EXTERNAL LOCKING FIXATION DEVICE FOR EXTRA-ARTICULAR FRACTURES

Abstract

A locking fixation device for treating extra-articular fractures includes a connector assembly connected to two end plates. Rotation of the connector assembly about an axis extending therethrough converts rotational motion to linear motion, and advances the end plates in a linear direction away from (lengthening) or toward (compression) each other.

Claims

1. A locking fixation device for treating extra-articular fractures and/or for performing bone lengthening surgeries, comprising: a first end plate; a second end plate; and, a connector assembly having two threaded ends; one threaded end of the connector assembly being operatively connected to the first end plate, and the other threaded end of the connector being operatively connected to the second end plate; one threaded connector assembly end and the second end plate being threaded in a first direction, and the other threaded connector assembly end and the second end plate being threaded in an opposite direction; the connector assembly being configured to be rotatable about an axis extending therethrough, and configured to convert rotational motion to linear motion, thereby advancing the first and second end plates in a linear direction towards or away from each other achieving compression or lengthening functions, respectively.

2. The device of claim 1, wherein the ends of the connector assembly are internally threaded.

3. The device of claim 2, wherein the connector assembly is at least partially hollow near the internally threaded end and is internally threaded in a first direction; and, wherein the connected assembly is at least partially hollow near the internally threaded another end and is internally threaded in the opposite direction.

4. The device of claim 2, wherein the first end plate includes a neck portion that extends in an angled direction from a surface of a screw receiving platform; and/or, wherein the second end plate includes a neck portion that extends from a surface of the screw receiving platform.

5. The device of claim 4, wherein the neck portion of the first end plate terminates at an externally threaded cylindrical portion, and is configured to engage the internally threaded end of the connector assembly; and/or, wherein the neck portion of the second end plate terminates at an externally threaded cylindrical portion, and is configured to engage the internally threaded end of the connector assembly.

6. The device of claim 2, wherein the connector assembly includes a central locking nut configured to be radially fixed to ensure that the connector assembly does not rotate after the locking fixation device is positioned on and secured to the patient.

7. The device of claim 2, wherein the connector assembly further include at least one nut positioned at the two ends of the connector assembly to allow for a tightening once a desired fixation position has been determined.

8. The device of claim 1, wherein the connector assembly has an externally threaded two ends.

9. The device of claim 8, wherein the connector assembly includes a connecting rod operatively connected at opposing ends to first and second connector modules; the connecting rod defining a longitudinally extending axis having a first end configured to threading engage the first connector module, and second end configured to engage the second connector module.

10. The device of claim 9, wherein one end of the connector rod is threadably connected in a first direction to a threaded portion of the adjacent connector module, and another end of the connector rod is threadably connected in an opposing direction to a threaded portion of the adjacent connector module.

11. The device of claim 8, wherein the connector assembly includes a co-axial central driving member, configured rotate the connector rod, whereby, when the connecting rod is rotated, the first and second connector modules are configured to be moved either towards or away from each other, depending on the direction of rotation of the connecting rod.

12. The device of claim 8, wherein the connector assembly includes one or more locking nuts with threads matching the direction of the corresponding ends of the connecting rods, whereby, when the connecting rod has been rotated to achieve the desired degree of compression or distraction, the locking nuts are configured to be tightened against the one and/or another connector modules to prevent further rotation.

13. The device of claim 8, wherein the one connector module defines an axially extending slot that is configured to accept a neck portion of the adjacent end plate; and/or wherein the other connector module defines an axially extending slot that is configured to accept a neck portion of the adjacent end plate.

14. The device of claim 8, wherein the one end plate includes one or more radially extending holes that align with corresponding holes that extend through the adjacent connector module, wherein the aligned holes are configured to receive a screw; and/or, wherein the another end plate includes with one or more radially extending holes that align with corresponding holes that extend through the adjacent connector module, wherein the aligned holes are configured to receive a screw.

15. The device of claim 8, wherein the connector assembly further includes one or more stabilizing rods configured to provide an anti-torque feature to prevent relative rotation of the two end plates while tightening the connecting device.

