WO2025118032A1

WO2025118032A1 - Bone fixation device

Info

Publication number: WO2025118032A1
Application number: PCT/AU2024/051318
Authority: WO
Inventors: Alistair George Royse; Colin Forbes ROYSE
Original assignee: Innovate Surgical Pty Ltd
Current assignee: Innovate Surgical Pty Ltd
Priority date: 2023-12-08
Filing date: 2024-12-06
Publication date: 2025-06-12
Anticipated expiration: 2026-06-08

Abstract

The present invention relates to a bone fixation device comprising: a guide block; and a tensioning band having a first end substantially fixed to the guide block, wherein a second end of the tensioning band is passed through the guide block, in use. The bone fixation device of the present invention may be adapted to be fixed to and encircle a bone that requires fixation to allow repair.

Description

BONE FIXATION DEVICE

FIELD OF INVENTION

[0001] The present invention relates to the field of medical surgery and to the fixation of bones in order to facilitate repair.

[0002] It will be convenient to hereinafter describe the invention in relation to a bone fixation device adapted to be fixed to and encircle the sternum, however it should be appreciated that the present invention is not limited to that use only.

BACKGROUND

[0003] Following a bone fracture, whether as a result of trauma or orthopaedic surgery, it is vitally important to keep the bone edges of the fracture aligned, adjacent and without movement for a 6-to-8-week period. This time is sufficient for new bone to form and provide strength to the union. Any foreign aids like metal plates or wires, or indeed external splints (like plaster of Paris splints) are used to achieve nothing more than prevention of movement at the fracture site, that is, stabilization. However, if movement occurs and the newly formed bone is broken at an early stage, proper healing will be delayed. If this happens frequently enough, then the two bone edges are adhered by scar tissue only (i.e. not by bone to bone union). The development of scar tissue between the two bone edges results in poor strength of the fracture site as well as chronic tenderness or pain.

[0004] More than 99% of cardiac surgery involves a midline division of the sternum into two halves (left and right), using a saw to divide the bone. This is a "fracture" of the bone. In 99.9% of cases worldwide, the two bone edges are reapposed using stainless steel wire which is passed through or around the bone and tensioned by twisting the wire (wire cerclage). [0005] Traditionally, closure of the sternum using stainless steel wires is associated with some degree of chronic pain in approximately 25% of cases, long-term. This may reflect imperfect bone to bone union from imperfect stabilization of the bone edges.

[0006] Further, the sternum (or ribs) may in fact represent the most difficult of all bones to immobilize at the fracture site. This is because people must continue to breathe, cough and move around. All of these activities result in distracting forces of the fracture site, and the most notable one is coughing (or sneezing). However, even breathing provides a reasonably large distraction force and moving (such as getting out of a chair using one's arms to assist) or many other activities such as opening a car door, the fridge door and so on, result in some distracting forces at the fracture site. Unlike many other fractures in orthopaedic surgery, one is not able to disable the use of the chest. For example, if a person fractured their arm, it may be placed in a sling and movement avoided in this manner, or if the leg was broken, crutches would be provided to prevent any weight-bearing and so on.

[0007] Finally, the events that create the greatest forces of distraction on the sternum or ribs are coughing and sneezing. Furthermore, the forces are not evenly distributed with far more force being applied to the lower chest than the upper chest due to the elasticity of the chest wall, cartilage components of ribs and the so called “bucket handle” movement of the ribs.

[0008] While there are bone fixation devices and systems currently available, these are typically difficult to use, or require specialized tools, or do not provide the necessary degree of stabilization/immobilization to achieve high strength bone healing. Further, certain prior art devices do not allow for rapid removal should, for example, the patient’s chest needs to be opened again under emergency circumstances. The present invention seeks to address one or more of the apparent shortcomings of previously available bone fixation devices.

[0009] It is to be appreciated that any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the present invention. Further, the discussion throughout this specification comes about due to the realisation of the inventor and/or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the invention in terms of the inventor’s knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art, on or before the priority date of the disclosure and claims herein.

SUMMARY OF INVENTION

[0010] It is an object of this invention to provide an improved bone fixation device.

[001 1] A further object of the present invention is to alleviate at least one disadvantage associated with the related art.

[0012] It is an object of the embodiments described herein to overcome or alleviate at least one of the above noted drawbacks of related publicly available art systems or to at least provide a useful alternative to related art systems.

[0013] In a first aspect of embodiments described herein there is provided a fixation device comprising: a guide block; and a tensioning band, wherein the tensioning band has a first end associated with the guide block, and a second end which is adapted to pass through the guide block. Preferably, the first end of the tensioning band is fixed to the guide block. Optionally, the tensioning band comprises a removable needle at its second end. Preferably, the guide block comprises a band entry port adapted to receive the second end of the tensioning band and a band exit port adapted to allow the second end of the tensioning band to pass therethrough. Optionally, the guide block comprises bone engagement members.

