Modular plate tip for prophylactic cervical fixation

Abstract

The present disclosure relates to modular plate tips for prophylactic cervical fixation for use in the treatment of metaphyseal fractures.SOLUTION: The device includes a body 110 having a connecting portion 130 connectable to a bone plate and an anchoring portion 120 attachable to a bone. The connecting portion 130 has a top surface 121 configured to face away from the bone and a bottom surface 122 configured to face toward the bone. The bottom surface 122 of the connection portion 130 has a first shelf 134 extending substantially perpendicularly from the bottom surface 122 at a first side 132a of the bottom surface 122 and a second shelf 135 extending substantially perpendicularly from the bottom surface 122 at a second side 132b of the bottom surface 122. The second shelf 135 includes a rail 136 that extends toward the first shelf 134 such that the second shelf 135 defines an undercut between the rail 136 and the bottom surface 132.SELECTED DRAWING: Figure 1A-B

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 63 / 678,648, filed August 2, 2024, the disclosure of which is incorporated herein by reference. [Background technology]

[0002] The present disclosure relates to a modular plate tip for prophylactic cervical fixation for use in treating metaphyseal fractures.

[0003] There are many instances in the treatment of complex fractures using intramedullary nails, locking plates, or combined nail-plate (NPC) techniques. Specifically, NPCs are utilized to treat fractures within the metaphyseal region of a patient's distal femur. However, abrupt changes in local construct stiffness can result in increased stress points proximal to the ends of the intramedullary nail and the locking plate, especially when the ends are close to each other within the bone. These increased stress points can result in an increased risk of fracture proximal to this intersection area of ​​the NPC. Furthermore, elderly patients often suffer from an increased risk of further fracture due to the increased incidence / frequency of postoperative injuries and the potential need for weight-bearing restrictions.

[0004] To protect patients from this increased fracture risk, plate-based prophylactic fixation or stabilization of the femoral neck is commonly utilized. Prophylactic stabilization of the femoral neck requires extended plate lengths to conform to the shape of the vastus humeri, along with lateral flexion and anterior external torsion to compensate for femoral neck anteversion. Therefore, preformed plates are economically unfeasible for prophylactic stabilization of the femoral neck due to the wide variability in patient anatomy and the need to optimize plate fit to the bone for fracture treatment. Furthermore, because plates for prophylactic stabilization of the femoral neck must provide maximum strength and stability for the fracture, they currently offer limited opportunities for intraoperative design and modification. Therefore, improvements in plate-based prophylactic stabilization of the femoral neck are needed. Summary of the Invention

[0005] A first aspect of the present invention is a bone plate and an extension plate attachable to a bone, the extension plate including a body having a connecting portion connectable to the bone plate and a fixing portion attachable to the bone, and a connecting portion having a top surface configured to face away from the bone and a bottom surface configured to face toward the bone, the bottom surface of the connecting portion having a first shelf extending substantially perpendicularly from the bottom surface at a first side of the bottom surface and a second shelf extending substantially perpendicularly from the bottom surface at a second side of the bottom surface, the second shelf including a rail extending toward the first shelf, the second shelf defining an undercut between the rail and the bottom surface.

[0006] According to another embodiment of the first aspect, the connecting portion may define a hole extending from the top surface to the bottom surface between a first side and a second side in which a locking element can be disposed. The extension plate may further include a locking element having a proximal end and a distal end and an intermediate portion therebetween, the proximal end and the distal end each having a diameter larger than the minimum diameter of the hole, and the intermediate portion having a diameter smaller than the minimum diameter of the hole. The locking element may include a locking screw and a locking collar, the proximal end of the locking element being the head of the locking screw and the distal end of the locking element being the locking collar. The locking screw may be configured to be threadably inserted into a passage of the locking collar, such that rotation of the locking screw relative to the locking collar changes the length of the locking element. The bottom surface of the connecting portion may define a recess coaxial with the hole, the recess having a non-circular periphery. An end of the locking collar may have a non-circular periphery dimensioned to be disposed within the recess so that the locking collar is rotatably secured relative to the recess.

