Intramedullary fracture correction device and bone fixation device

Abstract

Various embodiments disclosed herein relate to bone fixation devices, including intramedullary fixation or fusion devices. The various devices disclosed include an intramedullary rod or device having a proximal portion and a distal portion. The proximal portion and the distal portion have articular ends that are connected to form a joint. The joint may be actuated to reduce the fracture and realign the bone after the device is inserted into the bone. Additionally, the device includes an adjustable joint formed between a proximal member and a distal member, the proximal member and the distal member being substantially radially movable relative to one another through the adjustable joint, and a drive mechanism operably coupled to the adjustable joint, the drive mechanism being configured and arranged to actuate the joint.

Description

[Technical field]

[0001] Various embodiments disclosed herein relate to bone fixation or fusion devices, including intramedullary fixation or fusion devices implanted in a target bone. In addition, other embodiments relate to systems and methods for the implantation and adjustment of bone fixation or fusion devices. [Background technology]

[0002] Fractures and dislocations, including fibula fractures and dislocations of the tibiofibular syndesmosis, are common injuries that commonly require correction with known fracture / dislocation fixation devices and procedures. Known fracture and / or dislocation fixation devices and systems typically include a central nail and a locking screw. Once the nail is implanted within the intramedullary canal of the target bone, there is little or no ability to adjust the nail or reduce the fracture. This lack of adjustability can result in inadequate fracture reduction, which can lead to inadequate or delayed healing and / or ankle displacement.

[0003] There is a need in the art for improved intramedullary devices and systems for the treatment of fractures and dislocations, including fibular fractures and tibiofibular syndesmosis. Summary of the Invention

[0004] Various bone fixation or fusion devices and related systems and methods are discussed herein. In Example 1, an intramedullary fracture correction device includes a first shaft, a second shaft operably connected to the first shaft at a joint, and a drive mechanism disposed within the second shaft to actuate the joint to move the first shaft and the second shaft between an insertion position and an articulation position.

[0005] Example 2 relates to the fracture correction device according to example 1, in which the drive mechanism comprises a drive shaft operably connected to a gear, the gear being operably connected to the first rod shaft.

[0006] Example 3 relates to the fracture correction device according to example 2, wherein the first shaft comprises a first engageable coupling mechanism, and the gear is operatively coupled to the first engageable coupling mechanism. Example 4 relates to the fracture correction device according to Example 2, wherein the drive shaft comprises an engageable coupling feature disposed at a distal end of the drive shaft, and the drive tool is connectable to the engageable coupling feature such that the drive tool rotates the drive shaft.

[0007] Example 5 relates to the fracture correction device according to example 1, wherein the first shaft further comprises a protrusion extending from a distal end of the first shaft, and the first engageable coupling mechanism is disposed on the protrusion.

[0008] Example 6 relates to the fracture correction device according to Example 5, wherein the second shaft further comprises a channel defined at a proximal end of the second shaft, and the protrusion is slidably disposed within and attached to the channel.

[0009] In Example 7, a bone fixation device comprises a device body comprising a proximal segment and a distal segment, an adjustable joint formed between a proximal member and a distal member, the proximal member and the distal member being substantially radially movable relative to one another via the adjustable joint, and a drive mechanism operably coupled to the adjustable joint, the drive mechanism being configured and arranged to actuate the joint.

[0010] Example 8 relates to the bone anchoring device according to example 7, in which the drive mechanism comprises a drive shaft and a gear operably connected to the drive shaft. Example 9 relates to the bone anchoring device according to example 8, in which the gear is operably connected to the proximal segment.

[0011] Example 10 relates to the bone anchoring device according to example 9, wherein the proximal segment comprises a first engageable coupling mechanism, and the gear is operably coupled to the first engageable coupling mechanism. Example 11 relates to the bone fixation device according to Example 8, wherein the drive shaft comprises a drive tool coupling feature disposed at a distal end of the drive shaft, and the drive tool is coupleable to the drive tool engageable coupling feature such that the drive tool can rotate the drive shaft.