[0014] In a second aspect of embodiments described herein there is provided a method of clamping a bone using the bone fixation device comprising a guide block and a tensioning band having a first end associated with, preferably substantially fixed, to the guide block, the method including the step of temporarily restraining the tensioning band position with the bone edges reapposed by:

• positioning the guide block on the bone;

• passing a second end of the tensioning band around or through the bone;

• inserting the second end of the tensioning band into a band entry port of the guide block and out of a band exit port of the guide block;

• pulling on the second end of the tensioning band, whereby the tensioning band tightens around the bone to substantially reappose the bone edges; and

• bending the protruding part of the tensioning band to maintain tension in the tensioning band.

[0015] The method may include the additional steps of:

• positioning one or more sleeves (“swages”) over the second end of the tensioning band;

• using a tensioning tool to apply tension to the tensioning band to thereby compress and accurately reappose the bone edges;

• deforming one of the sleeves to thereby retain the applied tension in the tensioning band;

• and

• cutting the tensioning band to remove excess tensioning band.

[0016] Other aspects and preferred forms are disclosed in the specification and/or defined in the appended claims, forming a part of the description of the invention. While the present description focusses primarily on reapposition of the sternum, it is to be understood that the device and methodology described herein may find application in many orthopaedic situations where rigid fixation of a bone to allow efficient repair is required.

[0017] Further scope of applicability of embodiments of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure herein will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further disclosure, objects, advantages and aspects of preferred and other embodiments of the present application may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the disclosure herein, and in which:

Figure 1 illustrates a prior art bone fixation device: A -prior to installation; B -in use on a sternum; and C - illustration of a tensioning device.

Figure 2 is a series of illustrations of a bone fixation device according to an embodiment of the present invention. Figure 2A shows the entire device. Figure 2B shows the guide block and first end of the tensioning band. Figure 2C shows the underside of the guide block shown in Figure 2B. Figure 2D shows a needle attached to the second end of the tensioning band.

Figure 3 is a series of illustrations of a bone fixation device according to an embodiment of the present invention. Figure 3A shows the guide block and first end of the tensioning band. Figure 3B shows the underside of the guide block shown in Figure 3A. Figure 3C shows an exploded view of the guide block shown in Figure 3A.

Figure 4 is a series of illustrations showing the use of spacers/sleeves (swages) in conjunction with a bone fixation device according to an embodiment of the present invention. Figure 4A shows the spacers/sleeves (swages) in isolation. Figures 4B and 4C show the spacers/sleeves (swages) installed on the second end of the tensioning band, including a deformed sleeve. Figure 5 is a perspective view of a bone fixation device according to an embodiment of the present invention, comprising connecting bars according to an embodiment of the present invention.

Figure 6 is a medial view of the device illustrated in Figure 5.

Figure 7 shows perspective views of a bone fixation device according to an embodiment of the present invention, comprising a connecting panel according to an embodiment of the present invention.

Figure 8 shows perspective views of a bone fixation device according to an embodiment of the present invention, comprising a connecting panel according to a further embodiment of the present invention.

DETAILED DESCRIPTION

[0019] The inventors have performed a randomised controlled study into the use of the commercially available device (prior art) and compared it to conventional wire or multifilament cable cerclage. They found that the commercially available device promoted superior healing. The implication of this finding is that the inventive device which employs similar broad principles of bone stabilization will also provide for better stabilization of the fracture than the conventional wire or cable treatment.

[0020] Prior art devices typically involve the use of conventional orthopaedic plate technology which comprises a device that spans the fracture and is fixed to both sides of the fracture by the use of screws which limits movement of one side over the other (subluxation). A more recent development has been the addition of a band system to wrap around the fractured bone to provide additional compression force support. The use of a band which is wider than a wire of cable, spreads forces across a larger surface area of the bone than that achievable with conventional stainless-steel wires and is less prone to penetrate the bone surface. The conventional wire or cable cerclage involves passing the wire or cable around the bone once or twice and then twisting the wire under tension or applying tension to cables and using a metal crimp to maintain that tension with a custom tool.

[0021] The SternaLock360 device (see Figure 1 A) is a currently available device which is designed for use in supporting the sternum during fracture repair. This device uses an orthopaedic plate 10 in combination with a band 20. The combination of plate 10 and band 20 is used on the sternum because the forces acting on the sternum during normal activities are substantially greater than those encountered in other typically fractured bones, such as the arm or leg. Further, simply breathing results in movement of the ribs and sternum. It is clear that standard technologies are insufficient to immobilize the chest during fracture healing in some patients. For example, a few patients coughed with such force that the titanium band surrounding the sternum was disengaged from its restrain block entirely, resulting in total loss of bone edge stabalisation and the need for reoperation.

