External fixator, kit comprising an external fixator, and method for fixation

Abstract

The present invention provides an external fixator (1) for the fixation of joints such as the proximal interphalangeal (PIP) joint of the finger and a kit comprising a pair of such external fixators (1). The external fixator (1) comprises a rigid planar member made of a radiolucent material. The planar member comprises a circular through-hole (6) and a linear main slot (10) radially aligned with the through-hole (6). The external fixator (1) can also comprise a circular arc (8) of a radiopaque material centered on the through-hole (6), a tail (14) to assist its manipulation, and one or more auxiliary slots (20). The main and auxiliary slots (10, 20) have a toothed inner surface. In addition to the pair of identical external fixators (1), the kit may further comprise a plurality of Kirschner wires and one or more stoppers (not shown). In use, the pair of external fixators are placed laterally on each outer side of the patient's finger, and a first Kirschner wire of the Kirschner wires passes through the through-hole (6) in each external fixator (1) and is inserted through the condyle or head of the proximal phalanx. A second Kirschner wire of the Kirschner wires passes through the main slot (10) in each external fixator (1) and is inserted through the middle phalanx. A third Kirschner wire passes through a convenient auxiliary slot of the auxiliary slots (20) in each external fixator (1) and is inserted through, over, or under the middle phalanx or a bone fragment thereof. Movement of the second Kirschner wire along the main slot (10) in the direction of arrow D can be used to apply traction to the joint. Movement of the third Kirschner wire along one of the auxiliary slots of the auxiliary slots (20) towards the main slot (10) can be used to reduce subluxation of the middle phalanx or a bone fragment thereof. One or more stoppers engaging the toothed inner surfaces of the main and auxiliary slots (10, 20) then prevent rearward movement of the Kirschner wires along the main and / or auxiliary slots (10, 20). The present invention also provides a method comprising providing a pair of such external fixators (1) for use in surgery.

Description

Technical Field

[0001] The present invention relates to an external fixator for the fixation of a fractured joint, a kit comprising at least a pair of such external fixators, and a method of using a pair of such external fixators in surgery. The external fixator of the present invention is particularly suitable for the fixation of fractured joints within a digit (i.e., within a finger or toe), such as the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints of the finger, but can also be used for the fixation of fractured wrist joints, such as joints presenting a die-punch injury.

Background Art

[0002] The proximal interphalangeal (PIP) joint is located in each finger of the human hand between the condyle or head of the proximal phalanx (P1) and the base of the middle phalanx (P2). The distal interphalangeal (DIP) joint is located in each finger of the human hand between the condyle or head of the middle phalanx (P2) and the base of the distal phalanx (P3). The PIP and DIP joints are liable to one of several different fracture injuries that require surgical intervention. These fracture injuries include subluxation of the bone and bone fragments in both the dorsal (back of the hand) and volar (palm of the hand) directions, pilon fracture, compression of one or more bone fragments, and further large fragmentation of the bone. The goal of managing such fractures is to reduce bone and bone fragment subluxation and dislocation, and to restore joint congruity as much as possible. These goals can be met in several different ways, depending on the configuration of the fracture and the degree of bone fragmentation.

[0003] A common surgical technique used to manage such injuries is ligamentotaxis. In ligamentotaxis, a traction (pulling-apart) force is applied to the fractured joint. When traction is applied, the collateral ligaments and other soft tissues around the joint constrict and help pull any attached bone fragments into a desired alignment.

[0004] Several devices for applying traction to the PIP joint exist in the prior art. Since traction is to be applied to the fractured joint, such devices must be mechanically connected to the joint on both the proximal and distal sides of the fracture. This is typically accomplished by passing a Kirschner wire (K-wire) horizontally through the finger on each side of the proximal and distal sides of the fracture and then applying a traction force to the inserted K-wires.

[0005] A first known device for applying a traction force to the inserted K-wires is the Allison device described in Ng, C.Y. and Oliver, C.W.: "Fractures of the Proximal Interphalangeal Joint of the Fingers", Journal Of Bone & Joint Surgery (June 2009), vol.91-B, No.6, pages 705 - 12. In the Allison device, a pair of torsion springs are placed under tension and attached to the K-wires on the proximal and distal sides of the fracture to pull the K-wires apart. This device has several drawbacks as follows. First, the Allison device is difficult to adjust. Second, the Allison device cannot be used to correct any subluxation or to realign compressed bone fragments. Third, the traction force applied to the K-wires by the torsion springs depends on the amount by which the torsion springs are initially tensioned and cannot be easily controlled.

[0006] The second known device is the Suzuki frame described in Suzuki, Y., Matsunaga, T., Sato, S. and Yokoi, T.: "The Pins and Rubbers Traction System for Treatment of Comminuted Intraarticular Fractures and Fracture-Dislocations in the Hand", Journal of Hand Surgery (Edinburgh, Scotland) (February 1994), vol. 19, No. 1, pages 98-107. In the Suzuki frame, the long proximal K-wire is bent perpendicularly at both ends to complete the distal end of the distal K-wire. Hooks are bent over the ends of both the proximal and distal K-wires, and then a pair of elastic bands are extended and attached to the hooks between the proximal and distal K-wires on each outside of the finger to pull the K-wires apart. The traction force can be controlled by adjusting the number of twists and / or loops within each elastic band. However, this control is not precise. A third K-wire can similarly be inserted laterally to correct subluxation. However, this correction of subluxation is not dynamic or adjustable without removing the third K-wire and reinserting it in a new position. Thirdly, the Suzuki frame cannot be used to correct the central fragment of a pilon fracture.

[0007] The third known device is the Hynes and Giddins device described in Hynes, M.C. and Giddins, G.E.: "Dynamic External Fixation for Pilon Fractures of the Inter-Phalangeal Joints", Journal of Hand Surgery (Edinburgh, Scotland) (April 2001), vol. 26, No. 2, pages 122-124. In the Hynes and Giddins device, the proximal and distal K-wires are bent in a Z-shape to press against each other. The traction force can be controlled by adjusting the angle of the Z-shape within the wire arms. However, this control is not precise. A third K-wire can be inserted laterally as well to correct subluxation. However, the Hynes and Giddins device has the same drawback as the Suzuki frame in that the correction of subluxation is not dynamic or adjustable without removing the third K-wire and reinserting it in a new position, and also in that the Hynes and Giddins device cannot be used to correct the central fragment of a pilon fracture.

[0008] Another known device is the "Banjo" splint originally described in Robertson, R.C., Cawley, J.J. and Faris, A.M.: "Treatment of Fracture-Dislocation of the Interphalangeal Joints of the Hand", Journal of Bone Joint Surgery (1946), No. 28, pp. 68-70. The "Banjo" splint was similarly modernized in Schenck, R.R.: "Dynamic Traction and Early Passive Movement for Fractures of the Proximal Interphalangeal Joint", Journal of Hand Surgery [of America] (1986), No. 11, pp. 850-858. However, the Banjo splint is difficult to handle because of its large external frame and cannot be used to correct any subluxations or realign fragments compressed, for example, in a pilon fracture.

[0009] Other prior art devices are also described in U.S. Patent No. 6,565,563 B and U.S. Patent No. 8,246,561 B, both assigned to John M. Agee, U.S. Patent Application Publication No. 2012 / 0029517 A by Virak Tan, and EP0512792 by Smith & Nephew Richards, Inc.

[0010] Further prior art is described in CN109171844A, GB2489471A, and CN102783998A. CN109171844A describes an osteotomy device used in tibial osteotomy and femoral osteotomy having the function of spreading and fixing bone sutures. GB2489471A describes a finger fixator comprising two-part elongated strut elements and two pin-engageable elements spaced apart on the two-part elongated strut elements. The two-part elongated strut elements include spacing adjustment means for selectively adjusting and setting the spacing between the two pin-engageable elements. The spacing adjustment means may take the form of a rotatable member or a releasable sliding or nested mechanism. The strut elements may have spaced arcuate arms for receiving pins. CN102783998A describes a hinged traction external fixation device comprising two parallel screws, a rotation central pin, a maintenance reset pin, a fixing and pulling pin, and a nut.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0012] Accordingly, an object of the present invention is to provide an improved external fixator for fixing a fractured joint, a kit comprising at least a pair of such external fixators, and a method of using a pair of such external fixators in surgery.

Means for Solving the Problems

[0013] Accordingly, in a first aspect, the present invention provides an external fixator for fixing a fractured joint. The fixator comprises a rigid planar member having a pair of parallel opposing side surfaces. The planar member comprises circular through-holes perpendicular to the parallel opposing side surfaces and a linear main slot connecting the parallel opposing side surfaces to each other. The main slot is radially aligned with the through-holes and has a toothed inner surface.

[0014] As used herein, the term "external" means external to the patient's body. Such an external fixator has the following advantages. Taking the example where the external fixator is used for fixing the proximal interphalangeal (PIP) joint, the circular through-hole of the external fixator provides a drill guide for inserting the first Kirschner wire through the dot initially marked on the patient's skin through the through-hole and then laterally inserting the first Kirschner wire through the head of the proximal phalanx P1 at the location of the dot.

[0015] When the first Kirschner wire is inserted as such, the second Kirschner wire can also be inserted laterally into the middle phalanx P2 at a convenient location distal to the fracture complex while taking care to ensure that the second Kirschner wire is parallel to the first Kirschner wire. The external fixator of the present invention can be inserted over the first and second Kirschner wires with one Kirschner wire on each outer side of the finger by passing the first Kirschner wire through the circular through-holes of each external fixator and also passing the second Kirschner wire through the main slots of each external fixator. Traction can then be applied to the PIP joint by moving the second Kirschner wire along the main slot in a direction away from the through-hole, thereby increasing the separation between the first Kirschner wire and the second Kirschner wire.

[0016] The toothed inner surface of the main slot acts as a ratchet, which has the advantage of controlling the application of this traction and helping to prevent the second Kirschner wire from sliding back in the direction towards the through-hole. When the required amount of traction is applied, the second Kirschner wire can then be locked in place. This can be done, for example, by inserting a stopper into the main slot on the side of the second Kirschner wire close to the through-hole, or by joining the second Kirschner wire to a planar member, or both. Alternatively or additionally, another Kirschner wire, pin, or screw that is thicker than the width of the main slot can be inserted into the main slot on the side of the second Kirschner wire closer to the through-hole, and thus bites into the planar member on either side of the main slot into which this thicker Kirschner wire, pin, or screw is inserted. This thicker Kirschner wire, pin, or screw cannot slide along the main slot in either direction because it is thicker than the main slot. The exposed ends of the first and second Kirschner wires, and, if used, the exposed ends of the thicker Kirschner wire, pin, or screw can then be bent and / or sized down so as not to be in the way.