[0012] Example 12 relates to the bone fixation device according to Example 7, further comprising one or more holes disposed in at least one of the proximal segment and the distal segment, the one or more holes being sized and shaped to receive an attachment screw.

[0013] Example 13 relates to the bone anchoring device according to example 7, wherein the distal segment comprises a generally bend sectioned along the length of the distal segment. In Example 14, a method for reducing a fracture includes inserting a device into an intramedullary canal of a target bone. The device includes a first shaft, a second shaft, the second shaft slidably coupled to the first shaft at a joint such that the first shaft and the second shaft are movable relative to one another along a path substantially transverse to a longitudinal axis of the first shaft, and a drive mechanism operably coupled to the joint. The method further includes actuating the drive mechanism to reduce the fracture of the target bone at the joint.

[0014] Example 15 relates to the method according to example 14, in which the joint comprises a first engageable coupling mechanism disposed at a distal end of the first shaft. Example 16 relates to the method according to example 14, wherein the drive mechanism comprises an elongate drive shaft disposed within and extending along the length of the second shaft, the elongate drive shaft comprising a driver tool attachment mechanism disposed at a distal end of the drive shaft, and a driven gear operably coupled to a proximal end of the elongate drive shaft, the driven gear operably coupled to the engageable first coupling mechanism.

[0015] Example 17 relates to the method according to example 14, in which the device further comprises one or more holes in at least one of the first shaft and the second shaft. Example 18 relates to the method according to example 17, further comprising the step of fixing the device to the target bone by inserting one or more screws through the one or more holes.

[0016] Example 19 relates to the method according to example 14, wherein the target bone is the fibula. Example 20 relates to the method according to Example 14, wherein the actuating the drive mechanism further comprises attaching a driver tool to the driver tool attachment mechanism and rotating the driver tool, whereby the first shaft and the second shaft move relative to each other along a path that is substantially transverse to the longitudinal axis of the first shaft, the path being an inclined path.

[0017] Although multiple embodiments are disclosed, still other embodiments of the present disclosure, exemplary embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes the present disclosure. As will be understood, the present disclosure can be modified in various obvious aspects without departing from the spirit and scope of the present disclosure. Thus, the drawings and detailed description should be regarded as illustrative in nature and not restrictive. [Brief description of the drawings]

[0018] [Figure 1A] Schematic diagram of a fractured tibia and fibula. [Figure 1B] Schematic diagram of a displaced fibula fracture. [Diagram 2] 1 illustrates a side view of a fixation device according to one implementation. [Diagram 3] 3 is a further side view of the fixation device of FIG. 2 in an articulated position according to one implementation. [Figure 4] FIG. 13 is a bottom perspective view of the fixation device and drive mechanism with some components removed for clarity, according to one implementation. [Figure 5A] FIG. 1 illustrates an exemplary rack and worm drive mechanism for incorporation into any of the embodiments herein, according to one embodiment. [Figure 5B] FIG. 13 illustrates another exemplary rack and pinion drive mechanism for incorporation into any of the embodiments herein, according to a further embodiment. [Figure 6A] FIG. 13 is a side view of a fixation device according to another implementation. [Figure 6B] 6B is a side view of an exemplary hole of the fixation device of FIG. 6A according to one implementation. [Figure 7A] 1 illustrates a side view of a patient's fibula with a fixation device implanted therein, according to one implementation. [Figure 7B] FIG. 7B is a posterior view of the patient's fibula (and foot) of FIG. 7A with a fixation device implanted therein, according to one implementation. [Figure 7C] FIG. 7B is a bottom perspective view of the patient's foot and fibula of FIG. 7A with a fixation device implanted therein, according to one implementation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Various embodiments disclosed and contemplated herein relate to adjustable intramedullary fixation and / or fusion devices and associated systems and methods. Each of the devices is configured to allow the device to be adjusted after implantation into the target bone. The devices disclosed and contemplated herein are described with respect to the fibula, but may be used with a variety of other bones, as will be understood by those skilled in the art. Certain implementations are specifically designed for fibula fractures and tibiofibular syndesmosis.