[0022] As illustrated in Figure 1 B, the plate 10 and band 20 of the SternaLock360 are used to appose the left 32 and the right 33 halves of the sternum. It is further shown that the Sternalock360 uses screws 15 to attach the plate 10 to the bone.

[0023] The principle of orthopaedic screw length measurement is that the screw should pass through the first thick cortical layer of bone, then through the soft marrow and then to engage (but not pass through) the deeper cortical bone. In this way, the sharp tip of the screw does not injure any structure underlying the bone.

[0024] The SternaLock360 also requires the use of a specialized tensioning device 40 with a screw thread to provide tension on the band bringing the two edges of the bone together, and then there are screws 15 placed through the plate 20 to hold the plate in place across the fracture line 34 in the sternum.

[0025] Another key consideration for closing the sternum is the occasional requirement to re-enter the sternum under rapid and emergency circumstances in order to evaculate clot around the heart or to address other immediately and lifethreatening problems requiring direct access to the heart. When a SternaLock360 device has been used, the surgeon requires a heavy-duty metal cutter to divide the band 20 and the plates 10. Additionally, the retained cut band and plate edges pose significant risks to the surgical team of injury to fingers on these sharp and serrated edges. While emergencies of this type represent 1% or less of cases, delays to reopening the sternum could result in death of the patient.

[0026] The device of the present invention seeks to provide an improved bone fixation device suitable for sternal fixation. While the present invention is described herein with specific reference to sternal fixation, the principles described are readily adaptable for use in relation to additional and alternative bone fractures at sites other than the sternum. These additional applications are intended to be encompassed by the present description.

[0027] The invention described herein is a major simplification of the technology (and technique) required to internally fixate the sternum (breastbone) following cardiac surgery. The technology simplifies both the manufacturing process leading to cheaper production, as well as to simplification of the technique of insertion leading to improved surgeon acceptance. Bone stabilisation occurs by way of three forces of restraint (1 ) compression applied by a tensioned band, (2) the surface of the guide blocks overlying both sides of the divided sternum seeking to prevent movement of one side over the other and (3) engagement members on the guide block actively entering the hard superficial cortex layer of the bone to further restrain movement of one side over the other of the divided sternum.

[0028] The present invention provides a bone fixation device comprising a guide block; and a tensioning band having a first end and a second end. The first end of the tensioning band is immobilized at, in or adjacent to the guide block. The second end of the tensioning band is adapted to be received through a band entry port into the guide block. In use, the second end of the band is passed through the guide block then pulled tight and optionally bent, whereby tension on the tensioning band is maintained in a temporary manner whereby the first stage of bone reapposition is performed without specific high tension yet being applied. In some embodiments, the tensioning band is passed around the fractured bone aided by a needle fixed to the second end of the tensioning band. Once the bone is encircled by the tensioning band, the needle is removed and the second end of the tensioning band is inserted into the band entry port of the guide block, through the guide block and out a band exit port. The tensioning band is then pulled tight whereby the tensioning band is brought to bear upon the outer surfaces of the fractured bone and the edges of the fractured bone are thereby brought into contact. There are no features within any embodiments of the guide block that are adapted to prevent the second end of the tensioning band from passing through the guide block in either direction.

[0029] In certain embodiments of the present invention, the guide block may further comprise bone engagement members. When the tensioning band is tightened around the fractured bone, the guide block is brought into close contact with the fractured bone and the bone engagement members bear against, and preferably pierce, only the superficial and hard or rigid part of the bone surface (the cortex), thereby fixing the fractured bone in the position in which it is to repair.

[0030] In further embodiments of the present invention, a band restraint may be incorporated into the device, either as a separate component or co-formed therewith. The band restraint may be employed to maintain a greater tension in the tensioning band than would be possible in the absence of the band restraint. Preferably, the band restraint is in the form of a sleeve applied to the tensioning band. More preferably, the band restraint is positioned around the tensioning band to prevent the second end of the tensioning band being able to pass, backwards, through the band exit port.

[0031] An exemplary embodiment of the present invention is illustrated in Figures 2A, 2B and 2C. A bone fixation device 100 of the present invention comprises a guide block 1 10 and a tensioning band 120. The tensioning band 120 having a first end 121 and a second end 122. In use, the tensioning band 120 is fixed at or near its first end 121 to the guide block 110 (see Figure 3C, for example). The free, second end 122 of the tensioning band 120 is passed around the sternum, or through the manubrium, then back into the guide block 110. Once the two halves of the sternum are aligned, the tensioning band 120 is pulled through the guide block 110. The tightening of the tensioning band 120 assists in bringing the two halves of the sternum together. Temporary restraint of tension may be achieved by bending the tensioning band at the exit port of the guide block 110.

