DEFORMABLE THREADED LOCKING STRUCTURES AND ASSOCIATED SYSTEMS AND METHODS - Patent application

Abstract

The bone plate (4) includes a plate (5) body defining a top surface (18), an opposing bone-facing surface, and a combination hole (90) including a locking hole (6) and a compression hole (92), the locking hole and compression hole intersecting each other and each extending from the outer surface to the bone-facing surface. The locking hole and compression hole extend away from each other along the longitudinal axis. The plate body further defines a locking surface (24a) defining the locking hole and a second surface (24b) defining the compression hole. The locking surface further defines a plurality of rows (26) positioned consecutively around a central axis (22) of the locking hole, a plurality of recesses (28) respectively positioned between at least some of the rows, and a plate thread (9) traversing each of the rows. The crests (56) of the plate threads extend linearly from the first side of each row to the second side of each row.

Description

[Technical Field]

[0001] The present invention relates to bone plates and bone anchors for coupling to the bone plates, and more particularly to threaded locking structures defined within fixation holes in the bone plates and complementary threaded locking structures defined in the heads of the bone anchors. [Background technology]

[0002] Bone plate systems for internal fixation of bone fractures are well known. Conventional bone plate systems are particularly well suited to promoting fracture healing. Bone anchors, such as bone screws, are inserted through fixation openings or holes in the bone plate and screwed into the bone to compress, neutralize, strengthen, tension, fasten, and / or bridge the fractured ends together. To transfer load from one fractured bone segment across the plate and onto another without pulling the bone against the plate, and to avoid loosening or pulling the bone screw relative to the plate (which can lead to poor alignment and poor clinical results), bone screws capable of locking the bone plate can be used. One known embodiment of such a screw uses a screw head with external threads for engaging corresponding threads on the inner surface of the fixation hole to lock the screw to the plate. These screws, hereinafter referred to as "locking screws" or "compression screws," may include standard locking screws that are configured to lock into fixation holes substantially only in a "nominal" orientation, where the central screw axis is substantially aligned with the central bore axis, as well as "variable-angle" (VA) locking screws that are configured to lock into fixation holes in either a nominal orientation or an "angled" orientation, where the central screw axis is oriented at an acute angle with respect to the respective central bore axis. Summary of the Invention [Means for solving the problem]

[0003] According to one embodiment of the present disclosure, a bone fixation system includes a plate body defining an inner surface defining at least one hole defining a central axis. The inner surface defines a plate thread within the hole. The system includes a bone screw having a shaft extending from a head along the central axis, the head having an outer surface defining threads configured to threadingly engage with the plate threads. The plate threads and the head threads each have a cross-sectional profile in a respective reference plane extending along the respective central axis. Each cross-sectional profile includes a root, a crest, and a flank extending therebetween. The root, crest, and flank collectively deviate from a reference cross-sectional profile, the reference cross-sectional profile being V-shaped in the respective reference plane and defining an apex reference point at an apex on a first side of the reference cross-sectional profile and a root reference point at an apex on a second side opposite the first side. Such deviations cause the thread height measured from crest to root to be less than the reference height measured from the crest reference point to the root reference point, whereby the ratio of the head threads' thread height to the head threads' reference height is 0.50:1 to 0.80:1 and the ratio of the plate threads' thread height to the plate threads' reference height is 0.50:1 to 1.00:1.

[0004] According to another embodiment of the present disclosure, a bone plate includes a plate body defining an outer surface, an opposing bone-facing surface, and combination holes including a locking hole and a compression hole, the locking hole and the compression hole intersecting each other and each extending from the outer surface to the bone-facing surface. The locking hole and the compression hole extend away from each other along the longitudinal axis. The plate body further defines a locking surface defining the locking hole and a second surface defining the compression hole. The locking surface further defines a plurality of rows positioned consecutively about the central axis of the locking hole in a polygonal pattern, a plurality of recesses respectively positioned between at least some of the rows, and plate threads traversing each of the rows. The crests of the plate threads extend linearly from the first side of each row to the second side of each row.

[0005] According to an additional embodiment of the present disclosure, a bone plate includes a plate body defining combination holes including a locking hole and a compression hole, the locking hole and the compression hole intersecting each other and each extending from the outer surface of the plate body to the bone-facing surface of the plate body. The locking hole and the compression hole extend away from each other along a longitudinal axis. The plate body further defines 1) a locking surface defining the locking hole, 2) a second surface defining the compression hole, and 3) an interface edge along the intersection interface between the locking surface and the second surface. The locking surface further defines first, second, and third rows positioned consecutively about the central axis of the locking hole, each row having a first side and a second side. The locking surfaces further define a first recess extending from the second side of the first row to the first side of the second row, an additional recess extending from the second side of the third row to the first side of the first row, and a transition zone between the first side of the second row and the second side of the third row, where the locking surfaces in the transition zone are elongated and extend to an intersecting boundary. The locking surfaces also define plate threads that traverse each of the rows and at least a portion of the first recess, the additional recess, and the transition zone. The crests of the plate threads extend linearly from the first side to the second side of each row. [Brief explanation of the drawings]