[0017] Furthermore, the external fixator of the present invention has the advantage that it can similarly be used to realign a bone fragment that is distally pushed into the middle phalanx P2 by inserting another Kirschner wire through the main slot in the external fixator between the pushed bone fragment and the middle phalanx P2. When this other Kirschner wire moves along the main slot in a direction towards the through-hole in the external fixator while the second Kirschner wire holds the middle phalanx P2 in a predetermined position relative to the proximal phalanx P1, this movement of the other Kirschner wire pushes the bone fragment towards the head of the proximal phalanx P1 and returns the bone fragment to an aligned state.

[0018] Advantageous embodiments of the present invention may be configured in accordance with any of the claims and / or part of the following description.

[0019] In some embodiments, the toothed inner surface of the main slot can comprise a first plurality of teeth, each tooth tapering in a direction along the main slot and away from the through-hole. This has the advantage of providing a ratchet that prevents the movement of a Kirschner wire inserted through the main slot in a direction towards the through-hole. Thus, the Kirschner wire can be held within the main slot to apply traction to P2.

[0020] In some embodiments, the rigid planar member may be made of a radiopaque material and the external fixator may further comprise a circular arc of a radiopaque material centered on the through-hole. Making the rigid planar member of a radiopaque material enables X-ray imaging through the rigid planar member of the fractured joint being fixed. Providing an external fixator having such an arc of a radiopaque material has the advantage of providing a guide that enables the circular through-hole of the fixator to be aligned with the center of rotation of the condyle or head of the proximal phalanx P1 by carefully aligning the arc of the radiopaque material and the contour of the head of the proximal phalanx P1 such that both the arc and the head appear together in the X-ray image. When positioned in this way, the patient's skin can be marked with a dot through the circular through-hole of the external fixator to indicate the center of rotation of the head of P1.

[0021] In some embodiments, the rigid planar member can further comprise auxiliary slots that connect parallel opposing side surfaces to each other, the auxiliary slots extending obliquely to the main slot away from the through hole and having a toothed inner surface. The addition of such auxiliary slots has the advantage that an external fixator can be similarly used to reduce subluxation of the middle phalanx P2 or a bone fragment thereof and to apply traction force to the PIP joint. Since the auxiliary slots are oblique to the main slot, the movement of the Kirschner wire along the auxiliary slots can be used to apply an appropriate oblique force to the middle phalanx P2 or a bone fragment thereof. The toothed inner surface of the auxiliary slot serves as a ratchet that has the advantage of controlling the movement of the Kirschner wire and preventing the Kirschner wire from sliding back in the direction opposite to its movement direction.

[0022] In some embodiments, the toothed inner surface of the auxiliary slot can comprise a second plurality of teeth, each tooth tapering in a direction along the auxiliary slot and towards the main slot. This has the advantage of providing a ratchet that impedes the movement of the Kirschner wire inserted through the auxiliary slot in a direction towards the main slot.

[0023] The auxiliary slot may be curved. If so, the direction of the curvature preferably is from the through hole towards the opposite end of the main slot. Preferably, however, the auxiliary slot is straight. This has the advantage that the amount of force that can be applied to the middle phalanx P2 or a bone fragment thereof by the movement of the Kirschner wire along the auxiliary slot can be more easily controlled.

[0024] In some embodiments, the rigid planar member may comprise a plurality of auxiliary slots arranged parallel to each other. This has the advantage that the plurality of auxiliary slots provide a corresponding plurality of different locations for the insertion of Kirschner wires through, over, or under the middle phalanx P2 or a bone fragment thereof, thereby enabling its subluxation to be corrected in a wide range of different fractures.

[0025] In some embodiments, the rigid planar member can comprise two such pluralities of the above auxiliary slots, each of the two pluralities of auxiliary slots being arranged on opposite sides of the main slot, the two pluralities of auxiliary slots being reflection-symmetric with respect to a line, and the main slot being present on the line. This has the advantage that one of the plurality of auxiliary slots can be used to reduce the dorsal subluxation of the middle phalanx P2 or a bone fragment thereof, and the other of the plurality of auxiliary slots can be used to reduce the palmar subluxation of the middle phalanx P2 or a bone fragment thereof simultaneously.

[0026] In some embodiments, the toothed inner surface of the main slot can comprise a third plurality of toothed portions located closer to the through-hole than the first plurality of toothed portions, each toothed portion tapering in a direction along the main slot and towards the through-hole. This has the advantage that such toothed portions provide a ratchet that prevents the movement of the Kirschner wire inserted through the main slot in a direction away from the through-hole. Therefore, the Kirschner wire may be held within the main slot in a position where it realigns the bone fragments within the pilon fracture in a direction towards the through-hole and towards the head of the proximal phalanx P1, while another Kirschner wire applies a traction force to P2 in the opposite direction by the first plurality of toothed portions.

[0027] In some embodiments, the rigid planar member can have a shape that is mirror symmetric about the longitudinal axis, and the through hole and the main slot are present on the longitudinal axis. In such a case, since the rigid planar member is not chiral and thus does not have a preferred correct orientation, it can be used on either side of the finger receiving PIP joint fixation without first having to be oriented in the correct direction, thereby having the advantage of saving time during surgery.

[0028] If the rigid planar member has a shape that is mirror symmetric as described above and the external fixator further comprises an arc of radiopaque material, in some embodiments, each end of the arc may define a line at an angle with the longitudinal axis, the angle being in the range of 100 degrees to 140 degrees, including 100 degrees and 140 degrees. This has the advantage that when the external fixator rotates through the same angle not aligned with the joint being fixed, the arc will be brought into alignment with the contour of the condyle or head of the proximal phalanx P1 in the X-ray image, and the external fixator can still be easily manipulated by the surgeon without interfering with the X-ray image.

[0029] If the rigid planar member has a shape that is mirror symmetric as described above, the shape of the rigid planar member can be any one of oblong, elliptical, oval, ovate, obovate, spatulate, rhomboidal, and deltoid. These preferred shapes have the advantage that one of the preferred shapes can be selected to match the shape of the tip of the finger receiving PIP joint fixation, which helps with the alignment of the fixator and the finger during surgery.

[0030] Alternatively, the rigid planar member may comprise a tail portion located at the opposite end of the main slot from the through-hole. Such a tail portion has the advantage of providing a handle that can be used by a surgeon to hold and manipulate the fixator during surgery. Such a tail portion has the advantage of providing a handle that can be used by a surgeon to hold and manipulate the fixator during surgery. In particular, since it is desirable to avoid exposure of the surgeon's finger to X-rays during X-ray radiography of the patient through the rigid planar member, the tail portion provides a handle by which the fixator can be manipulated using an instrument such as an arterial clip or a tourniquet. On the other hand, since the tail portion does not conform to the shape of the tip of the finger receiving the PIP joint fixation, there is no risk that such manipulation of the fixator will interfere with the finger.

[0031] If the rigid planar member actually comprises such a tail portion, preferably, the tail portion has a delta or bifurcated shape and comprises a flat or concave surface at the opposite end of the rigid planar member from the through-hole. This has the advantage that as the Kirschner wire is moved relative to the fixator, the flat or concave surface provides a convenient surface against which the surgeon can press when moving the Kirschner wire along the main slot in a direction away from the through-hole to hold the external fixator in place. Further, if the tail portion actually has such a delta or bifurcated shape, overall, the rigid planar member presents the appearance of a fish, where the through-hole and the main slot represent the eye and backbone of the fish, respectively, and, if one or more auxiliary slots are also present within the rigid planar member, the appearance of the other bones of the fish radiating from the backbone. This fish-like appearance has the advantage that it may be useful for accelerating the identification of a given portion of the fixator when training a surgeon during the use of the fixator, and for avoiding miscommunication, thereby saving time during surgery.

[0032] In some embodiments, the arc of the radiopaque material can be embedded within and enclosed by the rigid planar member. This can protect the radiopaque material from corrosion by the rigid planar member when the radiopaque material includes, for example, metal while the rigid planar member is, for example, an inert plastic material. Conversely, the radiopaque material has the advantage that there is no risk of interaction with other surgical elements (such as Kirschner wires) or, for example, the patient's finger or other limb when the fixator is installed if the patient has an allergy to a particular metal. However, in other embodiments, the arc of the radiopaque material can instead be provided as an insert within the planar member for ease of manufacture.

[0033] In a second aspect, the present invention also provides a kit comprising a pair of external fixators as described herein that are congruent. As used herein, the term "congruent" is used to mean that the pair of external fixators are geometrically congruent to each other. Such a kit provides a pair of external fixators having the same shape and size as each other, and thus has the advantage that the external fixators can be positioned on both outer sides of the finger receiving fixation of the PIP joint.

[0034] In some embodiments, the pair of external fixators within the kit may carry different markings and / or have different colors from each other. This has the advantage that the external fixators can subsequently be distinguishable from each other by their different markings and / or colors, which enables the surgeon to quickly and easily identify to a colleague which of the two fixators they are referring to, thereby saving time during surgery.

[0035] In some embodiments, the kit can further comprise a plurality of Kirschner wires, wherein a first Kirschner wire of the Kirschner wires has a diameter that passes through the through-holes in each of the pair of external fixators, and a second Kirschner wire of the Kirschner wires has a diameter that passes through the main slots in each of the pair of external fixators but is restricted by the toothed inner surface of the main slots to slide freely along the main slots. This has the advantage that the pair of external fixators are provided with Kirschner wires that are the correct size for use with the pair of external fixators.

[0036] If the kit actually comprises such a plurality of Kirschner wires, the sharp ends of the Kirschner wires in the kit may each be provided with a respective cap to protect the person handling the wire from the sharp ends. Each such cap may take the form of a soft silicone tube, a rubber bung, or the like.

[0037] Preferably, the main slot has a width that is the same as the diameter of the through-hole in the external fixator. This has the advantage that the first and second Kirschner wires can then also have the same diameter as each other and can therefore be used interchangeably.

[0038] In some embodiments, the kit may further comprise a stopper adapted to engage the toothed inner surface of the main slots in each of the pair of external fixators. Such a stopper has the advantage that it can be used to prevent the Kirschner wire from sliding along the main slot in a direction opposite to the direction in which the Kirschner wire is moved to apply force to the anatomical elements of the joint.

[0039] In some embodiments, when each of the rigid planar members of the pair of external fixators further comprises an auxiliary slot, the kit may further comprise a third Kirschner wire having a diameter that passes through the auxiliary slot but is restricted by the toothed inner surface of the auxiliary slot from freely sliding along the auxiliary slot. This has the advantage that the pair of external fixators are provided with Kirschner wires that are the correct size for use in the auxiliary slots of the external fixators.

[0040] Preferably, the auxiliary slot has the same width as the width of the main slot and the same width as the diameter of the through-hole in the external fixator. This has the advantage that the third Kirschner wire can then have the same diameter as the first and second Kirschner wires and can thus be used interchangeably with the first and second Kirschner wires.