[0032] In further embodiments of the present invention, such as illustrated in Figures 3A and 3B, bone engagement members 111 are positioned, or co-formed with, a bone-facing side 112 of the guide block 110. In use, as the tensioning band 120 is tightened, bone engagement members 111 are pressed against and into the underlying hard cortex forming the surface of the bone. The bone engagement members 111 essentially fix the guide block to the underlying bone and thereby eliminates the need for screws to fix the guide block 110 relative to the bone. The guide block overlies both sides of the fracture line in the sternum, acting to stabilise one side relative to the other and acting to prevent one side overriding the other (subluxation) and thereby maintaining accurate cortex to cortex apposition between the two sides which facilitated optimal bone healing.

[0033] Together, the bone engagement members 111 and guide block 110 of the inventive device perform a similar function to that of previous devices in that it is intended for the guide block 110 to span the bone fracture, whereby the bone is fixed in position for healing or repair. Unlike previous devices, the guide block 110 of the inventive device is not screwed to the bone. Engagement with the fractured bone is preferably achieved through bone engagement members 111 which are preferably coformed with the guide block 110. In the illustrated embodiment, the bone engagement members 11 1 are in the form of pointed projections, or teeth.

[0034] In certain embodiments of the present invention, the bone engagement members may be forcibly engaged to the bone prior to the tightening of the tensioning band 120, for example, by pushing the guide block 110 against the bone, or through the use of a hammer or mallet. In other embodiments, the tightening of the tensioning band 120 may force the bone engagement members 111 into the bone.

[0035] The tensioning band 120 comprises a first end 121 and a second end 122. The tensioning band is preferably a substantially flexible, flat band having a narrow, substantially rectangular cross-section. In order to function within the present invention, the first end 121 of the tensioning band must be securely fixed to or adjacent to the guide block 110. For example, in the illustrated embodiment (Figure 3C), the first end 121 is sandwiched within the guide block 1 10. In alternative, non-illustrated embodiments, such a structure may not be required. In an exemplary alternative embodiment, a portion of the first end of the tensioning band may comprise a folded over or folded back section, a sleeve may be adapted to move freely along the tensioning band but be substantially prevented from falling off the first end of the tensioning band by the folded over/back portion. In use, this alternative embodiment may function in a similar manner to the embodiments illustrated herein: the second end of the tensioning band may be passed around the bone requiring fixation, then passed through the sleeve in a similar manner to passing through the guide block.

[0036] It is intended that embodiments of the present invention include a guide block, or similar component, that allows the tensioning band to encircle a bone and pass back over the first end of the tensioning band and lie substantially parallel thereto, whereby the tensioning band may be then tightened without the second end of the tensioning band becoming displaced from its substantially parallel arrangement.

[0037] In use, the tensioning band 120 is adapted to be passed around the fractured bone and back to the guide block 110. Alternatively, the band may be passed through the manubrium (upper part of the sternum). The tensioning band 120 may therefore further comprise a needle 123 at its second end 122. The needle 123 is intended to facilitate the looping of the tensioning band 120 around or through the bone. The needle 123 is the removed before the second end 122 is passed through the guide block 1 10 for tensioning.

[0038] Typically, a plurality of fixation devices 100 would be used to fix the sternum, for example, one through the manubrium, and two or three around the body of the sternum. The fracture would run at right angles to the tensioning band 120, and the guide block 1 10 would straddle the fracture. The bone engagement members 1 11 of the guide block 110, when present, would pass into (or even through) the superficial and very rigid or hard cortex layer of the sternum and provide rigid fixation of the guide block 1 10 to the bone. [0039] Typically, one of the guide block 1 10 within a set to be used will not contain the engagement members 11 1 , and will have a flat profile in contact with the surface of the bone. This will typically be the first to be tensioned, whereby accurate reapposition of the bone edges is facilitated when the guide block 110 does not have the engagement members 111 which could otherwise, potentially, interfere with the initial reapposition of the bone edges. Once the two halves of the sternum are reapposed, then the remaining bands are tensions with guide blocks 110 containing the engagement members 111.

[0040] The guide block 1 10 further comprises a band entry port 113 and a band exit port 114. Wherein the band entry port 113 is adapted to receive a second end 122 of the tensioning band 120. The tensioning band 120 is able to be threaded into the guide block 1 10 via the band entry port 113 and exit the guide block 1 10 via a band exit port 114. Once through, the second end 122 of the tensioning band 120 may be bent to restrict reverse movement and loosening of the tensioning band 120.

[0041] Figure 3C illustrates the depth of the bone engagement members 111 from the guide block 110. It will be apparent to the skilled person how the bone engagement members 111 are intended to penetrate the cortex of the bone when force is applied. As noted above, a small hammer can be used to further apply downward pressure on the guide block 110 to assist with penetration of the bone engagement members 111 into the bone.