[0006] The foregoing summary and the following detailed description of exemplary embodiments of the present application will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the locking structure of the present application, there are shown in the drawings exemplary embodiments. It should be understood, however, that the present application is not limited to the precise arrangements and instrumentalities shown. The drawings are as follows: [Figure 1A] FIG. 1 is a perspective view of a bone fixation system including a bone plate and a plurality of locking screws disposed in locking holes of the bone plate according to one embodiment of the present disclosure; [Figure 1B] 1B is a cross-sectional side view of a bone fixation system taken along section line 1B-1B of FIG. 1A secured to multiple bone segments. [Figure 2A] FIG. 2 is a perspective view of a locking hole of the bone plate shown in FIGS. 1A and 1B. [Figure 2B]2B is a cross-sectional perspective view of the locking hole shown in FIG. 2A. FIG. [Figure 2C] 2B is another cross-sectional perspective view of the locking hole shown in FIG. 2A. [Figure 2D] FIG. 2B is a top view of the locking hole of FIG. 2A. [Figure 2E] FIG. 2E is a side cross-sectional view of the locking hole taken along section line 2E-2E shown in FIG. 2D, showing a threaded locking structure defined by an inner surface of the locking hole, the threaded locking structure configured to lock with a locking bone screw. [Figure 2F] FIG. 2F is an enlarged cross-sectional view of the threaded locking structure shown in FIG. 2E. [Figure 2G] FIG. 2F is a further enlarged cross-sectional view of a portion of the threaded locking structure shown in FIG. 2F. [Figure 2H] FIG. 2H is an enlarged cross-sectional view of a portion of a threaded locking structure having an alternative geometry to that shown in FIG. 2G. [Figure 2I] FIG. 2C is another view of the enlarged cross-sectional view of FIG. 2H. [Figure 3A] 1B is a side view of the head of a variable angle (VA) locking screw configured to be locked into the bone plate of FIG. 1A within one of the locking holes. FIG. [Figure 3B] FIG. 3B is a cross-sectional side view of the VA locking screw shown in FIG. 3A taken along the central axis of the screw. [Figure 3C] FIG. 3C is an enlarged cross-sectional side view of a portion of the VA locking screw shown in FIG. 3B. [Figure 4A] 3B is a cross-sectional perspective view of the head of the VA locking screw shown in FIG. 3A in locking engagement with the locking hole shown in FIG. 2A. [Figure 4B] FIG. 4B is a cross-sectional side view of the head of a VA locking screw in locking engagement with the locking hole shown in FIG. 4A. [Figure 5A] FIG. 10 is a top view of another locking hole having a threaded locking structure defined by an inner surface of the locking hole according to another embodiment of the present disclosure. [Figure 5B] FIG. 5B is an enlarged cross-sectional view of the threaded locking structure of the locking hole shown in FIG. 5A. [Figure 5C]FIG. 5B is a cross-sectional side view of the threaded head of another VA locking screw configured to lock with at least the locking hole shown in FIG. 5A. [Figure 5D] FIG. 5D is a cross-sectional side view of the head of the VA locking screw shown in FIG. 5C in locking engagement with the locking hole shown in FIG. 5A. [Figure 6A] FIG. 10 is a perspective view of another locking hole having a triangular horizontal hole profile and including a threaded locking structure defined by an inner surface of the locking hole according to an additional embodiment of the present disclosure. [Figure 6B] FIG. 6B is a top view of the locking hole shown in FIG. 6A. [Figure 6C] 6C is a cross-sectional side view of the locking hole taken along section line 6C-6C shown in FIG. 6B, showing the threaded locking structure of the hole. [Figure 7A] FIG. 6B is a perspective view of another locking hole according to a further embodiment of the present disclosure, the locking hole having a triangular horizontal hole profile with a smaller corner radius relative to the locking hole of FIG. 6A and including a threaded locking structure defined by the inner surface of the locking hole. [Figure 7B] FIG. 7B is a top view of the locking hole shown in FIG. 7A. [Figure 8A] FIG. 10 is a perspective view of another locking hole having a square horizontal hole profile and including a threaded locking structure defined by an inner surface of the locking hole according to yet another embodiment of the present disclosure. [Figure 8B] 8B is a top view of the locking hole shown in FIG. 8A. FIG. [Figure 8C] 8C is a cross-sectional side view of the locking hole taken along section line 8C-8C shown in FIG. 8B, showing the threaded locking structure of the hole. [Figure 9] FIG. 2E is a top view of a locking hole having three threaded locking structures and three recesses, and otherwise configured similarly to the locking hole shown in FIG. 2D. [Figure 10] FIG. 10 is a perspective view of another locking hole having eight threaded locking structures and eight recesses according to another embodiment of the present disclosure. [Figure 11A] FIG. 10 is a perspective view of a bone plate having combination holes including triangular locking holes intersected by compression holes according to another embodiment of the present disclosure; [Figure 11B] FIG. 11B is another perspective view of the bone plate shown in FIG. 11A. [Figure 11C] FIG. 11B is a top view of the combination hole shown in FIG. 11A. [Figure 11D] FIG. 11B is a bottom view of the combination hole shown in FIG. 11A. [Figure 11E] 11E is a cross-sectional perspective view of the combination hole taken along section line 11E-11E shown in FIG. 11C. [Figure 11F] FIG. 11E is a cross-sectional side view of the combination hole taken along section line 11E-11E shown in FIG. 11C. [Figure 11G] FIG. 11B is an enlarged top view of the combination hole shown in FIG. 11A. [Figure 12A] FIG. 10 is a top view of a combination hole with a clearance surface according to another embodiment of the present disclosure. [Figure 12B] FIG. 12B is an enlarged perspective view of the clearance face of the combination hole shown in FIG. 12A. [Figure 13A] FIG. 10 is a top view of a combination hole having a linear elongated thread transition zone between the triangular locking hole and the compression hole according to another embodiment of the present disclosure. [Figure 13B] FIG. 13B is a top view of a basic version of a locking hole used in the combination hole shown in FIG. 13A. [Figure 13C] FIG. 13C is a cross-sectional side view of the combination hole taken along section line 13C-13C shown in FIG. 13A. [Figure 13D] FIG. 13B is a perspective view of the combination hole shown in FIG. 13A. [Figure 13E] FIG. 13B is another perspective view of the combination hole shown in FIG. 13A. [Figure 13F] 13C is an enlarged perspective cross-sectional view of the triangular locking hole taken along section line 13C-13C shown in FIG. 13A. FIG. [Figure 13G] FIG. 13B is a top view of a bone fixation system including a bone screw fully seated within the triangular locking hole of the combination hole shown in FIG. 13A, with the bone screw angled within the hole intersection zone between the triangular locking hole and the compression hole. [Figure 13H]FIG. 13H is a cross-sectional perspective view of the combination hole taken along section line 13H-13H shown in FIG. 13G, illustrating the engagement between the threads of the angled bone screw head and the threads of the triangular locking hole within the thread transition zone. [Figure 14A] FIG. 10 is a top view of a combination hole having an arcuate and convex transition zone between the triangular locking hole and the compression hole according to another embodiment of the present disclosure. [Figure 14B] FIG. 14B is a top view of a basic version of a locking hole used in the combination hole shown in FIG. 14A. [Figure 14C] FIG. 14C is a cross-sectional side view of the combination hole taken along section line 14C-14C shown in FIG. 14A. [Figure 14D] FIG. 14B is a perspective view of the combination hole shown in FIG. 14A. [Figure 14E] FIG. 14B is another perspective view of the combination hole shown in FIG. 14A. [Figure 15A] FIG. 10 is a top view of a combination hole having an arcuate, elongated, convex transition zone between the triangular locking hole and the compression hole according to another embodiment of the present disclosure. [Figure 15B] FIG. 15B is a top view of a basic version of a locking hole used in the combination hole shown in FIG. 15A. [Figure 16A] FIG. 10 is a perspective view of a bone plate having triangular locking holes according to another embodiment of the present disclosure; [Figure 16B] 16B is a perspective view of a bone plate having a triangular locking hole, seen from the opposite side to the view shown in FIG. 16A. FIG. [Figure 16C] FIG. 16B is a top view of the triangular locking hole shown in FIG. 16A. [Figure 16D] FIG. 16B is a bottom view of the triangular locking hole shown in FIG. 16A. [Figure 16E] 16E is a cross-sectional side view of the triangular locking hole taken along section line 16E-16E shown in FIG. 16C. [Figure 16F] 16F is a cross-sectional side view of the triangular locking hole taken along section line 16F-16F shown in FIG. 16C. [Figure 16G] 16G is a cross-sectional side view of the triangular locking hole taken along section line 16G-16G shown in FIG. 16C. [Figure 16H] 16H is a cross-sectional side view of the triangular locking hole taken along section line 16H-16H shown in FIG. 16C. [Figure 17] FIG. 10 is a top view of a combination hole with an elongated compression hole according to another embodiment of the present disclosure. [Figure 18] FIG. 13B is a perspective view of a bone plate having a combination hole including a triangular locking hole crossed by another triangular locking hole according to another embodiment of the present disclosure, both triangular locking holes being similar in shape to the triangular locking holes illustrated in FIG. 13A . [Figure 19] FIG. 14B is a perspective view of a bone plate having a combination hole including a triangular locking hole crossed by another triangular locking hole according to another embodiment of the present disclosure, both triangular locking holes being similar in shape to the triangular locking holes illustrated in FIG. 14A . [Figure 20] FIG. 15B is a perspective view of a bone plate having a combination hole including a triangular locking hole crossed by another triangular locking hole according to another embodiment of the present disclosure, both triangular locking holes being similar in shape to the triangular locking holes illustrated in FIG. 15A . [Figure 21A] 21A-21G show respective views of a first additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 21A), a top view (FIG. 21B), a right side view (FIG. 21C), a bottom view (FIG. 21D), a left side view (FIG. 21E), a front view (FIG. 21F), and a back view (FIG. 21G) of the bone plate. [Figure 21B] 21A-21G show respective views of a first additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 21A), a top view (FIG. 21B), a right side view (FIG. 21C), a bottom view (FIG. 21D), a left side view (FIG. 21E), a front view (FIG. 21F), and a back view (FIG. 21G) of the bone plate. [Figure 21C]21A-21G show respective views of a first additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 21A), a top view (FIG. 21B), a right side view (FIG. 21C), a bottom view (FIG. 21D), a left side view (FIG. 21E), a front view (FIG. 21F), and a back view (FIG. 21G) of the bone plate. [Figure 21D] 21A-21G show respective views of a first additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 21A), a top view (FIG. 21B), a right side view (FIG. 21C), a bottom view (FIG. 21D), a left side view (FIG. 21E), a front view (FIG. 21F), and a back view (FIG. 21G) of the bone plate. [Figure 21E] 21A-21G show respective views of a first additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 21A), a top view (FIG. 21B), a right side view (FIG. 21C), a bottom view (FIG. 21D), a left side view (FIG. 21E), a front view (FIG. 21F), and a back view (FIG. 21G) of the bone plate. [Figure 21F] 21A-21G show respective views of a first additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 21A), a top view (FIG. 21B), a right side view (FIG. 21C), a bottom view (FIG. 21D), a left side view (FIG. 21E), a front view (FIG. 21F), and a back view (FIG. 21G) of the bone plate. [Figure 21G] 21A-21G show respective views of a first additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 21A), a top view (FIG. 21B), a right side view (FIG. 21C), a bottom view (FIG. 21D), a left side view (FIG. 21E), a front view (FIG. 21F), and a back view (FIG. 21G) of the bone plate. [Figure 22A]22A-22G show respective views of a second additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 22A), a top view (FIG. 22B), a right side view (FIG. 22C), a bottom view (FIG. 22D), a left side view (FIG. 22E), a front view (FIG. 22F), and a back view (FIG. 22G) of the bone plate. [Figure 22B] 22A-22G show respective views of a second additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 22A), a top view (FIG. 22B), a right side view (FIG. 22C), a bottom view (FIG. 22D), a left side view (FIG. 22E), a front view (FIG. 22F), and a back view (FIG. 22G) of the bone plate. [Figure 22C] 22A-22G show respective views of a second additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 22A), a top view (FIG. 22B), a right side view (FIG. 22C), a bottom view (FIG. 22D), a left side view (FIG. 22E), a front view (FIG. 22F), and a back view (FIG. 22G) of the bone plate. [Figure 22D] 22A-22G show respective views of a second additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 22A), a top view (FIG. 22B), a right side view (FIG. 22C), a bottom view (FIG. 22D), a left side view (FIG. 22E), a front view (FIG. 22F), and a back view (FIG. 22G) of the bone plate. [Figure 22E] 22A-22G show respective views of a second additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 22A), a top view (FIG. 22B), a right side view (FIG. 22C), a bottom view (FIG. 22D), a left side view (FIG. 22E), a front view (FIG. 22F), and a back view (FIG. 22G) of the bone plate. [Figure 22F]22A-22G show respective views of a second additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 22A), a top view (FIG. 22B), a right side view (FIG. 22C), a bottom view (FIG. 22D), a left side view (FIG. 22E), a front view (FIG. 22F), and a back view (FIG. 22G) of the bone plate. [Figure 22G] 22A-22G show respective views of a second additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 22A), a top view (FIG. 22B), a right side view (FIG. 22C), a bottom view (FIG. 22D), a left side view (FIG. 22E), a front view (FIG. 22F), and a back view (FIG. 22G) of the bone plate. [Figure 23A] 23A-23G show views of a third additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 23A), a top view (FIG. 23B), a right side view (FIG. 23C), a bottom view (FIG. 23D), a left side view (FIG. 23E), a front view (FIG. 23F), and a back view (FIG. 23G) of the bone plate. [Figure 23B] 23A-23G show views of a third additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 23A), a top view (FIG. 23B), a right side view (FIG. 23C), a bottom view (FIG. 23D), a left side view (FIG. 23E), a front view (FIG. 23F), and a back view (FIG. 23G) of the bone plate. [Figure 23C] 23A-23G show views of a third additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 23A), a top view (FIG. 23B), a right side view (FIG. 23C), a bottom view (FIG. 23D), a left side view (FIG. 23E), a front view (FIG. 23F), and a back view (FIG. 23G) of the bone plate. [Figure 23D]23A-23G show views of a third additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 23A), a top view (FIG. 23B), a right side view (FIG. 23C), a bottom view (FIG. 23D), a left side view (FIG. 23E), a front view (FIG. 23F), and a back view (FIG. 23G) of the bone plate. [Figure 23E] 23A-23G show views of a third additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 23A), a top view (FIG. 23B), a right side view (FIG. 23C), a bottom view (FIG. 23D), a left side view (FIG. 23E), a front view (FIG. 23F), and a back view (FIG. 23G) of the bone plate. [Figure 23F] 23A-23G show views of a third additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 23A), a top view (FIG. 23B), a right side view (FIG. 23C), a bottom view (FIG. 23D), a left side view (FIG. 23E), a front view (FIG. 23F), and a back view (FIG. 23G) of the bone plate. [Figure 23G] 23A-23G show views of a third additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 23A), a top view (FIG. 23B), a right side view (FIG. 23C), a bottom view (FIG. 23D), a left side view (FIG. 23E), a front view (FIG. 23F), and a back view (FIG. 23G) of the bone plate. [Figure 24A] 24A-24G show views of a fourth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 24A), a top view (FIG. 24B), a right side view (FIG. 24C), a bottom view (FIG. 24D), a left side view (FIG. 24E), a front view (FIG. 24F), and a back view (FIG. 24G) of the bone plate. [Figure 24B]24A-24G show views of a fourth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 24A), a top view (FIG. 24B), a right side view (FIG. 24C), a bottom view (FIG. 24D), a left side view (FIG. 24E), a front view (FIG. 24F), and a back view (FIG. 24G) of the bone plate. [Figure 24C] 24A-24G show views of a fourth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 24A), a top view (FIG. 24B), a right side view (FIG. 24C), a bottom view (FIG. 24D), a left side view (FIG. 24E), a front view (FIG. 24F), and a back view (FIG. 24G) of the bone plate. [Figure 24D] 24A-24G show views of a fourth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 24A), a top view (FIG. 24B), a right side view (FIG. 24C), a bottom view (FIG. 24D), a left side view (FIG. 24E), a front view (FIG. 24F), and a back view (FIG. 24G) of the bone plate. [Figure 24E] 24A-24G show views of a fourth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 24A), a top view (FIG. 24B), a right side view (FIG. 24C), a bottom view (FIG. 24D), a left side view (FIG. 24E), a front view (FIG. 24F), and a back view (FIG. 24G) of the bone plate. [Figure 24F] 24A-24G show views of a fourth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 24A), a top view (FIG. 24B), a right side view (FIG. 24C), a bottom view (FIG. 24D), a left side view (FIG. 24E), a front view (FIG. 24F), and a back view (FIG. 24G) of the bone plate. [Figure 24G]24A-24G show views of a fourth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 24A), a top view (FIG. 24B), a right side view (FIG. 24C), a bottom view (FIG. 24D), a left side view (FIG. 24E), a front view (FIG. 24F), and a back view (FIG. 24G) of the bone plate. [Figure 25A] 25A-25G show views of a fifth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 25A), a top view (FIG. 25B), a right side view (FIG. 25C), a bottom view (FIG. 25D), a left side view (FIG. 25E), a front view (FIG. 25F), and a back view (FIG. 25G) of the bone plate. [Figure 25B] 25A-25G show views of a fifth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 25A), a top view (FIG. 25B), a right side view (FIG. 25C), a bottom view (FIG. 25D), a left side view (FIG. 25E), a front view (FIG. 25F), and a back view (FIG. 25G) of the bone plate. [Figure 25C] 25A-25G show views of a fifth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 25A), a top view (FIG. 25B), a right side view (FIG. 25C), a bottom view (FIG. 25D), a left side view (FIG. 25E), a front view (FIG. 25F), and a back view (FIG. 25G) of the bone plate. [Figure 25D] 25A-25G show views of a fifth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 25A), a top view (FIG. 25B), a right side view (FIG. 25C), a bottom view (FIG. 25D), a left side view (FIG. 25E), a front view (FIG. 25F), and a back view (FIG. 25G) of the bone plate. [Figure 25E]25A-25G show views of a fifth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 25A), a top view (FIG. 25B), a right side view (FIG. 25C), a bottom view (FIG. 25D), a left side view (FIG. 25E), a front view (FIG. 25F), and a back view (FIG. 25G) of the bone plate. [Figure 25F] 25A-25G show views of a fifth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 25A), a top view (FIG. 25B), a right side view (FIG. 25C), a bottom view (FIG. 25D), a left side view (FIG. 25E), a front view (FIG. 25F), and a back view (FIG. 25G) of the bone plate. [Figure 25G] 25A-25G show views of a fifth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 25A), a top view (FIG. 25B), a right side view (FIG. 25C), a bottom view (FIG. 25D), a left side view (FIG. 25E), a front view (FIG. 25F), and a back view (FIG. 25G) of the bone plate. [Figure 26A] 26A-26G show views of a sixth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 26A), a top view (FIG. 26B), a right side view (FIG. 26C), a bottom view (FIG. 26D), a left side view (FIG. 26E), a front view (FIG. 26F), and a back view (FIG. 26G) of the bone plate. [Figure 26B] 26A-26G show views of a sixth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 26A), a top view (FIG. 26B), a right side view (FIG. 26C), a bottom view (FIG. 26D), a left side view (FIG. 26E), a front view (FIG. 26F), and a back view (FIG. 26G) of the bone plate. [Figure 26C]26A-26G show views of a sixth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 26A), a top view (FIG. 26B), a right side view (FIG. 26C), a bottom view (FIG. 26D), a left side view (FIG. 26E), a front view (FIG. 26F), and a back view (FIG. 26G) of the bone plate. [Figure 26D] 26A-26G show views of a sixth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 26A), a top view (FIG. 26B), a right side view (FIG. 26C), a bottom view (FIG. 26D), a left side view (FIG. 26E), a front view (FIG. 26F), and a back view (FIG. 26G) of the bone plate. [Figure 26E] 26A-26G show views of a sixth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 26A), a top view (FIG. 26B), a right side view (FIG. 26C), a bottom view (FIG. 26D), a left side view (FIG. 26E), a front view (FIG. 26F), and a back view (FIG. 26G) of the bone plate. [Figure 26F] 26A-26G show views of a sixth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 26A), a top view (FIG. 26B), a right side view (FIG. 26C), a bottom view (FIG. 26D), a left side view (FIG. 26E), a front view (FIG. 26F), and a back view (FIG. 26G) of the bone plate. [Figure 26G] 26A-26G show views of a sixth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 26A), a top view (FIG. 26B), a right side view (FIG. 26C), a bottom view (FIG. 26D), a left side view (FIG. 26E), a front view (FIG. 26F), and a back view (FIG. 26G) of the bone plate. [Figure 27A]27A-27G show views of a seventh additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 27A), a top view (FIG. 27B), a right side view (FIG. 27C), a bottom view (FIG. 27D), a left side view (FIG. 27E), a front view (FIG. 27F), and a back view (FIG. 27G) of the bone plate. [Figure 27B] 27A-27G show views of a seventh additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 27A), a top view (FIG. 27B), a right side view (FIG. 27C), a bottom view (FIG. 27D), a left side view (FIG. 27E), a front view (FIG. 27F), and a back view (FIG. 27G) of the bone plate. [Figure 27C] 27A-27G show views of a seventh additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 27A), a top view (FIG. 27B), a right side view (FIG. 27C), a bottom view (FIG. 27D), a left side view (FIG. 27E), a front view (FIG. 27F), and a back view (FIG. 27G) of the bone plate. [Figure 27D] 27A-27G show views of a seventh additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 27A), a top view (FIG. 27B), a right side view (FIG. 27C), a bottom view (FIG. 27D), a left side view (FIG. 27E), a front view (FIG. 27F), and a back view (FIG. 27G) of the bone plate. [Figure 27E] 27A-27G show views of a seventh additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 27A), a top view (FIG. 27B), a right side view (FIG. 27C), a bottom view (FIG. 27D), a left side view (FIG. 27E), a front view (FIG. 27F), and a back view (FIG. 27G) of the bone plate. [Figure 27F]27A-27G show views of a seventh additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 27A), a top view (FIG. 27B), a right side view (FIG. 27C), a bottom view (FIG. 27D), a left side view (FIG. 27E), a front view (FIG. 27F), and a back view (FIG. 27G) of the bone plate. [Figure 27G] 27A-27G show views of a seventh additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 27A), a top view (FIG. 27B), a right side view (FIG. 27C), a bottom view (FIG. 27D), a left side view (FIG. 27E), a front view (FIG. 27F), and a back view (FIG. 27G) of the bone plate. [Figure 28A] 28A-28G show views of an eighth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 28A), a top view (FIG. 28B), a right side view (FIG. 28C), a bottom view (FIG. 28D), a front view (FIG. 28E), a left side view (FIG. 28F), and a back view (FIG. 28G) of the bone plate. [Figure 28B] 28A-28G show views of an eighth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 28A), a top view (FIG. 28B), a right side view (FIG. 28C), a bottom view (FIG. 28D), a front view (FIG. 28E), a left side view (FIG. 28F), and a back view (FIG. 28G) of the bone plate. [Figure 28C] 28A-28G show views of an eighth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 28A), a top view (FIG. 28B), a right side view (FIG. 28C), a bottom view (FIG. 28D), a front view (FIG. 28E), a left side view (FIG. 28F), and a back view (FIG. 28G) of the bone plate. [Figure 28D]28A-28G show views of an eighth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 28A), a top view (FIG. 28B), a right side view (FIG. 28C), a bottom view (FIG. 28D), a front view (FIG. 28E), a left side view (FIG. 28F), and a back view (FIG. 28G) of the bone plate. [Figure 28E] 28A-28G show views of an eighth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 28A), a top view (FIG. 28B), a right side view (FIG. 28C), a bottom view (FIG. 28D), a front view (FIG. 28E), a left side view (FIG. 28F), and a back view (FIG. 28G) of the bone plate. [Figure 28F] 28A-28G show views of an eighth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 28A), a top view (FIG. 28B), a right side view (FIG. 28C), a bottom view (FIG. 28D), a front view (FIG. 28E), a left side view (FIG. 28F), and a back view (FIG. 28G) of the bone plate. [Figure 28G] 28A-28G show views of an eighth additional bone plate according to another embodiment of the present disclosure, the bone plate having various combination holes including triangular locking holes intersected by compression holes, the views being a perspective view (FIG. 28A), a top view (FIG. 28B), a right side view (FIG. 28C), a bottom view (FIG. 28D), a front view (FIG. 28E), a left side view (FIG. 28F), and a back view (FIG. 28G) of the bone plate. [Figure 29A] 29A-29G show views of a bone plate having triangular locking holes, including a perspective view (FIG. 29A), a top view (FIG. 29B), a right side view (FIG. 29C), a bottom view (FIG. 29D), a front view (FIG. 29E), a left side view (FIG. 29F), and a back view (FIG. 29G) of the bone plate. [Figure 29B]29A-29G show views of a bone plate having triangular locking holes, including a perspective view (FIG. 29A), a top view (FIG. 29B), a right side view (FIG. 29C), a bottom view (FIG. 29D), a front view (FIG. 29E), a left side view (FIG. 29F), and a back view (FIG. 29G) of the bone plate. [Figure 29C] 29A-29G show views of a bone plate having triangular locking holes, including a perspective view (FIG. 29A), a top view (FIG. 29B), a right side view (FIG. 29C), a bottom view (FIG. 29D), a front view (FIG. 29E), a left side view (FIG. 29F), and a back view (FIG. 29G) of the bone plate. [Figure 29D] 29A-29G show views of a bone plate having triangular locking holes, including a perspective view (FIG. 29A), a top view (FIG. 29B), a right side view (FIG. 29C), a bottom view (FIG. 29D), a front view (FIG. 29E), a left side view (FIG. 29F), and a back view (FIG. 29G) of the bone plate. [Figure 29E] 29A-29G show views of a bone plate having triangular locking holes, including a perspective view (FIG. 29A), a top view (FIG. 29B), a right side view (FIG. 29C), a bottom view (FIG. 29D), a front view (FIG. 29E), a left side view (FIG. 29F), and a back view (FIG. 29G) of the bone plate. [Figure 29F] 29A-29G show views of a bone plate having triangular locking holes, including a perspective view (FIG. 29A), a top view (FIG. 29B), a right side view (FIG. 29C), a bottom view (FIG. 29D), a front view (FIG. 29E), a left side view (FIG. 29F), and a back view (FIG. 29G) of the bone plate. [Figure 29G] 29A-29G show views of a bone plate having triangular locking holes, including a perspective view (FIG. 29A), a top view (FIG. 29B), a right side view (FIG. 29C), a bottom view (FIG. 29D), a front view (FIG. 29E), a left side view (FIG. 29F), and a back view (FIG. 29G) of the bone plate. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present disclosure may be understood more readily by reference to the following detailed description in conjunction with the accompanying drawings and examples, which form a part of this disclosure. It is to be understood that the present disclosure is not limited to the specific devices, methods, applications, conditions, or parameters described and / or illustrated herein, and that the terminology used herein is for the purpose of describing specific embodiments, by way of example, only and is not intended to limit the scope of the present disclosure. Also, as used in the specification, including the appended claims, the singular forms "a," "an," and "the" include plurals, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0008] The term "plurality," as used herein, means more than one. When a range of values ​​is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed in approximation, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.

[0009] When used herein with respect to dimensions, angles, and other shapes, the terms "about" and "substantially" take into account manufacturing tolerances. Furthermore, the terms "about" and "substantially" can include values ​​10% greater or less than the stated dimension or angle. Furthermore, the terms "about" and "substantially" can equally apply to the specific values ​​stated.

[0010] Variable angle (VA) locking screws tend to create and exhibit cross-threading in the locking holes into which they are inserted, especially when the VA locking screws are inserted into the locking holes at an angled trajectory. Cross-threading of the plate threads can be caused by external threads on the screw head that do not fit (i.e., interfere) with the internal threads of the locking hole, thus cross-threading the internal threads of the locking hole. Such thread interference can also cause cross-threading of the external threads of the screw head. The contact area between the crest of the screw head threads and a portion of the internal threads, especially the contact area at or near the crest of angled internal threads, can be particularly susceptible to cross-threading. Cross-threading is problematic because it reduces the intended interference fit (also referred to as a "form fit") between the screw head threads and the internal threads of the locking hole, which can reduce the stability and mechanical strength of the locking interface between the screw head and the locking hole.