[0020] As shown in Figures 1A and 1B, in one exemplary fracture that may be treated by various embodiments herein, the fibula 2 may be fractured or dislocated, requiring surgical intervention to reduce and stabilize the injury. The fibula fracture 4 (or any target bone fracture) may be non-displaced (as shown in Figure 1A) or displaced (as shown in Figure 1B). The displaced fracture 4 must be reduced and realigned to allow for proper healing. Known fixation devices provide little or no ability to adjust the placement of the fixation device and / or reduce the fracture 4 after insertion of the fixation device. In contrast, various fixation device implementations disclosed and / or discussed herein have adjustable joints that allow for post-insertion adjustment of the fixation device.

[0021] As shown in Figures 2-4 and 6A-7C, a fibula fixation device (also referred to herein as a "nail" or "rod") 10 according to one implementation is an elongated device that is placed in the medullary canal of the fibula 2 or other target bone for fixation of the bone after injury. The device 10 has a device body 11 with an elongated proximal portion 12 and an elongated distal portion 14. The two portions 12, 14 of the body 11 are adjustably connected to each other at a joint 16. Figure 2 shows the device body 11 in an aligned position (also referred to herein as an "insertion position"). Figure 3 shows the device body 11 in an articulated position. Figure 4 shows a close-up view of the joint (also referred to herein as an "adjustment mechanism") 16.

[0022] The two sections 12, 14 of the body 11 are identified as a proximal section 12 and a distal section 14 based on the positioning of the body 11 within the target bone and the subsequent resulting positions of each of the sections 12, 14. That is, upon insertion into the target bone (as described in more detail below with respect to Figures 7A and 7B), the proximal section 12 is disposed toward the proximal end of the bone and the distal section 12 is disposed toward the distal end of the bone.

[0023] As shown in FIGS. 7A and 7B , the proximal portion (also referred to as the “first shaft”, “proximal member”, “proximal shaft”, “proximal pin”, or “first rod”) 12 of the device body 11 is an elongated structure having a blunt tip 13 at a proximal end to allow for insertion into the medullary canal. As best shown in FIGS. 2-4 , the distal end of the proximal shaft 12 forms a joint 16 with the proximal end of the distal shaft 14. The distal portion (also referred to as the “second shaft”, “distal member”, “distal shaft”, “distal pin”, or “second rod”) 14 is coupled to the proximal portion 12 at the proximal end of the distal portion 14 via the joint 16. The joint 16 is positioned such that the proximal portion 12 and the distal portion 14 can move relative to each other through the joint 16 in the direction of reference arrow A, which is substantially transverse to the longitudinal axis of the device body 11. That is, a drive mechanism 20 is provided which is capable of actuating the two shafts 12 , 14 to move substantially radially relative to one another at the joint 16 .

[0024] In the particular embodiment described herein, the joint 16 is configured as follows: the distal end of the proximal shaft 12 has an engageable mechanism or feature 18 disposed thereon, as shown, that is engageably and movably coupled to a driven gear (also referred to herein as a "cam drive" or "worm") 22 on the proximal end of the distal shaft 14. In one exemplary implementation as shown, the engageable mechanism 18 is a plurality of grooves 18 that may engageably couple to threads or teeth of the driven gear 22 such that rotation of the gear 22 causes movement of the engageable mechanism 18 (and thus the proximal shaft 12). Alternatively, the engageable mechanism 18 may be any known structure, feature, or mechanism that may also engageably couple to a driven gear, including teeth, threads, and the like. Further, driven gear 22 may be any known type of gear and therefore may have any type of engageable structure that may be engageably coupled to engageable mechanism or structure 18 such that rotation of gear 22 may cause movement of mechanism 18.