[0042] Figure 3C is a cross-sectional view of an embodiment of the guide block 110 according to an embodiment of the present invention. Preferably, as described above, the first end 121 of the tensioning band 120 is retained firmly by the guide block 110. In alternative embodiments of the invention, the first end 121 may be folded over a structure within the guide block 1 10 wherein tensioning of the tensioning band 120 causes the first end 121 to be held securely within the guide block 1 10.

[0043] Maintaining tension in the tensioning band 120 is an important aspect of the present invention which allows the bones to remain in a fixed position to allow proper and effective healing. In certain embodiments of the present invention, a restraint in the form of a sleeve (“swage”) 130 is located on the second end 122 of the tensioning band 120, i.e. the part that protrudes from the band exit port 1 14. In the illustrated embodiment (Figure 4A and 4B), the sleeve 130 is a metal component that is positioned around the tensioning band 120. In further embodiments, a gap in the sleeve 131 allows for easy manipulation and installation adjacent the second end 122 of the tensioning band 120, after deployment of the tensioning band 120 and tensioning. Once the tensioning band 120 has been tensioned to the required level, a laterally directed force on both sides of the sleeve 130 may be applied bringing the central portion of the sleeve 130 closer together to fix it to the tensioning band 120 and thus deforming the sleeve 130 to form a "waist" which would then permanently retain that applied force. Notably, this embodiment could employ a continuous sleeve (not illustrated), since the tensioning band 120 could be cut to length before slipping the sleeve on the second end 122 of the tensioning band 120.

[0044] In certain embodiments of the present invention, one or more sleeves 130 applied to the tensioning band 120 prevents slippage of the tensioning band 120 after tensioning.

[0045] Figure 4B illustrates the position of the sleeve 130 adjacent to the exit port 114 of the guide block 110. Once deformed and fixed in place adjacent the second end 122 of the tensioning band 120, the sleeve 130 would prevent the tensioning band 120 being drawn back through the band exit port 1 14 and thereby securely restrict movement of the tensioning band 120.

[0046] Figure 4A and 4B shows views of embodiments of the present invention that incorporate the use of a second sleeve 130A positioned between the band exit port 114 and the sleeve 130. The second sleeve 130A cannot be pulled through the band exit port 114 and effectively provides a spacer to allow easier manipulation and deformation of the sleeve 130. In certain embodiments of the present invention, the sleeve 130 may include a gap 131 to allow easy manipulation after an initial deployment and tensioning of the tensioning band 120. [0047] An advantage over previous devices is that the present inventive device may be readily removed in an emergency. Typically, an emergency re-entry occurs within hours to a couple of days after surgery, whereby there is no solid new bone formation as yet. Usually, the patient is about to enter cardiac arrest or has arrested, and the circumstances are extremely dire, and urgency is substantial. The present device would be easily removed, if required, by simply dividing the tensioning band with a metal cutter. Thereafter, the entire device would simply be removed from the chest with a single forceful traction on the guide block itself. This would be considerably superior to the existing devices, which require screws to be removed or a plate to be divided. Notably, the entirety of the inventive device is able to be removed, and no sharp or irregular metal edges remain that may pose a safety threat to the operating surgeon.

[0048] In summary, the presently described device could provide for all of the stability of standard plating engagement with the bone by way of the guide blocks exerting restraining pressure to the two sides of the divided sternum, and the sharp projections passing into the bone cortex itself, as well as all of the compression force being applied to the two halves of the sternum, and that force being retained.

[0049] The present invention also provides a method of using the device of the present invention. A non-limiting example of such a method is as follows: a) The needle at the end of the tensioning band, is passed around both sides of the sternum, then returned to the opposite side of the guide block from which it originates. The needle is then cut off. The cut second end of the tensioning band is then passed through the guide block to come and lie above the first end of the tensioning band (which originates from the guide block). Initially, hand tension placed on the tensioning band to bring to two sides of the sternum into close proximity so they touch - and then the band is bent at right angles to the block so that the tensioning band does not slip back into the guide block. b) Then the two sleeves are slipped over the cut second end of the tensioning band. The second end of the tensioning band is then passed through a tensioning tool, and then, for example, up to the circular tensioning “wheel” where the band is passed into the slit in an inverted manner (i.e. passed around the side of the circular wheel, and then into the slot from the aspect of the wheel most distant from the jaws/sternum). c) The tensioning wheel is then turned such that it continues to tension the tensioning band, whereby it becomes flattened from its position at right angles to the guide block, and come to lie parallel to the origin of the guide block. When the desired tension is reached, the second of the sleeves (furthest from the block) is crimped by the jaws of the tensioning tool.