[0041] When each of the rigid planar members of the pair of external fixators further comprises an auxiliary slot, in some embodiments, the kit may further comprise a stopper adapted to engage the toothed inner surface of the auxiliary slot in each of the external fixators of the pair of external fixators. Such a stopper has the advantage that it can be used to prevent the Kirschner wire from sliding along the auxiliary slot in a direction opposite to the direction in which the Kirschner wire is moved to apply force to the anatomical elements of the PIP joint.

[0042] In some embodiments, the stopper can comprise a cross-shaped head having arms joined to each other by a circular arc, and a body attached to the head, the body having a maximum width equal to the maximum separation between the toothed inner surfaces of each of the main and auxiliary slots. Such a stopper has the advantage that the shape of the head engages the circular cross-section of the cylindrical Kirschner wire, while the cylindrical body forms a friction fit with one of each of the main and auxiliary slots.

[0043] Alternatively or additionally, the stopper may be made of a thermoplastic material. Such a stopper has the advantage that it can be joined to the planar member at the desired location by applying heat to the stopper using an instrument such as, for example, a diathermy or electrocautery device until the stopper melts.

[0044] In some embodiments, the kit may further comprise a container of adhesive for joining at least one Kirschner wire of the at least one Kirschner wire to at least one external fixator of the pair of external fixators. The container may be, for example, a sachet or a tube. The adhesive may be, for example, an epoxy resin or a polystyrene cement and may be of medical grade.

[0045] In some embodiments, the kit may further comprise a Kirschner wire, pin, or screw having a diameter larger than the width of the main slot within each external fixator of the pair of external fixators. Such a thick-walled Kirschner wire, pin, or screw can be used to lock the position of one or more other Kirschner wires in place by inserting it into the main slot. This is because, when inserted, the thick-walled Kirschner wire, pin, or screw will not be able to slide in either direction along the main slot.

[0046] In some embodiments, the thick-walled Kirschner wire, pin, or screw can carry a different mark and / or have a different color than any other Kirschner wire in the kit, thereby enabling the surgeon to quickly and easily distinguish the thick-walled Kirschner wire from the other Kirschner wires.

[0047] In some embodiments, the kit may further comprise a pair of wire benders and / or wire cutters for bending and / or cutting at least one Kirschner wire of the Kirschner wires. Since the wire benders and / or wire cutters are not disposable and may be reusable after appropriate sterilization, for example, one pair of wire benders and / or wire cutters may be included only once for every five such kits supplied to, for example, the same surgeon or hospital.

[0048] In a third aspect, the present invention also provides a method comprising providing the combined pair of external fixators described herein for use in a surgical procedure.

[0049] The method includes laterally inserting a first Kirschner wire having a diameter passing through a through-hole in each external fixator of a pair of external fixators through a condyle of a first bone proximal to the fracture complex, and laterally inserting a second Kirschner wire having a diameter passing through a main slot in each external fixator of the pair of external fixators but restricted by a toothed inner surface of the main slot to freely slide along the main slot, through a second bone distal to the fracture complex and parallel to the first Kirschner wire; inserting the first external fixator of the pair of identical external fixators over the first and second Kirschner wires and into a first outer side of the fracture complex by passing the first Kirschner wire through a circular through-hole of the first external fixator and passing the second Kirschner wire through the main slot of the first external fixator; inserting the second external fixator of the pair of identical external fixators over the first and second Kirschner wires and into a second opposing outer side of the fracture complex by passing the first Kirschner wire through a circular through-hole of the second external fixator and passing the second Kirschner wire through the main slot of the second external fixator; applying traction force to the fracture complex by increasing the separation between the first Kirschner wire and the second Kirschner wire by moving the second Kirschner wire along the main slot of each external fixator of the pair of external fixators in a direction away from the through-hole of each external fixator of the pair of external fixators; and further including locking by at least one of inserting a stopper into the main slot on a side of the second Kirschner wire closer to the through-hole than the second Kirschner wire at a predetermined location of each external fixator of the pair of external fixators, joining the second Kirschner wire to a rigid planar member, and inserting a pin or screw having a thickness greater than the width of the main slot into the main slot on a side of the second Kirschner wire closer to the through-hole than the second Kirschner wire.

[0050] In some embodiments, when the fracture complex comprises a bone fragment that has suffered a subluxation and each rigid planar member of the pair of external fixators of the matching pair further comprises an auxiliary slot that connects parallel opposing sides of the rigid planar member to each other, the auxiliary slot extends obliquely away from the through hole with respect to the main slot of each rigid planar member of the rigid planar member, has a toothed inner surface, and the method passes through the auxiliary slot in each external fixator of the pair of external fixators, but the diameter that is restricted from sliding freely along the auxiliary slot by the toothed inner surface of the auxiliary slot. Inserting a third Kirschner wire horizontally through the auxiliary slot in each external fixator of the pair of external fixators and through the bone fragment that has suffered a subluxation, parallel to the first and second Kirschner wires; reducing the subluxation of the bone fragment by moving the third Kirschner wire in a direction towards the main slot of each external fixator of the matching pair of external fixators; placing the third Kirschner wire at a predetermined location in each external fixator of the matching pair of external fixators, on the side of the third Kirschner wire farther from the main slot than the third Kirschner wire, inserting a stopper, pin, or screw into the auxiliary slot, and joining the third Kirschner wire to the rigid planar member. It can further include locking by at least one of the above.

[0051] In some embodiments, where the fracture complex includes a bone fragment that is driven distally into the head of the first bone, the method includes inserting a fourth Kirschner wire having a diameter that passes through the main slot in each external fixator of the pair of external fixators but is restricted by the toothed inner surface of the main slot from sliding freely along the main slot, horizontally through the main slot in each external fixator of the pair of external fixators, between the driven bone fragment and the second bone, parallel to the first and second Kirschner wires; moving the fourth Kirschner wire along the main slot in each external fixator of the pair of external fixators in a direction toward the through-hole in each external fixator of the pair of external fixators; locking the fourth Kirschner wire by at least one of inserting a stopper, pin, or screw into the main slot on a side of the fourth Kirschner wire farther from the through-hole than the fourth Kirschner wire at a predetermined location in each external fixator of the pair of external fixators, and joining the fourth Kirschner wire to a rigid planar member.

[0052] In some embodiments, the rigid planar member of at least one external fixator of the pair of external fixators is made of a radiopaque material, and at least one external fixator of the pair of external fixators includes a circular arc of a radiopaque material centered on the through-hole of each external fixator of the external fixator. The method may further include aligning the through-hole of at least one external fixator of the pair of external fixators with the center of rotation of the head of the first bone by aligning the arc of the radiopaque material and the contour of the head of the first bone such that both the arc and the contour appear in the x-ray image; and marking the patient's skin through the through-hole of at least one external fixator of the pair of external fixators having the center of rotation of the head of the first bone.

[0053] Further features and advantages of the present invention will become apparent from the following detailed description given by way of example and with reference to the accompanying drawings.

Brief Description of the Drawings

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Figure 22

Figure 23

[0055] FIG. 1 schematically shows a first embodiment of an external fixator 1 for joint fixation. The external fixator 1 includes a rigid planar member 2 of an X-ray transmissive material, i.e., a material that is transmissive to X-rays, enabling fluoroscopic imaging of a patient through the planar member 2. For example, the planar member 2 may be made of a rigid plastic material manufactured by injection molding. The plastic material may include an antibacterial additive such as a silver compound. The planar member 2 has a pair of parallel opposing side surfaces 4a, 4b, which in this embodiment give the external fixator 1 an elliptical shape. The planar member 2 includes circular through-holes 6 and linear main slots 10. The through-holes 6 are oriented perpendicular to the parallel opposing side surfaces 4a, 4b of the planar member 2, and the main slots 10 connect the parallel opposing side surfaces 4a, 4b to each other. Thus, a straight rod or wire passing through the through-hole 6 or the main slot 10 will adopt an orientation perpendicular to the parallel opposing side surfaces 4a, 4b of the planar member 2.

[0056] Figure 1 also schematically shows an enlargement of the main slot 10. The main slot 10 is radially aligned with the through-hole 6. As shown by the enlargement in Figure 1, the main slot 10 has a pair of opposing inner surfaces 12, and the pair of opposing inner surfaces 12 are both serrated, corrugated, or saw-toothed. Therefore, a straight rod or wire passing through the main slot 10 is restricted by the pair of serrated inner surfaces 12 of the main slot 10 from freely sliding along the main slot 10 in the direction indicated by the arrow Y - Y'. The ability of the straight rod or wire to slide along the main slot 10 will depend on the diameter of the rod or wire relative to the width w of the main slot 10. If the rod or wire has a diameter that is only slightly smaller than the width w of the main slot 10, the rod or wire is slid along the main slot 10 by being pushed strongly enough in the direction indicated by the arrow Y - Y', inducing a slight flexure of the rigid planar member 2, thereby facilitating the pair of serrated inner surfaces 12 of the main slot 10 to move slightly away from each other and making it possible to temporarily increase the width w of the main slot 10 by a small amount due to the elastic deformation of the planar member 2. On the other hand, if the rod or wire has a diameter that is considerably smaller than the width w of the main slot 10, the ability of the rod or wire to slide along the main slot 10 will still be hindered by the serrated inner surfaces 12. For example, the main slot 10 may have a width w of about 1.2 mm, designed to accommodate a rod or wire having a diameter of 1.1 mm. Preferably, the width w of the main slot 10 should be substantially the same as the diameter of the through-hole 6 so that rods or wires of the same diameter can pass through both the through-hole 6 and the main slot 10 together.

[0057] Figure 2 schematically shows a second embodiment of the external fixator 1 for joint fixation. The external fixator 1 in Figure 2 is identical in all respects to the external fixator shown in Figure 1, except that it further comprises a semi-circular arc 8 of radiopaque material centered on the through-hole 6. Since the semi-circular arc 8 is made of radiopaque material, it will appear on the X-ray image during fluoroscopy of the patient through the rigid planar member 2. For example, the arc 8 may be made of a metal alloy such as metal or stainless steel. In this embodiment, the arc 8 is embedded within the planar member 2 and enclosed by the planar member 2. In this embodiment, the arc 8 is shown as being semi-circular, but the arc 8 may be any portion of the outer circumference of a circle, from a small circle of about 45 degrees to a complete circle including a complete circle. Further, although the semi-circular arc 8 of the embodiment of Figure 2 is shown as being continuous, in other possible embodiments, it may be discontinuous in a dashed and / or dotted manner. Finally, in the embodiment of Figure 2, the arc 8 is shown as having a finite width, but the arc 8 may alternatively be the inner or outer arcuate edge of a more extended piece of radiopaque material, provided that the piece of radiopaque material is not so extensive as to interfere with X-ray imaging of other anatomical elements of the patient.

[0058] Preferably, when the external fixator 1 is intended for fixation of a fractured PIP joint, the arc 8 should have a radius approximately equal to the average radius of the condyle or head of the proximal phalanx (P1) within an adult human finger. However, this is not exact. For example, a smaller radius arc 8 would be more suitable for fixation of the PIP joint within a child's finger. A range of external fixators 1 with different radius arcs 8 can be conveniently provided for fixation of PIP joints within different patients.