[0025] As best shown in FIG. 4, according to one particular implementation, the engageable feature or structure 18 is disposed or formed on a protrusion 19 disposed on the distal end of the proximal shaft 12. Alternatively, the feature 18 may be disposed or formed directly on the distal end of the proximal shaft 12. Additionally, in certain embodiments, including the device shown in FIG. 4, the driven gear 22 is disposed at a location that is a distance distal from the proximal end of the distal shaft 14. That is, the proximal end of the distal shaft 14 has a channel 21 defined therein such that the threads or teeth of the gear 22 are disposed within the channel 21. In such an implementation, the protrusion 19 of the proximal shaft is disposed within the channel 21 such that the engageable feature or structure 18 on the protrusion 19 is coupled with the teeth or threads of the gear 22. According to certain embodiments, the protrusion 19 has a coupling mechanism that slidably engages and couples with a coupling mechanism associated with the channel 21. This ensures that the two shafts 12, 14 remain coupled to one another while the drive mechanism 20 moves the two shafts 12, 14 relative to one another as described herein.

[0026] The drive mechanism 20 disposed within the distal shaft 14 includes a drive shaft 26 and a rotatable driven gear 22. The shaft 26 is rotatably coupled to the gear 22 at an engageable mechanism or structure 28 disposed at or near the proximal end of the shaft 26. In one embodiment, the engageable mechanism or structure 28 is a set of screw threads 28. Alternatively, any known engageable mechanism or structure capable of engaging the gear 22 may be used. Thus, the gear 22 is operably coupled to both the engageable mechanism or structure 18 of the proximal portion 12 and the engageable mechanism or structure 28 of the drive shaft 26 such that rotation of the drive shaft 26 causes rotation of the engageable mechanism or structure 28, thereby actuating the gear 22 to rotate about an axis different from the axis of the drive shaft 26. Actuation of the driven gear 22 causes the gear 22 to rotate, thereby engageably coupling to the engageable feature or structure 18 of the proximal portion 12 and causing the engageable feature or structure 18, and therefore the proximal shaft 12, to move angularly relative to the distal shaft 14 in the direction of reference arrow A.

[0027] As best shown in FIG. 3, according to certain implementations, regardless of the drive mechanism incorporated in the device 10, the distal end 13 of the proximal shaft 12 and the proximal end 15 of the distal shaft 14 are angled. That is, the two ends 13, 15 of the two shafts 12, 14 are each disposed at an angle as shown to generate angular motion when the drive mechanism 20 is actuated to move the two shafts 12, 14 relative to one another. More specifically, the distal end 13 of the proximal shaft 12 is disposed at an angle that is not perpendicular to the longitudinal axis of the shaft 12. Similarly, the proximal end 15 of the distal shaft 14 is disposed at an angle that is parallel to and engageable with the angle of the distal end 13 of the proximal shaft 12, such that the two ends 13, 15 can be engageably coupled to one another or disposed in movably contact with one another as shown. Additionally, the screw thread 18 is disposed at the same angle or parallel to the angle of the two ends 13, 15. It will be appreciated that the angular arrangement of the two ends 13, 15 as shown allows for both radial and axial movement of the two shafts 12, 14 relative to one another. This both radial and axial angular movement can provide for adjustment of the fracture to bring two misaligned lengths of bone into desired alignment.

[0028] Additionally, the drive shaft 26 extends to the distal end of the distal shaft 14 and has a connection component 30 at the distal end of the drive shaft 26 accessible through an opening 31 at the distal end of the distal shaft 14 so that a driver tool may be coupled to the connection component 30. The connection component 30 may be an opening, a protrusion, or any engageable connection mechanism 30 to which a driver tool may be coupled. For example, the engageable connection mechanism 30 in this particular embodiment is an opening 30 defined at the distal end of the connection mechanism 30. The drive shaft 26 may thereby be rotated by inserting a mechanical actuation component (not shown herein, also referred to as a "driver component," "hex driver," or "driver") into the opening 30. More specifically, the opening 30 has a hexagonal shape (or any known engageable and actuable shape) engageable with the distal end of a driver (not shown), so that a driver may be used to rotate the shaft 26 through the hexagonal opening 30. Alternatively, the distal end of the drive shaft 26 may have any known coupling mechanism or connection component that may be engagably coupled to an appropriate corresponding driver tool. The drive tool may be used by a user (such as a surgeon) to actuate the drive mechanism 20 to adjust the joint 16. More specifically, rotation of the connection mechanism 30 (via the tool) causes rotation of the drive shaft 26, which in turn causes rotation of the gear 22, thereby adjusting the position of the proximal shaft 12 relative to the distal shaft 14.