16. The device of claim 15, wherein the stabilizing rods have first threaded ends which threadably engage axially extending openings in the one module; and, wherein the stabilizing rods have opposing second ends which slidably engage axially extending openings in the other module.

17. The device of claim 8, wherein the connector modules are integrally formed with the two end plates.

18. The device of claim 15, wherein the connector modules are integrally formed with the two end plates.

19. The device of claim 1, wherein one end plate has a screw receiving platform having a planar surface through which a plurality of threaded openings extend; the threaded opening being configured to receive a polyaxial cannulated screw and/or a fixed locking screw; and/or, wherein the other end plate has a screw receiving platform having a planar surface through which a plurality of threaded openings extend; the threaded opening being configured to receive a polyaxial cannulated screw and/or a fixed locking screw.

20. The device of claim 19, wherein the one or more of the openings extend in a generally perpendicular direction with the respect screw-receiving platform, and/or wherein one or more of the opening extend at an angle with respect to the screw-receiving platform.

21. The device of claim 19, wherein the screw-receiving platform has a plurality of openings that are generally in a series of rows.

22. The device of claim 1, wherein one end plate includes one or more bars which extends outwardly therefrom, the bar configured for allowing for placement of one or more screws and a wide variety angle appropriately to fracture anatomy; and/or wherein the other end plate includes one or more bars which extends outwardly therefrom, the bar configured for allowing for placement of one or more screws and a wide variety of angles appropriately to fracture anatomy.

23. The device of claim 19, wherein one or more of the two end plates define a screw receiving platform having a bottom surface that is at least partially curved so that the proximal plate and/or distal plate generally conforms to a patient's external lower extremity without touching the patient.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1. Schematic exploded perspective view of one embodiment of a locking fixation device.

[0023] FIG. 2. Schematic perspective view of the embodiment shown in FIG. 1.

[0024] FIG. 3. Schematic perspective view of another embodiment of a locking fixation device.

[0025] FIG. 4. Schematic perspective view of a proximal plate with side bar of a locking fixation device.

[0026] FIG. 5. Exploded perspective view of a connector assembly of a locking fixation device.

[0027] FIG. 6. Exploded perspective view of the connection between a plate and connector module of a locking fixation device.

[0028] FIG. 7. Exploded perspective view, partially broken away, of an unassembled polyaxial variable angle screw having a hemispherical, flat-topped, slotted head in a portion of a locking fixation device; a wedge and a cap (broken away) useful with the polyaxial variable angle screw.

[0029] FIG. 8. Schematic perspective view showing one combination of the tibia plates. This combination is good for tibia diaphysis fractures.

[0030] FIG. 9. Schematic perspective view showing another combination of the tibia plates. This combination is good for the tibia fractures located to either proximal or distal tibia.

[0031] FIG. 10. Schematic perspective view showing another combination of the tibia plates. This combination is good for the fractures involved in both proximal and distal tibia.

[0032] FIG. 11. Schematic perspective view showing another combination of the tibia plates. This combination is good for the tibia fractures located to either proximal or distal tibia, and the proximal or distal tibia fractures are comminuted. It potentially needs added more polyaxial screws for fixations.

[0033] FIG. 12. Schematic perspective view showing another combination of the tibia plates. This combination is good for the fractures involved in both proximal and distal tibia. One end is comminuted and another end is not.

[0034] FIG. 13. Schematic perspective view showing another combination of the tibia plates. This combination is good for the fractures involved in both proximal and distal tibia and both ends fractures are comminuted.

DETAILED DESCRIPTION

[0035] Throughout this disclosure, various publications, patents and published patent specifications are referenced by an identifying citation. The disclosures of these publications, patents and published patent specifications are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.

[0036] FIGS. 1-2 show one embodiment of a locking fixation device 10 having a central connector assembly 12, a first end plate 14, which can be used proximally or distally, and a second end plate 16, which also can be used proximally or distally.