[0011] The embodiments disclosed herein relate to locking structures used within a locking hole and complementary locking structures on the head of a locking screw. These complementary locking structures define mating threads with complementary geometries that provide enhanced control over deformation of the mating threads, particularly deformation of the internal threads of the locking hole, which are effectively realigned with the screw shank upon angled insertion. Such preferred geometries include the respective cross-sectional profiles (referred to in the art as "thread forms") of the screw head threads and plate hole threads. These complementary geometries and profiles can be collectively characterized as the "thread ratios" of the plate and screw threads. One way the thread profiles disclosed herein control thread deformation is by providing a stronger (e.g., larger) profile for the screw head threads that abuts against the intentionally more malleable (e.g., thinner) profile of the plate hole threads. Another way in which thread deformation is controlled is by adjusting the geometry of the edges of the thread profile, such as at the crest, to reduce undesirable mechanical interference at the thread interface in angled thread orientations. The thread ratios disclosed herein have been shown to avoid or reduce cross-threading during angled screw insertion, and also when screw insertion involves a "timing error," which is axial misalignment of the screw head threads relative to the plate hole threads. Thus, the threaded locking structures described herein can lock with both angled VA locking screw heads and VA and standard locking screws in nominal orientations, preventing (or at least reducing) cross-threading or at least substantially ensuring that any cross-threading occurs substantially entirely within the plate threads as a function of plastic and elastic thread deformation. The threaded locking structures described herein have also been demonstrated to increase the overall cantilever strength at the locking thread interface.

[0012] 1A , a bone fixation system 2 includes a bone plate 4 having a plate body 5 defining one or more fixation holes therein, such as variable angle (VA) locking holes 6. The VA locking holes 6 are configured to receive anchoring members, such as locking screws 8, configured to secure the bone plate 4 to one or more portions of a bone. The plate body 5 defines internal threads 9 within the VA locking holes 6. Accordingly, the internal threads 9 may also be referred to as "plate hole threads" or simply "plate threads" or "hole threads." The plate threads 9 traverse locking structures, such as rows 26 defined within the VA locking holes 6. Accordingly, the rows 26 may be referred to as "threaded rows." The threaded row 26 is configured such that during insertion of the locking screw 8 into the VA locking hole 6, the threaded shaft 25 of the locking screw 8 bypasses the row 26, thereby engaging with the external threads 29 on the screw head 27 of the locking screw 8 in a manner that enhances the locking engagement between the locking screw 8 and the bone plate 4, as described in more detail below.

[0013] The bone plate 4 may be a bridge plate as shown, although other bone plate types and configurations are within the scope of this disclosure. The plate body 5 may define a first end 10 and a second end 12 spaced apart from one another along a longitudinal direction X and a first side 14 and a second side 16 spaced apart from one another along a transverse direction Y that is substantially perpendicular to the longitudinal direction X. The bone plate 4 may also define an upper plate surface 18 configured to face away from the bone and an opposing lower plate surface 20 configured to face the bone. The upper plate surface 18 and the lower plate surface 20 are spaced apart from one another along a vertical direction Z that is substantially perpendicular to each of the longitudinal direction X and the transverse direction Y. As used herein, the terms “longitudinal,” “longitudinally,” and their derivatives should be understood to refer to the longitudinal direction X. The terms “transverse,” “laterally,” and their derivatives should be understood to refer to the transverse direction Y, and the terms “vertical,” “vertically,” and their derivatives should be understood to refer to the vertical direction Z.

[0014] The VA locking hole 6 extends along a center hole axis 22 from the upper plate surface 18 to the lower plate surface 20. The center hole axis 22 is oriented along the axial hole direction. As used herein, the term "axial direction" (e.g., "axial hole direction" and "axial thread direction") is defined as the direction along which the respective axes extend. Furthermore, the directional terms "axial," "axially," and their derivatives refer to the direction of the respective axes. Therefore, as used herein, the directional term "axially upward" and its derivatives refer to the axial hole direction from the lower plate surface 20 toward the upper plate surface 18. Conversely, the term "axially downward" and its derivatives refer to the axial hole direction from the upper plate surface 18 toward the lower plate surface 20. Therefore, "axially upward" and "axially downward" are each unidirectional components of the bidirectional "axial" direction. In the illustrated embodiment, the axial hole direction (and therefore the center hole axis 22) is oriented along the vertical direction Z. Therefore, the axial hole direction is also represented by "Z" throughout this disclosure. However, it should be understood that the scope of the present disclosure encompasses embodiments in which the axial bore direction (and therefore the central bore axis 22) is offset at an oblique angle from the vertical direction Z. It should also be understood that when terms such as "axially upper," "axially lower," and the like are used in reference to the VA locking screw 8, such terms refer to the central axis 23 of the screw 8, and in particular the central axis 23 when the screw 8 is oriented within the VA locking bore 6.

[0015] The plate body 5 and the locking screw 8 can each comprise one or more biocompatible materials. By way of non-limiting example, the plate body 5 can be formed from a material selected from the group including metals such as titanium, titanium alloys (e.g., titanium-aluminum-niobium (TAN) alloys such as Ti-6Al-7Nb, and titanium-aluminum-vanadium (TAV) alloys such as Ti-6Al-4V, titanium-molybdenum alloys (Ti-Mo) or any other molybdenum metal alloys, and nickel-titanium alloys such as Nitinol), stainless steel, and cobalt-based alloys (e.g., cobalt-chromium alloys), composite materials, polymeric materials, ceramic materials, and / or absorbable materials including absorbable versions of the aforementioned material categories (metals, composites, polymers, ceramics). Also, by way of non-limiting example, the locking screw 8 can be formed from a material selected from the group including: titanium, titanium alloys (e.g., TAN alloys, TAV alloys such as Ti-6Al-4V, titanium-molybdenum alloys (Ti-Mo) or any other molybdenum metal alloys, and nickel-titanium alloys such as Nitinol), stainless steel, metals such as cobalt-based alloys (e.g., cobalt-chromium alloys), composite materials, polymeric materials, ceramic materials, and / or resorbable materials, including resorbable versions of the aforementioned material categories (metals, composites, polymers, ceramics). Preferably, the material of the locking screw 8 has a hardness greater than the hardness of the material of the plate body 5. This parameter contributes to the locking characteristics described throughout this disclosure. Preferably, the plate body 5 comprises primarily or entirely titanium, and the locking screw 8 comprises primarily or entirely TAN. However, it should be understood that other material compositions for the bone plate 4 and / or the locking screw 8 are within the scope of this disclosure.

[0016] Additionally, the surfaces of the plate body 5 and / or the locking screw 8 can optionally undergo one or more processes, such as coatings, treatments, and / or finishing processes, which can be performed to provide specific properties to such surfaces or the underlying body material, such as to adjust the hardness, softness, and / or friction parameters of the body material. Non-limiting examples of coatings include DLC, TiN, AlTiN, and other coatings, which provide, among other things, lubrication, a coefficient of friction different from that of the underlying material, and / or a surface hardness different from that of the underlying material. Non-limiting examples of surface treatments include processes for hardening the outer surface of the body material, such as hard anodizing and diffusion hardening, which can include the diffusion of nitrogen, oxygen, carbon, and / or zirconium into the surface of the plate body 5 and / or the locking screw 8. Additional or alternative surface treatments can include annealing or other processes to soften the body material, particularly the material of the plate body 5, although such softening processes can also be used on the body material of the screw 8. The aforementioned processes can be used, for example, as described throughout this disclosure, to provide beneficial thread deformation capabilities at the thread interface and / or to allow mating thread surfaces to effectively slide relative to one another with less friction and therefore less undesired deformation. It should be understood that the plate body 5 and the locking screw 8 can undergo different processes. Moreover, either or each of the plate body 5 and the locking screw 8 need not undergo any of the aforementioned processes.

[0017] Furthermore, the dimensions described throughout this disclosure are set forth with respect to a bone fixation system 2 including at least one VA locking hole 6 and at least one VA locking screw 8 configured for nominal or angled insertion into the at least one VA locking hole 6, the threaded shaft 25 of the VA locking screw 8 defining an outer diameter in the range of about 0.5 mm to about 10.0 mm, more specifically in the range of about 1.0 mm to about 7.0 mm, more specifically in the range of about 2.0 mm to about 4.0 mm, and more specifically in the range of about 3.5 mm. The aforementioned size of the threaded shaft 25 can correspond to a threaded head 27 defining an outer diameter in the range of about 0.7 mm to about 15.0 mm, more specifically in the range of about 1.0 mm to about 12.0 mm, more specifically in the range of about 2.0 mm to about 10.0 mm, and more specifically in the range of about 3.0 mm to about 7.0 mm. However, it should be understood that any of the embodiments described below can be scaled up or down in size as needed for use in larger or smaller bone fixation systems.

[0018] 1B , the VA locking holes 6 can be configured to provide enhanced fixation with multiple types of locking screws 8, including VA locking screws 8 and standard locking screws, including such screws of various lengths, to allow a physician to implant the bone plate 4 into one or more bones or bone segments as desired. As a non-limiting example, as shown, the bone plate 4 can be coupled to a long bone 100 via locking screws 8 to secure the fractured segments 101, 102 of the bone together. The VA locking holes 6 described herein can be locked with VA locking screws 8 or standard locking screws in a nominal orientation, whereby their central thread axes 23 are substantially aligned with the central bore axes 22. The VA locking holes 6 can also be locked with VA locking screws 8 in an angled orientation, where the central thread axes 23 are oriented at an acute angle A1 with respect to the respective central bore axes 22. The acute angle A1 may also be referred to as the “angle of angulation” or simply “angulation.” The VA locking screw 8 and standard locking screws and their locking features are more fully described in U.S. Patent No. 9,314,284, issued April 19, 2016 in the name of Chan et al. ("Reference '284"), U.S. patent application Ser. No. 15 / 940,761, filed March 29, 2018 in the name of Bosshard et al. ("Reference '761"), and U.S. patent application Ser. No. 15 / 966,047, filed April 30, 2019 in the name of Bosshard et al. ("Reference '047"), the disclosures of each of which are incorporated herein by reference as if set forth in their entirety.

[0019] During a bone plating procedure, the threaded shaft 25 of the locking screw 8 may be inserted through one of the VA locking holes 6 and driven into the underlying bone 100. Specifically, rotation of the locking screw 8 causes its threaded screw head 27 to threadingly engage with the VA locking hole 6. As a result, the screw head 27 fastens the bone plate 4 to the underlying bone 100 without substantially applying a compressive force to the bone plate 4 against the underlying bone 100. When the bone plate 4 is locked onto the threaded screw head 27, it may be spaced apart from the underlying bone 100. Alternatively, the bone plate 4 may abut against the underlying bone 100 when locked onto the threaded screw head 27.

[0020] It will be appreciated that during a plating procedure, a first locking screw 8 inserted through one of the VA locking holes 6 into the underlying bone 100 has the benefit of being able to generally mate with the plate threads 9 such that the crests of the screw head threads 29 advance helically substantially along the roots of the plate threads 9. However, once the first locking screw 8 is locked to the bone plate 4, thereby fastening the plate 4 to the underlying bone 100, subsequent locking screws 8 often lack the ability to advance the crests of their external threads helically along the roots of the plate threads 9. This results because, as the threaded shafts 25 of these subsequent locking screws 8 advance through the VA locking hole 6 and threadably engage into the underlying bone 100, the relative axial positions of the screw head threads 29 and plate threads 9 are substantially a function of the leverage of the screw threads with the underlying bone 100. This axial misalignment of the screw head threads 29 relative to the plate threads 9 is referred to herein as a "timing error."

[0021] 2A-2C and 2E, each of the VA locking holes 6 can be defined by an inner surface 24 of the plate body 5. Alternatively, the inner surface 24 can be defined by an insert plate body 5a, which may also be referred to as an "insert" or "inlay," that fits into an axial opening or receptacle 95 in the plate body 5, as shown by the dashed line in FIG. 2E. It should be understood that the bone fixation system 2 can include multiple interchangeable inserts 5a, each having different hole 6 shapes and geometries and / or different thread parameters, insertable into the receptacle 95, such that a physician can select a particular insert 5a having a desired VA locking hole 6 geometry as needed. Typically, at least a portion of the inner surface 24 tapers as it extends axially downward. Thus, the inner surface 24 is configured to prevent a screw head 27 from passing completely through the VA locking hole 6.

[0022] The inner surface 24 can define threaded rows 26. The rows 26 extend axially between the upper plate surface 18 and the lower plate surface 20. Within each (or at least some) of the VA locking holes 6, the rows 26 are located consecutively around the circumference of the inner surface 24. The inner surface 24 also defines a plurality of recesses 28 located consecutively around the circumference between the rows 26. The recesses 28 extend axially between the upper plate surface 18 and the lower plate surface 20. The rows 26 and recesses 28 can be evenly spaced around the circumference of the inner surface 24 within the VA locking hole 6. However, in other embodiments, the rows 26 and / or recesses 28 can be unevenly spaced around the circumference of the VA locking hole 6.

[0023] The plate threads 9 extend through at least a portion of the rows 26 and recesses 28 along one or more thread paths between the upper plate surface 18 and the lower plate surface 20. As shown, the one or more thread paths can include a pair of non-intersecting thread paths (i.e., double lead). However, in other embodiments, the one or more thread paths can include a single thread path (i.e., single lead) or three or more thread paths (e.g., triple lead, etc.). While the thread paths are preferably helical, other thread path types are within the scope of the present disclosure. As shown, some of the recesses 28 can circumferentially interrupt the plate threads 9. Stated differently, the plate threads 9 can "bottom out" along one or more, and up to all, of the recesses 28. However, in other embodiments, the plate threads 9 can circumferentially traverse one or more, and up to each, of the recesses 28 in an uninterrupted manner (i.e., the plate threads 9 need not bottom out within the recesses 28).

[0024] The plate thread 9 has a cross-sectional profile in a reference plane extending along the central bore axis 22. Such a cross-sectional profile, also referred to as a "thread form," includes a crest 56, a root 58, and an upper flank 55 and a lower flank 57 extending between the crest 56 and the root 58, as shown in FIG. 2B . As used herein with reference to the plate thread 9, the term "crown" refers to the apex of a fully developed thread form. Each threaded row 26 defines one or more thread segments 52 extending along a thread path. As used herein, the term "thread segment" refers to any portion of a thread, such as the plate thread 9 and the screw head thread 29, having a thread form and a length along its thread path. The thread segments 52 of the plate thread 9 may also be referred to herein as "plate thread segments" 52. The plate thread segments 52 that intersect a row 26 may be referred to herein as "row threads" 54.

[0025] The inner surface 24 can define an upper periphery 30 of the VA locking hole 6 at its interface with the upper plate surface 18 and a lower periphery 32 of the VA locking hole 6 at its interface with the lower plate surface 20. The upper periphery 30 and the lower periphery 32 can each be circular, although other shapes are within the scope of this disclosure, as described in more detail below. The inner surface 24 can also define one or more lead-in surfaces 34 that taper axially downward from the upper periphery 30 to one or more of the rows 26. As shown, the one or more lead-in surfaces 34 can include a single lead-in surface 34 that can be circumferentially interrupted by one or more of the recesses 28. Alternatively, the lead-in surface 34 can be circumferentially continuous and extend uninterrupted along a complete circumference about the central bore axis 22. The inner surface 24 can also define an undercut surface 36 that tapers axially upward from the lower periphery 32. The undercut surface 36 may be circumferentially continuous and extend uninterrupted along a complete circumference about the central bore axis 22. Alternatively, the undercut surface 36 may be circumferentially interrupted by one or more recesses 28.

[0026] 2D , in the exemplary embodiment, the VA locking hole 6 may include four rows 26 and four recesses 28 evenly spaced about the central bore axis 22. The rows 26 may include a first row 26a, a second row 26b, a third row 26c, and a fourth row 26d evenly spaced about the central bore axis 22. The recesses 28 may include a first recess 28a circumferentially located between the first row 26a and the second row 26b, a second recess 28b circumferentially located between the second row 26b and the third row 26c, a third recess 28c circumferentially located between the third row 26c and the fourth row 26d, and a fourth recess 28d circumferentially located between the fourth row 26d and the first row 26a. It should be understood that the design of the VA locking holes 6 is not limited by the number of rows 26 and recesses 28, as will be explained in more detail below.