[0029] It will be understood that any other known drivers and similar mechanisms for use in medical devices may be used in place of the drive mechanism 20 as shown in Figures 2-4. For example, various other drive mechanisms 20 may be used in conjunction with the device 10, as shown in Figures 5A and 5B. In one example, a rack and worm mechanism 20 may be implemented as shown in Figure 5A. In another example, a rack and pinion or gear drive 20 may be implemented as shown in Figure 5B.

[0030] As shown in Figures 6A and 6B, in one embodiment, the device 10 may include one or more holes 32, 34 for inserting a set screw, ligament syndesmosis screw, or other similar known fixation device. Various screws or other types of known mechanisms may be placed in the device 10 through the holes 32, 34 to secure the device 10 to the target bone of the patient and reduce instability. For example, the proximal hole 32 is placed in the proximal shaft 12 to allow a tibiofibular syndesmosis screw or other screw to be angled across the tibiofibular syndesmosis and into the tibia. The distal hole 34 is provided for securing the distal shaft 14 of the device 10 in the bone.

[0031] In some implementations, each of the holes 32, 34 is arranged in the shape of a frustum cone, as best shown in the exemplary depiction of one such hole 32, 34 in Figure 6B. In these implementations, the inner portion of hole 32A is wider than the outer portion of hole 32B. It will be understood that various other configurations and shapes are possible.

[0032] In some implementations, device 10 may be formed from one or more metals. For example, device 10 may be formed from titanium, stainless steel, or other suitable metallic materials or combinations of metallic materials, as would be understood by one of ordinary skill in the art. Alternatively, device 10 may be formed from any known material used in bone fixation and / or other medical devices.

[0033] It will be appreciated that the device 10 may be of various sizes and shapes as required for the target bone, medullary canal, fracture, and particular anatomy of the patient. Various lengths and widths of the device 10 may be used.

[0034] In use, as shown in FIGS. 7A-7C, the fixation device 10 according to any embodiment disclosed or discussed herein may be placed in the medullary canal of the fibula 2 or other target bone by any suitable surgical technique. For example, the other target bone may include, but is not limited to, the humerus, tibia, femur, or any other long bone. In some implementations, the distal portion 14 has a bend (also referred to as an "angle" or "curve") 40 configured to ensure intramedullary placement by substantially replicating the bend or curvature of the target fibula 2, as best shown in FIG. 7B. In various implementations, the bend 40 has a bend of about 7°. Alternatively, any known angle that improves placement of the device 10 may be used depending on the target bone and any curvature of the target bone. Additionally, other shapes are possible.

[0035] In one example, the device 10 is inserted by drilling a pilot hole in the distal end of the patient's fibula 2. A guidewire is then inserted into the medullary canal through the pilot hole and the hole drilled through the guidewire. The device 10 may be inserted into the hole in the medullary canal of the fibula 2. Additionally, various other techniques and methods may be used, as will be appreciated by those skilled in the art.

[0036] An external targeting device (not shown) may be used to assist in accurate and reproducible placement of the device 10 and / or screws. The external targeting device may be placed outside of the fracture 4. It is understood that a variety of targeting devices are well known in the art.