[0007] Continuing with another embodiment of the first aspect, the anchoring portion may have an upper surface configured to face away from the bone, a bottom surface configured to face toward the bone, and a hole extending from the upper surface of the anchoring portion to the bottom surface of the anchoring portion, in which a fastener can be disposed. A central axis of the hole in the connecting portion and a central axis of the hole in the anchoring portion may be non-parallel. Along the axis extending from the connecting portion to the anchoring portion, the upper surface of the connecting portion may extend along a substantially straight axis, or the upper surface of the anchoring portion may extend along a substantially curved axis. The bottom surface of the connecting portion may further include an end shelf extending substantially perpendicularly from the bottom surface and connecting an end of the first shelf to an end of the second shelf. The bottom surface of the connecting portion may define a ridge. The ridge may be configured to engage with a detent on the bone plate.

[0008] A second aspect of the present invention is a bone plate system including a bone plate having an anchoring portion and a distal end extending from the anchoring portion, the anchoring portion defining a hole in which a fastener can be disposed to secure the bone plate to a bone, and an extension plate of the first aspect, wherein the connecting portion of the extension plate is configured to be secured to the distal end of the bone plate, and the anchoring portion of the extension plate can be secured to the bone such that the bone plate system has a length longer than the length of the bone plate.

[0009] According to another embodiment of the second aspect, the distal end of the bone plate may extend away from the anchoring portion of the bone plate along a plate axis, and may have first and second side edges extending parallel to the plate axis. The distal end of the bone plate may have a top surface configured to face away from the bone and a bottom surface configured to face toward the bone. The outer surface of the first edge may extend from the top surface to the bottom surface along the first edge axis, and the outer surface of the second edge may extend from the top surface to the bottom surface along a second edge axis angled relative to the first edge axis. The top surface of the distal end of the bone plate may include a detent protruding upwardly away from the top surface. The detent may be positioned to engage a ridge on the bottom surface of the connecting portion of the extension plate. The outer surface of the second edge may extend from the top surface to the bottom surface toward the first edge.

[0010] Continuing with another embodiment having the second aspect, the distal end of the bone plate may extend away from the anchoring portion of the bone plate along the plate axis, may have first and second side edges extending parallel to the plate axis, may have a top surface configured to face away from the bone and a bottom surface configured to face toward the bone, and may define an opening extending parallel to the plate axis between the first and second edges. The first width at the proximal portion of the opening may be greater than the second width at the distal portion of the opening. The proximal portion of the opening may be substantially circular in shape, and the distal end of the opening may be substantially capsule-shaped in shape. The distal portion of the opening may include a rim extending inward toward the center of the opening.

[0011] In the extension plate, the rail may be a protrusion disposed at the end of an arm. The arm may be a cantilever defined by a notch in the second shelf. The arm may be configured to bend toward and away from the first shelf. The length of the protrusion may be shorter than the length of the second shelf. The first shelf may include a rail extending toward the second shelf, such that the first shelf defines an undercut between the rail and a bottom surface of the first shelf. The rail of the first shelf may be a protrusion disposed at the end of the arm. The arm of the first shelf may be a cantilever defined by a notch in the first shelf. The arm of the first shelf may be configured to bend toward and away from the second shelf. The length of the protrusion of the first shelf may be shorter than the length of the first shelf. The first shelf may be a mirror image of the second shelf. The extension plate may further include a locking element. The locking element may be a locking screw.

[0012] Another aspect of the invention is a bone plate system including a bone plate having an anchoring portion and a distal end extending from the anchoring portion, the anchoring portion defining a hole in which a fastener can be disposed to secure the bone plate to a bone, and an extension plate of any of the aforementioned aspects. The connecting portion of the extension plate is configured to be secured to the distal end of the bone plate, and the anchoring portion of the extension plate can be secured to the bone such that the bone plate system has a length longer than the length of the bone plate.

[0013] In another embodiment of this aspect, the distal end of the bone plate may extend away from the anchoring portion of the bone plate along a plate axis, the distal end of the bone plate having first and second side edges extending parallel to the plate axis, the distal end of the bone plate having a top surface configured to face away from the bone and a bottom surface configured to face toward the bone, the outer surface of the first edge extending from the bottom surface to a ledge at the top surface along the first edge axis, and the outer surface of the second edge extending from the bottom surface to a ledge at the top surface along the second edge axis. The outer surfaces of the first edge and the second edge may each include a ridge. The ridge may be configured to engage a protrusion disposed on the end of the arm.

[0014] A third aspect of the present invention is a method for extending a length of a bone plate system along a bone, the method comprising the steps of: anchoring a proximal end of a bone plate to a first portion of the bone, wherein the bone plate extends along a plate axis; securing a connecting portion of an extension plate to a distal end of the bone plate, wherein the connecting portion is tilted at a first angle about the plate axis to engage the distal end and then rotated by a second angle about the plate axis to be secured to the distal end; sliding the extension plate in a first direction along the plate axis away from the bone plate; locking the connecting portion to the distal end; and anchoring the distal end of the extension plate to a second portion of the bone.