[0027] Each of the recesses 28a-28d can define a central recess axis 37, each of which can be parallel to the central bore axis 22, although other central recess axis 37 orientations are possible. Each central recess axis 37 can also be radially spaced a radial distance R1 from the central bore axis 22. Each recess defines a recess radius R10. As shown, each of the recesses 28a-28d has a horizontal profile (i.e., a profile in a reference plane perpendicular to the central bore axis 22) that encompasses approximately half of a circle. In the illustrated embodiment, each of the recesses 28a-28d is generally shaped as a portion of a cylinder. In other embodiments, one or more, and up to all, of the recesses can have a downwardly tapering frustoconical shape. Other recess shapes are also within the scope of the present disclosure. Each recess 28 defines a radially outermost region or apex 39, measured from the central bore axis 22. Each recess apex 39 can extend along a plane that also extends along the central bore axis 22. In the illustrated embodiment, the recess apex 39 is parallel to the central bore axis 22. In other embodiments, the recess apex 39 can be oriented at an acute angle relative to the central bore axis 22.

[0028] Each row 26 may define a first surface 42 that substantially faces the central bore axis 22. The first surface 42 may also be referred to as the “innermost surface” of the row 26. Thus, the first surface 42 defines the crest 56 of the row thread 54. In a horizontal reference plane (such as the reference plane M shown in FIG. 2E ), the first surface 42 of each row 26 preferably extends arcuately around the central bore axis 22 and defines a shared or common radius R8. The first surface 42 of each row 26 may also extend between a first side 44 and a circumferentially opposed second side 45 of the row 26. The first side 44 and the second side 45 of each row 26 may define an interface between the row 26 and a circumferentially adjacent recess 28. For example, the first side 44 of the first row 26 a may define the interface between the first row 26 a and the fourth recess 28 d. The second side 45 of the first row 26 a can define an interface between the first row 26 a and the first recess 28 a, the first side 44 of the second row 26 b can define an interface between the second row 26 b and the first recess 28 a, the second side 45 of the second row 26 b can define an interface between the second row 26 b and the second recess 28 b, and so on circumferentially around the inner surface 24. The first surfaces 42 of the rows 26 can collectively define a downwardly tapering frustoconical circumferential segment that defines a central cone axis that, in particular, coincides with the central bore axis 22.

[0029] 2E , each row 26 may define a crest centerline 46 circumferentially equidistantly disposed between the first side 44 and the second side 45 of the row 26. In each row 26, the crest centerline 46 extends along the first surface 42 and thus intersects the crests 56 of the row threads 54. The crest centerline 46 of each row 26 is coplanar with the central bore axis 22 in a respective axial reference plane. In this manner, each crest centerline 46 also defines the crest orbits of the row threads 54 in the axial reference plane. Therefore, the crest centerline 46 may also be referred to as the “crest orbit axis” 46. Each row 26 may also define a root centerline 48 circumferentially equidistantly disposed between the first side 44 and the second side 45 of the row 26. In each row 26, the root centerline 48 intersects the roots 58 of the row threads 54. The root centerline 48 of each row 26 is coplanar with the crest centerline 46 and the center bore axis 22 in a respective axial reference plane. In this manner, each root centerline 48 also defines the root trajectories of the row threads 54 in the axial reference plane. Accordingly, the root centerline 48 may also be referred to as the "root trajectory axis" 48. The crest trajectory axis 46 may be oriented at an acute angle A2 with respect to the center bore axis 22. The root trajectory axis 48 may also be oriented at an acute angle A3 with respect to the center bore axis 22. The acute angles A2 and A3 may range from about 5 degrees to about 30 degrees. In additional embodiments, the angles A2 and A3 may range from about 10 degrees to about 20 degrees, and further may range from about 13 degrees to about 17 degrees. The crest trajectory axis 46 and the root trajectory axis 48 are preferably parallel, as shown. However, in other embodiments, the apex and root raceway axes 46, 48 of one or more, and up to all, of the rows 26 can be oriented at an acute angle relative to one another, as described in the '761 reference. The row threads 54 can also define a thread centerline 60, which can be in a common plane with the apex and root raceway axes 46, 48 and the central bore axis 22, as also shown in FIG. 2F. The thread centerline 60 is spaced equidistant between the apex and root raceway axes 46, 48.

[0030] The crest orbital axis 46 may be radially spaced apart from the center bore axis 22 by a distance R2 measured along a reference plane M that is perpendicular to the center bore axis 22 and located at the vertical center of the VA locking hole 6. Accordingly, the reference plane M may be characterized as the axial “mid-plane” of the VA locking hole 6. The thread centerline 60 may be radially spaced apart from the center bore axis 22 by a distance R3 measured along the bore mid-plane M. The root orbital axis 48 may be radially spaced apart from the center bore axis 22 by a distance R4 measured along the bore mid-plane M. The distance R2 may be characterized as the average crest radius of the row threads 54. The distance R3 may be characterized as the average radius of the row threads 54. The distance R4 may be characterized as the average root radius of the row threads 54. It should be understood that any of the average crest radius R2, the average radius R3, and the average root radius R4 may optionally be used as a metric for classifying the size of the hole 6.

[0031] 2F , each plate thread segment 52, as an internal thread, may be axially centered about a root 58 and includes an upper flank 55 extending from the root 58 to an axially upper crest 56, and also includes a lower flank 57 extending from the root 58 to an axially lower crest 56. Each plate thread segment 52 is configured to mate with (i.e., at least partially receive) at least one associated thread segment of the screw head thread 29, as described in more detail below. The plate thread 9 defines a thread pitch P1 extending along the axial direction between axially adjacent crests 56. The plate thread 9 also defines a thread lead L1, which may also be defined at the crest 56. The thread pitch P1 of the row threads 54 can be in the range of about 0.05 mm to about 5.0 mm, more specifically about 0.05 mm to about 2.0 mm, more specifically about 0.1 mm to about 1.5 mm, more specifically about 0.2 mm to about 1.0 mm, about 0.3 mm to about 0.8 mm, about 0.4 mm to about 0.6 mm, or about 0.15 mm to about 0.6 mm, preferably about 0.4 mm. The thread lead L1 can be in the range of 0.05 mm to about 5.00 mm, about 0.05 mm to about 2.0 mm, about 0.1 mm to about 1.5 mm, about 0.2 mm to about 1.0 mm, about 0.3 mm to about 0.8 mm, about 0.4 mm to about 0.6 mm, about 0.3 mm to about 1.2 mm, or about 0.15 mm to about 0.6 mm, or about 0.4 mm, preferably about 0.8 mm. It should be understood that in embodiments where the plate thread 9 is a double-lead thread as shown, the thread lead L1 is twice the distance of the thread pitch P1 (i.e., L1 = 2 x P1). In embodiments where the plate thread 9 is a single-lead thread, the thread lead L1 and the thread pitch P1 are equal to one another. In embodiments where the plate thread 9 is a triple-lead thread, the thread lead L1 is three times the distance of the thread pitch P1 (i.e., L1 = 3 x P1). Thus, the thread "lead" factor is the multiple by which the thread lead L1 is measured relative to the thread pitch P1.

[0032] 2G, the cross-sectional profiles (i.e., thread forms) of the plate threads 9 in the axial reference plane will now be described. These cross-sectional profiles may also be referred to herein simply as "thread profiles." In the illustrated embodiment, this reference plane also includes the root track axis 48. The thread profiles of the plate screws 9 are substantially similar in each of the respective axial reference planes of the various thread rows 26. As discussed above, these thread profiles and the geometry of their edges are configured complementary to those of the head threads 29 to provide a preferred mating engagement therebetween, such as to control thread deformation of the plate threads 9 and the head threads 29 and / or reduce undesired mechanical interference between the plate threads 9 and the head threads 29.

[0033] The first flank 55 and the second flank 57 are offset from one another by an angle A4, which defines a thread angle of the plate thread 9. Accordingly, the angle A4 may also be referred to as the "thread angle" A4 or the "plate thread angle" A4 of the plate thread 9. In the illustrated embodiment, the apex 56 of the plate thread segment 52 is truncated to reduce undesired mechanical interference with the screw head threads 29. Additionally, the first flank 55 and the second flank 57 may be offset from one another by multiple angles. For example, in the illustrated embodiment, the upper flank 55 and the lower flank 57 of the plate thread segment 52 are also truncated adjacent the apex 56 to provide the plate thread segment 52 with a second thread angle A5 adjacent the apex 56. The plate thread 9 of such an embodiment may be referred to as a "dual angle" thread. It should be understood that the flanks 55, 57 of the plate thread segment 52 can define even additional thread angles, such as a third thread angle, a fourth thread angle, etc. In such multi-angle embodiments, including dual-angle embodiments, the thread angle A4 can be referred to as the "first thread angle" A4. In still further embodiments, the flanks 55, 57 (or at least a portion thereof) can have an arcuate profile that can theoretically define an infinite number of thread angles. The particular edge geometries of the thread profile defined by the truncated crest 55 and truncated flank 57 are described in more detail below.

[0034] In each plate thread segment 52, the root 58 defines a root profile, the crest 56 defines a crest profile, and the upper flank 55 and lower flank 57 define upper and lower flank profiles, respectively. In the illustrated embodiment, with respect to the radially inward direction, the profile of the upper flank 55 is: a) a first upper flank portion 55a extending from a first upper flank reference point 55-1 to a second upper flank reference point 55-2; b) a second or "main" upper flank portion 55b extending along a consistent geometry from the second upper flank reference point 55-2 to the third upper flank reference point 55-3; c) a third upper flank portion 55c extending from a third upper flank reference point 55-3 to a lower apex reference point 56-1.

[0035] Similarly, in the illustrated embodiment, with respect to the radially inward direction, the profile of the lower flank 57 is: a) a first lower flank portion 57a ​​extending from a first lower flank reference point 57-1 to a second lower flank reference point 57-2; b) a second or main lower flank portion 57b extending along a consistent geometry from the second lower flank reference point 57-2 to the third lower flank reference point 57-3; c) a third lower flank portion 57c extending from the third lower flank reference point 57-3 to the upper apex reference point 56-2.

[0036] The first upper flank portion 55a and the first lower flank portion 57a ​​are coincident with each other and with a root reference point 58-1 located at the root 58 (i.e., the location on the thread segment 52 spaced farthest from the crest raceway axis 46). Additionally, the first upper flank portion 55a and the first lower flank portion 55b may each define a relief surface extending from the root 58. As shown, the first upper flank portion 55a and the first lower flank portion 57a ​​may each be arcuate and define a shared or common relief radius R5 configured to reduce stress concentrations at the root 58. Accordingly, the first upper flank portion 55a and the first lower flank portion 57a ​​may be referred to as the “root relief” portions 55a, 57a of the upper flank 55 and the lower flank 57, respectively. Because the root relief portions 55 a, 57 a in the illustrated embodiment have a common boundary at the first root reference point 58-1, the profile of the root 58 of each thread segment 52 consists essentially of a single point in the axial reference plane. However, in other embodiments (as described in more detail below with reference to the embodiment shown in FIGS. 5B and 5C ), the root 58 may define an elongated root profile that may extend linearly along the root trajectory axis 48 between the first upper flank reference point 55-1 and the lower flank reference point 57-1.

[0037] The major upper flank portion 55b and the lower flank portion 57b each extend along a consistent geometric shape in an axial reference plane. As used herein, the term "consistent geometric shape" means a line, a regular curve, or a portion of an irregular curve, a portion that does not include bends or return on itself. Non-limiting examples of such curves having consistent geometric shapes include involute curves, as more fully described in the '047 reference, and curves having a constant, relatively large radius. In the illustrated embodiment, the major flank portions 55b, 57b extend linearly and define a first thread angle A4. Additionally, the third upper flank portion 55c and the third lower flank portion 57c of the illustrated embodiment define a second thread angle A5 therebetween and are offset from the respective major flank portions 55b, 57b. The plate's first thread angle A4 may be in the range of about 28 degrees to about 32 degrees, about 20 degrees to about 40 degrees, or even about 15 degrees to about 50 degrees. The plate's second thread angle A5 may be in the range of about 53 degrees to about 57 degrees, about 45 degrees to about 65 degrees, or even about 40 degrees to about 75 degrees. In other embodiments, any and up to each of the flank profiles, including the major flank portions 55b, 57b and the respective third upper and lower flank portions 55c, 57c, need not share a common boundary at the third lower flank reference point 57-3. For example, such flank profiles may include transition portions, which may be arcuate, extending between the major flank portions 55b, 57b and the respective third upper and lower flank portions 55c, 57c. It should be appreciated that in such an embodiment, the third upper flank reference point 55-3 and lower flank reference point 57-3 continue to define the radially inward ends of the major flank portions 55b, 57b.

[0038] Additionally, the thread profile of the row threads 54 includes a truncated crest profile 56a. In the illustrated embodiment, the crest profile 56a extends linearly from the lower crest reference point 56-1 to the upper crest reference point 56-2 along the crest raceway axis 46, which is also linear. This linear crest profile 56a is configured to further reduce stress concentrations at the crests 56. Additionally, each crest profile 56a may define a crest width W1 measured between the upper and lower crest reference points 56-1 and 56-2 along the axial plate direction. Additionally, it should be appreciated that the third upper and lower flank portions 55c and 57c, which may be characterized as chamfers or bevels, may effectively define relief surfaces for the crests 56, which relief surfaces are configured to further reduce stress concentrations at the crests 56. Thus, the third upper flank portion 55c and the lower flank portion 57c may be referred to as the "top relief" portions of the flank 55, 57 profiles, respectively.

[0039] The aforementioned geometries of the plate thread profiles are provided by way of example, and it should be understood that other profile geometries are within the scope of this disclosure. For example, one or more, and up to all, of the crest profiles 56a of the thread segments 52 in row 26 may optionally be radiused, rounded, chamfered, and / or beveled, with the crest 56 itself located at the apex of the crest profile 56a. Furthermore, the root relief portions 55a, 57a of the flanks 55, 57 may be straight or may extend to the root 58.

[0040] The row threads 54 define a thread height H1 measured from the crest 56 to the root 58 along a direction DP1 perpendicular to the crest track axis 46. In particular, the thread height H1 of any of the plate thread segments 52 may be measured from the crest 56 to the root 58 of the respective thread segment 52 along the direction DP1. Alternatively or additionally, the thread height H1 of any of the plate thread segments 52 may be measured from the crest 56 to the root track axis 48 along the direction DP1. The thread height H1 of the plate row threads 54 can be in the range of about 0.05 mm to about 2.0 mm, more specifically in the range of about 0.1 mm to about 1.5 mm, more specifically in the range of about 0.2 mm to about 1.0 mm, and even more specifically in the ranges of about 0.3 mm to about 0.55 mm, about 0.35 mm to about 0.48 mm, and about 0.40 mm to about 0.44 mm, and can also be in the range of about 0.32 mm to about 0.48 mm, and even about 0.20 mm to about 0.55 mm. It should be understood that the thread height H1 of the plate thread segments 52 can be constant along the top 56 of the row 26.

[0041] 2G , it should be understood that the thread profile of the row thread 54 described above deviates from a reference cross-sectional thread profile (i.e., thread form) that is V-shaped in an axial reference plane, such as the standardized reference thread forms of the Unified Thread Standard (UTS) and the International Organization for Standardization (ISO). The reference cross-sectional thread profile is also referred to herein as the “reference profile” of the row thread 54. The deviation of the thread profile from the reference profile of the row thread 54 causes the actual thread height H1 to be less than the theoretical maximum thread height H2 defined by the reference profile. This theoretical maximum thread height H2 may also be referred to herein as the “reference height” H2 of the row thread 54. The truncated and / or relieved crests 56 and the relieved roots 58 collectively (and each individually) provide such deviation from the reference profile. Additionally, the multi-angled flanks 55, 57 and / or arcuate flank portions also provide deviations from the reference cross-sectional thread profile. The reference height H2 of the row thread 54 is measured in the axial reference plane along a direction DP1 from the root reference axis 48a to the crest reference axis 46a. The crest reference axis 46a intersects a crest reference point 56-3 defined at the apex of the reference profile on its first side. Similarly, the root reference axis 48a intersects a root reference point 58-2 defined at the apex of the reference profile on its second side, opposite the first side.

[0042] The reference profile is defined by the actual thread profile of the row threads 54. For example, the reference profile has a thread pitch and a thread lead equal to the thread pitch and thread lead of the row threads 54. In addition, the reference profile matches the thread profile at at least one repeating position of each thread segment 52 in the axial reference plane. For example, as shown in FIG. 2G , the reference profile can match each of the upper flank 55 and the lower flank 57 at each position along the linear major flank portions 55 b, 57 b, including at least at their second reference points 55-2, 57-2 and at their third reference points 55-3, 57-3. Thus, for linear major flank portions 55b, 57b, as in the embodiment shown in FIG. 2G, each apex reference point 56-3 can also be defined as the intersection of (1) protrusion 55d of the respective major upper flank portion 55b, extending from the third upper flank reference point 55-3 along the consistent linear geometry of the major upper flank portion 55b toward the central bore axis 22, and (2) protrusion 57d of the respective major lower flank portion 57b of the adjacent axially upper thread segment 52, extending from the third lower flank reference point 57-3 along the consistent linear geometry of the major lower flank portion 57b toward the central bore axis 22. In such an embodiment, the apex reference point 56-3 of the row thread 54 represents the theoretical apex position where these linear main upper flank portion 55b and lower flank portion 57b would converge if they extended uninterrupted (i.e., in an untruncated manner) toward the central bore axis 22.