[0037] In various implementations, the device 10 should be placed in the fibula 2 or other target bone such that the joint 16 is substantially adjacent to the fracture 4. After the device 10 is placed in the fibula or other target bone, the drive mechanism 20 may be manipulated to actuate the joint 16 to move the two shafts 12, 14 relative to one another to reduce the fracture 4 and realign the bone. The ability to actuate the proximal portion 12 relative to the distal portion 14 (and / or the distal portion 14 relative to the proximal portion 12) after insertion allows the surgeon or other user to make corrections and adjustments to the bone alignment and fracture reduction after implantation of the device 10. The device 10 is placed in the bone and actuated to hold the bone in proper alignment during the healing process. Improved fracture reduction and proper bone alignment may result in faster healing and better outcomes for the patient.

[0038] Although various embodiments have been described in this disclosure, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the various implementations herein.

Claims

1. 1. An intramedullary fracture correction device, comprising: (a) a first shaft having a first end; (b) a second shaft operatively connected to the first shaft at a joint, the second shaft having a second end disposed in slidable contact with the first end; (c) a channel defined in one of the first end and the second end; (d) a protrusion extending from the other of the first end and the second end, the protrusion being slidably disposed within and attached to the channel such that the first shaft is translatably attached to the second shaft at the first end and the second end; (e) a drive mechanism disposed within the second shaft; the drive mechanism includes a drive shaft operatively coupled to a gear; the gear is operably coupled to the first shaft; The drive mechanism is configured to actuate the protrusion and the channel to slide translationally relative to each other so that the first and second shafts translate between an insertion position in which the first and second shafts are coaxial and an articulated position in which the first and second shafts are non-coaxial.

2. The fracture correction device of claim 1 , wherein the first shaft includes a first engageable coupling mechanism, and the gear is operably coupled to the first engageable coupling mechanism.

3. 2. The fracture correction device of claim 1, wherein the drive shaft comprises an engageable connection mechanism disposed at a distal end of the drive shaft, and a drive tool is connectable to the engageable connection mechanism such that the drive tool can rotate the drive shaft.

4. A fracture correction device as described in claim 2, wherein the engageable first connecting mechanism is positioned on the protrusion.

5. 1. A bone fixation device, comprising: (a) a device body, (i) a proximal segment having a first end; (ii) a distal segment having a second end disposed in slidable contact with the first end; (b) an adjustable joint disposed at the first end and the second end, (i) a channel defined in one of the first end and the second end and extending radially across the end; (ii) a protrusion extending from the other of the first end and the second end, the protrusion being slidably disposed within and attached to the channel, wherein the proximal segment and the distal segment are movable via the adjustable joint between a first coaxial configuration and a second non-coaxial configuration; (c) a drive mechanism operatively coupled to the adjustable joint, the drive mechanism comprising a drive shaft and a gear operatively coupled to the drive shaft, the drive mechanism constructed and arranged to actuate the proximal and distal segments to move the proximal and distal segments between the first and second configurations via the adjustable joint; A bone fixation device comprising:

6. The bone fixation device of claim 5 , wherein the gear is operably coupled to the projection.

7. The bone fixation device of claim 5 , wherein the protrusion comprises a first engageable coupling mechanism, and the gear is operably coupled to the first engageable coupling mechanism.

8. 6. The bone fixation device of claim 5, wherein the drive shaft comprises a drive tool connection mechanism disposed at a distal end of the drive shaft, and a drive tool is connectable to the drive tool connection mechanism such that the drive tool can rotate the drive shaft.

9. The bone fixation device of claim 5 , wherein each of the proximal and distal segments has one or more holes extending radially therethrough and sized and shaped to receive a mounting screw.

10. A bone fixation device as described in claim 5, wherein the distal segment has a generally curved portion defined along the length of the distal segment.

11. A fracture correction device as described in claim 1, wherein the first shaft and the second shaft are configured to simultaneously translate relative to each other in both axial and radial directions between the insertion position and the joint position.

12. A bone fixation device as described in claim 5, wherein the proximal segment and the distal segment are simultaneously translatable relative to each other in both axial and radial directions.

Images