[0015] The connecting portion can define a first hole extending therethrough from the top surface to a bottom surface of the connecting portion, and the distal end can define a second hole extending therethrough from the top surface to a bottom surface of the distal end, and the locking step can further include fastening locking screws disposed through the first and second holes to secure the connecting portion to the distal end.

[0016] In other embodiments of the third aspect, the method may further include sliding the extension plate in a second direction along the plate axis toward the bone plate. Securing the distal end of the extension plate may further include moving the distal end of the extension plate away from the plate axis. Securing the distal end of the extension plate may further include rotating the distal end of the extension plate about an axis parallel to the plate axis. Securing the distal end of the extension plate may further include rotating the distal end of the extension plate about an axis transverse to the plate axis.

[0017] Another aspect of the present invention is a method for extending a length of a bone plate system along a bone, comprising the steps of: securing a proximal end of a bone plate to a first portion of the bone; securing a connecting portion of the extension plate to the distal end of the bone plate by sliding the extension plate over the distal end of the bone plate and along the plate axis toward the bone plate; locking the connecting portion to the distal end; and securing the distal end of the extension plate to a second portion of the bone. The securing step may include passing protrusions of the first and second shelves over ridges on the outer surfaces of the first and second edges of the distal end of the bone plate and engaging the protrusions with the ridges to temporarily secure the extension plate to the bone plate. The securing step may include passing ridges on the bottom surface of the connecting portion of the extension plate over detents on the top surface of the distal end of the bone plate and engaging the detents with the ridges to temporarily secure the extension plate to the bone plate. The connecting portion may define a first hole extending therethrough from the top surface to the bottom surface of the connecting portion, and the distal end may define a second hole extending therethrough from the top surface to the bottom surface of the distal end, and the locking step may further include fastening locking screws disposed through the first and second holes to secure the connecting portion to the distal end.

[0018] The drawings described herein are only for purposes of illustrating selected embodiments and not all possible implementations, and therefore are not intended to limit the scope of the present disclosure. [Brief explanation of the drawings]

[0019] [Figure 1A-B] FIG. 1 is a perspective view of an extension plate of a bone plate system according to one embodiment of the present disclosure; [Figure 2A-C] FIG. 1 is a perspective view of a distal end of a bone plate of the bone plate system. [Figure 3A-B] FIG. 1 is a cross-sectional view of a bone plate system. [Figure 4A]2A-2C are perspective views of the extension plate shown in FIGS. 1A-1B and the bone plate shown in FIGS. 2A-2C. [Figure 4B] 2A-2C are perspective views of the extension plate shown in FIGS. 1A-1B and the bone plate shown in FIGS. 2A-2C. [Figure 4C] 2A-2C are perspective views of the extension plate shown in FIGS. 1A-1B and the bone plate shown in FIGS. 2A-2C. [Figure 4D] 2A-2C are perspective views of the extension plate shown in FIGS. 1A-1B and the bone plate shown in FIGS. 2A-2C. [Figure 4E] 2A-2C are perspective views of the extension plate shown in FIGS. 1A-1B and the bone plate shown in FIGS. 2A-2C. [Figure 5A] FIG. 10 is a perspective view of a bone plate system installed on a bone according to another embodiment of the present disclosure. [Figure 5B] FIG. 10 is a perspective view of a bone plate system installed on a bone according to another embodiment of the present disclosure. [Figure 5C] FIG. 10 is a perspective view of a bone plate system installed on a bone according to another embodiment of the present disclosure. [Figure 6A] FIG. 10 is a bottom perspective view of an extension plate associated with a bone plate system according to another embodiment of the present disclosure. [Figure 6B] 6B is a perspective view of the distal end of the bone plate of the bone plate system according to the embodiment of FIG. 6A. [Figure 6C] 6B is a perspective view of the extension plate of FIG. 6A and the bone plate of FIG. 6B installed on a bone. [Figure 7A-B] 10A-10C are perspective views of left and right prophylactic cervical attachments associated with a bone plate system according to another embodiment of the present disclosure; [Figure 7C] FIG. 7C is a perspective view of a connection screw for use with the cervical attachment of FIGS. 7A and 7B. [Figure 8A] FIG. 10 is a bottom perspective view of an extension plate associated with a bone plate system according to another embodiment of the present disclosure. [Figure 8B-C]8B is a perspective view of the distal end of the bone plate of the bone plate system according to the embodiment of FIG. 8A. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1A-1E, an expandable bone plate system 10 including an extension plate 100 and a bone plate 200 is shown. The bone plate system 10 is designed to be secured to a patient's bone by conventional fixation elements, such as conventional bone screws, prophylactic nails, or any combination of conventional fixation elements. The bone plate system 10 is a combination of a bone plate and prophylactic screws used for stabilization of the femoral neck and is used for treating a patient's long bone fracture, as described in more detail below. While the bone plate system 10 is specifically described for treating fractures in the metaphyseal region of the femur, the bone plate system 10 may be designed and used for treating fractures of any other long bone, such as the tibia, fibula, humerus, radius, or ulna. In use, the extension plate 100 allows for length adaptation and optimal fit of the bone plate system 10 for prophylactic stabilization or fixation along the vastus humerus of the femoral neck in the metaphyseal region of the femur.