[0059] In the embodiment of FIG. 2, since the arc 8 is positioned and oriented within the external fixator 1 as shown in FIG. 2, when the external fixator 1 is longitudinally aligned with the middle phalanx P2 of the patient's finger, any interference of the arc 8 with any possible bone fragment of P2 in the case of a pilon fracture is avoided when taking an X-ray image. On the other hand, when the fixator 1 deviates from the alignment with P2 and rotates counterclockwise about the through-hole 6 through an angle of approximately 100 degrees to 140 degrees, the arc 8 will be brought into alignment with the contour of the condyle or head of the proximal phalanx P1 in the X-ray image. Therefore, with the fixator 1 in such an orientation, the fixator 1 can be accurately attached through the center of the condyle of P1 by inserting a straight rod or wire through the through-hole 6. Thereafter, by rotating the fixator 1 clockwise through approximately the same angle and back into alignment with P2 again, the fixator 1 can be similarly attached to the middle phalanx P2 by inserting another rod or wire through the main slot 10 without the X-ray image of P2 being obstructed by the arc 8.

[0060] Figure 3 schematically shows a third embodiment of the external fixator 1 for joint fixation. The external fixator 1 of Figure 3 is identical in all respects to the external fixator 1 of Figure 2, except that the rigid planar member 2 further comprises auxiliary slots 20 connecting the parallel opposing side surfaces 4a, 4b of the planar member 2 to each other. As shown in Figure 3, the auxiliary slots 20 extend at an angle oblique to the main slot 10, away from the through-hole 6. Like the main slot 10, the auxiliary slots 20 have a pair of opposing inner surfaces 22, which together are serrated, corrugated, or saw-toothed, as shown in the enlarged portion of the auxiliary slot 20 also included in Figure 2. Similar comments apply to a straight rod or wire passing through the auxiliary slot 20 as were made above in connection with a straight rod or wire passing through the main slot 10. Preferably, the width z of the auxiliary slot 20 is the same as the width w of the main slot 10, and the serrated inner surface 22 of the auxiliary slot 20 has the same shape and size as the serrated inner surface 12 of the main slot 10. In that case, a straight rod or wire of the same diameter as the straight rod or wire passing through the main slot 10 can pass through the auxiliary slot 20 and will behave in the same manner as the rod or wire passing through the main slot 10.

[0061] The auxiliary slots 20 can have any convenient shape and length. For example, the auxiliary slots 20 may be curved. However, the auxiliary slots 20 are preferably straight, as in the embodiment shown in Figure 3.

[0062] Figure 4 schematically shows a fourth embodiment of the external fixator 1 for joint fixation. The external fixator 1 of Figure 4 is identical in all respects to the external fixator 1 of Figure 2, except that it further comprises a plurality of auxiliary slots 20a, 20b, 20c, …, 20n of the same type as those shown and described above in connection with Figure 3. In other words, each of the plurality of auxiliary slots 20a, 20b, 20c, …, 20n has a pair of opposing inner surfaces 22, each of which together is serrated, corrugated, or saw-toothed.

[0063] The plurality of auxiliary slots 20a, 20b, 20c, …, 20n are arranged parallel to each other. However, the number of the auxiliary slots 20a, 20b, 20c, …, 20n is not fixed, and their intervals do not have to be constant. Any convenient number of auxiliary slots 20a, 20b, 20c, …, 20n can exist, and the auxiliary slots can have any convenient interval between adjacent pairs of auxiliary slots. For example, in the embodiment shown in FIG. 4, the plurality of auxiliary slots 20a, 20b, 20c, …, 20n are four in number and are spaced at regular intervals.

[0064] Furthermore, the plurality of auxiliary slots 20a, 20b, 20c, …, 20n do not have to have the same length as each other. In fact, the length of the auxiliary slots can be adapted to match the shape of the external fixator 1. However, the widths of the auxiliary slots are preferably the same as each other and also the same as the width of the main slot 10, so that a straight rod or wire of the same diameter can pass through any one of the plurality of auxiliary slots 20a, 20b, 20c, …, 20n and will behave in the same way as when passing through another one of the plurality of auxiliary slots 20a, 20b, 20c, …, 20n or through the main slot 10.

[0065] FIG. 5 schematically shows a fifth embodiment of the external fixator 1 for joint fixation. The external fixator 1 in FIG. 5 is the same in all respects as the external fixator 1 in FIG. 4, except that the rigid planar member 2 is provided with two pluralities of auxiliary slots 20a, 20b, 20c, …, 20n and 20p, 20q, 20r, …, 20z as shown and described above in connection with FIG. 3. Each of the two pluralities of auxiliary slots 20a, …, 20n and 20p, …, 20z is arranged on the opposite sides of the main slot 10. The two pluralities of auxiliary slots 20a, …, 20n and 20p, …, 20z are mirror-symmetrical to each other with respect to the line X-X' where the main slot 10 is located.

[0066] The external fixator 1 according to the present invention may be of any size. A range of different sizes may be conveniently provided to match different sizes of fingers within a certain range for different patients. For example, a smaller-sized external fixator 1 may be used for fixing the joints of a child's finger or toe than for fixing the corresponding joints of an adult's finger or toe. The planar member 2 of the external fixator 1 according to the present invention may have any shape. In other words, the contour or boundary of the planar member 2 may have any convenient form as long as the rigid member 2 is flat. The shape of the planar member 2 can be adapted during manufacture to match the shape of any joint for which the external fixator 1 is intended to be used for ligament taxis therewith. Preferably, however, as in the case of the sixth embodiment of the external fixator 1 shown in FIG. 6, the planar member 2 has a shape that is mirror-symmetrical with respect to the longitudinal axis L-L', and the through holes 6 and the main slots 10 are located on the longitudinal axis L-L'.

[0067] Figs. 7A to 7H show external fixators 1 of a plurality of different embodiments that conform to this preferred shape. Figs. 7A to 7H each show an embodiment of the external fixator 1 in which the shape of the planar member 2 is rectangular, elliptical, oval, leaf-shaped, obovate, spatula-shaped, rhomboid, and delta-shaped. The leaf-shaped and obovate forms differ only in that the orientation of the contour or boundary of the planar member 2 is reversed with respect to the positions of the through holes 6, the arc 8 of the radiopaque material, and the main slots 2 within the planar member 2.

[0068] Figure 8 schematically shows a seventh embodiment of the external fixator 1 for joint fixation. The external fixator 1 of Figure 8 is identical in all respects to the external fixator 1 of Figure 2, except that the planar member 2 comprises a tail portion 14 located at the opposite end of the main slot 10 from the through-hole 6. The tail portion 14 provides a handle that facilitates holding and / or manipulating the fixator during surgery. The tail portion 14 has a delta or bifurcated shape, similar to the case of the eighth embodiment of the external fixator 1 shown in Figure 9, and may comprise a flat or concave surface 140 at the opposite end of the planar member 2 from the through-hole 6. The surface 140 can be used by the surgeon to press against when moving the Kirschner wire in a direction away from the through-hole 6 along the main slot 10, thereby holding the fixator 1 in place as the Kirschner wire moves relative to the fixator. Further, the tail portion 14 having such a shape gives the fixator 1 the overall appearance of a fish. This has the advantage that during surgery and during training of the surgeon when using the fixator, the tail can be used to help accelerate the identification of the predetermined portion of the fixator 1.

[0069] FIG. 10 schematically shows a first embodiment of a kit 100 comprising a pair of identical external fixators 1a, 1b. In other words, the kit 100 comprises a pair of external fixators 1a, 1b having the same shape and size as each other. This includes that the circular through-holes 6a, 6b, the arcs 8a, 8b of radiopaque material, and the main slots 10a, 10b have the same shape and size as each other, and not only that, but the contours or boundaries of the planar members 2a, 2b have the same shape and size as each other. Each one of the pair of identical external fixators 1a, 1b can be of any type according to the present invention, including the embodiments of the external fixator 1 already described above in connection with any of FIGS. 1 - 9. However, in the embodiment shown in FIG. 10, the pair of external fixators 1a, 1b also carry different markings 16a, 16b, and the markings 16a, 16b enable the pair of external fixators 1a, 1b to be distinguished from each other. For example, the different markings 16a, 16b may be "L" and "R" indicating the left and right external fixators of the pair of external fixators 1a, 1b, respectively. Alternatively or additionally, the pair of external fixators 1a, 1b may have different colors. In use, the pair of external fixators 1a, 1b are arranged side by side on each outer side of the patient's finger in the same orientation as each other and with one side of the parallel opposing sides 4a, 4b of the first external fixator 1a of the external fixator facing one side of the parallel opposing sides 4a, 4b of the second external fixator 1b of the external fixator. Therefore, the different markings 16a, 16b and / or different colors of the pair of external fixators 1a, 1b can be used by the surgeon to quickly and easily identify for colleagues which of the two fixators they are referring to.

[0070] FIG. 11 schematically shows a second embodiment of a kit 101 comprising such a pair of combined external fixators 1a, 1b and two Kirschner wires 31, 32. The first Kirschner wire 31 of the Kirschner wires has a diameter that passes through the through holes 6a, 6b in each of the external fixators of the pair of external fixators 1a, 1b. The second Kirschner wire 32 of the Kirschner wires passes through the main slots 10a, 10b in each of the external fixators of the pair of external fixators 1a, 1b in the manner described above in connection with FIG. 1, but has a diameter that is restricted by the toothed inner surfaces 12a, 12b of the main slots 10a, 10b from sliding freely along the main slots 10a, 10b. When the width of the main slots 10a, 10b is the same as the diameter of the through holes 6a, 6b, the diameter of the first Kirschner wire 31 of the Kirschner wires may be the same as the diameter of the second Kirschner wire 32 of the Kirschner wires.

[0071] In use, the patient's finger is inserted between the pair of combined external fixators 1a, 1b. The first Kirschner wire 31 passes through the through hole 6a in the first external fixator 1a of the pair of external fixators, through the head of the proximal phalanx P1 of the patient's finger, and is inserted through the through hole 6b in the second external fixator 1b of the pair of external fixators. The second Kirschner wire 32 passes through the main slot 10a in the first external fixator 1a of the pair of external fixators, through the middle phalanx P2 of the patient's finger, and is inserted through the main slot 10b in the second external fixator 1b of the pair of external fixators. To apply traction to the PIP joint between P1 and P2, the second Kirschner wire 32 is moved along the main slots 10a, 10b in a direction away from the through holes 6a, 6b.