[0043] Similarly, in embodiments in which the major flank portions 55b, 57b are linear, each root reference point 58-2 can also be defined as the intersection of (1) the protrusion 55e of the respective major upper flank portion 55b, which extends from the second upper flank reference point 55-2 away from the central bore axis 22 along the consistent linear geometry of the major upper flank portion 55b, and (2) the protrusion 57e of the respective major lower flank portion 57b of the adjacent axially lower thread segment 52, which extends from the second lower flank reference point 57-2 away from the central bore axis 22 along the consistent linear geometry of the major lower flank portion 57b. In such an embodiment, root reference point 58-2 of row thread 54 represents the theoretical root location where these linear major top flank portion 55 b and lower flank portion 57 b would converge if they extended uninterrupted (i.e., in an unrelieved manner) away from central bore axis 22. Additionally, in view of the above, it should be understood that reference height H2 represents the theoretical maximum thread height if major top flank portion 55 b and lower flank portion 57 b of row thread 54 extended in a straight line from their untruncated or unrelieved crest (i.e., crest reference point 56-3) to their unrelieved intersecting root (i.e., root reference point 58-2).

[0044] 2H, an exemplary embodiment of a row thread 54 is shown having an arcuate flank profile that deviates from a nominal profile, resulting in a thread height H1 that is less than a nominal height H2. In this exemplary embodiment, the consistent geometry of the main portions 55b, 57b of the upper and lower flanks 55, 57 is an involute curve extending radially inward from respective second flank reference points 55-2, 57-2. In this particular example, the main portions 55b, 57b extend all the way to an apex reference point 56-1 located at the apex 56. It should be understood that the apex 56 may optionally be further relieved and / or truncated, such as by being chamfered, beveled, and / or radiused, as non-limiting examples. The reference profile can coincide with each of the upper flank 55 and the lower flank 57 at least at its second flank reference point 55-2, 57-2, i.e., where the major flank portion 55b, 57b intersects with the root relief portion 55a, 57a. It should be understood that if the root relief portion 55a, 57a is arcuate (including following an involute curve as shown), the line of the V-shaped reference profile can be defined as extending tangentially from the root relief portion 55a, 57a at the second reference point 55-2, 57-2. As noted above, the line of the reference profile extends from the apex reference point 56-3 to the root reference point 58-2.

[0045] 2I, the curved profiles of the flanks 55, 57 define a varying thread angle A10. At any radial location RD of the row thread 54, the varying thread angle A10 can be defined as the angle between a pair of tangent lines T1, T2 that intersect the major flank portions 55b, 57b at respective locations L10, L20 along a reference line L30 that is parallel to the thread centerline 60 and coincident with the radial location RD. In such embodiments, the varying thread angle A10 can vary within any of the ranges described above with reference to angle A4.

[0046] 3A , the head 27 of the VA locking screw 8 defines a proximal end 70 and a distal end 72 spaced apart from the proximal end 70 along an axial thread direction Z2 oriented along the central screw axis 23. The head 27 also defines an outer surface 74 that extends from the proximal end 70 to the distal end 72 and defines an external head thread 29. In the illustrated embodiment, the external head thread 29 extends substantially from the proximal end 70 to the distal end 72 of the head 27 along one or more thread paths, which may be helical. The external head thread 29 defines a crest 76 that is spaced radially outward from a root 78 relative to the central screw axis 23. The head thread 29 also defines an upper flank 75 and a lower flank 77 that extend from the crest 76 to the axially upper and lower roots 78, respectively.

[0047] The screw head threads 29 can define a thread pitch P2 and a thread lead L2, which can be measured relative to the root 78. As shown, the one or more thread paths can include a pair of non-intersecting thread paths, such as a double-lead thread, in which the threads 29 define a thread lead L2 equal to twice the thread pitch P2. However, in other embodiments, the one or more thread paths of the screw head threads 29 can include a single thread path (i.e., single lead) or three or more thread paths (e.g., triple lead, etc.). The one or more thread paths of the plate head threads 29 are configured to be complementary to one or more thread paths of the plate threads 9. However, it should be understood that the screw head threads 29 and the plate threads 9 need not have the same number of thread paths. By way of non-limiting example, one of the plate threads 9 and the screw head threads 29 can be a double-lead thread defining a thread pitch, and the other of the plate threads 9 and the screw head threads 29 can be a single-lead thread having a thread lead substantially equal to said thread pitch. Other variations in the thread paths of the plate threads 9 and the screw threads 29 are also within the scope of the present disclosure.

[0048] 3B , in an axial reference plane extending along central thread axis 23, external head thread 29 defines a crest track axis 86 that intersects crest 76 and a root track axis 88 that intersects root 78. As shown, crest track axis 86 and root track axis 88 can define an arcuate convex shape, which is advantageous for angled locking with plate threads 9. In additional embodiments, crest track axis 86 and root track axis 88 can be generally spherical. As used herein, the term “spherical,” and derivatives thereof, means at least a portion of a sphere or at least a portion of a spheroid, including, by way of non-limiting example, such portions of a prolate spheroid and / or an oblate spheroid, and also encompasses substantial approximations of such portions of a sphere and / or a spheroid. However, it should be understood that other apex orbital axis 86 and root orbital axis 88 geometries are within the scope of this disclosure, including those more fully described in the '284 reference.

[0049] The external head thread 29 can be characterized as defining a series of helically adjacent head thread segments 73, which can extend continuously or discontinuously along one or more thread paths. As shown, the head thread 29 can define axially adjacent thread segments 73. Because the head thread 29 is externally threaded, each of its thread segments 73 can be axially centered about a crest 76 and includes an upper flank 75 that rises from the crest 76 to an axially upper root 78, and also includes a lower flank 77 that descends from the crest 76 to an axially lower root 78. Thus, each thread segment 73 of the head thread 29 is configured to mate with (i.e., reside at least partially within) at least one associated thread segment 52 of the plate thread 9. The upper flank 75 and the lower flank 77 of axially adjacent thread segments 73 are offset from one another by an angle A6, which defines the thread angle of the head thread 29. Therefore, angle A6 may also be referred to as "head thread angle" A6.

[0050] Referring now to FIG. 3C, the thread profile (i.e., thread shape) of the screw head thread 29 as defined in an axial reference plane that includes (and is therefore oriented along) the central screw axis 23 will now be described.

[0051] As noted above, the crest 76 defines a crest profile, the root 78 defines a root profile, and the upper flank 75 and lower flank 77 define respective upper and lower flank profiles. In the illustrated embodiment, with respect to a radially outward direction away from the central screw axis 23, the profile of the upper flank 75 is: a) a first upper flank portion 75a (also referred to as a "root relief portion") extending from a first upper flank reference point 75-1 to a second upper flank reference point 75-2; b) a second or "main" upper flank portion 75b extending along a consistent geometry from a second upper flank reference point 75-2 to an upper apex reference point 76-1.

[0052] Similarly, in the illustrated embodiment, with respect to the radially inward direction, the profile of the lower flank 77 is: a) a first lower flank portion 77a (also referred to as a "root relief portion") extending from a first lower flank reference point 77-1 to a second lower flank reference point 77-2; b) a second or main lower flank portion 77b extending along a consistent geometry from the second lower flank reference point 77-2 to the lower apex reference point 76-2.

[0053] As described above, root relief portions 75a, 77a are configured to reduce stress concentrations at the root 78 of the head thread 29. In the illustrated embodiment, the lower root relief portion 77a of thread segment 73 is coincident with the upper root relief portion 75a of the axially lower head thread segment 73. In particular, reference points 77-1 and 75-1 are coincident with each other and with root reference point 78-1, which is coincident with the root 78 (i.e., the bottom of thread segment 73). As shown, these adjacent root relief portions 77a, 75a may each be arcuate and define a common relief radius R6, which may be in the range of about 0.005 mm to about 0.10 mm, more specifically in the range of about 0.02 mm to about 0.08 mm, more specifically in the range of about 0.03 mm to about 0.05 mm, and may be greater than 0.10 mm (i.e., 0.10 mm or greater), including a relief radius large enough to approximate a linear root profile in the axial reference plane. Accordingly, the first lower flank portion 77a and the upper flank portion 77a may also be referred to as the respective "root relief" portions of the flanks 77, 75. As shown, the root 78 profile of each head thread segment 73 may consist of a single point 78-1, although in other embodiments, the root profile may be elongated, including linear, in the axial reference plane.

[0054] In the illustrated embodiment, the consistent geometry of major flank portions 75b, 77b is linear and defines a head thread angle A6 that may range from about 48 degrees to about 52 degrees, from about 40 degrees to about 60 degrees, or even from about 25 degrees to about 75 degrees. It should be understood that major flank portions 75b, 77b may alternatively define a consistent geometry that is not linear, such as a curved, including an involute curve or a curve having a constant, relatively large radius, similar to that described above with reference to Figures 2H and 2I.

[0055] The head thread segment 73 defines a crest profile 76a extending between an upper crest reference point 76-1 and a lower crest reference point 76-2. The crest profile 76a may be convex and preferably is radiused, rounded, chamfered, beveled, or otherwise truncated and / or relieved to reduce stress concentrations along the crest profile 76a. As shown, the crest profile 76a may define a relief radius R7 that may be in the range of about 0.01 mm to about 0.40 mm, and / or in the range of about 0.11 mm to about 0.13 mm, and / or in the range of about 0.07 mm to about 0.15 mm, and / or in the range of about 0.03 mm to about 0.18 mm. With such a convex profile, a crest tip reference point 76-3 is defined at the apex of the crest profile 76a, as measured from the central thread axis 23. The apex trajectory axis 86 intersects each of the apex tip reference points 76-3. Additionally, the apex profiles 76a may define respective apex widths W2 as measured between the upper apex reference point 76-1 and the lower apex reference point 76-2 along a direction DP3 oriented along the apex trajectory axis 86 at the apex tip reference point 76-3. The apex widths W2 may range from about 0.11 mm to about 0.15 mm, and / or from about 0.08 mm to about 0.18 mm, and / or from about 0.01 mm to about 0.20 mm. In some embodiments, the apex widths W2 are 0.10 mm or greater (i.e., 0.10 mm or greater). The aforementioned geometries of the apex profiles 76a are provided as non-limiting examples, and it should be understood that other apex profile geometries, including linear apex profiles 76a, are within the scope of the present disclosure.

[0056] The screw head threads 74 define a head thread height H3 measured in an axial reference plane from the crest 76 to the root 78. In particular, the head thread height H3 of any of the head thread segments 73 is measured between the root reference point 78-1 and the crest raceway axis 86 along a direction DP2 perpendicular to that portion of the crest raceway axis 86. The head thread height H3 may range from about 0.05 mm to about 2.00 mm, or from about 0.10 mm to about 1.50 mm, or from about 0.11 mm to about 0.50 mm, or from about 0.24 mm to about 0.28 mm, or from about 0.20 mm to about 0.30 mm, or even from about 0.12 mm to about 0.34 mm.

[0057] Similar to that described above with respect to plate thread 9, the thread profile of head thread 29 deviates from a reference cross-sectional thread profile (i.e., "reference profile") that is V-shaped in the axial reference plane. This deviation from the reference profile of head thread 29 causes the actual head thread height H3 to be less than a theoretical maximum head thread height H4, which includes an unattenuated and / or unrelieved crest 76 and an unrelieved root 78. This theoretical maximum head thread height H4 may also be referred to herein as the "reference height" H4 of head thread 29. The reference height H4 of head thread 29 is measured in the axial reference plane along direction DP2 from root reference axis 88a to crest reference axis 86a. The crest reference axis 86a intersects reference point 76-4 defined at the apex of the reference profile on its first side. Similarly, root reference axis 88a intersects reference point 78-2 defined at the apex of the reference profile on a second side thereof opposite the first side. Reference height H4 of head thread 29 represents the theoretical maximum head thread height when major upper flank portion 75b and lower flank portion 77b extend from their untruncated crests to their unrelieved roots.

[0058] As described above, the reference profile of the head thread 29 is defined by the actual thread profile of the head thread 29 and has a thread pitch and a thread lead equal to the thread pitch and the thread lead of the head thread 29. In addition, the reference profile matches the thread profile at at least one repeating position of each thread segment 73 in the axial reference plane. For example, as shown in FIG. 3C , the reference profile can match each of the upper flank 75 and the lower flank 77 at least at their second flank reference points 75-2, 77-2 and at each position along the linear major flank portions 75b, 77b, including the reference points 76-1 and 76-2. Thus, with respect to the straight major flank portions 75b, 77b, each apex reference point 76-4 can also be defined by the intersection of the projections 75c, 77c of the upper and lower major flank portions 75b, 77 along their respective consistent geometric shapes away from the central thread axis 23, and each root reference point 78-2 can also be defined by the intersection of the projections 75d, 77d of the major flank portions 75b, 77 along their respective consistent geometric shapes toward the central thread axis 23.

[0059] 4A and 4B, the above-described complementary thread ratios can enhance the mechanical strength of the locked thread interface between the plate thread 9 and the screw head thread 29. For example, the geometry of the thread profile of the dual angle row thread 54 can provide an increased form fit, particularly in angled screw 9 insertion trajectories, such as those illustrated in FIGS. 4A and 4B. Additionally, the axial space between the opposing flank profiles 55a-55c, 57a-57c provides a favorable clearance between the root 58 of the plate thread 9 and the crest 76 of the screw head thread 29. Such crest-to-root 76-58 clearance is particularly beneficial in angled insertion trajectories because it prevents or at least reduces undesired mechanical interference between the crest 76 and the plate root 58. Additionally, the rounded top profile 76a of the screw head threads 29, particularly the top profile 76a having the relatively large relief radius R7, effectively rounds off or eliminates sensitive edges of the screw head threads 29 that could otherwise adversely mechanically interfere with the plate threads 9.

[0060] An additional advantage provided by the thread ratios described herein is that they provide a means of control over thread deformation at the thread interface. In particular, the stiffer profile of the head thread segment 73 can be brought into contact with the more malleable profile of the plate thread segment 52, thereby imparting a majority of the thread deformation to the plate thread 9. At an angled screw 9 insertion trajectory, such controlled deformation can allow the plate thread 9 to deform to effectively realign with the angled central screw axis 23. Such controlled deformation also provided enhanced locking with the angled screw head 27. Once a form fit is achieved, further rotational advancement of the VA locking screw 8 relative to the row threads 54 can cause deformation of one or more row threads 54, preferably beginning at the apex 56, as shown in the interference region 99 in FIG. 4B. While this deformation occurs primarily radially outward, some measure of axial and / or circumferential deformation may occur (most often when timing errors are present). Moreover, the radial deformation can include plastic and elastic deformation that compresses one or more row threads 54, primarily at their roots 78, in a manner that exerts a counter-compressive force on the associated head threads 29 to achieve a locking press fit with the head 27. It should be appreciated that the plate threads 9 are also axially deformable, allowing the plate threads 9 to deform axially downward or upward, such as when the VA locking screw 8 is inserted with a timing error.

[0061] With regard to the aforementioned objectives of increasing the mechanical strength of the locked thread interface, reducing cross-threading, particularly at angled screw heads 27, and limiting cross-threading that occurs substantially entirely within plate threads 29 as a function of plastic and elastic thread deformation, the inventors have, through their extensive testing, identified particularly effective parameters for the thread ratios described above. One such thread ratio parameter for plate threads 9 and screw head threads 29 is the relationship between actual thread heights H1, H3 and reference heights H2, H4. For example, plate threads 9, and particularly row threads 54, define a plate thread height factor ("HF-P"), calculated as the ratio of actual thread height H1 to reference height H2 of row threads 54 (i.e., (HF-P)=H1 / H2). The plate thread height factor (HF-P) preferably ranges from about 0.50 to about 0.60, and may range from about 0.40 to about 0.75, or even from about 0.30 to about 1.00. Similarly, the head threads 29 define a head thread height factor ("HF-S"), calculated as the ratio of the actual thread height H3 to the nominal height H4 of the head threads 29 (i.e., (HF-S) = H3 / H4). The head thread height factor (HF-S) preferably ranges from about 0.63 to about 0.67, and may range from about 0.55 to about 0.75, or even from about 0.40 to about 0.90. The head thread height factor (HF-S) is preferably combined with a rounded head profile 76a having a relatively large head width W2 and a relatively large relief radius R7, such as the W2 and R7 values ​​described above.

[0062] Additionally, the plate threads 9 (particularly the row threads 54) and the head threads 29 may define a comparative height factor ("CHF"), calculated herein as the ratio of the actual thread height H1 of the plate threads 9 to the actual thread height H3 of the head threads 29 (i.e., CHF=H1 / H3). The comparative height factor (CHF) is preferably in the range of about 1.58 to about 1.62, and may also be in the range of about 1.30 to about 1.90, and may further be in the range of about 1.00 to about 2.00.