[0021] 1A-1B, the extension plate 100 includes a body 110 that extends the length of the extension plate 100. The body 110 includes an anchoring portion 120 and a connecting portion 130. As will be described in more detail below, the extension plate 100 is configured to be secured to a bone plate 200 and positioned against the femoral neck in the metaphyseal region of the femur.

[0022] The fixation portion 120 is designed to be attachable to a bone at the distal end of the extension plate 100 and bone plate system 10, as best shown in FIGS. 1A-1B. The fixation portion 120 includes an upper surface 121 configured to face away from the bone and a bottom surface 122 configured to face toward the bone. The bottom surface 122 may be curved to match the contours of the bone. The fixation portion 120 also includes a hole 123 extending through the fixation portion 120 from the upper surface 121 to the bottom surface 122. The hole 123 may be designed to accept a prophylactic screw for fixation within the femoral neck of the patient's bone. In the present embodiment shown in FIGS. 1A-1B, the fixation portion 120 includes a first and second hole 123. However, in other embodiments, the fixation portion 120 may include only a single hole 123 for accepting only a single prophylactic screw, or multiple holes 123 for accepting multiple respective prophylactic screws, as needed for the desired prophylactic stabilization. Additionally, holes 123 may be designed to receive conventional locking or non-locking bone screws.

[0023] 1A-1B, the connecting portion 130 is designed to be proximal to the anchoring portion 120 within the extension plate 100 and along the bone plate system 10. The connecting portion 130 includes a top surface 131 configured to face away from the bone and a bottom surface 132 configured to face toward the bone. The connecting portion 130 is substantially rectangular in shape, but may be designed in other shapes or configurations.

[0024] As best shown in FIGS. 3A-3B , bottom surface 132 of connecting portion 130 has a first shelf 134 extending substantially perpendicularly from a first side 132 a of bottom surface 132. Additionally, bottom surface 132 includes a second shelf 135 opposite first shelf 134 extending substantially perpendicularly from a second side 132 b of bottom surface 132. Second shelf 135 includes a rail 136 extending toward first shelf 134. The extension of rail 136 toward first shelf 134 defines an undercut 137 between rail 136 and bottom surface 132 of connecting portion 130. As best shown in FIG. 1B , bottom surface 131 of connecting portion 130 further includes an end shelf 139 extending substantially perpendicularly from bottom surface 130 and connecting ends of first and second shelves 134, 135. The first and second shelves 134, 135 may be interchangeable such that the first and second shelves 134, 135 are on opposite sides of the connecting portion 130 from the design shown in this embodiment.

[0025] Connecting portion 130 further defines a bore 133 extending from a top surface 131 to a bottom surface 132 of connecting portion 130. Bore 133 is disposed at a location proximal to connecting portion 130 and fixation plate 120, although bore 133 may be positioned to extend through connecting portion 130 at any location on connecting portion 130. The top surface of connecting portion 130 extends along a substantially straight axis, and the top surface of fixation portion 120 extends along a substantially curved axis. Due to this curvature or angle between connecting portion 130 and fixation plate 120, the central axes of bore 123 in connecting portion 120 and bore 133 in fixation portion 130 may be non-parallel. This design allows fixation portion 120 to conform to the curvature of the bone as it extends from connecting portion 130. More specifically, when used with a femur, fixation portion 120 extends to the patient's femoral neck along the curved vastus humerus of the femur.