[0072] To prevent the second Kirschner wire 32 of the Kirschner wire from sliding back along the main slots 10a, 10b in the direction towards the through holes 6a, 6b, the kit may further comprise one or more stoppers 40 adapted to engage the toothed inner surfaces 12a, 12b of the main slots 10a, 10b, as shown in FIG. 12. FIG. 12 schematically shows a part of a third embodiment of a kit comprising such a stopper 40 as well as a pair of identical external fixators 1a, 1b and a plurality of Kirschner wires. The fitting of each stopper 40 with one of the main slots 10a, 10b may be, for example, a friction fit or a click fit. Each stopper 40 may be made of a rigid plastic material, for example, manufactured by injection molding. The plastic material may contain an antibacterial additive such as a silver compound.

[0073] Each stopper 40 may have any convenient shape for engaging the toothed inner surfaces 12a, 12b of the main slots 10a, 10b. For example, the stopper 40 may comprise a head 45 and a body 46. The head 45 enables the surgeon to manipulate the stopper 40 and insert the stopper 40 into one of the main slots 10a, 10b. The body 46 has a maximum width to fit between an adjacent pair of teeth on the inner surfaces 12a, 12b of the main slots 10a, 10b, but cannot slide along the main slots 10a, 10b from between one adjacent pair of teeth to between the next adjacent pair of teeth. FIG. 12 shows a stopper 40 inserted into one of the main slots 10a, 10b, abutting against the second Kirschner wire 32 of the Kirschner wire and being on the side of the Kirschner wire 32 closer to the through hole 6 than the Kirschner wire 32. Thus, the Kirschner wire 32 is prevented by the stopper 40 from sliding along the main slots 10a, 10b in the direction towards the through holes 6a, 6b.

[0074] FIG. 13 schematically shows a fourth embodiment of a kit 102 comprising a pair of external fixators 1a, 1b and three Kirschner wires 31, 32, 33. The pair of external fixators 1a, 1b is the same as the external fixator shown in the embodiment of FIG. 11, except that each external fixator 1a, 1b further comprises respective auxiliary slots 20a, 20b that connect the parallel opposing side surfaces of the planar members 2a, 2b to each other in the manner of the slots 20 of the external fixator 1 shown and described above in connection with FIG. 3. The first Kirschner wire 31 of the Kirschner wires has a diameter that passes through the through holes 6a, 6b in the respective external fixators of the pair of external fixators 1a, 1b. The second Kirschner wire 32 of the Kirschner wires passes through the main slots 10a, 10b in the respective external fixators of the pair of external fixators 1a, 1b in the manner described above in connection with FIG. 1, but has a diameter that is restricted by the toothed inner surfaces 12a, 12b of the main slots 10a, 10b from sliding freely along the main slots 10a, 10b. The third Kirschner wire 33 of the Kirschner wires passes through the auxiliary slots 20a, 20b in the respective external fixators of the pair of external fixators 1a, 1b, but has a diameter that is restricted by the toothed inner surfaces 22a, 22b of the auxiliary slots 20a, 20b from sliding freely along the auxiliary slots 20a, 20b. If the width of the auxiliary slots 20a, 20b is the same as the width of the main slots 10a, 10b and the diameter of the through holes 6a, 6b, the diameter of the third Kirschner wire 33 may be the same as the diameters of the first and second Kirschner wires 31, 32.

[0075] During use, the patient's finger is inserted between the paired external fixators 1a, 1b, and the first and second Kirschner wires 31, 32 are inserted as described in connection with FIG. 11. The third Kirschner wire 33 passes through the auxiliary slot 20a in the first external fixator 1a of the pair of external fixators, through the middle phalanx P2 of the patient's finger, above or below it (or, if P2 is fragmented, through the bone fragments of P2, above or below them), and is inserted through the auxiliary slot 20b in the second external fixator 1b of the pair of external fixators. To reduce subluxation (or its bone fragments) of the middle phalanx P2, the third Kirschner wire 33 is moved along the auxiliary slots 20a, 20b in the direction towards the through holes 6a, 6b.

[0076] To prevent the third Kirschner wire 33 of the Kirschner wires from sliding back along the auxiliary slots 20a, 20b, the kit may further comprise one or more stoppers 42 adapted to engage the toothed inner surfaces 22a, 22b of the auxiliary slots 20a, 20b, as shown in FIG. 14. FIG. 14 schematically shows a part of a fifth embodiment of a kit comprising such a stopper 42 as well as a pair of external fixators 1a, 1b and a plurality of Kirschner wires including the third Kirschner wire 33 of the Kirschner wires. The fitting of each stopper 42 with one of the auxiliary slots of the auxiliary slots 20a, 20b may be, for example, a friction fit or a click fit. Each stopper 42 may be made of a rigid plastic material manufactured, for example, by injection molding. The plastic material may contain an antibacterial additive such as a silver compound.

[0077] Each stopper 42 may have any convenient shape that engages the toothed inner surfaces 22a, 22b of the auxiliary slots 20a, 20b. For example, the stopper 42 may comprise a head 45 and a body 46 in a similar manner to the stopper 40 described above in connection with FIG. 11. The head 45 of the stopper 42 enables a surgeon to manipulate the stopper 42 and insert the stopper 42 into one of the auxiliary slots of the auxiliary slots 20a, 20b. The body 46 fits between an adjacent pair of toothed portions on the inner surfaces 22a, 22b of the auxiliary slots 20a, 20b and has a maximum width such that it cannot slide along the auxiliary slots 20a, 20b from between one adjacent pair of toothed portions to between the next adjacent pair of toothed portions.

[0078] The stopper 42 can be inserted into one of the auxiliary slots of the auxiliary slots 20a, 20b on either side of the Kirschner wire 33 depending on which direction the movement of the Kirschner wire 33 along one of the auxiliary slots of the auxiliary slots 20a, 20b is prevented. FIG. 14 shows an example where the stopper 42 is inserted into one of the auxiliary slots of the auxiliary slots 20a, 20b, abuts against a third Kirschner wire 33 of the Kirschner wire, and is on the side of the Kirschner wire 33 further from the through holes 6 than the Kirschner wire 33. Thus, the Kirschner wire 33 is prevented by the stopper 42 from sliding along the auxiliary slots 20a, 20b in a direction away from the through holes 6a, 6b.

[0079] Advantageously, the head 45 of either of the stoppers 40, 42 shown and described in connection with FIGS. 12 and 14 may have a shape that is complementary to the circular cross-section of the cylindrical Kirschner wires 32, 33. Both stoppers 40, 42 shown in FIGS. 12 and 14 have a disc-shaped head 45, which thus has a circular cross-section, but such a cross-section only engages tangentially with the cylindrical Kirschner wires. In contrast, FIG. 14A schematically shows a top view of an alternative embodiment of the stoppers 40, 42 with a cross-shaped head 45, the arms of the cross-shaped head 45 being joined to each other by circular arcs. Each of these circular arcs has a radius equal to but slightly larger than the radius of the Kirschner wires 32, 33 for which the stoppers 40, 42 are designed to be used with. Thus, when the stoppers 40, 42 of FIG. 14A are placed in contact with the Kirschner wires 32, 33, one of these circular arcs contacts the Kirschner wires 32, 33 in the manner shown in FIG. 14A.

[0080] FIG. 15 schematically shows a ninth embodiment of the external fixator 1 in its original position on the proximal interphalangeal (PIP) joint. The PIP joint comprises a proximal phalanx P1 and an intermediate phalanx P2. The PIP joint is formed by a condyle or head H1 of the proximal phalanx P1 and a base B2 of the intermediate phalanx P2. The external fixator 1 comprises a circular through-hole 6, a semi-circular arc 8 of radiopaque material, a main slot 10, a tail 14, and a plurality of auxiliary slots 20. To fix the external fixator 1 to the PIP joint, the arc 8 is carefully aligned with the contour of the head H1 of the proximal phalanx P1 using fluoroscopy until the through-hole 6 is centered on the head H1. The first Kirschner wire 31 is then inserted through the through-hole 6 and the center of the head H1 of the proximal phalanx P1. The second Kirschner wire 32 is then inserted through the main slot 10 and the intermediate phalanx P2 at a convenient location. To apply traction to the PIP joint, the second Kirschner wire 32 is moved along the main slot 10 in the direction of arrow D while pressing the surface 140 of the tail 14 in a direction opposite to arrow D, holding the fixator 1 in place as the second Kirschner wire 32 moves relative to the fixator 1. Finally, a stopper 40 is inserted into the main slot 10 and abuts against the second Kirschner wire 32 on the side of the second Kirschner wire 32 close to the through-hole 6, preventing the second Kirschner wire 32 from sliding back along the main slot 10 towards the through-hole 6, which would normally reduce the applied traction.

[0081] FIG. 15 shows only a single external fixator 1, but a second identical external fixator is similarly positioned on the opposite side of the PIP joint from the external fixator 1 shown in FIG. 15. Thus, the first and second Kirschner wires 31, 32 each exit the proximal phalanx P1 and the intermediate phalanx P2 and pass through the through-hole 6 and the main slot 10 of the second identical external fixator, respectively. A second stopper 40 is then similarly inserted into the main slot 10 of the second identical external fixator at a location opposite to the location of the stopper 40 shown in FIG. 15, also preventing the Kirschner wire 32 from sliding along the main slot 10 of the second identical external fixator.

[0082] Figure 16 schematically shows the external fixator 1 of FIG. 15 in the original position on another PIP joint. In this case, the middle phalanx P2 is fractured, resulting in a dorsal subluxation of the bone fragment BF and the middle phalanx P2. To fix the external fixator 1 to this PIP joint, the same steps described above in connection with FIG. 15 are first performed. The third Kirschner wire 33 is then inserted through an auxiliary slot and the middle phalanx P2 that are conveniently located in a plurality of auxiliary slots. To reduce the subluxation of the middle phalanx P2, the third Kirschner wire 33 is then moved in the direction of arrow A along the selected auxiliary slot 20. Finally, the stopper 42 is inserted into the same auxiliary slot 20 and abuts against the third Kirschner wire 33 on the side of the third Kirschner wire 33 far from the through hole 6, preventing the third Kirschner wire 33 from sliding away from the through hole 6 along this auxiliary slot 20, which would otherwise normally increase the dorsal subluxation of the middle phalanx P2 again.

[0083] Similar to the case of FIG. 15, a second identical external fixator located on the opposite side of the PIP joint is not shown in FIG. 16. However, when the third Kirschner wire 33 exits the middle phalanx P2, it passes through the corresponding auxiliary slot of the auxiliary slot of the second identical external fixator. The second stopper 42 is then similarly inserted into this auxiliary slot of the second identical external fixator at a location opposite to the location of the stopper 42 shown in FIG. 15, also preventing the third Kirschner wire 33 from sliding along this auxiliary slot of the second identical external fixator.

[0084] FIG. 17A schematically shows a fractured PIP joint, where the middle phalanx P2 shows multiple fractures, but the bone fragments of the middle phalanx P2 remain separated from each other. FIG. 17B schematically shows an embodiment of the external fixators 1 and two Kirschner wires 31, 32 fixed to the PIP joint of FIG. 17A for applying traction to the PIP joint. The external fixator 1 is fixed to the PIP joint using the same technique as described above in connection with FIG. 15.