[0050] In alternative embodiments, even greater rigidity of the chest wall could be achieved through the use of connecting bars 140, as illustrated in Figures 5 and 6. Alternatively the guide block may take the form of the sternal guide block 110 and with engagement members 111. By way of example, the plates at the upper end of the sternum will allow for retardation of movement at the lower end of the sternum due to the redistribution of lateral force along the length of the connecting bars 140. In other words, the rigid joining of a device at each end of the sternum provides rigidity along the full length of the sternum. The devices therefore act as a single unit rather than each individual band and plate acting in isolation to redistribute a distracting force from a first plate to second, adjacent, plate.

[0051] As illustrated, the connecting bars 140 may be locked in position by teeth 141 that interlock with the bone engagement members 111. In alternative embodiments, the connecting bars 140 do not have teeth. In such embodiments, it is envisaged that the connecting bars 140 may engage a flange on the guide block 1 10 (not shown), in an insertable fashion which would allow for some repositioning of the guide blocks 1 10 during deployment, but later having sufficient grip on the guide block 110, via the flange, to allow full redistribution of lateral forces between guide blocks 110. In this embodiment, the number of teeth on the side of guide block 110 are reduced to affect the use of a wider bar which then engages with end and central teeth.

[0052] While the device and inventive concept described herein has been described with reference to fractures of the sternum, the device and adaptations thereof may be used in other “flexible” bone systems. Fractured ribs, particularly ribs displaced due to more substantial force of injury, cause considerable morbidity in patients. The importance of rib fractures is generally underappreciated or underreported, and this is primarily because they are so difficult to treat.

[0053] There is no “non-operative” approach to the reduction (realignment) and fixation of rib fractures because there is no way of being able to satisfactorily stabilise the fracture externally. Since the patient still needs to breathe, move, cough, undergo activities of daily living and so on, it is simply not possible to immobilise the fracture edges, non-invasively. This results in significant pain (pain at a fracture site is principally related to movement). Also, in order to avoid pain, marked reduction in the excursion of breathing on the affected side frequently results in severe lung dysfunction due to interference in the normal mechanics of ventilation, pneumonia et cetera.

[0054] Therefore, whilst most severe and displaced rib fractures are not treated by operative intervention, considerable discomfort results. Usually, surgery is reserved for those where the lung dysfunction is so great that it interferes with the ability to breathe independently. Typically, a motor vehicle accident victim with a major chest injury will be on the ventilator in the ICU, and have multiple fractures at the front and the back of the chest, resulting in the chest wall being “sucked in” during inspiration, and “blown out” during expiration (“flail segment”), which seriously interferes with the mechanics of breathing and can result in respiratory failure. Therefore, the principle of surgical intervention is to rigidly fix the fracture site to re-establish the bony integrity of the chest wall, and facilitate breathing, as a way of being able to wean from the ventilator.

[0055] While there are a number of proprietary stabilisation devices to be used with rib fixation, these are far from satisfactory. [0056] Using the same principles as applied to the sternum, and described above, the tensioning band in this instance is passed around the rib on one side of the fracture, and then is passed through the guide block, and tensioned. The bone engagement members of the guide block will then further add to stability by passing into the bone of the rib. The same process is then applied to the rib on the other side of the fracture.

[0057] Given that ribs are smaller than the sternum, a range of guide block sizes is available so that a selection appropriate to the patient could be made. In other words, the two rib ends are mobilised and reduced so that they now align correctly, and the intended sites for encirclement of the rib on either side of the fracture is identified, then a measurement is made of the distance between these two points, and an appropriate length of guide block selected from a range of sizes available. Appropriately sized and curved connecting bars are also employed to provide support for the correct curvature of the ribs across the fracture site and to assist with the distribution of forces exerted in a novel manner.

[0058] The tensioning bands are then passed around the rib on either side of the fracture, and then passed through respective guide blocks, and then tensioned sequentially. Apart from the specific design features, the critical element here is the ease of use by the surgeon in deploying these two devices.

[0059] As noted above, the connecting bars can be used in respect of fractures of the sternum and ribs. In the case of the sternum, since each side of the sternum is a single piece of bone, one could deploy the tensioning band and guide block device in isolation without the connecting bar which runs parallel to the long axis of the sternum (thereby relying on the hemi-sternum to provide strength between these devices), i.e. the devices are not deployed on either side of the fracture. But if there is a problem, and the tensioning band “cuts through” the bone (not uncommon) then each side of the sternum is now effectively fractured in the short axis of the sternum in addition to the long axis. Hence, the use of connecting bars would act to distribute this lateral distracting force across the whole of the sternum rather than just in one site (greatest at the lower end). [0060] Connecting bars may have other uses. For fixation of every other fracture by the device of the present invention, the two tensioning bands/guide blocks would be installed on either side of the fracture. Thus, having a rigid connecting bar between the two tensioning bands/guide blocks is necessary in order to bridge the fracture and connect the two tensioning bands and guide blocks together rigidly, i.e. it acts as the “plate” used in contemporary devices, crossing from one side of the fracture to the other. In this scenario it would be much stronger (but less flexible) to manufacture two guide blocks and a connecting bar(s) than to use a separate serrated bar as in the case of the sternum; although this would still be possible and of course more flexible as fewer bespoke sizes would need to be manufactured.