[0026] 3A-3B, locking element 140 is disposed through hole 133 for locking extension plate 100 to bone plate 200. Locking element 140 includes a proximal end 141, a distal end 143, and an intermediate portion 142 between proximal end 141 and distal end 143. Proximal and distal ends 141, 143 each have a diameter greater than the minimum diameter of hole 133. However, intermediate portion 142 has a diameter smaller than the minimum diameter of hole 133.

[0027] The locking element 140 includes a locking screw 144 and a locking collar 146. The proximal end 141 of the locking element 140 is a head 145 of the locking screw 144. Additionally, the distal end 143 of the locking element 140 is a locking collar 146. The locking screw 144 is configured to be threadably inserted into a passage 147 of the locking collar 146, such that rotation of the locking screw 144 relative to the locking collar 146 changes the length of the locking element 140, as measured between the proximal end 141 and the distal end 143. The head 145 of the locking screw 144 includes a recess configured to accommodate the end of a tool that can be used to rotate the locking screw 144 in either direction relative to the locking collar 146. As described further below, the locking element 140 is configured to secure the extension plate 100 to the bone plate 200 in a desired position relative to the bone plate 200 and the patient's bone.

[0028] Connecting portion 130 further defines a recess 148 coaxial with and disposed within bore 133. Recess 148 has a non-circular perimeter, but may be designed using other shapes and configurations. Similarly, distal end 143 of locking collar 146 is designed to have a non-circular perimeter dimensioned to be disposed within recess 148 such that locking collar 146 is rotatably secured relative to recess 148.

[0029] As previously described, the bone plate system 10 further includes a bone plate 200. The bone plate 200 has an anchoring portion 220 that extends the length of the bone. The anchoring portion 220 includes a plurality of holes 223 into which fasteners or locking screws may be disposed to secure the bone plate 200 to the bone. As best shown in Figures 5A-5B, the bone plate is secured to the patient's femur, but may also be secured to other long bones as previously described.

[0030] As best shown in FIGS. 2A-2C , the distal end 210 of the bone plate 200 extends away from the anchoring portion 220 along the plate axis A1. In this embodiment, the anchoring portion 220 extends along the length of the patient's femur such that the distal end 210 is positioned proximal to the patient's femoral neck and head. The distal end 210 includes a top surface 213 configured to face away from the bone and a bottom surface 214 configured to face toward the bone. The distal end 210 includes a first edge 215 and a second edge 216, each of which extends parallel to the plate axis A1. The outer surface 215a of the first edge 215 extends from the top surface 213 to the bottom surface 214 along the first edge axis, and the outer surface 216a of the second edge 216 extends from the top surface 213 to the bottom surface 214 along the second edge axis. The outer surfaces 216a of the second edges 216 are angled relative to the outer surfaces 215a of the first edges 215, such that the outer surfaces 216a of the second edges 216 extend from the top surface 213 to the bottom surface 214 toward the first edges 215. Thus, as best shown in FIG. 2B , the outer surfaces 215a extend substantially perpendicular to the plate axis A1. However, the outer surfaces 216a are beveled along an angle that forms a slope or inclined surface of the second edges 216 that is not parallel or perpendicular to the outer surfaces 215a.

[0031] The distal end 210 of the bone plate 200 defines an opening 217 extending parallel to the plate axis A1 between a first edge 215 and a second edge 216. A proximal portion 217a of the opening 217 is substantially circular in shape. Extending from the proximal portion is a distal portion 217b of the opening 217, which is substantially capsule-shaped in shape. The width of the circular shape of the proximal portion 217a in a direction perpendicular to the axis A1 is greater than the width of the capsule-shaped shape of the distal portion 217b in a direction perpendicular to the axis A1. However, the opening 217 may be modified to accommodate different shapes at either the proximal portion 217a and / or the distal portion 217b. The distal portion 217b of the opening 217 includes a rim 218 extending inward toward the center of the opening. Rim 218 extends along the entire inner surface of distal portion 217 b of opening 217 .

[0032] 5A-5C show the extension plate 1100 and bone plate 1200 secured within a patient's bone. This embodiment has differently configured components, but shows the final configuration of the system 10. That is, the extension plate 1100 includes elongated openings into which the fixation screws are inserted into circular openings in the plate 1200 beneath. This allows the extension plate 1100 to be moved to different positions relative to the implanted bone plate 1200 before the fixation screws are tightened to secure the extension plate 1100 to the bone plate 1200.