[0063] In combination with the aforementioned recited values ​​for the plate thread height factor (HF-P), head thread height factor (HF-S), and comparative height factor (CHF), the inventors have discovered through their extensive testing that particularly favorable thread deformation occurs when the plate thread angle A4 is in the range of 25 degrees to 35 degrees and the head thread angle A6 is in the range of 45 degrees to 60 degrees, including multi-angle embodiments where A4 is the first thread angle of the plate thread 9. The inventors have surprisingly and unexpectedly discovered that the combination of the aforementioned parameters can cause most, if not substantially all, of the thread deformation at the locking interface between the plate thread 9 and the head thread 29 to occur within the plate thread 9. Stated another way, the inventors have discovered a particular combination of thread parameters that effectively plastically deforms the plate thread 9 without the head thread 29 itself undergoing substantial plastic deformation.

[0064] It should be understood that the design of the VA locking hole 6 and the screw head 27, including their thread ratio parameters, may be adjusted while remaining within the scope of the present disclosure. For example, with reference to FIGS. 5A-9D , additional embodiments of the VA locking hole 6 are now described. The VA locking hole 6 of these additional embodiments is generally similar to the VA locking hole 6 described above with reference to the previous embodiment described above with reference to FIGS. 2A-2G . Accordingly, similar reference numerals as in the previous embodiment are used in these additional embodiments. Moreover, it should be understood that, for the sake of brevity, the following disclosure will primarily focus on the differences between the VA locking hole 6 of these additional embodiments and the previous embodiment.

[0065] 5A-5D, additional embodiments of VA locking holes 6 are shown, including, among other things, a thinner thread profile and larger recesses 28 than those of the previous embodiments. As shown in FIG. 5A, the recesses 28 of the present disclosure define a recess radius R10 that is larger than the recess radius of the previous embodiments, such that the recesses 28 of this embodiment each have a horizontal profile that encompasses a majority of a circle. Accordingly, at least a portion of the first side 44 and second side 45 of each threaded row 26, particularly the portions adjacent the first surface 42, may taper toward one another. As shown, the VA locking hole 6 of this embodiment can have three threaded rows 26 and three recesses 28 circumferentially contiguously positioned between the rows 26, although this embodiment can have fewer or more than three rows 26 and recesses 28. As shown in FIG. 5B, the hole 6 can also have a first lead-in surface 34a that is steeper than the lead-in surface 34 of the previous embodiment. A second lower lead-in surface 34b may be adjacent to the first lead-in surface 34a or may be oriented at a shallower angle relative to the first lead-in surface 34a.

[0066] 5B and 5C , as described above, the crest 56 of the row thread 54 extends along the crest track axis 46, and the row thread root 58 extends along the root track axis 48. The row thread 54 also defines a thread angle A4 measured between the upper flank 55 and the lower flank 57 of the thread segment 52. In addition to having a thinner profile, the row thread 54 of this embodiment defines a single thread angle A4, which may be in the range of about 25 degrees to about 35 degrees, or in the range of about 20 degrees to about 50 degrees, or even in the range of about 15 degrees to about 75 degrees. The row thread 54 of this embodiment defines a thread height H1 and a reference height H2. As noted above, thread height H1 represents the actual thread height of row thread 54, while reference height H2 represents the theoretical maximum thread height including untruncated crest 56 and unrelieved root 58. For any thread segment 52, thread height H1 is measured along a direction DP1 perpendicular to crest raceway axis 46 from crest orbit axis 46 to root 58, while reference height H2 is measured along direction DP1 from crest reference axis 46a to root reference axis 48a.

[0067] 5C, the root 58 in this embodiment defines an elongated root profile 58a that extends linearly along the root track axis 48, which increases the total area between the opposing flanks 55, 57. This increases the area between the flanks 55, 57, and in combination with the thinner thread profile, allows the row threads 54 to have beneficial malleability (and therefore deformability) when engaged with the head threads 29. Furthermore, with respect to the radially inward direction, the profile of the top flank 55 is a) a first upper flank portion 55a (or upper "root relief" portion 55a) extending from a first upper flank reference point 55-1 to a second upper flank reference point 55-2; b) a second or "main" upper flank portion 55b extending along a consistent geometry from the second upper flank reference point 55-2 to the third upper flank reference point 55-3; c) a third upper flank portion 55c (or upper "top relief" portion 55c) extending from a third upper flank reference point 55-3 to a lower top reference point 56-1.

[0068] Similarly, in the radially inward direction, the profile of the lower flank 57 is: a) a first lower flank portion 57a ​​(or lower "root relief" portion 57a) extending from a first lower flank reference point 57-1 to a second lower flank reference point 57-2; b) a second or main lower flank portion 57b extending along a consistent geometry from the second lower flank reference point 57-2 to the third lower flank reference point 57-3; c) a third lower flank portion 57c (or lower "top relief" portion 57c) extending from a third lower flank reference point 57-3 to an upper top reference point 56-2.

[0069] In this embodiment, root profile 58a extends from upper root reference point 58-1, which coincides with first upper flank reference point 55-1, to lower root reference point 58-2, which coincides with first lower flank reference point 57-1. As previously described, upper root relief portion 55a and lower root relief portion 57a ​​can each be arcuate and define a root relief radius for reducing stress concentrations at root 58. Root relief radius R5 may optionally be the same (i.e., common) for upper root relief portion 55a and lower root relief portion 57a. It should be understood that root relief radius R5 of plate thread 9 can optionally be substantially equal to crest relief radius R7 of head thread 29. Additionally, in this embodiment, upper apex relief portion 55c and lower apex relief portion 57c can be arcuate and define a crest relief radius for reducing stress concentrations at crest 56. As shown, one or more of the thread segments 52 in this embodiment can have major flank profile portions 55b, 57b that extend to a respective upper apex reference point 56-1 or lower apex reference point 56-2. Stated differently, one or more of the apexes 56 need not have both an upper apex relief portion 55c and a lower apex relief portion 57c. Moreover, as noted above, a transition portion, which may be arcuate, can optionally extend between any and up to all of the major flank portions 55b, 57b of the profile flanks 55, 57 and the respective third upper and lower flank portions 55c, 57c.

[0070] As described above, the apex reference axis 46a intersects the apex reference point 56-3 of the reference profile, and the root reference axis 48a intersects the root reference point 58-3 of the reference profile. Also, similar to the above, if the major flank portions 55b, 57b are straight, the apex reference point 56-3 and the root reference point 58-3 can also be defined by the intersections of the protrusions 55d, 57d and 55e, 57e, respectively, of the major flank portions 55b, 57b along their consistent geometric shapes.

[0071] In this embodiment, the thread height H1 can be within a range substantially similar to that described above with reference to FIG. 2G. Additionally, the plate thread height factor (HF-P) of this embodiment can be in the range of about 0.36 to about 0.40, or in the range of about 0.34 to about 0.70, or even in the range of about 0.30 to about 1.00. It should be understood that the elongated root profile 58a of this embodiment effectively moves the root reference axis 48a further away from the central bore axis 22 relative to the previous embodiment, which can also reduce the plate thread height factor (HF-P) relative to the previous embodiment.

[0072] 5D , the thinner thread profile of this embodiment can also provide improved locking with the VA screw head 27, including advantageous thread deformation and improved mechanical locking strength, compared to prior art thread designs. While the row threads 54 of this embodiment may not provide as much radial clearance between the row thread roots 58 and the crests 76 of the head threads 29 as in the previous embodiment, the thinner profile of the row threads 54 of this embodiment can allow the row threads 54 to deform more easily upon engagement with a head thread 29 that includes an angled thread insertion trajectory. For example, as shown in FIG. 5D , in an angled state (e.g., an angulation A1 of about 15 degrees), the row threads 54 can preferably deform in the radial direction R (and along the direction DP1) at their crests 56 and flanks 55, 57 in response to engagement with the head thread 29 at the interference region 99. Additionally, the upper and lower flanks 55, 57 of the row threads 54 are generally positioned in a complementary orientation with the upper and lower flanks 75, 77 of the head threads 29 in the angled condition, which provides a beneficial form-fit in the angled condition. As noted above, the stronger profile of the head threads 29 contacts the thinner, malleable profile of the row threads 54 in this embodiment, thereby imparting the majority of the thread deformation to the plate threads 9, allowing the plate threads 9 to deform to effectively realign with the angled central screw axis 23. Additionally, while such prior deformation occurs primarily radially outward, some measure of axial and / or circumferential deformation may occur (most often when timing errors are present).

[0073] 6A and 6B, in additional embodiments, the VA locking hole 6, or at least an axial portion thereof, can have a horizontal hole profile that is non-circular. As a non-limiting example, at least an axial portion of the hole 6 can have a generally polygonal horizontal hole profile. Notably, while this embodiment of the VA locking hole 6 is shown as having a triangular (i.e., generally triangular) horizontal profile, other polygonal shapes are within the scope of the present disclosure. The inner surface 24 of the plate body 5 within the hole 6, or at least an axial portion thereof, defines a corresponding non-circular (e.g., triangular) horizontal profile. In addition, the plate threads 9 extend along a thread path having a corresponding non-circular (e.g., triangular) horizontal profile. Moreover, one or more, and up to each, of the upper periphery 30, one or more lead-in surfaces 34, one or more undercut surfaces 36, and lower periphery 32 of the hole 6 can also have a corresponding non-circular (e.g., triangular) horizontal profile.

[0074] In the illustrated embodiment, the first surfaces 42 of the row 26 have a linear horizontal profile. In other embodiments, one or more of the first surfaces 42 can have an arcuate profile with a relatively large radius. In any such embodiment, the first surfaces can intersect a reference circle 43 tangentially about the central bore axis 22. In particular, the first surfaces 42 can intersect the reference circle 43 substantially at the top orbital axis 46. It should be understood that the reference circle 43 indicates the deviation of the hole from a circular horizontal profile. The reference circle 43 in FIG. 6B is shown intersecting the axially lowest one of the first surfaces 42 within the polygonal hole 6, and at this axial location, the reference circle 43 also indicates the minimum diameter within the hole 6 (and therefore the minimum internal diameter of the plate threads 9). The reference circle 43 defines a radius R8, which, with respect to the illustrated reference circle 43, is equal to one-half (½) of the minimum internal diameter of the threads of the hole 6. For the illustrated reference circle 43, radius R8 may be in the range of about 2.0 mm to about 2.1 mm, or in the range of about 1.8 mm to about 2.5 mm. In additional embodiments, including those for use with VA locking screws 8 having threaded shafts 25 with outer diameters in the ranges enumerated above with reference to FIG. 1A (i.e., about 0.5 mm to about 10.0 mm, about 1.0 mm to about 7.0 mm, about 2.0 mm to about 4.0 mm, and more specifically about 3.5 mm), radius R8 may be in the range of about 0.5 mm to about 15.0 mm, more specifically about 1.0 mm to about 10.0 mm, more specifically about 1.0 mm to about 5.0 mm, more specifically about 1.5 mm to about 5.0 mm, and even more specifically about 2.0 mm to about 4.0 mm, about 0.5 mm to about 3.5 mm, about 1.8 mm to about 2.5 mm, and about 2.0 mm to about 2.1 mm. It should be appreciated that radius R8 may optionally be used as a metric for classifying the size of holes 6 (e.g., as an alternative to, or in addition to, any of the average crest radius R2, average radius R3, and average root radius R4 described above). As noted above, first surface 42 of each row 26 extends between first side 44 and second side 45, which sides 44, 45 define an interface between row 26 and circumferentially adjacent recesses 28.However, in this embodiment, the recesses 28 extend tangentially from the first side 44 and second side 45 of the associated row 26. Thus, when viewed in a horizontal reference plane, the first surface 42 of the row 26 effectively defines the sides of a triangle, while the recesses 28 effectively define the corners of the triangle. Accordingly, the rows 26 and recesses 28 of this embodiment may also be referred to as the "sides" and "corners" 28, respectively, of the triangular-shaped hole 6. Each of the corners 28 may define a corner radius R9 measured from the corner axis 37 to the corner apex 39. The corner radius R9 may range from approximately 0.0 mm to slightly less than R8, and even up to approximately R8. The crests 56 and roots 58 of the plate threads 9 extend along respective splines that spiral around the central hole axis 22 along the triangular profile of the inner surface 24 between the upper plate surface 18 and the lower plate surface 20. Additionally, the inner surface 24, including the rows 26 and corners 28, tapers inwardly from the upper plate surface 18 to the lower plate surface 20 toward the central bore axis 22. Moreover, as shown, the plate threads 9 may circumferentially traverse the rows 26 and corners 28 in an uninterrupted manner (i.e., the plate threads 9 need not bottom out at the corners 28). Thus, the plate threads 9 may provide a smooth, continuous transition between the row threads 54 and the portion of the threads 9 that traverse the corners 28.

[0075] The first surface 42 of each row 26 defines a row length LC measured between the sides 44, 45 of the row 26. In this embodiment, the row length LC may be substantially constant within each row 26 as the thread path advances between the upper surface 18 and the lower surface 20 of the plate 4. In such an embodiment, the row length LC may also be referred to as the "side length" LC of the triangular-shaped hole 6. The rows 26 of this embodiment may have substantially equal row lengths LC, thus providing holes 6 having a substantially equilateral triangular shape, as shown. The row length LC may range from about 0.010 mm to about 4.00 mm, more specifically from about 0.25 mm to about 3.25 mm, and even more specifically from about 0.50 mm to about 2.85 mm. For example, in a preferred embodiment, the row length LC may range from about 0.20 mm to about 0.35 mm. In another embodiment, the row length LC can be in the range of about 0.50 mm to about 0.60 mm, preferably in the range of about 0.530 mm to about 0.570 mm. Alternatively, the row lengths LC of two or all of the rows can be different from one another. In a further embodiment, the length LC of one or more, and up to all, of the rows 26 can increase continuously as the thread path progresses from the upper surface 18 toward the lower surface 20 of the plate 4, thereby gradually decreasing the corner radius R9 toward the lower surface 20 of the plate 4.

[0076] 6C , the plate threads 9 of the present embodiment can have a substantially consistent thread profile and thread height H1 as the threads 9 travel along their thread path around the central bore axis 22, including along one or more turns. Thus, the thread height H1 can be substantially equal at the crest centerline 46 and corner apex 39 of the row 26, as well as at the portion of the row 26 and the corner 28 therebetween. As shown in FIG. 6C , the corner apex 39 can be defined along the crest 56 of the thread 9, and the corner root axis 39a can extend linearly so as to intersect with the root 58 of the thread 9. At the corner apex 39, the thread height H1 is measured along a direction DP4 perpendicular to the corner apex 39, between the crest 56 (or corner apex 39) and the root 58 (or corner root axis 39a). In this embodiment, each corner apex 9 and corner root axis 39a shares a common axial plane with the crest raceway axis 46 and root raceway axis 48 of the opposing one of the rows 26. Thus, in terms of the thread profile, the recess apex 39 is analogous to the crest raceway axis 46, while the corner root axis 39a is analogous to the root raceway axis 48. Thus, the crest raceway axis 46 and the corner apex 39 may each be oriented at the angle A2 described above, while the root raceway axis 48 and the corner root axis 39a may each be oriented at the angle A3 described above.

[0077] Moreover, the plate thread 9 of this embodiment can also define a helical series of thread segments 52 having a substantially consistent thread profile along the thread path, including at the crest centerline 46, the corner apex 39, and circumferential locations therebetween. In particular, the crest 56, root 58, and top flank 55 and bottom flank 57 of the thread 9 of this embodiment can each have a substantially consistent profile along the thread path. It should be understood that in this embodiment, the crest 56 can define a crest profile 56a, the root can define a root profile 58a, and the top flank 55 and bottom flank 57 can define respective top flank profile portions 55a-55c and bottom flank profile portions 57a-57c (including optional transition portions), in a manner similar to that described above with reference to FIG. 2G . Thus, the thread 9 in the row 26 and corner 28 can be a multi-angle thread, including a double-angle thread, particularly having a first thread angle A4 and a second thread angle A5 as described above. Alternatively, as shown in Figures 16A-16H, the plate thread profile of the triangular-shaped VA locking hole can be configured similarly to the single-angle thread described above with reference to Figures 5B-5D, or can include an arcuate thread profile as described above with reference to Figures 2H and 2I. Moreover, the thread segment 52 of the row thread 54 also defines a reference thread height H2 measured between the crest reference axis 46a and the root reference axis 48a, similarly defined in the manner described above with reference to Figure 2G. It should be understood that the thread 9 of the corner 28 also defines a reference height H2, which is measured along the direction DP4 at the corner apex 39 between an untruncated crest reference point and an unrelieved root reference point defined by the thread profile at the corner, in a manner similar to that described above with reference to Figure 2G. It should also be understood that the thread height H1 and the reference thread height H2 can be substantially equal at the row 26 and the corner, respectively, and can be within the respective ranges described above.