[0037] The connector assembly 12 defines a longitudinally extending axis, and has a first end 24, which is adjacent to the first end plate 14, and second end 26, which is adjacent the second end plate 16. In the embodiment shown, the connector assembly 12 has a cylindrical cross-sectional area, but it is to be understood that in other embodiments, the outer surface can have other cross-sectional shapes, such as hexagonal, rectangular, square, and the like.

[0038] The connector assembly 12 has a threaded portion 24a that is at least partially hollow near the first end 24 and is internally threaded in a first direction. The second end 26 of the connector assembly 12 has a threaded portion 26a that is also partially hollow, and is internally threaded in an opposite direction to the threaded portion 24a of the first end 24.

[0039] The first end plate 14 has a screw receiving platform 28. In the embodiment in FIGS. 1-2, the first end plate 14 can have top surface 30 so that the first end plate 14 generally conforms to a patient's external lower extremity without touching the patient, thereby preventing skin and soft tissue ulcers or necrosis from undue pressure points.

[0040] A plurality of openings 32 extend through the screw receiving platform 28. One or more of the openings 32 can extend in a generally perpendicular direction with respect to a plane defined by the screw receiving platform 28, or can extend at an angle with respect thereto.

[0041] In the embodiment shown in FIG. 1, the screw-receiving platform 28 can have the plurality of openings 32 that are generally in a series of rows (shown as 32) in order to allow physician to determine which particular opening (and type of screw) would be best suited for fixation. The openings 32 can be in a particular pattern allows for passage of locking-screws 150 (as shown in FIG. 3) at fixed or variable angles, which will pierce the skin and fix bone and bone fragments avoiding major neurovascular bundles and eliminating extensive tissue dissection.

[0042] Also, the plurality of openings 32 can extend along the first end plate 14 in a direction toward a neck portion 34 of the first end plate 14. It is to be understood that in other embodiments, the screw-receiving platform 28 can have other configurations of rows of openings 32. The variety of opening 32, 32 in a particular pattern allows for passage of locking-screws at fixed angles, which will pierce the skin and fix bone and bone fragments avoiding major neurovascular bundles and eliminating extensive tissue dissection.

[0043] The neck portion 34 extends in an angled direction from the angled surface 30 such that the neck portion 34 is resting comfortably on the external skin without causing undue pressure.

[0044] The neck portion 34 terminates at an externally threaded cylindrical portion 36. The threads of the threaded portion 36 are configured to engage in the threaded first end 24 of the connector assembly 12.

[0045] A first nut 48 can be positioned at the first end 24 of the connector assembly 12 and the threaded portion 36 to allow for a tightening once a desired fixation position has been determined. The connector assembly 12 can include radially extending holes 13 which are configured to allow the insertion of radially extending tightening screws 13 which secure the threaded portion 36 of the first end plate 14 and the connector assembly 12 in the desired fixation position.

[0046] In certain embodiments, the first end plate 14 can further include one or more bars 54 which extends outwardly from a far end of the screw-receiving platform 28. FIGS. 1-2 show the bar 54 hold the screw 60 which is configured to receiving a polyaxial cannulated screw 60. The bar 54 allows for placement of polyaxial cannulated screws 60 at a wide variety of angles appropriately adapted to the fracture anatomy.

[0047] In a configuration similar to the first end plate 14, the second end plate 16 has a screw receiving platform 38 which can have a top surface 40 that at least partially conforms to a patient's external leg. A plurality of openings 42 extend through the screw receiving platform 38. One or more of the openings 42 can extend in a generally perpendicular direction with respect to the screw receiving platform 38, or can extend at an angle with respect thereto.

[0048] The plurality of openings can extend along the second end plate 16 in a direction toward a neck portion 44. It is to be understood that in other embodiments, the screw-receiving platform 38 can have other configurations of rows of openings 42. The variety of openings 42 in a particular pattern allows for passage of locking-screws at fixed angles, which will pierce the skin and fix bone and bone fragments.

[0049] The neck portion 44 extends in a sloped from the surface 40 such that the neck portion 44 is in a somewhat spaced apart relationship to the patient's leg.