[0085] FIG. 18A schematically shows another fractured PIP joint, where the middle phalanx P2 is broken, resulting in a dorsal subluxation of the bone fragment BF and the middle phalanx P2. FIGS. 18B and 18C schematically show successive stages when applying traction to the PIP joint and fixing the external fixator 1 of the same embodiment as shown in FIG. 17B and three Kirschner wires 31, 32, 33 to the PIP joint of FIG. 18A to reduce the dorsal subluxation of the middle phalanx P2. The external fixator 1 is fixed to the PIP joint using the same technique as described above in connection with FIG. 16.

[0086] FIG. 18B shows the state of the external fixator 1 after the third Kirschner wire 33 has been inserted through the auxiliary slot and the middle phalanx P2, which is conveniently located in a plurality of auxiliary slots within the external fixator 1, but before it is moved along the selected auxiliary slot. FIG. 18C shows the state of the external fixator 1 after the third Kirschner wire 33 has been moved along this auxiliary slot in the direction towards the main slot to reduce the subluxation of the middle phalanx P2, thereby returning the middle phalanx P2 to an aligned state with the proximal phalanx P1 and a contact state with the bone fragment BF. The third Kirschner wire 33 can then be held in place by appropriately positioned stoppers inserted into the auxiliary slot in the manner described above in connection with FIG. 16.

[0087] FIG. 19A schematically shows a PIP joint showing a pilon fracture, where the middle phalanx P2 is broken, resulting in a plurality of bone fragments BF. The first bone fragment BF1 of these bone fragments shows a dorsal subluxation, and the second bone fragment BF2 of these bone fragments shows a palmar subluxation. The third bone fragment BF3 of these bone fragments is distally pushed into the middle phalanx P2. FIGS. 19B - 19D schematically show successive stages when fixing the external fixator 1 of the same embodiment as shown in FIG. 17B and a plurality of Kirschner wires to the PIP joint of FIG. 19A to correct this pilon fracture.

[0088] First, in FIG. 19B, the first Kirschner wire 31 is inserted through the through-hole of the external fixator 1 and the knuckle or head of the proximal phalanx P1 in the manner described above in connection with FIG. 15. The second Kirschner wire 32a is then inserted through the main slot in the external fixator 1 and through the middle phalanx P2, and the third Kirschner wire 33a is inserted through the auxiliary slot and the bone fragment BF1, which is conveniently located in the auxiliary slot in the external fixator 1.

[0089] FIG. 19C shows the state of the external fixator 1 after the third Kirschner wire 33a has been moved along this auxiliary slot in the direction towards the main slot to reduce the dorsal subluxation of the bone fragment BF1. FIG. 19C also shows that the fourth Kirschner wire 32b has been inserted between the bone fragment BF3, which has been pushed through the main slot in the external fixator 1, and the middle phalanx P2. Further, the fifth Kirschner wire 33b has been inserted through another auxiliary slot and the bone fragment BF2, which is conveniently located in the auxiliary slot in the external fixator 1.

[0090] FIG. 19D shows the state of the external fixator 1 after the fifth Kirschner wire 33b has been moved along this auxiliary slot in the direction towards the main slot to reduce the palmar subluxation of the bone fragment BF2. Further, the fourth Kirschner wire 32b has been similarly moved along the main slot in the direction towards the through-hole in the external fixator 1, while the second Kirschner wire 32a holds the middle phalanx P2 in a predetermined position relative to the proximal phalanx P1. This movement of the fourth Kirschner wire 32b pushes the bone fragment BF3 towards the head of the proximal phalanx P1 and brings the bone fragment BF3 back into alignment with the bone fragments BF1 and BF2. All of the Kirschner wires can then be held in place by appropriately positioned stoppers inserted into the main and auxiliary slots in the manner described above in connection with FIGS. 15 and 16.

[0091] FIGS. 19A - 19D demonstrate that two or more Kirschner wires can be inserted through any of the main and auxiliary slots within an embodiment of the external fixator according to the present invention to correct a complex fracture of the PIP joint.

[0092] Figure 20 schematically shows a tenth embodiment of the external fixator 1. The external fixator 1 in Figure 20 has a form similar to the forms shown in Figures 17B, 18B - 18C, and 19B - 19D, but is different from them in several respects as follows.

[0093] First, the external fixator 1 in Figure 20 further includes a tail portion 14. The bifurcated tail portion 14 is symmetrically arranged with respect to the longitudinal axis L - L' of the planar member 2 of the fixator 1 and has a concave surface 140 from the through - hole 6 to the opposite end of the planar member 2. The tail portion 14 enables the operation of the fixator 1, for example, by providing a handle to which the fixator 1 can be held for attaching instruments such as artery clips or tourniquets as described above. The concave surface 140 provides a point of purchase where a surgeon can apply force to the fixator 1 in the direction shown in Figure 20 by the arrow labeled D'.

[0094] Second, the external fixator 1 in Figure 20, in this case, instead of having an arc 8 of radiopaque material centered in the through - hole 6 and being embedded and enclosed thereby in the planar member 2, includes a stainless - steel insert. The stainless - steel insert of the arc 8 is fastened in a groove 80 formed on the surface of the planar member 2, which is different from the external fixator 1 shown in Figures 17B, 18B - 18C, and 19B - 19D in that it is fastened in the groove 80 to facilitate manufacturing. The stainless - steel insert of the arc 8 is held in a predetermined position within the groove 80 by a lip 81 that protrudes above the groove 80. Each end of the arc 8 defines a line M - M' that makes an angle θ with the longitudinal axis L - L' of the planar member 2. In this embodiment, the angle θ is approximately equal to 120 degrees.

[0095] Furthermore, in order to improve the strength and hardness of the external fixator 1, the planar member 2 is surrounded by an outer peripheral wall 50 having a thickness thicker than the remaining portion of the planar member 2. For the same reason, the wall 50 similarly extends around the main slot 10 and around each of the auxiliary slots 20a, 20b, 20c, and 20d. The through-hole 6 is similarly surrounded by a circular wall 60. For example, the planar member 2 may have a thickness of about 2 to 3 mm, while the walls 50, 60 may each have a thickness of about 4 mm.

[0096] As can be seen in FIG. 20, the toothed inner surface of the main slot 10 includes a first plurality of toothed portions 121, and each of the first plurality of toothed portions 121 is tapered in a direction along the main slot 10 and away from the through-hole 6. Further, the toothed inner surface of each of the auxiliary slots 20a, 20b, 20c, and 20d respectively includes a second plurality of toothed portions 221, and each of the second plurality of toothed portions 221 is tapered in a direction along each of the auxiliary slots 20a, 20b, 20c, and 20d toward the main slot 10. Finally, the toothed inner surface of the main slot 10 further includes a third plurality of toothed portions 122, the third plurality of toothed portions 122 being located closer to the through-hole 6 than the first plurality of toothed portions 121, and each being tapered in a direction along the main slot 10 and toward the through-hole 6, and thus in a direction opposite to the direction in which the first plurality of toothed portions 121 are tapered.

[0097] The first plurality of serrations 121 enable the Kirschner wire to be ratcheted in the direction shown in FIG. 20 by the arrow labeled D as follows. If the Kirschner wire has a diameter that is smaller than the widest part of the serration 121 but larger than the narrowest part of the serration 121, when the wire moves from one serration of the serration 121 to the next adjacent serration, it will induce a slight flexion of the rigid planar member 2, thereby facilitating the inner serrated surfaces of the main slot 10 to move slightly away from each other and temporarily increasing the width of the main slot 10 by a small amount through the elastic deformation of the planar member 2. Therefore, the Kirschner wire can be pushed against the force applied to the concave surface 140 of the tail portion 14, and that force is applied in the direction shown in FIG. 20 by the arrow labeled D' and opposite to the direction of movement of the Kirschner wire. Thus, such movement of the Kirschner wire is similar to the movement described above in relation to the Kirschner wire 32a shown in FIGS. 19B - 19D.

[0098] On the other hand, the third plurality of serrations 122 within the main slot 10 enable the Kirschner wire to be ratcheted in the opposite direction as shown in FIG. 20 by the arrow labeled D' as follows. Again, if the Kirschner wire has a diameter that is smaller than the widest part of the serration 122 but larger than the narrowest part of the serration 122, when the wire moves from one serration of the serration 122 to the next adjacent serration, it will similarly induce a slight flexion of the rigid planar member 2. Therefore, such a Kirschner wire can be pushed in the direction shown in FIG. 20 by the arrow labeled D' to realign bone fragments of a pilon fracture, such as the bone fragment BF3 shown in FIG. 19A. Thus, the movement of the Kirschner wire in this case is similar to the movement described above in relation to the Kirschner wire 32b shown in FIGS. 19B - 19D.

[0099] Finally, the second plurality of toothed portions 221 formed in each of the auxiliary slots 20a, 20b, 20c, and 20d act in the same way as to induce a slight bending of the rigid planar member 2, thereby similarly enabling the Kirschner wire to be ratcheted in the direction towards the main slot 10. Therefore, such a Kirschner wire can be pushed along each of the auxiliary slots of the auxiliary slots 20a, 20b, 20c, and 20d and towards the main slot 10, for example, to realign the fragments of a Pilon fracture such as the bone fragments BF1 and BF2 shown in FIG. 19A. Thus, the movement of such a Kirschner wire in this case is similar to the movement described above in connection with the Kirschner wires 33a and 33b shown in FIGS. 19B to 19D.

[0100] Nevertheless, in the case of the first, second, and third pluralities of toothed portions 121, 221, 122, pushing against the dominant direction of the toothed portions, and thus, for example, releasing the traction already applied to the joint, or repositioning the Kirschner wire at different locations within one of the main slot 10 or each of the auxiliary slots 20a, 20b, 20c, and 20d, remains possible with the application of sufficient force in the right direction.

[0101] Generally, the external fixator according to the present invention allows various different joint fractures to be corrected by passing Kirschner wires through, over, or under different anatomical components of a joint and then applying forces to these anatomical components in a controlled manner by using the pair of external fixators of the present invention in combination. These forces can be applied by moving the Kirschner wires along the main slots and possibly the auxiliary slots of the external fixator in either direction of any of the respective slots. One or more Kirschner wires can be similarly inserted through the same slots according to the requirements of the fractured joint to be fixed and can be moved in the same or opposite directions relative to each other. There is likewise no limit to the maximum number of wires that can be accommodated within the slots of the fixator, up to the maximum number of wires that depends on the length of the slot, with respect to the number of Kirschner wires that can be used in combination with the external fixator according to the present invention.