[0078] It should be appreciated that the triangular VA locking hole 6 described above increases the total contact area between the plate thread 9 and the head thread 29, while also providing the plate thread 9, and particularly its row threads 54, with the aforementioned preferred means of deformation quality. In this manner, the locking interface between the plate thread 9 and the head thread 29 can provide the locking screw 8 with greater overall cantilever strength (i.e., resistance to forces applied perpendicular to the central axis 23 of the screw 8) than that of the previous embodiment, while plastically and elastically imparting most, if not substantially all, of the thread deformation at the locking thread interface to the plate thread 9. The inventors have surprisingly and unexpectedly discovered through their own extensive testing that the plate thread 9 of this embodiment and the head thread 27 described above have locking thread interfaces with cantilever strengths that can approach and even exceed the ultimate bending strength of the screw 8 at certain angulations. For example, our testing has shown that a VA locking screw 8 configured as described above and fully seated within the VA locking hole 6 of this embodiment at an angle up to about 6 degrees from the nominal angle will fail (i.e., break or bend to a degree that would be classified as a failure of the VA locking screw) at a location on the screw shaft 25 proximate the distal end 72 of the head 27. In other words, under the aforementioned conditions, the screw shaft 25 will fail before the locking thread interface fails. Furthermore, for fully seated insertions at an angle ranging from about 6 degrees to about 15 degrees, the cantilever strength of the locking thread interface is reduced to within about 30 percent to 40 percent of the ultimate bending strength of the screw 8. These cantilever strengths of the locking thread interface represent a significant improvement over prior art VA locking hole-screw systems, particularly at angled conditions.

[0079] 7A and 7B, in a further embodiment, the corner radius R9 of the polygonal-shaped (e.g., triangular) VA locking hole 6 can be reduced and the row length LC (i.e., the length of the first surface 42 of the thread row 26 as measured between sides 44, 45) can be increased relative to the hole 6 shown in FIGS. 6A-6C, thereby providing the polygonal hole 6 of this embodiment with sharper corners 28 and thus a deeper polygonal (e.g., triangular) shape. Accordingly, the plate threads 9, and thus their crests 56 and roots 58, can extend along a thread path that similarly has a deeper triangular shape as it traverses the row 26 and corners 28. Other parameters of the triangular-shaped hole 6 can be maintained as described above with reference to FIGS. 6A-6C, including the radius R8 of the reference circle 43, the axial taper angles A2, A3, the thread profile, the thread angles A4, A5, the thread height H1, and the reference height H2. Alternatively, one or more of these other parameters may be adjusted as desired.

[0080] It should be appreciated that reducing the corner radius R9 and increasing the length of the first surface 42 of the polygonal VA locking hole 6 effectively distributes the forces between the plate threads and the screw head threads 29 in a more tangential direction relative to the force distribution of the polygonal VA locking hole 6 described above with reference to Figures 6A-6C.

[0081] 8A and 8B, in an additional embodiment, the VA locking hole 6 can have a polygonal horizontal profile in the shape of a rectangle (i.e., a four-sided polygon). Accordingly, the inner surface 24 of the plate body 5 within the hole 6 defines a corresponding rectangular horizontal profile. Additionally, the upper periphery 30, one or more lead-in surfaces 34, one or more undercut surfaces 36, and the lower periphery 34 of the hole 6 can also preferably have a corresponding rectangular horizontal profile.

[0082] Similar to the polygon-shaped holes described above, the first surfaces 42 of the rows 26 have a linear horizontal profile that intersects the reference circle 43 tangentially. In particular, each of the first surfaces 42 intersects the reference circle 43 substantially at the apex orbital axis 46. The radius R8 of the reference circle 43 can be within the ranges described above. Corners 28 extend tangentially from the first side 44 and the second side 45 of each row 26, such that the first surfaces 42 define the sides of a rectangle extending between the corners 28. In this embodiment, the corner radius R9 can be within any of the ranges described above with reference to FIGS. 6A-7C.

[0083] In this embodiment, the length of the first surface 42, and therefore the distance between the sides 44, 45 of each row 26, can continuously increase as the thread path advances toward the lower surface 20 of the plate 4. Thus, the respective engagement forces between the plate threads 9 and the head threads 29 can be progressively more tangentially distributed as the screw head 27 advances within the hole 6, including along an angled insertion trajectory. Alternatively, the first surface 42 of each row 26 can have a substantially consistent length along the thread path.

[0084] Similar to the method described above, the crests 56 and roots 58 of the plate threads 9 extend along respective splines that spiral around the central bore axis 22, following the square profile of the inner surface 24 between the upper plate surface 18 and the lower plate surface 20. Additionally, the inner surface 24, including the rows 26 and corners 28, tapers inwardly toward the central bore axis 22 from the upper plate surface 18 toward the lower plate surface 20. Moreover, as shown, the plate threads 9 can circumferentially traverse one or more, and up to each, of the corners 28 in an uninterrupted manner (i.e., the plate threads 9 need not bottom out within the corners 28).

[0085] 8C, the plate threads 9 of this embodiment can define a thread profile similar to that described above with reference to FIG. 2G and with reference to the triangular-shaped VA locking hole 6. Moreover, it should be understood that the thread profile, including its crest 56, root 58, and flanks 55, 57, can be substantially consistent along the thread path, including at the rows 26 and corners 28, as described above with reference to the triangular-shaped hole 6. Thus, the threads 9 can have a substantially consistent thread height H1 and a substantially consistent datum height H2 along the thread path. The thread height H1 and datum height H2 can be defined as described above.

[0086] Similar to the triangular VA locking holes 6 described above, the square shaped holes 6 of this embodiment effectively increase the total contact area between the plate threads 9 and the head threads 29, while also providing the threads 9 with the preferred deformation qualities described above. In this manner, the locking thread interface of the square shaped holes 6 can exhibit greater overall cantilever strength than that of the embodiments described above with reference to Figures 2A-2G and 4A-5D.

[0087] It should be understood that the VA locking holes 6 of the present disclosure can have other polygonal horizontal profiles, including pentagonal (i.e., five sides 42 and five corners 28), hexagonal (i.e., six sides 42 and six corners 28), heptagonal (i.e., seven sides 42 and seven corners 28), octagonal (i.e., eight sides 42 and eight corners 28), nonagonal (i.e., nine sides 42 and nine corners 28), decagonal (i.e., ten sides 42 and ten corners 28), etc. It should also be understood that in any of the polygonal-shaped VA locking holes 6 of the present application, the threads 9 can extend in a continuous and uninterrupted manner along the rows 26 and corners 28, or, optionally, the threads 9 can bottom out at the corners 28. Moreover, the thread profile in any of the non-circular (e.g., polygonal-shaped) VA locking holes 6 of the present application may be single-angle (e.g., similar to that described above with reference to Figures 5B-5D), double or additional multi-angle, or arcuate, as described above.

[0088] In further embodiments, the VA locking holes 6 of the present disclosure can have horizontal hole profiles according to any of the shapes described above, which themselves orbit around a central hole axis 22 from the upper plate surface 18 toward the lower plate surface 20, thereby defining a twisted or spiral hole profile geometry. Moreover, the VA locking holes 6 of the present disclosure can extend obliquely through the bone plate 4, such that the central hole axis 22 is oriented at a non-orthogonal angle relative to one or both of the upper plate surface 18 and the lower plate surface 20. Furthermore, the upper plate surface 18 and the lower plate surface 20 of the bone plate 4, or at least portions thereof, need not be flat, but instead may be curved, contoured, textured, roughened, dimpled, raised, or have any other geometric shape to provide an improved interface or fit with the underlying bony anatomy. In additional embodiments, the VA locking holes 6 of the present disclosure can have multiple horizontal hole profiles (i.e., hole shapes) along the central hole axis 22. For example, the interior surface 24 of any of the VA locking holes 6 can optionally include at least a first axial portion adjacent the upper plate surface 18 and defining a first horizontal hole profile, and at least a second axial portion extending axially between the first axial portion and the lower plate surface 20 and defining a second horizontal hole profile different from the first horizontal hole profile. As one non-limiting example, the first axial portion of the interior surface 24 can extend from the upper periphery 30 of the hole 6 and can include a lead-in surface 34 and threads 9 having a fully developed thread form, while the second axial portion of the interior surface 24 can include an undercut surface 36 and can extend to the lower periphery 32 of the hole 6. The first axial portion can have any of the circular or non-circular horizontal profiles described herein (including any of the polygonal profiles), while the second axial portion can have any of the aforementioned profiles that differ from the first axial portion.In such multi-profile hole embodiments, the interior surface 24 can also include a transition portion between the first axial portion and the second axial portion, where the horizontal hole profile transitions between the first horizontal hole profile and the second horizontal hole profile. It should be understood that the interior surface 24 can also include one or more additional axial portions, each having a horizontal hole profile that is different from at least one other one of the horizontal hole profiles in the VA locking hole 6.

[0089] Furthermore, as previously mentioned, the design of the VA locking hole 6 is not limited by the number of rows and recesses or corners 28. Thus, as a non-limiting example, the hole 6 can have three rows 26 circumferentially spaced between three recesses 28, as shown in FIG. 9 . Moreover, the hole 6 can alternatively have more than four rows 26 and recesses 28, respectively. In further embodiments, the VA locking hole 6 can have five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, or more than sixteen rows 26 and recesses 28, respectively. As another non-limiting example, FIG. 10 illustrates a VA locking hole 6 having eight rows 26 circumferentially spaced between eight recesses 28. Additionally, as shown, the recesses 28 can define a central recess axis 37 oriented at an acute angle A9 with respect to the central hole axis 22. In such an embodiment, angle A9 may be substantially equal to angle A2 at which apex orbital axis 46 is oriented, as described above with reference to FIG. 2E.

[0090] It should also be understood that any of the VA locking holes 6 described above, including any of their features (such as, by way of non-limiting example, thread geometry), can be incorporated into a combination hole (also referred to as a "combination hole") with another hole, such as a compression hole, in the bone plate 4. Referring to Figures 11A-15B and 17-20, an embodiment of a combination hole 90 is described in which the VA locking hole 6 portion is triangular, similar to the embodiment described above with reference to Figures 6A-7B.

[0091] 11A and 11B, one example of such a combination hole 90 includes a compression hole 92 interlocked with a VA locking hole 6 such that the VA locking hole 6 and the compression hole 92 overlap and open to one another. Thus, the inner surface 24 of the plate body 5 can define both the VA locking hole 6 and the compression hole 92, each extending from the upper plate surface 18 to the lower plate surface 20. The upper periphery 30 of the combination hole 90 can define an upper opening to each of the VA locking hole 6 and the compression hole 92. Similarly, the lower periphery 32 of the combination hole 90 can define a lower opening to each of the VA locking hole 6 and the compression hole 92. It should be understood that the VA locking hole 6 and the compression hole 92 can be referred to as respective "portions" of the combination hole 90, and each can be referred to as a respective "hole." Additionally, the portion of the inner surface 24 defining the VA locking hole 6 can be referred to as the first or "locking" surface 24a. Similarly, the portion of the inner surface 24 of the combination bore 90 that defines the compression bore 92 may be referred to as the second surface 24b. The locking surface 24a may define one or more lead-in surfaces 34 that taper axially downward from the upper periphery 30 to the plate threads 9 in the VA locking bore 6.

[0092] The second surface 24b can define a compression surface 96 of the compression hole 92. At least a portion, up to the entirety, of the compression surface 96 can be unthreaded. Thus, the compression surface 96 defines a compression surface configured to compress the unthreaded compression head of the compression screw to apply a compressive force against the bone plate 4 toward the underlying bone. In one example, the compression surface 96 can be axially concave with respect to the central bore axis 94 of the compression hole 92. For example, the compression surface 96 can be dished or hemispherical. Alternatively, the compression surface 96 can have a linear profile that tapers radially inward toward the central bore axis 94 from the upper plate surface toward the lower plate surface 20. The locking surface 24a can define a first undercut surface 36a that tapers axially upward from the lower outer periphery 32 of the combination hole 90 to the plate thread 9. The second surface 24b may define a second undercut surface 36b that tapers axially upward from the lower periphery 32 to the compression surface 96.

[0093] 11C and 11D , in the combination hole 90, the VA locking hole 6 and the compression hole 92 can open toward each other along a direction X1, which is preferably oriented along a cross axis 97 that intersects the central hole axis 22 of the VA locking hole 6 and the central hole axis 94 of the compression hole 92. The direction X1 may be referred to as the “longitudinal hole direction” X1 and may be oriented along the longitudinal direction X of the plate 4 or along any suitable alternative direction as desired. The compression hole 92 can be elongated along the longitudinal hole direction X1. For example, the compression hole 92 can have a substantially elliptical horizontal hole profile. In such an embodiment, the cross axis 97 can be coextensive with the major axis of the elliptical horizontal hole profile. Moreover, the central axis 94 of the compression hole 90 can be located at the midpoint between the foci of the elliptical horizontal hole profile. The combination bore 90 defines a first axial separation distance LA1 between the central axes 22, 94 of the VA locking bore 6 and the compression bore 92 along the longitudinal bore direction X1. It should be understood that in other embodiments, the compression bore 92 can have a non-elliptical horizontal bore profile. For example, the compression bore 92 can have a circular horizontal bore profile. As shown in FIG. 17 , the combination bore 90 can optionally have a compression bore 92 having semicircular ends and an elongated side 96a extending therebetween along the longitudinal bore direction X1, or a similar such geometric shape.

[0094] For purposes of this disclosure, the central axis 94 of the compression hole 92 extends through the geometric midpoint of a theoretically completed version of the compression hole 92. Stated another way, the central axis 94 extends through what could be considered the geometric midpoint of the compression hole 92 if it were not interrupted by the VA locking holes 6. The intersecting axis 97 may also intersect the midpoint 46 of the first of the rows or “legs” 26 a of the triangular VA locking holes 6. Stated another way, the intersecting axis 97 may intersect the apex centerline 46 of the first row 26 a of the triangular VA locking holes 6, which row 26 a may be referred to as the “base” row 26 a. In such an embodiment, the second row 26 b and the third row 26 c of the triangular VA locking holes 6 may be spaced equidistant from the intersecting axis 97 along a transverse bore direction Y1 oriented perpendicular to the longitudinal bore direction X1. The locking surface 24a and the second surface 24b can intersect one another along an intersection boundary 119. In particular, a first portion of the intersection boundary 119 on a first side of the intersecting axis 97 is separated from a second portion of the intersecting boundary 119 on a second side of the intersecting axis 97 by a gap 124 (FIG. 11C) that is open to the triangular VA locking hole 6 and the compression hole 92. The gap 124 defines a minimum gap distance G (FIG. 11D) measured along the transverse hole direction Y1. The inner surface 24 can also define a hole intersection zone 120 in which the intersection boundary 119 is located.

[0095] 11E and 11F , the intersection boundary 119 can be defined by an interface edge 122 between the locking surface 24 a and the second surface 24 b. In particular, the interface edge 122 includes the edge between the plate thread 9 and the compression surface 96, and the edge 122 tends to be steep and / or sharp as a result of the process by which the combination hole 90 is formed. Accordingly, the inner surface 24 within the hole intersection zone 120 is preferably adapted to reduce the steepness and / or sharpness of the interface edge 122 to avoid, minimize, or at least reduce contact between such steep and / or sharp edges 122 of the plate thread 9 and the surface of the screw head 27, such as the illustrated screw head threads 29. One way to achieve this is to truncate, chamfer, bevel, or otherwise trim the inner surface 24 within the hole intersection zone 120 to define a relief surface 126 therein. The relief surface 126 may be planar and parallel to the intersecting axis 97, although other relief configurations are within the scope of this disclosure.

[0096] The interface edge 122 can be spaced apart from a reference point along the central axis 22, such as the axial midpoint 22a, between the upper surface 18 and the lower surface 20 of the plate 4. The axial midpoint 22a coincides with the intersection of the central axis 22 with a reference plane M that is perpendicular to the central bore axis 22 and located at the vertical center of the VA locking hole 6, as described above with reference to FIG. 2E. The axial midpoint 22a is therefore located at what can be considered the geometric midpoint of the VA locking hole 6 if it did not intersect with the compression hole 92. The VA locking hole 6 can define a minimum linear distance D1 between the axial midpoint 22a and the nearest interface edge 122 of the plate thread 9, which in this embodiment can be located at the apex 56 or, for example, on the upper flank 55 near the apex truncated by the flank 126. The flank 126 can therefore be configured to increase the minimum linear distance D1 to the intersection boundary 119. The VA locking hole 6 can also define a maximum linear distance D2 between the axial midpoint 22a and the farthest interface edge 122 of the plate thread 9, which in this embodiment can be located at the root 58 adjacent the lead-in surface 34. While FIG. 11E illustrates the intersection boundary 119 on only one side of the combination hole 90, it should be understood that the minimum linear distance D1 and maximum linear distance D2 can be substantially similar at the intersection boundary 119 on the other side of the combination hole 90 (i.e., the opposite side of the gap 124 along the transverse hole direction Y1, as shown in FIG. 11C ).