[0050] The neck portion 44 terminates at a cylindrical externally threaded portion 46. The threads of the threaded portion 46 are configured to engage in the threaded second end 26 of the connector assembly 12.

[0051] A second nut 58 can be positioned at the second end 26 of the connector assembly 12 and the threaded portion 46 to allow for a tightening once a desired fixation position has been determined. As noted above, the connector assembly 12 can include radially extending holes 13 which are configured to allow the insertion of radially extending tightening screws 13 which secure the threaded portion 46 of the second end plate 16 and the connector assembly 12 in the desired fixation position.

[0052] In certain embodiments, the locking fixation device 10 can include a central locking section 70 that can be radially fixed, using, for example a cotter pin (not shown) to ensure that the connector assembly does not rotate after the locking fixation device 10 is positioned on and secured to the patient.

[0053] FIGS. 3-6 show another embodiment of a locking fixation device 110 having a central connector assembly 112, a first end plate 114 and a second end plate 116. It is to be understood that while FIGS. 3-6 show a male connector, in other embodiments, the arrangements shown in FIG. 306 can be assembled as in FIG. 1, with the female parts built as part of the plates instead of an attachment.

[0054] The first end plate 114 has a screw receiving platform 128. In the embodiment in FIGS. 3-6, the first end plate 114 can have bottom surface 130 that is at least partially curved so that the first end plate 114 generally conforms to a patient's external lower extremity without touching the skin, thereby reducing skin and soft tissue ulcers or necrosis from undue pressure points.

[0055] A plurality of openings 132 extend through the screw receiving platform 128. One or more of the openings 132 can extend in a generally perpendicular direction with respect to a plane defined by the surface 130, or can extend at an angle with respect to the curved surface 130.

[0056] The screw-receiving platform 128 can have the plurality of openings 132 that are generally in a series of rows (shown as 132) in order to allow physician to determine which particular opening would be best suited for fixation. Also, a further plurality of openings 132 can extend along the first end plate 114 in a direction toward a neck portion 134 of the first end plate 114. It is to be understood that in other embodiments, the screw-receiving platform 128 can have other configurations of rows of openings 132. The variety of opening 132, 132, 132 in a particular pattern allows for passage of locking-screws 150 at fixed or variable angles, which will pierce the skin and fix bone and bone fragments avoiding major neurovascular bundles and eliminating extensive tissue dissection.

[0057] The neck portion 134 extends in an angled direction from the surface 130 such that the neck portion 134 is resting comfortably on the external skin without causing undue pressure.

[0058] In a configuration similar to the first end plate 114, the second end plate 116 has a screw receiving platform 138 which can have a bottom surface 140 that at least partially conforms to a patient's external leg. A plurality of openings 142 extend through the screw receiving platform 138. One or more of the openings 142 can extend in a generally perpendicular direction with respect to the surface 140, or can extend at an angle with respect to the curved surface 140.

[0059] The screw-receiving platform 138 can have a plurality of openings 142 that are generally in a series of rows in order to allow physician to determine which particular opening would be best suited for fixation. Also, the plurality of openings 142 can extend along the second end plate 116 in a direction toward a neck portion 144. It is to be understood that in other embodiments, the screw-receiving platform 138 can have other configurations of rows of openings 142. The variety of openings 142, 142 in a particular pattern allows for passage of locking-screws 150 at fixed angles, which will pierce the skin and fix bone and bone fragments.

[0060] The neck portion 144 is shaped to conform to the opening 177 in the connector module 174 in order to provide a rigid connection when joined.

[0061] Referring in particular to FIG. 3, the connector assembly 112 includes a connecting rod 113, a first connector module 172 and a second connector module 174.

[0062] The connecting rod 122 defines a longitudinally extending axis, and has a first 124, which is adjacent to the first end plate 114, and a second end 126, which is adjacent the second end plate 116.

[0063] The first end 124 of the connector rod 122 is threadably connected to a threaded portion 124a of the first connector module 172, while the second end 126 of the connector rod 122 is threadably connected to a threaded portion 126a of the second connector module 174. The first end 124 of connector rod 122 is threaded in a first direction. The second end 126 of the connector rod 113 is threaded in the opposite direction as the first end 124.