[0102] Figure 21 schematically shows a first embodiment 200A of a method of using a pair of external fixators in combination in a surgical procedure. Method 200A includes 201 providing a pair of external fixators 1a, 1b of the type described above. In this embodiment, the rigid planar members 2a, 2b of each of the external fixators of the pair of external fixators 1a, 1b are made of a radiopaque material, and each of the external fixators of the pair of external fixators 1a, 1b includes circular arcs 8a, 8b of a radiopaque material centered on the through holes 6a, 6b of one of the respective external fixators of the external fixators 1a, 1b. The through holes 6a, 6b of each of the external fixators of the pair of external fixators 1a, 1b are aligned with the center of rotation of the proximal first bone fragment of the fracture complex 202a by aligning the circular arcs 8a, 8b of the radiopaque material with the contour of the first bone fragment of the first bone when both appear on an X-ray image. The patient's skin is then marked 202b through the through holes 6a, 6b of one of the respective external fixators of the pair of external fixators 1a, 1b having the center of rotation of the first bone fragment.

[0103] These marks are then used as guides or targets for inserting a first Kirschner wire 31 having a diameter that passes laterally through the nodules of the first bone and through the through holes 6a, 6b in each of the pair of external fixators 1a, 1b. Second Kirschner wires 32, 32a having a diameter that passes through the main slots 10a, 10b in each of the pair of external fixators 1a, 1b but is restricted by the toothed inner surfaces 12a, 12b of the main slots 10a, 10b to slide freely along the main slots 10a, 10b are inserted in a similar manner laterally through the distal second bone of the fracture complex and parallel to the first Kirschner wire 31 203b. The first and second Kirschner wires 31, 32, 32a can be inserted in this way in either order.

[0104] Next, the first external fixator 1a of the pair of identical external fixators is inserted over the first Kirschner wire 31 and the second Kirschner wires 32, 32a through the circular through hole 6a of the first external fixator 1a and through the main slot 10a of the first external fixator 1a, into the first outer side of the fracture complex 204a. The second external fixator 1b of the pair of identical external fixators is inserted in a similar manner over the first Kirschner wire 31 and the second Kirschner wires 32, 32a through the circular through hole 6b of the second external fixator 1b and through the main slot 10b of the second external fixator 1b, into the second opposing outer side of the fracture complex 204b. Again, the first and second external fixators of the pair of identical external fixators 1a, 1b are inserted in this way over the first and second Kirschner wires 31, 32, 32a in either order.

[0105] The traction force then increases the separation between the first Kirschner wire 31 and the second Kirschner wires 32, 32a by moving the second Kirschner wires 32, 32a along the main slots 10a, 10b of each of the external fixators of the pair of external fixators 1a, 1b in a direction away from the through holes 6a, 6b of each of the external fixators of the pair of external fixators. Finally, the second Kirschner wires 32, 32a are locked in place on each of the external fixators of the pair of external fixators 1a, 1b by at least one of the following techniques. Inserting a stopper of the type described above into the main slots 10a, 10b on the side of the second Kirschner wires 32, 32a closer to the through holes 6a, 6b than the second Kirschner wires 32, 32a 206a. For example, joining the second Kirschner wires 32, 32a to the rigid planar members 2a, 2b by an adhesive 206b. Inserting a pin or screw thicker than the width of the main slots 10a, 10b into the main slots 10a, 10b on the side of the second Kirschner wires 32, 32a closer to the through holes 6a, 6b than the second Kirschner wires 32, 32a 206c.

[0106] Figure 22 schematically shows a second embodiment 200B of a method of using a pair of external fixators in a surgical procedure. The method 200B includes at least one of the at least the same steps 201, 203a, 203b, 204a, 204b, 205 and 206a, 206b, 206c as described above in connection with Figure 21. In this embodiment, however, the fracture complex includes a bone fragment that has suffered a subluxation. To address this situation, the rigid planar members 2a, 2b of each of the pair of external fixators 1a, 1b provided have additional slots 20a, 20b connecting the parallel opposing sides 4a, 4b of the rigid planar members 2a, 2b to each other, the additional slots 20a, 20b extending obliquely away from the through holes 6 with respect to the main slots 10a, 10b of the respective rigid planar members of the rigid planar members 2a, 2b and having toothed inner surfaces 22a, 22b. The method thus further includes inserting third Kirschner wires 33, 33a, 33b having a diameter restricted by the toothed inner surfaces 22a, 22b of the additional slots 20a, 20b that pass through the additional slots 20a, 20b in each of the pair of external fixators 1a, 1b but are restricted from sliding freely along the additional slots 20a, 20b, laterally through the additional slots 20a, 20b in each of the pair of external fixators 1a, 1b and through the bone fragment that has suffered a subluxation, parallel to the first Kirschner wire 31 and the second Kirschner wires 32, 32a. Next, the subluxation of the bone fragment is reduced by moving the third Kirschner wires 33, 33a, 33b in a direction towards the main slots 10a, 10b of each of the pair of external fixators 1a, 1b. The third Kirschner wires 33, 33a, 33b are then locked in place in each of the pair of external fixators 1a, 1b by at least one of the following techniques.Inserting into the auxiliary slots 20a, 20b on the side of the third Kirchner steel wires 33, 33a, 33b that is farther from the main slots 10a, 10b than the third Kirchner steel wires 33, 33a, 33b, pins or screws having a diameter larger than the width of the auxiliary slots 20a, 20b in each external fixator of the stoppers or pairs of external fixators of the type described above, 216a and, for example, using an adhesive to join the third Kirchner steel wires 33, 33a, 33b to the hard planar members 2a, 2b, 216b.

[0107] Figure 23 schematically shows a third embodiment 200C of a method of using a pair of external fixators in a surgical procedure. The method 200C includes at least one of the at least same steps 201, 203a, 203b, 204a, 204b, 205 and 206a, 206b, 206c as described above in connection with FIG. 21 and can be used in combination with the method 200B described above in connection with FIG. 22 in a similar manner. In this embodiment, however, the fracture complex comprises a bone fragment that is pushed distally against the granules of the first bone. To address this situation, the method thus further includes inserting a fourth Kirschner wire 32b having a diameter that passes through the main slots 10a, 10b in each of the respective external fixators of the pair of external fixators 1a, 1b but is restricted from freely sliding along the main slots 10a, 10b by the toothed inner surfaces 12a, 12b of the main slots 10a, 10b, laterally through the main slots 10a, 10b in each of the respective external fixators of the pair of external fixators 1a, 1b, between the pushed bone fragment and the second bone, parallel to the first Kirschner wire 31 and the second Kirschner wires 32, 32a. The pushing of the bone fragment is then reduced by moving the fourth Kirschner wire 32b along the main slots 10a, 10b in each of the respective external fixators of the pair of external fixators 1a, 1b in a direction towards the through holes 6a, 6b in each of the respective external fixators of the pair of external fixators 1a, 1b. Finally, the fourth Kirschner wire 32b is locked in place in each of the respective external fixators of the pair of external fixators 1a, 1b by at least one of the following techniques: inserting a stopper of the type described above or a pin or screw having a diameter larger than the width of the main slots 10a, 10b in each of the respective external fixators of the pair of external fixators on the side of the fourth Kirschner wire 32b further from the through holes 6a, 6b than the fourth Kirschner wire 32b, and joining the fourth Kirschner wire 32b to the rigid planar members 2a, 2b.

[0108] The present invention has been described above with reference to specific examples and embodiments, but the scope of the present invention should not be considered to be limited thereby. Instead, it is defined by the appended claims. In particular, the present invention has been described with particular reference to and using the example of fixation of a fractured PIP joint. However, the external fixator and kit comprising the external fixator according to the present invention still have the same features as defined by the claims and are equally applicable more broadly for the fixation of other fractured joints, such as the DIP joint, as well as for use in ligamentotaxis, when appropriately adapted in terms of shape and size.

Claims

1. An external fixator (1, 1a, 1b) for fixing a fractured joint, comprising a rigid planar member (2) having a pair of parallel opposing side surfaces (4a, 4b), wherein said planar member (2) is, a circular through-hole (6) perpendicular to said parallel opposing side surfaces (4a, 4b), and a linear main slot (10) connecting said parallel opposing side surfaces (4a, 4b) to each other, the external fixator (1, 1a, 1b). The main slot (10) is radially aligned with the through-hole (6) and has a toothed inner surface (12).

2. The toothed inner surface (12) of the main slot (10) comprises a first plurality of toothed portions (121), each toothed portion tapering in a direction along the main slot (10) and away from the through-hole (6), the external fixator (1, 1a, 1b) according to claim 1.

3. The rigid planar member (2) is made of an X-ray transmissive material, and the external fixator (1, 1a, 1b) further comprises a circular arc (8) of an X-ray non-transmissive material centered on the through-hole (6), the external fixator (1, 1a, 1b) according to claim 1 or 2.

4. The rigid planar member (2) further comprises an auxiliary slot (20) connecting the parallel opposing side surfaces (4a, 4b) to each other, the auxiliary slot (20) extends obliquely to the main slot (10) away from the through-hole (6) and has a toothed inner surface (22), the external fixator (1, 1a, 1b) according to any one of claims 1 to 3.

5. The toothed inner surface (22) of the auxiliary slot (20) comprises a second plurality of toothed portions (221), each toothed portion (221) tapering in a direction along the auxiliary slot (20) and towards the main slot (10), the external fixator (1, 1a, 1b) according to claim 4.

6. The auxiliary slot (20) is linear, the external fixator (1, 1a, 1b) according to claim 4 or 5.

7. The rigid planar member (2) comprises a plurality of said auxiliary slots (20a, 20b, 20c,..., 20n) arranged parallel to each other, the external fixator (1) according to any one of claims 4 to 6.

8. The rigid planar member (2) comprises two such plural auxiliary slots (20a, 20b, 20c, …, 20n; 20p, 20q, 20r, …, 20z), each of the two plural auxiliary slots (20a, …, 20n; 20p, …, 20z) is disposed on the opposite side of the main slot (10), the two plural auxiliary slots (20a, …, 20n; 20p, …, 20z) are mirror-symmetrical to each other with respect to the line (X-X'), and the main slot (10) is present on the line (X-X'), the external fixator (1) according to claim 7.

9. The toothed inner surface (12) of the main slot (10) comprises a third plural toothed portions (122) located closer to the through hole (6) than the first plural toothed portions (121), and each toothed portion (122) is tapered in a direction along the main slot (10) and towards the through hole (6), the external fixator (1, 1a, 1b) according to any one of claims 2 to 8.

10. The rigid planar member (2) has a shape that is mirror-symmetrical with respect to the longitudinal axis (L-L'), and the through hole (6) and the main slot (10) are present on the longitudinal axis (L-L'), the external fixator (1, 1a, 1b) according to any one of claims 1 to 9.

11. The rigid planar member (2) is made of an X-ray transmissive material, and the external fixator (1, 1a, 1b) further comprises a circular arc (8) of an X-ray non-permeable material centered on the through hole (6), Each end of the arc (8) of the X-ray non-permeable material forms an angle (θ) with the longitudinal axis (L-L'), and the angle (θ) is in the range of 100 degrees to 140 degrees including 100 degrees and 140 degrees, defining a line (M-M') having the angle (θ), the external fixator (1, 1a, 1b) according to claim 10.