[0033] A method for extending the length of a bone plate system along a bone is performed using bone plate system 10. While bone plate system 10 may be used for the treatment of fractures of the femoral neck in the metaphyseal region of the femur, other long bones requiring fracture treatment may also utilize bone plate system 10. The method for using bone plate system 10 may be for prophylactic fixation or stabilization of the femoral neck of a patient's femur bone. While bone plate system 10 will be primarily used in the following description, other aforementioned systems may also be used in the same or similar manner when considering the structural variations described above.

[0034] The fixation portion 220 of the bone plate 200 is fixed onto a patient's bone. The fixation portion 220 is designed to be fixed to the bone by a common fixation element such as a bone screw, a locking screw, or the like. The fixation portion 220 is fixed to the bone along a plate axis A1 that extends substantially along the length of the bone. As previously described and illustrated in this embodiment, the bone is the patient's femur, and the fixation portion 220 extends along the plate axis toward the patient's femoral neck and femoral head.

[0035] The connecting portion 130 of the extension plate 100 is secured to the distal end 210 of the bone plate 200. As best shown in FIGS. 4A-4E , the connecting portion 130 is first tilted at an angle about the plate axis A1 to engage the distal end 210. As best shown in FIGS. 3A-3B , the connecting portion 130 is positioned so that the outer surface 216a of the second edge 216 is disposed within the undercut 137. Once positioned, the connecting portion 130 is rotated by another angle about the plate axis A1 until the connecting portion 130 is properly secured to the distal end 210, as best shown in FIG. 3B . A benefit of this tilting motion to secure the connecting portion 130 to the distal end is that an increased incision length does not need to be made in the patient to accommodate the extension plate 100. For example, the same incision used to secure the bone plate 200 to the bone can be used to secure the extension plate into the patient and onto the bone plate 100 and bone. This step of securing the connecting portion 130 to the distal end 210 of the bone plate 200 tends to be performed after securing the anchoring portion 220 to the bone, although these steps may be performed in either order.

[0036] After securing the connecting portion 130 to the distal end 210 as described, the extension plate 100 is slid along the plate axis A1 to reach a desired position along the bone as needed for the patient's particular anatomy. The extension plate 100 is configured to slide in a first direction along the plate axis A1 away from the bone plate 200 and / or in a second direction along the plate axis A1 toward the bone plate 200. For example, the sliding movement of the extension plate 100 allows the anchoring portion 120 to be positioned in various positions relative to the patient's femoral neck. This provides additional modularity to the bone plate system 10 by allowing the positioning of the extension plate 100 relative to the bone plate 200 to be designed and changed intraoperatively. The connecting portion 130 of the extension plate 100 is configured to be secured to the distal end 210 of the bone plate 200, and the anchoring portion 120 of the extension plate 100 is configured to be secured to the bone so that the bone plate system 10 has a length longer than the length of the bone plate 200 alone. The sliding step may be performed prior to securing any components to the bone plate.

[0037] After the extension plate 100 has been slid to a desired position along the bone and the bone plate 200 is preferably secured to the bone, the connecting portion 130 is locked and secured to the distal end 210. The locking step includes securing a locking screw 144 that extends through the opening 217 in the distal end 210 and through the hole 133 in the connecting portion. The proximal portion 217a of the opening 217 is configured to have a larger diameter than the distal portion 217b of the opening 217 to first receive the locking element 140 prior to the sliding step. Only after the locking element 140 is fully disposed through the proximal portion 217a and the extension plate 100 has been slid to a desired position along the bone can the locking element 140 be locked in any position, including the distal portion 217b of the opening 217. Locking element 140 is secured to distal portion 217b of opening 217 when locking screw 144 is rotated sufficiently so that locking collar 146 engages rim 218 of distal portion 217b.

[0038] After the connecting portion 130 is locked to the distal end 210, the anchoring portion 120 of the extension plate 100 is secured to the bone. The extension plate 100 may be anchored to the bone by moving the anchoring portion 120 in either direction away from the plate axis A1. For example, the anchoring portion 120 may be rotated about an axis parallel to the plate axis A1, or the anchoring portion 120 may be rotated about an axis transverse to the plate axis A1. For example, this flexibility allows the anchoring portion to be positioned along various points on the femoral neck. In embodiments in which the extension plate 100 is rigid, sliding of the extension plate 100 relative to the bone plate 200 is sufficient to align the extension plate 100 at an appropriate angle against the surface of the femur adjacent the femoral neck so that a fixation screw can be secured through the extension plate 100 to the femoral neck.