[0064] In the embodiment shown in FIGS. 3-6, the connector rod 122 includes a co-axial central driving member 180, such as a hexagonal nut. It is to be understood, however, that in other embodiments, the outer surface of the driving feature 180 can have other cross sectional shapes, such as rectangular, square, circular with holes, and the like.

[0065] The threaded portions 124a, 126a of the connector modules 172, 174 co-axially aligned with the axis defined by the connector rod 122. When the connecting rod 122 is rotated, the connector modules 172, 174 are moved either towards or away from each other, depending on the direction of rotation of the connecting rod 122.

[0066] In the embodiment shown in FIGS. 3 and 5, one or both of the ends 124, 126 of the connecting rod 122 are provided with locking nuts 148, 158 with threads matching the direction of the corresponding ends of the connecting rod 122. When the connecting rod 122 has been rotated to achieve the desired degree of compression or distraction, the locking nuts 148, 158 are tightened against the connector modules 172, 174 to prevent further rotation. It is to be understood, that in other embodiments, this tightening function could be accomplished with other means, such as one or more set screws mounted on the connector modules. With multiple set screws and multiple longitudinal grooves in the threads of the connector rods, the connector rod could be locked in small, discrete increments.

[0067] The first module 172 defines an axially extending slot 175 that is configured to accept the neck portion 134 of the first end plate 114. That is, the neck portion 134 slidably engages/dovetails into and can be axially moved along the slot 175. The first end plate 114 can be provided with one or more holes 180 that align with holes 180 that extend through the first connector module 172 to receive one or more screws 181. Similarly, the second module 174 defines an axially extending slot 177 that is configured to accept the neck portion 144 of the second end plate 116. That is, the neck portion 144 slidably engages/dovetails into and can be axially moved along the slot 177. The second end plate 116 can be provided with one or more holes 183 that align with holes 183 that extend through the second connector module 174 to receive one or more screws 181.

[0068] Although a dovetail is shown, other shapes could be used, as well as other fastening schemes, so long as clearance is maintained for the travel of the connector rod 122 above and for the patient's skin below.

[0069] Also, in certain embodiments, the connector assembly 112 can include one or more stabilizing rods 190, 190 to provide an anti-torque feature to prevent relative rotation of the two end plates 114, 116 while tightening the connecting device. The stabilizing rods 190,190 can have first threaded ends 191, 191 which threadably engage axially extending openings 193, 193 in the first module 172. The stabilizing rods 190, 190 can have opposing second ends 195, 195 which slidably engage axially extending openings 197, 197 in the second module 174.

[0070] FIG. 4 shows another embodiment of a first end first end plate 214. For ease of explanation and comparison to FIG. 3, where the same features are shown, the same reference numbers are shown. Thus, the first end plate 214 has a screw receiving platform 128, a bottom surface 130, a plurality of openings 132, and a neck portion 134. Here, the first end plate 214 can further include one or more bars 154 which extends outwardly from a far end of the screw-receiving platform 128. The bar 154 allows for placement of polyaxial cannulated screws 60 at a wide variety of angles appropriately adapted to the fracture anatomy. In certain embodiments, as best shown in FIG. 4, the pedicle screw 60 has a cylinder 60a has a U-shaped notch 60b that acts as screw head. In the case of a variable screw, the U-shaped notch 60b engages the screw with a ball and socket type joint. The bar 154 lays in the U-shaped notch 60b, and the screw 60 is locked therein a set screw 60c. In use, when tightening the set screw, friction locks the ball and socket in place as well, fixing the angle of the screw.

[0071] Referring now to FIG. 7, one embodiment of a suitable polyaxial cannulated screw 60 having a threaded shank 61 and a head 62 is shown. A spherical underside of the head 62 fits in a spherical bottom of a desired screw hole 62 in the first end plate 14/114, the second end plate 16/116 and/or a bar 54/154. The screw 60 is driven at a desired angle using a drill guide. A wedge 63, keyed to the screw head 62 and matching the driven angle of the screw, is placed on the screw head 62. The wedge 63 is tapered so as to present a top surface that is parallel to the proximal screw receiving platform 28/128, the distal screw receiving platform, 38/138 and/or a top surface of bars 54/154. A cap 65 is screwed onto or over the wedge 63, fixing the screw 60.