[0061] Additionally, the “bar” is present on one side of the bone only, and logically the strength of the bar would be greater in one direction (force directed towards the bar) than in the opposite direction (force directed away from the bar). However, the skilled person could deploy two tensioning band/guide block and bar devices - on both sides of a fractured bone (or even more than two). Take for example, fixation of a rib, clavicle or humerus, if two devices of the present invention, on diametrically opposite sides of the bone (180 degrees apart), then there would be bars present on both sides of the bone and this would result in considerably greater strength. However, there are surgical reasons why this may not often be undertaken, since the degree of surgery separating tissues from the bone would be greater, the devascularisation (loss of blood supply) to the bone is potentially greater, and if the intent was to subsequently remove the metal device after 6 - 12 months, this would require greater surgical intervention in order to do so. Nevertheless, from the mechanics of bone strength this is a theoretical possibility.

[0062] Accordingly, the present invention also encompasses a bone fixation system comprising: a first fixation device; and a second fixation device; and a connector bar linking the first and second fixation devices. The bone fixation system may be employed in a method of clamping a bone, the method comprising the steps of:

• applying the guide block of the first fixation device to the bone, wherein the bone engagement members bear against the bone; • adjusting the connector bar to permit correct positioning of the guide blocks of the first and second fixation devices;

• applying the guide block of the second fixation device to the bone, wherein the bone engagement members bear against the bone;

• passing the second end of each tensioning band around or through the bone;

• inserting the second end of each tensioning band into a respective band entry port of a respective guide block and out of a band exit port of the guide block;

• pulling on the second end of each tensioning band, whereby the tensioning band tightens around the bone to pull the bone engagement members into the bone; and

• cutting each tensioning band to remove excess band.

[0063] As discussed in detail above, each tensioning band may be held in place by the guide block 1 10 in association with spacers/sleeves (swages) 130, 132.

[0064] It should noted that there are no features within the guide block that are adapted to prevent the tensioning band from passing through the guide block.

[0065] The above description focusses on the use of the present invention in respect of fractures of the sternum and ribs. However, the present invention is not intended to be so limited in its application. The present invention may be used for any bone that allows for “encirclement” by the tensioning band as the force of retention mechanism. Therefore, bones that are most suitable for devices of the present invention include the sternum and cylindrical bones such as larger/longer bones - femur, tibia, fibula, humerus, radius, ulna; smaller/shorter bones - hands/feet: metacarpals, phalanges (fingers/toes); ribs; and clavicle (collar bone). In all of these cases the connecting bars seek to maintain rigid orientation of the guide blocks for forces of all vectors thereby maintaining the relative position of the adjacent bone edges at all times irrespective of the nature or direction of forces applied. [0066] The mechanism of this aspect of the present invention allows guide blocks to be rigidly fixed on either side of a fracture by the tensioning band and guide block mechanism being a combination of encirclement and direct engagement of the cortical bone and a connecting bar of metal to then rigidly fix these two guide blocks together which crosses from one side of the fracture to the other.

[0067] In further embodiments of the present invention illustrated in Figures 7 and 8, an elongated plate 150 may be employed, wherein the elongated plate 150 comprises guide blocks, and associated tensioning bands 120, adjacent each end of the elongated plate 150. Two exemplary embodiments of such a device are shown herein. It will be apparent to the skilled person, that these embodiments may be used in similar situations to a device comprising one or more connecting bars. In particular, the device may be installed wherein a bone fracture is located between the tensioning bands 120, and the elongated plate 150 prevents or at least severely restricts relative movement of the fractured bone during healing. The device illustrated in Figure 8 includes an opening 151 in the elongated plate 150. In use, the opening 151 may allow examination of the underlying fracture and/or bone during healing. For example, ultrasound may be used to image the underlying fracture and/or bone through the opening 151. In the absence of an opening (see Figure 7), examination of the underlying fracture and/or bone would be difficult.

[0068] The device of the present invention has been described and illustrated in a manner that implies only encircling of bones by the tensioning band(s) 120. The skilled person will readily recognise that this is not always possible. For example, in some situations the tensioning band 120 must be passed through a bone in order to avoid other internal structures such as connected bones, or to provide a stronger installation. It is therefore envisaged that, in certain embodiments of the present invention, prior to installation the tensioning band 120 may include at its second end 122 a needle for passing through a bone. In such embodiments, the needle may be removed prior to the second end 122 being received in the band entry port 1 13.

