to select a third setting in which the ratchet 140 locks the arms 20, 30 at a desired distance apart relative to each other. The device 10 is thereby operable to hold the bones or bone fragments at a desired relative distance apart or compressed together.

[0070] Rotating the knurled knobs 41 , 51 of the actuator mechanisms 40, 50 progressively adjusts the overall lengths of the arms 20, 30. Adjustment of the lengths of the arms 20, 30 permits adjustment of the relative positions of the bones in a direction parallel to a plane of an interface between the bones or bone fragments. Accordingly, whereas the butterfly shaped knob 134 is rotated to adjust the compression or distraction distance between the bones or the bone fragments, adjustment of the lengths of the arms 20, 30 adjusts the relative positions of the bones or the bone fragments in a direction perpendicular to the compression or distraction direction.

[0071 ] The user can pivot each holder 60, 70 multi-directionally, preferably about a single point located at or near the centre of the hemispherical part 145, 155 of the recess 140, 150 up to about 20 degrees from a central axis Y1-Y1, Y2- Y2 passing through the central pivot point represented by the angle 01, 02. This may be achieved by gripping and moving the free ends of the wires 2, 4 fixed within the holders 60, 70. Thus, a user can adjust the positions of the bones or bone fragments, in which the other ends of the wires 2, 4 are embedded, relative to each other in the sagittal, coronal and frontal planes with fine precision. When a desired relative position of the bones or bone fragments is achieved the knurled knobs 147, 157 can be rotated to thereby tighten the lugs 148, 158 against the exterior surfaces 62, 72 of the body 61 , 71 of each holder 60, 70. In so doing, the position of the body 61 , 71 of each holder 60, 70 relative to the recess 140, 150 is fixed to thereby maintain the positions of the bones or bone fragments relative to each other in the sagittal, coronal and frontal planes.

[0072] Each threaded shaft 42, 52 is captured by the opening 45, 55 through the closed ends 21 , 31 of the proximal parts 22, 32 of the arms 20, 30 such that the threaded shaft does cannot move axially relative to the proximal parts 22, 32. The hollow longitudinal internal passage 23, 33 of the proximal parts 22, 32 are configured to receive the distal parts 24, 34 in a manner that permits relative longitudinal movement but to prevent relation rotational movement. In the illustrated embodiment, this is achieved by the exterior shape of the distal parts 24, 34 having a substantially polygonal (e.g. square) cross section and the interior shape of the longitudinal internal passage 23, 33 having a complementary shaped cross-section.

[0073] The pivot joints 29, 39 permit the pivoting parts 105, 115 of each arm 20, 30 supporting the wire holders 60, 70 to pivot passively about the transverse axes X1 -X1 , X2-X2. Thus, the wire holders 60, 70 can pivot passively relative to the arms 20, 30 in the plane of the interface between the bones or bone fragments.

[0074] While various embodiments of the invention have been set forth above, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover such modifications and variations as fall within the scope of the appended claims and their equivalents.

Claims

Claims:

1 . An orthopaedic distraction and compression device for positioning bones or bone fragments relative to each other, the device including: a pair of arms being movable relative to each other; each arm including a wire holder at a distal end thereof; the wire holder including an opening for receiving a wire axially therethrough; a wire engaging member for limiting axial movement of the wire relative to the holder; and the holder being pivotally coupled to the arm for allowing the wire to pivot relative to the arm.

2. The device of claim 1 , wherein at least one of the holders is pivotal multi- directionally relative to one of the arms for allowing the wire located within the holder to pivot multi-directionally relative to the arm.

3. The device of claim 1 or claim 2, wherein at least one of the holders and the wire positioned therethrough is rotatable about a central pivot point relative to one of the arms up to about 20 degrees from a central axis passing through the central pivot point.

4. The device of any one of the preceding claims, wherein at least one of the holders includes a body comprising a rounded exterior surface and at least one of the arms includes a rounded interior surface defining a recess shaped at least in part complementarily with the rounded exterior surface of the holder, wherein the rounded exterior surface of the holder is receivable within the recess.

5. The device of claim 5, wherein a small tolerance exists between a dimension of the rounded exterior surface of the holder and a dimension of the rounded interior surface of the arm whereby the holder is received within the recess in a tight fit.