[0039] 6A-6C, a bone plate system 601 includes an extension plate 600 and a bone plate 700 that utilizes a snap-on connection with a ratchet mechanism. Many of the features of system 601 are similar to those of system 10, and therefore, the differences are described below.

[0040] The extension plate 600 includes a body 610 having an anchoring portion 620 and a connecting portion 630. Extending from a bottom surface 632 of the connecting portion 630 are a first shelf 634 and a second shelf 635. The second shelf 635 includes a rail 636 in the form of a protrusion extending toward the first shelf 634. The protrusion 636 is disposed at the end of an arm 646 that is separate from the remainder of the second shelf 635 so that it acts as a cantilever. The protrusion 636 is relatively short and small compared to the second shelf 635 such that it has a length that is shorter than the length of the second shelf 635 when measured along the same longitudinal axis of the extension plate 600. The arm 646 is defined by a notch in the second shelf 635 and is attached at one end to the remainder of the second shelf 635, with the protrusion 636 disposed at another end of the arm 646. In this manner, arm 646 can bend in different directions, including toward and away from first shelf 634, by pivoting it about its anchor point along with the rest of second shelf 635. Protrusion 636 protrudes toward first shelf 635 such that undercut 638 is formed between protrusion 636 and bottom surface 632.

[0041] The first shelf 635 also includes a rail 637 in the form of a protrusion in the same manner and with the same structure as described in connection with the protrusion 636. In some embodiments, the connecting portion 630 is symmetrical such that the first and second shelves 634, 635 are mirror images of each other. A hole 633 is disposed in the connecting portion 630 between the first shelf 634 and the second shelf 635.

[0042] The distal end 710 of the bone plate 700 includes first and second edges 715, 716. The outer surface 715a of the first edge 715 extends from the top surface 713 to the bottom surface 714 along a first edge axis. The same is true for the outer surface 716a of the second edge 716. Both surfaces 715a and 716a include ridges or scallops such that there are a series of depressions, one after the other, in which the protrusions 636 and 637 may be disposed. Both surfaces 715a and 716a are directly beneath overhanging ledges that may be disposed between the protrusions 636 and 637 and the bottom surface 632 when the extension plate 600 is attached with the bone plate 700.

[0043] The method of using bone plate system 601 is similar to that described above, except for the process of securing connecting portion 630 of extension plate 600 to distal end 710 of bone plate 700. In system 601, the securing step is performed by sliding extension plate 600 over distal end 710 and along the plate axis toward bone plate 700. During this transition, protrusions 636 and 637 rattle past ridges on surfaces 715 a and 716 a, while also passing beneath overhanging ledges on surfaces 715 a and 716 a, allowing protrusions 636 and 637 to engage specific ridges and temporarily secure extension plate 600 to bone plate 700. This allows extension plate 600 to be placed in one of many positions along distal end 710 before being secured to bone plate 700 and the underlying bone. In system 601, extension plate 600 includes a slotted hole and distal end 710 of bone plate 700 includes a plurality of circular holes so that a fixation screw can be disposed in any one of the holes on distal end 710 after passing through the slotted hole in extension plate 600. This allows for attachment in many relative positions between extension plate 600 and bone plate 700 when extension plate 600 is clicked into place along bone plate 700.

[0044] 7A-7C, an extension plate 800 is shown with two slotted holes 823. Also shown is a fixation screw 850 that can be disposed in one of the slotted holes 823 to secure the extension plate 800 to a bone plate.

[0045] 8A-8C, a bone plate system includes an extension plate 900 and a bone plate 950 that also utilizes a snap-on connection with a ratchet mechanism. Many of the features of this system are similar to those of system 601, with only the differences described below.

[0046] The extension plate 900 includes a body 910 having an anchoring portion 920 and a connecting portion 930. The plate 900 also includes a first shelf 934 having a rail 937 and a second shelf 935 having a rail 936, as described in connection with the system 601. The bottom surface 932 of the extension plate 900 includes a series of ridges 939 in a linear arrangement parallel to an axis along which the extension plate 900 can be slid over the bone plate 950. The ridges 939 can be a series of recesses or grooves in the material of the extension plate 900 such that ridges are formed between adjacent recesses or grooves. The ridges 939 can be positioned adjacent the first shelf 934 and / or adjacent the second shelf 936 such that they are on either or both sides of the hole 933.