[0072] With such configuration, the radial direction of the screw is infinitely variable. Each desired angle from the vertical is set using the wedge and a drill guide. For example, one reasonable set would be 0, 5, 10, and perhaps 15.

[0073] FIGS. 8-13 provide schematic perspective view showing non-limiting examples of different combinations of the tibia plates. The FIG. 8 combination is good for tibia diaphysis fractures. The FIG. 9 combination is good for the tibia fractures located in either proximal or the distal tibia. The FIG. 10 combination is good for fractures involved in both proximal and distal tibia. The FIG. 11 combination is good for comminuted tibia fractures located at either the proximal or distal tibia. The FIG. 12 combination is good for the fractures involved in both proximal and distal tibia, where one end is comminuted and another end is not. The FIG. 13 combination is good for both proximal and distal tibia fractures where both ends are comminuted.

[0074] Examples of Tibia Fractures

[0075] The locking fixation device is an adjustable device size that allows for a universal tibial fracture device. Use of the locking fixation device significantly lower revision rates and provides better fracture union rates.

[0076] Table 1 below show results of healing times and complications of patients with extra articular distal tibia fractures treated with external locking plate versus intramedullary rods.

TABLE-US-00001 Number of Healing time Device Patients (weeks) Complications External locking 28 15.1 (9-22) 0 plate fixation Intramedullary 30 17.8 (12-26) Non-unions: 5 Rods Delayed union: 2 Infection: 1

[0077] Then the locking fixation device is in use, the length and angles between the proximal plate and the distal plate may be adjusted by turning the connector assembly in a screw-like manner, thus allowing for lengthening and/or compression of the limb as needed.

[0078] The locking fixation device provides for a better biological environment for fracture healing, as the proximal/distal plates are placed less invasively as only incisions for the screws must be made in the patient. Another benefit is the easy removal of the device in an outpatient setting that does not require a second major procedure as there are no internal plates.

[0079] The locking fixation device does not disrupt the underlying cortical bone perfusion, and decreases incidence of inflammatory complications from loosening of hardware.

[0080] The locking fixation device also provides for a better biomechanical environment for fracture healing, as the proximal/distal plates and resulting screw placement do not require precise adaptation of the proximal/distal plates to the underlying bone. This feature makes it impossible for the screw insertion to alter the reduction. Further, each screw plays an equal role in fixation, which reduces the changes for screws from pulling out or breaking as the screws are unlikely to loosen from the plate.

[0081] The external fixation devices are designed to sit above the skin, further from the bone than a conventional locking plate. As such, the external fixation devices are especially useful with variable angle screws that allow for better hit (or avoid) fracture lines, joint surfaces, and the like.

[0082] Also, the low-profile nature of the device provides a convenience to the patient and allows the device to be concealable under clothing.

[0083] Also, in certain uses, based on a clinical detailed situation, e.g., different fracture types and locations, the proximal plate and/or the distal plates can replace each other.

[0084] In still other uses, the proximal/distal plates can each be used alone when appropriate, as shown in FIG. 4. For example, in cases where both a distal and proximal plate are not needed, (e.g., where a fracture is very near either end of the tibia), the connector assembly may not be needed. Because of this, the connector assembly otherwise incorporated on the plates may consist of a separate part that can be removably attached to the plates for use only when needed.

[0085] While the invention has been described with reference to various and preferred embodiments, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the essential scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof.

[0086] Therefore, it is intended that the invention not be limited to the particular embodiment disclosed herein contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.

[0087] Citation of the any of the documents recited herein is not intended as an admission that any of the foregoing is pertinent prior art. All statements as to the date or representation as to the contents of these documents is based on the information available to the applicant and does not constitute any admission as to the correctness of the dates or contents of these documents.