6. The device of claim 5, wherein the rounded exterior surface is at least in part substantially spherical and the rounded interior surface is at least in part substantially spherical.

7. The device of any one of the preceding claims, including a restraining mechanism for selectively maintaining at least one of the holders and the wire positioned therethrough at a desired rotational position about the central pivot point relative to one of the arms.

8. The device of claim 7, wherein the restraining mechanism includes a manually rotatable threaded shaft received within a threaded opening within the arm, wherein manually tightening the threaded shaft causes the threaded shaft to engage the holder to prevent movement of the holder relative to the arm.

9. The device of any one of the preceding claims, wherein the overall length of at least one of the arms is adjustable.

10. The device of any one of the preceding claims, wherein at least one of the arms includes a proximal portion and a distal portion, wherein the proximal and distal portions are movably coupled to be extendable and retractable relative to each other.

11 . The device of claim 10, including an actuator mechanism for progressively extending and retracting the proximal and distal portions relative to each other to thereby adjust the overall length of the arm.

12. The device of claim 10 or claim 11 , wherein the actuator mechanism includes a rotatable threaded shaft located within a threaded opening whereby rotation of the shaft causes the shaft to translate axially within the opening to thereby extend and retract the distal portion relative to the proximal portion.

13. The device of any one of the preceding claims, wherein at least one of the arms includes a pivoting portion at the distal end at which the holder is coupled, wherein the pivoting portion is pivotally coupled at an elbow joint with the remainder of the arm for permitting the pivoting portion and the holder to pivot about a transverse axis relative to the remainder of the arm.

14. The device of any one of the preceding claims, wherein the arms are movably coupled together to be movable relative to each other in a plane.

15. The device of claim 14, wherein the arms are movable so that a distance between the arms is adjustable whilst the arms are maintained parallel to each other.

16. The device of claim 15, wherein a transverse bar extends between and links proximal ends of the arms, wherein the length of the bar between the proximal ends of the arms is adjustable to thereby adjust the distance between the arms.

17. The device of claim 16, wherein the bar is fixed to the proximal end of one of the arms and is moveable relative to the proximal end of the other one of the arms.

18. The device of claim 17, wherein the proximal end of the other one of the arms includes an opening for slidably receiving the rod therewithin and a rack and pinion gear mechanism for driving linear movement of the rod within the opening.

19. The device of claim 18, further including a ratchet for allowing linear movement of the rod in only one direction while preventing motion in the opposite direction.

20. The device of any one of the preceding claims, wherein the wire engaging member includes a mechanism for selectively clamping the wire within the opening of the wire holder and limiting axial movement of the wire relative to the holder. 21

21 . The device of any one of the preceding claims, wherein the mechanism for selectively clamping the wire includes a collar threadably coupled to a set of jaws wherein rotating the collar causes the jaws to tighten or loosen from engagement with the wire.

22. A surgical method for positioning bones or bone fragments relative to each other using an orthopaedic distraction and compression device, the method including: driving the ends of a two of wires into respective bones or bone fragments; positioning the wires axially within openings of a pair of wire holders pivotally coupled at distal ends of a pair of arms, operating wire engaging members to limit axial movement of the wires relative to the holders, moving the arms relative to each other; and pivoting the wire holders relative to the arms to thereby position the bones or bone fragments relative to each other.

23. The method of claim 22, including m ultidirectionally pivoting the wire holders relative to the arms to thereby m ultidirectionally pivot the wires positioned within the holders relative to the arms to thereby adjust the positions of the bones or bone fragments, in which the other ends of the wires are embedded, relative to each other in the sagittal, coronal and frontal planes.

24. The method of claim 23, including manually rotating a threaded shaft within a threaded opening in the arm to bring the threaded shaft into engagement with the holder to prevent movement of the holder relative to the arm.

25. The method of any one of claims 22 to 24, including operating an actuator mechanism for progressively extending or retracting proximal and distal portions of arms relative to each other to thereby adjust the relative position of the bones or bone fragments in a direction parallel to a plane of an interface between the bones or bone fragments. 22

26. The method of any one of claims 22 to 25, including manually rotating a pinion gear in meshing engagement with a linear gear provided on a transverse bar extending between the arms to progressively adjust a distance between the arms while maintaining the arms parallel and in a single plane to thereby compress or distract the bones or bone fragments.