[0069] As is typical for implanted devices, the bone fixation devices of the present invention are made of titanium, titanium alloys or medical grade stainless steel. [0070] For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” “interior,” “exterior,” and derivatives thereof shall relate to the invention as oriented in Figure 2A. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Additionally, unless otherwise specified, it is to be understood that discussion of a particular feature of component extending in or along a given direction or the like does not mean that the feature or component follows a straight line or axis in such a direction or that it only extends in such direction or on such a plane without other directional components or deviations, unless otherwise specified.

[0071] While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth.

[0072] As the present invention may be embodied in several forms without departing from the spirit of the essential characteristics of the invention, it should be understood that the above-described embodiments are not to limit the present invention unless otherwise specified, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims. The described embodiments are to be considered in all respects as illustrative only and not restrictive. [0073] Various modifications and equivalent arrangements are intended to be included within the spirit and scope of the invention and appended claims. Therefore, the specific embodiments are to be understood to be illustrative of the many ways in which the principles of the present invention may be practiced. In the following claims, means-plus-function clauses are intended to cover structures as performing the defined function and not only structural equivalents, but also equivalent structures. For example, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface to secure wooden parts together, in the environment of fastening wooden parts, a nail and a screw are equivalent structures.

[0074] When a Markush group or other grouping is used herein, all individual members of the group and all combinations and sub-combinations possible of the group members are intended to be individually included in the disclosure. Every combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated.

[0075] Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

[0076] As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. The broad term "comprising" is intended to encompass the narrower "consisting essentially of and the even narrower "consisting of." Thus, in any recitation herein of a phrase "comprising one or more claim element" (e.g., "comprising A), the phrase is intended to encompass the narrower, for example, "consisting essentially of A" and "consisting of A" Thus, the broader word "comprising" is intended to provide specific support in each use herein for either "consisting essentially of or "consisting of." The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

[0077] One of ordinary skill in the art will appreciate that materials and methods, other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by examples, preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

EMBODIMENTS

[0078] Embodiment 1 . A bone fixation device comprising: a guide block; and a tensioning band, wherein the tensioning band has a first end associated with the guide block, and a second end which is adapted to pass through the guide block.

[0079] Embodiment 2. The bone fixation device of embodiment 1 , wherein the first end of the tensioning band is fixed to the guide block.

[0080] Embodiment 3. The bone fixation device of embodiment 1 or embodiment 2, wherein the tensioning band comprises a removable needle at its second end. [0081] Embodiment 4. The bone fixation device of any one of embodiments 1 to

3, wherein the guide block comprises a band entry port adapted to receive the second end of the tensioning band and a band exit port adapted to allow the second end of the tensioning band to pass therethrough.

[0082] Embodiment 5. The bone fixation device of any one of embodiments 1 to

4, wherein the guide block comprises bone engagement members.

[0083] Embodiment 6. The bone fixation device of any one of embodiments 1 to

5, wherein the second end further comprising one or more deformable spacers or sleeves.

[0084] Embodiment 7. A method of clamping a bone using a bone fixation device according to any one of embodiments 1 to 6, the method comprising:

• positioning the guide block on the bone;

• passing a second end of the tensioning band around or through the bone;

[0085] Embodiment 8. The method of embodiment 7, further comprising the steps of:

• applying one or more deformable spacers or sleeves onto the protruding end of the tensioning band;

• using a tensioning tool to tension the tensioning band;

• deforming at least one of the deformable spacers or sleeves to prevent slippage of the tensioning band and retention of tension so applied. List of parts - Figures 2 to 8:

Claims

1 . A bone fixation device comprising: a guide block; and a tensioning band, wherein the tensioning band has a first end associated with the guide block, and a second end which is adapted to pass through the guide block.

2. The bone fixation device of claim 1 , wherein the first end of the tensioning band is fixed to the guide block.

3. The bone fixation device of claim 1 or claim 2, wherein the tensioning band comprises a removable needle at its second end.

4. The bone fixation device of any one of claims 1 to 3, wherein the guide block comprises a band entry port adapted to receive the second end of the tensioning band and a band exit port adapted to allow the second end of the tensioning band to pass therethrough.

5. The bone fixation device of any one of claims 1 to 4, wherein the guide block comprises bone engagement members.

6. The bone fixation device of any one of claims 1 to 5, wherein the second end further comprising one or more deformable spacers or sleeves.

7. A method of clamping a bone using a bone fixation device according to any one of claims 1 to 6, the method comprising:

• positioning the guide block on the bone;

• passing a second end of the tensioning band around or through the bone;

• inserting the second end of the tensioning band into a band entry port of the guide block and out of a band exit port of the guide block; • pulling on the second end of the tensioning band, whereby the tensioning band tightens around the bone to substantially reappose the bone edges; and

8. The method of claim 7, further comprising the steps of:

• using a tensioning tool to tension the tensioning band;

• deforming at least one of the deformable spacers or sleeves to prevent slippage of the tensioning band and retention of tension so applied.