12. The shape of the rigid planar member (2) is any one of a rectangle, an ellipse, an oval, a leaf shape, an obovate shape, a spatula shape, a rhomboid shape, and a delta shape, the external fixator (1, 1a, 1b) according to claim 10 or 11.

13. The rigid planar member (2) comprises a tail portion (14) located at the opposite end of the main slot (10) from the through hole (6), the external fixator (1) according to any one of claims 1 to 12.

14. The external fixator (1) according to claim 13, wherein the tail part (14) has a delta shape or a branched shape and has a flat or concave surface (140) at the opposite end of the hard planar member (2) from the through hole (6).

15. The arc (8) of the radiopaque material is embedded inside the hard planar member (2) and enclosed by the hard planar member (2), and the external fixator (1, 1a, 1b) according to any one of claims 3 to 14.

16. A kit (100, 101, 102) comprising a pair of external fixators (1a, 1b) as defined in any one of claims 1 to 15.

17. The pair of external fixators (1a, 1b) of the kit (100, 101, 102) according to claim 16, which carry different marks (16a, 16b) and / or have different colors from each other.

18. Further comprising a plurality of Kirschner wires (31, 32, 32a, 32b, 33, 33a, 33b), wherein the first Kirschner wire (31) of the Kirschner wires has a diameter passing through the through holes (6a, 6b) inside each of the external fixators of the pair of external fixators (1a, 1b), wherein the second Kirschner wires (32, 32a, 32b) of the Kirschner wires pass through the main slots (10a, 10b) inside each of the external fixators of the pair of external fixators (1a, 1b), but the diameter that is restricted by the toothed inner surfaces (12a, 12b) of the main slots (10a, 10b) to slide freely along the main slots (10a, 10b). The kit (101, 102) according to claim 16 or 17.

19. The kit (101, 102) according to any one of claims 16 to 18, further comprising a stopper (40) adapted to engage with the toothed inner surfaces (12a, 12b) of the main slots (10a, 10b) inside each of the external fixators of the pair of external fixators (1a, 1b).

20. Inside each of the external fixators of the pair of external fixators (1a, 1b), the hard planar member (2) further comprises auxiliary slots (20) connecting the parallel opposing side surfaces (4a, 4b) to each other, and the auxiliary slots (20) are away from the through holes (6) and extend obliquely with respect to the main slots (10) and have toothed inner surfaces (22). The third Kirschner wires (33, 33a, 33b) of the Kirschner wires pass through the auxiliary slots (20a, 20b) inside each of the pair of external fixators (1a, 1b), but have a diameter that is restricted by the toothed inner surfaces (22a, 22b) of the auxiliary slots (20a, 20b) from sliding freely along the auxiliary slots (20a, 20b). The kit (102) according to claim 18 or 19.

21. The kit (102) according to claim 20, further comprising a stopper (42) adapted to engage the toothed inner surfaces (22a, 22b) of the auxiliary slots (20a, 20b) inside each of the pair of external fixators (1a, 1b).

22. The stoppers (40, 42) have a cross-shaped head (45) with arms joined to each other by circular arcs, and a body (46) attached to the head (45). The body (46) has a maximum width equal to the maximum separation between the respective toothed inner surfaces (12a, 12b; 22a, 22b) of the main and auxiliary slots (10a, 10b; 20a, 20b). The kit (101, 102) according to claim 19 or 21.

23. The stopper is made of a thermoplastic material. The kit (101, 102) according to any one of claims 19, 21, and 22.

24. The kit (101, 102) according to any one of claims 18 to 23, further comprising a container of an adhesive for joining at least one Kirschner wire of the Kirschner wires (31, 32, 32a, 32b, 33, 33a, 33b) to at least one of the pair of external fixators (1a, 1b).

25. The kit (101, 102) according to any one of claims 18 to 24, further comprising a Kirschner wire, a pin, or a screw having a diameter larger than the width (w) of the main slots (10a, 10b) inside each of the pair of external fixators (1a, 1b).

26. A method (200A, 200B, 200C) including providing (201) the combined pair of external fixators (1a, 1b) according to any one of claims 1 to 15 for use in surgery.

27. Insert a first Kirschner wire (31) having a diameter that passes through the through holes (6a, 6b) inside each of the pair of external fixators (1a, 1b) horizontally through the head of the first bone (P1) proximal to the fracture complex (203a). Insert a second Kirschner wire (32, 32a) having a diameter that passes through the main slots (10a, 10b) inside each of the pair of external fixators (1a, 1b) and is restricted by the toothed inner surfaces (12a, 12b) of the main slots (10a, 10b) from freely sliding along the main slots (10a, 10b) horizontally through the second bone (P2) distal to the fracture complex and parallel to the first Kirschner wire (31) (203b). By passing the first Kirschner wire (31) through the circular through hole (6a) of the first external fixator (1a) and the second Kirschner wire (32, 32a) through the main slot (10a) of the first external fixator (1a), insert the first external fixator (1a) of the pair of identical external fixators over the first (31) and second (32, 32a) Kirschner wires and into the first outer side of the fracture complex (204a). By passing the first Kirschner wire (31) through the circular through hole (6b) of the second external fixator (1b) and the second Kirschner wire (32, 32a) through the main slot (10b) of the second external fixator (1b), insert the second external fixator (1b) of the pair of identical external fixators over the first (31) and second (32, 32a) Kirschner wires and into the second opposing outer side of the fracture complex (204b). Apply traction to the fracture complex (205) by moving the second Kirschner wire (32, 32a) along the main slots (10a, 10b) of each of the pair of identical external fixators (1a, 1b) in a direction (D) away from the through holes (6a, 6b) of each external fixator of the pair of identical external fixators, thereby increasing the separation between the first (31) and second (32, 32a) Kirschner wires. placing the second Kirschner wire (32, 32a) at a predetermined location of each of the external fixators of the pair of identical external fixators (1a, 1b), inserting a stopper (40) into the main slots (10a, 10b) on the side of the second Kirschner wire (32, 32a) closer to the through holes (6a, 6b) than the second Kirschner wire (32, 32a) (206a), joining the second Kirschner wire (32, 32a) to the rigid planar members (2a, 2b) (206b), and inserting a pin or screw having a thickness greater than the width of the main slots (10a, 10b) into the main slots (10a, 10b) on the side of the second Kirschner wire (32, 32a) closer to the through holes (6a, 6b) than the second Kirschner wire (32, 32a) (206c) locking (206a, 206b, 206c) by at least one of the above The method (200A, 200B, 200C) according to claim 26, further comprising. **Claim 28** The fracture complex includes bone fragments (BF1, BF2) that have suffered subluxation, The rigid planar members (2a, 2b) of each of the external fixators of the pair of identical external fixators (1a, 1b) further include auxiliary slots (20a, 20b) that connect the parallel opposing side surfaces (4a, 4b) of the rigid planar members (2a, 2b) to each other, The auxiliary slots (20a, 20b) extend obliquely away from the through holes (6) with respect to the main slots (10) of the respective rigid planar members of the rigid planar members (2a, 2b) and have toothed inner surfaces (22a, 22b), The method includes inserting a third Kirschner wire (33, 33a, 33b) having a diameter restricted by the toothed inner surfaces (22a, 22b) of the auxiliary slots (20a, 20b) through the auxiliary slots (20a, 20b) inside each of the external fixators of the pair of external fixators (1a, 1b) but sliding freely along the auxiliary slots (20a, 20b), horizontally through the auxiliary slots (20a, 20b) inside each of the external fixators of the pair of external fixators (1a, 1b) and through the bone fragments (BF1, BF2) that have suffered subluxation, parallel to the first (31) and second (32, 32a) Kirschner wires (213). Reducing (215) the subluxation of the bone fragments (BF1, BF2) by moving the third Kirschner wire (33, 33a, 33b) in a direction (A) towards the main slots (10a, 10b) of the respective external fixators of the pair of identical external fixators (1a, 1b), placing the third Kirschner wire (33, 33a, 33b) at a predetermined location of each of the external fixators of the pair of identical external fixators (1a, 1b), inserting (216a) a stopper (42), a pin, or a screw into the auxiliary slots (20a, 20b) on the side of the third Kirschner wire (33, 33a, 33b) further away from the main slots (10a, 10b) than the third Kirschner wire (33, 33a, 33b), and joining (216b) the third Kirschner wire (33, 33a, 33b) to the rigid planar members (2a, 2b), locking (216a, 216b) by at least one of the above, The method (200B) according to claim 27, further comprising. **Claim 29** The fracture complex comprises a bone fragment (BF3) that is pushed distally against the condyle of the first bone (P1), and the method comprises inserting (223) a fourth Kirschner wire (33b) having a diameter restricted by the toothed inner surfaces (12a, 12b) of the main slots (10a, 10b) that passes through the main slots (10a, 10b) inside each of the external fixators of the pair of external fixators (1a, 1b) but slides freely along the main slots (10a, 10b), transversely between the pushed bone fragment (BF3) and the second bone (P2), parallel to the first (31) and second (32, 32a) Kirschner wires, moving (225) the fourth Kirschner wire (32b) along the main slots (10a, 10b) of each of the external fixators of the pair of identical external fixators (1a, 1b) in a direction towards the through holes (6a, 6b) of each of the external fixators of the pair of identical external fixators (1a, 1b), and placing the fourth Kirschner wire (32b) at a predetermined location of each of the external fixators of the pair of identical external fixators (1a, 1b), Inserting a stopper (40), a pin, or a screw into the main slots (10a, 10b) on the side of the fourth Kirschner wire (32b) farther from the through holes (6a, 6b) than the fourth Kirschner wire (32b) (226a), and joining the fourth Kirschner wire (32b) to the rigid planar members (2a, 2b) (226b) locking (226a, 226b) by at least one of the above The method (200C) according to claim 27 or 28, further comprising.

30. The rigid planar members (2a, 2b) of at least one of the external fixators (1a, 1b) of the combined pair are made of a radiopaque material, At least one of the external fixators (1a, 1b) of the combined pair of external fixators (1a, 1b) comprises circular arcs (8a, 8b) of a radiopaque material centered on the through holes (6a, 6b) of the respective external fixators of the external fixators (1a, 1b), The method comprises Aligning the arcs (8a, 8b) of the radiopaque material and the contour of the nodules of the first bone (P1) such that both the arcs (8a, 8b) and the contour appear in the X-ray image, thereby aligning the through holes (6a, 6b) of at least one of the external fixators (1a, 1b) of the combined pair of external fixators (1a, 1b) with the center of rotation of the nodules of the first bone (P1) (202a), and marking the patient's skin through the through holes (6a, 6b) of at least one of the external fixators (1a, 1b) of the combined pair of external fixators (1a, 1b) having the center of rotation of the nodules of the first bone (P1) (202b). The method (200A, 200B, 200C) according to any one of claims 27 to 29, further comprising.

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