[0047] The distal end of bone plate 950 includes an upper surface 963 having one or more detents 964 projecting upwardly away from upper surface 963 that are configured to engage with ridges 939 .

[0048] The method of using the bone plate system is similar to that described above with respect to system 601. The extension plate 900 is slid over and toward the bone plate 950 along the plate axis. During this movement, the ridges 939 ratchet past the detents 934. This allows the extension plate 900 to be placed in one of many positions along the distal end of the bone plate 950 before being secured to the bone plate 950 and the underlying bone. This allows for many relative positions of attachment between the extension plate 900 and the bone plate 950.

[0049] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and other arrangements may be devised without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A bone plate and an extension plate attachable to the bone, a body having a connecting portion connectable to a bone plate and a fixing portion attachable to a bone; the connecting portion has a top surface configured to face away from the bone and a bottom surface configured to face toward the bone; the bottom surface of the connecting portion has a first shelf extending substantially perpendicularly from the bottom surface at a first side of the bottom surface and a second shelf extending substantially perpendicularly from the bottom surface at a second side of the bottom surface; the second shelf includes a rail extending toward the first shelf such that the second shelf defines an undercut between the rail and the bottom surface of the extension plate.

2. The extension plate of claim 1 , wherein the connecting portion defines a hole extending from the top surface to the bottom surface between the first and second sides in which a locking element can be disposed.

3. 3. The extension plate of claim 2, wherein the anchoring portion has a top surface configured to face away from the bone, a bottom surface configured to face toward the bone, and a hole extending from the top surface of the anchoring portion to the bottom surface of the anchoring portion, in which a fastener can be disposed.

4. The extension plate according to claim 3 , wherein a central axis of the hole in the connection portion and a central axis of the hole in the fixing portion are non-parallel.

5. 2. The extension plate of claim 1, wherein along an axis extending from the connecting portion to the anchoring portion, the upper surface of the connecting portion extends along a substantially straight axis and the upper surface of the anchoring portion extends along a substantially curved axis.

6. The extension plate of claim 1 , wherein the bottom surface of the connecting portion further includes an end shelf extending substantially perpendicularly from the bottom surface and connecting an end of the first shelf and an end of the second shelf.

7. The extension plate of claim 1 , wherein the bottom surface of the connecting portion defines a ridge.

8. The extension plate of claim 7 , wherein the ridges are configured to engage with detents on a bone plate.

9. The extension plate of claim 1 , wherein the rail is a protrusion disposed on the end of an arm.

10. The extension plate of claim 9 , wherein the arm is a cantilever defined by a notch in the second shelf.

11. The extension plate of claim 10 , wherein the arms are configured to bend toward and away from the first shelf.

12. The extension plate of claim 9 , wherein the length of the protrusion is less than the length of the second shelf.

13. 10. The extension plate of claim 9, wherein the first shelf includes a rail extending toward the second shelf such that the first shelf defines an undercut between the rail and the bottom surface of the first shelf, the rail of the first shelf being a protrusion disposed at the end of an arm, and the arm of the first shelf being a cantilever defined by a notch in the first shelf.

14. 14. The extension plate of claim 13, wherein the first shelf is a mirror image of the second shelf.

15. The extension plate of claim 9 further comprising a locking element.

16. The extension plate of claim 15 , wherein the locking element is a locking screw.

17. 1. A bone plate system comprising: a bone plate having an anchor portion and a distal end extending from the anchor portion, the anchor portion defining a hole in which a fastener is disposable to secure the bone plate to a bone; The extension plate according to claim 9 ; Equipped with The connecting portion of the extension plate is configured to be secured to the distal end of the bone plate, and the fixing portion of the extension plate can be secured to the bone such that the bone plate system has a length longer than a length of the bone plate.

18. the distal end of the bone plate extends along a plate axis away from the anchoring portion of the bone plate, the distal end of the bone plate has first and second side edges extending parallel to the plate axis, and the distal end of the bone plate has a top surface configured to face away from the bone and a bottom surface configured to face toward the bone; 18. The bone plate system of claim 17, wherein an outer surface of the first edge extends from the bottom surface to a ledge at the top surface along a first edge axis, and an outer surface of the second edge extends from the bottom surface to a ledge at the top surface along a second edge axis.

19. The bone plate system of claim 18 , wherein the outer surfaces of the first and second edges each include a ridge.

20. 20. The bone plate system of claim 19, wherein the ridge is configured to engage the protrusion disposed on the end of the arm.

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