[0097] One of the challenges of providing a combination hole 90 incorporating the triangular VA locking hole 6 of the present disclosure is to provide sufficient threaded engagement between the screw head 27 (particularly its screw head threads 29) and the plate thread 9 within the hole intersection zone 120, while also minimizing contact between the screw head 27 (particularly its screw head threads 29) and the sharp edges of the plate thread 9 (particularly its interface edge 122), especially when the screw head 27 is angled within the hole intersection zone 120 and therefore also within the gap 124. Such an angulation A1 of approximately 15 degrees between the screw axis 23 and the central axis 22 of the triangular VA locking hole 6 is shown in FIG. 11F. It should be appreciated that, alternatively or in addition to the flank 126, the geometry of the combination hole 90 may be further adapted to avoid, minimize, or at least reduce contact between the screw head 27 and the steep and / or sharp edges 122 of the plate thread 9, while also providing sufficient threaded engagement within the gap 124 at high angulations A1.

[0098] 11G, such a fit to the geometry of the combination hole 90 can be aided in the explanation by reference to a reference triangle RT, shown by dashed lines intersecting the reference circle 43 at each location where the aforementioned reference circle 43 intersects the plate thread 9 and / or the apex track axis 46 (see FIGS. 6B and 7B). The triangular VA locking hole 6 of this embodiment is substantially equilateral, i.e., the rows 26 have substantially equidistant side lengths LC, and the corners 28 have substantially equidistant corner radii R9. Thus, the reference triangle RT is substantially equilateral, having first, second, and third sides S1, S2, S3 extending between first, second, and third vertices V1, V2, V3 that define respective angles AV1, AV2, AV3, each of which is approximately 60 degrees. A first vertex V1 is located opposite the first column 26a, a second vertex V2 is located opposite the second column 26b, and a third vertex V3 is located opposite the third column 26c. For purposes of the following disclosure, the first side S1 intersects the reference circle 43 tangentially at the same location as the first surface 42 of the first column 26a intersects the reference circle 43, the second side S2 intersects the reference circle 43 tangentially at the same location as the first surface 42 of the second column 26b intersects the reference circle 43, and the third side S3 intersects the reference circle 43 tangentially at the same location as the first surface 42 of the third column 26c intersects the reference circle 43. The combination bore 90 in this embodiment is configured so that the first vertex V1 is substantially coincident with the central axis 94 of the compression bore 92, although in other embodiments, the first vertex V1 may be offset from the central axis 94 of the compression bore 92. It should be understood that the central axes 22, 94 of the combination bore 90 need not be parallel, but may be (as shown).

[0099] Exemplary dimensions of the combination bores 90 of the present disclosure are now described, particularly a subset of combination bores 90 configured to receive locking screws 8 having shafts 25 with outer diameters ranging from about 0.5 mm to about 10.0 mm, more specifically from about 1.0 mm to about 7.0 mm, and more specifically from about 2.0 mm to about 4.0 mm, preferably about 3.5 mm. It should be understood that the following dimensions are provided for illustrative purposes, and these combination bore sizes may be increased or decreased in size as needed depending on the desired medical procedure. The radius R8 of the reference circle 43 may range from about 0.40 mm to about 5.50 mm, more specifically from about 1.00 mm to about 3.00 mm, and even more specifically from about 1.40 mm to about 2.00 mm. The first axial separation distance LA1 may range from about 0.80 mm to about 10.00 mm, more specifically from about 2.00 mm to about 5.00 mm, and even more specifically from about 3.00 mm to about 4.00 mm. The corner radius R9 can be in the range of about 0.20 mm to about 4.50 mm, more specifically in the range of about 0.50 mm to about 2.00 mm, and even more specifically in the range of about 0.75 mm to about 1.60 mm. The distance R1 between the central axis 22 of the triangular VA locking hole 6 and the corner axis 37 can be in the range of about 0.01 mm to about 3.50 mm, more specifically in the range of about 0.15 mm to about 0.75 mm, and even more specifically in the range of about 0.300 mm to about 0.325 mm. The row length LC can be in the range of about 0.01 mm to about 4.00 mm, more specifically in the range of about 0.25 mm to about 3.25 mm, and even more specifically in the range of about 0.50 mm to about 2.85 mm.

[0100] According to one non-limiting example of this embodiment, the radius R8 of the reference circle may be approximately 2.050 mm, the first axial separation distance LA1 may be in the range of approximately 4.0 mm to 4.8 mm, the corner radius R9 of each corner 28a to 28c may be approximately 1.95 mm, the distance R1 between the central axis 22 of the triangular VA locking hole 6 and the corner axis 37 may be approximately 0.142 mm, and the first surfaces 42a to 42c of the rows 26a to 26c are each linear and have a row length LC of approximately 0.2 mm to approximately 0.35 mm, more specifically, approximately 0.274 mm to approximately 0.276 mm. As shown, the hole intersection zone 120 can be located along the second corner 28b of the triangular VA locking hole 6 (i.e., the corner 28b opposite the base row 26a) and, optionally, can be completely contained within the second corner 28b such that the interface surface 122 between the VA locking hole 6 and the compression hole 92 is completely spaced apart from the second row 26b and the third row 26c.

[0101] 12A , in additional embodiments, a combination bore 90 can be configured such that its triangular VA locking hole 6 and compression hole 92 retain their respective basic geometries, while the first axial separation distance LA1 is increased by an axial distance LA3 relative to that of the embodiment shown in FIG. 11G . Stated differently, in the combination bore 90 of this embodiment, the VA locking hole 6 and compression hole 92 can be spaced slightly apart from one another. In this manner, as shown in FIG. 12B , the interface edge 122 can be effectively limited to several roots 58 and the adjacent regions of the upper and lower flank portions 55 b and 57 b of the plate thread 9. When used herein with respect to holes (e.g., the VA locking hole 6 and compression hole 92), the terms “basic geometry,” “basic version,” and their derivatives refer to a stand-alone version of the hole 6, 92 that is not intersected by another hole. Thus, a "basic geometry" or "basic version" of a VA locking hole 6 refers to a stand-alone version of a VA locking hole 6 that is not intersected by a compression hole 92 or another type of hole, and a "basic geometry" or "basic version" of a compression hole 92 refers to a stand-alone version of a compression hole 92 that is not intersected by a VA locking hole 6 or another type of hole. For example, FIGS. 13B, 14B, and 15B show the respective basic versions of the VA locking holes 6 of the combination holes 90 shown in FIGS. 13A, 14A, and 15A. Thus, the features and geometries of the basic versions of the VA locking holes 6 shown in FIGS. 13B, 14B, and 15B (and the reference numbers therein) are indicative of such features and geometries of the respective VA locking holes 6 of the combination holes 90 shown in FIGS. 13A, 14A, and 15A. Therefore, the reader will understand that Figures 13A and 13B should be viewed together, as should Figures 14A and 14B and Figures 15A and 15B.

[0102] 13A-13E, in a further embodiment, the locking surface 24a can define a thread transition zone 130 in which the horizontal bore profile (and thread path about the central axis 22) deviates from an equilateral configuration to lengthen the thread path as it approaches and moves away from the bore intersection zone 120. In the illustrated embodiment, such deviation occurs between the column axes 46b of the second and third rows 26b, 26c, respectively, which are positioned and oriented where the column centerlines 46 of the second and third rows 26b, 26c would be if these rows 26b, 26c were equilateral with the base row 26a. As shown in FIG. 13A, the thread transition zone 130 can effectively move the bore intersection zone 120 entirely outside the radius R8 of the reference circle 43. Therefore, it can be said that the radius R8 is less than the smallest distance measured in the longitudinal bore direction from the central axis 22 of the VA locking hole 6 to the intersection boundary 119.

[0103] As shown in FIGS. 13A and 13B , the second and third rows 26 b, 26 c can be linearly elongated along the thread transition zone 130 to define a row length LC-2 that is longer than the row length LC of the base row 26 a. The plate threads 9 on either side of the intersection axis 97 can define a transition length LT measured from the row axis 46 b of the second and third rows 26 b, 26 c, respectively, to the intersection boundary 119. As best shown in FIG. 13B , which illustrates an uninterrupted, or “base,” version 6′ of the triangular VA locking hole 6 used in the combination hole 90 of FIG. 13A , the distance R1-2 between the central axis 22 and the corner axis 37 of the second corner 28 b is therefore greater than the distance R1 between the central axis 22 and the corner axes 37 of the first and third corners 28 a, 28 c. To maintain a smooth thread path along the second corner 28b of the basic triangular VA locking hole 6', the second corner 28b can extend tangentially from the second side 45 of the second row 26b to the first side 44 of the third row 26c. Accordingly, the second corner 28b of the basic triangular VA locking hole 6' can define a corner radius R9-2 that is smaller than the corner radius R9 of the first corner 28a and the third corner 28c. Additionally, to maintain the thread pitch P1 on both the outside and inside of the thread transition zone 130, the helix angle of the plate thread 9 is smaller on the inside of the thread transition zone 130 and larger on the outside of the thread transition zone 130. Stated another way, the helix angle is reduced or "flattened out" on the inside of the thread transition zone 130.

[0104] The thread transition zone 130 provides the plate thread 9 with a smoother entry into and exit from the intersection boundary 119 along the thread path about the central axis 22. In this manner, the thread transition zone 130 provides a reduced sharpness of the interface edge 122 while maintaining the thread profile of the plate thread 9 to a greater extent in the hole intersection zone 120, such as having a narrower lateral clearance distance G and / or a shallower flank 126 (or optionally no flank 126) therein. Thus, even when the screw 8 is inserted with a high angulation A1 that causes the head 27 to enter the hole intersection zone 120, the thread transition zone 130 can provide an increased (and therefore overall) locking thread interface between the plate thread 9 and the head thread 29 in the hole intersection zone 120, while also avoiding, minimizing, or at least reducing contact between the steep and / or sharp edges of the plate thread 9 and the head thread 29.

[0105] In embodiments in which the combination hole 90 has a linear, elongated transition zone 130, the corner radius R9-2 of the second corner 28b of the basic triangular VA locking hole 6' can be in the range of about 0.10 mm to about 2.5 mm, more specifically in the range of about 0.15 mm to about 0.90 mm, and even more specifically in the range of about 0.175 mm to about 0.825 mm. Moreover, the distance R1-2 between the central axis 22 and the corner axis 37 of the second corner 28b can be in the range of about 0.40 mm to about 6.00 mm, more specifically in the range of about 0.75 mm to about 4.50 mm, and even more specifically in the range of about 1.50 mm to about 3.75 mm. Additionally, the row length LC-2 of the second row 26b and the third row 26c can be in the range of about 0.20 mm to about 6.00 mm, more specifically in the range of about 0.40 mm to about 3.40 mm, and even more specifically in the range of about 0.50 mm to about 2.85 mm. It should be understood that the dimensions R8, LA1, R9, R1, and LC can be within the respective ranges described above.

[0106] According to a first non-limiting example of this embodiment, the radius R8 of the reference circle 43 may be approximately 2.050 mm, the first axial separation distance LA1 may be approximately 4.0 mm to approximately 4.8 mm, the corner radii R9 of the first corner 28a and the third corner 28c may be approximately 1.95 mm, the corner radius R9-2 of the second corner 28b (i.e., the "second corner radius") may be approximately 1.10 mm, and the distance between the central axis 22 and the first corner 28a may be approximately 1.10 mm. The distance R1 between the central axis 22 and the corner axis 37 of the second corner 28a and the third corner 28c may be approximately 0.142 mm, the distance R1-2 between the central axis 22 and the corner axis 37 of the second corner 28b may be approximately 1.824 mm, the basic row 26a may have a row length LC of approximately 0.2 mm to approximately 0.35 mm, particularly approximately 0.274 mm, and the second row 26b and the third row 26c may each have a row length LC-2 of approximately 1.763 mm.

[0107] According to a second non-limiting example of this embodiment, the dimensions R8, R9, LA1, LC, and R1 may be substantially the same as in the first example, while the second row 26b and the third row 26c may each have a row length LC-2 of approximately 2.802 mm, the second corner radius R9-2 may be approximately 0.200 mm, and the distance R1-2 may be approximately 2.918 mm.

[0108] In some embodiments, such as those employing second and third rows 26b, 26c in which triangular VA locking holes 6 define an equilateral reference triangle RT and thread transition zones 130 are linearly elongated, second corner radius R9-2 can range from about 0 mm (i.e., first surfaces 42 of second and third rows 26b, 26c can intersect at substantially a single point) to substantially equal corner radius R9. Additionally or alternatively, the ratio between row length LC of base row 26a and row lengths LC-2 of the second and third rows can be, by way of non-limiting example, in the range of about 1:1.0 to about 1:100.0, more specifically in the range of about 1:2.0 to about 1:15, more specifically in the range of about 1:5 to about 1:8, and even more specifically about 1:6.43. In further embodiments employing a linear, elongated transition zone 130, the ratio of corner radius R9-2 to radius R8 can be in the range of about 0.0:1 to about 0.904:1, more specifically in the range of about 0.400:1 to about 0.600:1, and more specifically about 0.54:1; the ratio of row length LC-2 to radius R8 can be in the range of about 0.0:1 to about 2.0:1, more specifically in the range of about 0.75:1 to about 0.95:1, and more specifically about 0.86:1; and the ratio of axial separation distance LA1 to radius R8 can be in the range of about 0.1:1 to about 4.0:1, more specifically in the range of about 1.0:1 to about 3.5:1, and more specifically about 2.34:1. It should be understood that in other embodiments, reference triangle RT need not be equilateral or isosceles. For example, rows 26a-26c can be oriented such that the vertex angles AV1, AV2, AV3 of reference triangle RT are different from one another. Additionally, in some embodiments, rows 26a-26c can each have a different row length.

[0109] 13F, the thread transition zone 130 beneficially increases the linear distance between the axial midpoint 22a of the central axis 22 and the intersection boundary 119. For example, in the present embodiment, the minimum linear distance D1 can be measured to the crest 56, which is not truncated by the flank 126. Moreover, the maximum linear distance D2 can be measured to the location where the root 58 of the plate thread 9 intersects the boundary between the compression surface 96 of the compression bore 92 and the undercut surface 36b. Thus, the thread transition zone 130 effectively increases these minimum and maximum linear distances D1 and D2, while also reducing the gap distance G relative to the above embodiment, thereby increasing the threaded engagement between the plate thread 9 and the head thread 29 at angulations of the screw head 27 toward the compression bore 92 and into the intersection zone 120, as described below. The minimum linear distance D1 may be in the range of about 0.5 mm to about 7.0 mm, more specifically about 1.0 mm to about 4.5 mm, and more specifically about 2.0 mm to about 3.0 mm. The maximum linear distance D2 may be in the range of about 0.5 mm to about 7.0 mm, more specifically about 1.5 mm to about 5.0 mm, and more specifically about 2.5 mm to about 3.5 mm. The ratio of the minimum linear distance D1 to the radius R8 may be in the range of about 0.05:1 to about 3.0:1. The ratio of the maximum linear distance D2 to the radius R8 may be in the range of about 0.05:1 to about 3.0:1. The minimum gap distance G may be in the range of about 0.0 mm to about 7.0 mm, more specifically about 0.80 mm to about 3.60 mm, and more specifically about 0.12 mm to about 2.40 mm. While FIG. 13F shows only the intersection boundary 119 on one side of the combination hole, it should be understood that the minimum linear distance D1 and maximum linear distance D2 may be substantially similar at the intersection boundary 119 on the other side of the combination hole 90.

[0110] 13G and 13H, the angulation of the screw head 27 into the hole intersection zone 120 is shown, particularly at an angulation A1 of approximately 15 degrees as shown in FIG. 13C. As shown in FIG. 13H, even at such a high angulation A1, contact between the screw head 27 (including its threads 29) and the interface edge 122 of the plate thread 9 can be significantly reduced, such as to some interference region 99. Similar to that described above, the thread ratios of the plate thread 9 and the screw head thread 29 can be configured to favorably deform the plate thread 9 and / or the screw head thread 29 at such interference region 99. It should be understood that in further embodiments, the transition zone 130 can be configured such that contact between the screw head 27 and the interface edge 122 can be completely avoided, even at high angulations.

[0111] 14A-14E, in a further embodiment, locking surface 24a can define a thread transition zone 130 in which transition portions 132 of locking surface 24a extend arcuately and convexly from second row 26b and third row 26c to intersection boundary 119. In particular, as shown in FIG. 14A, second row 26b and third row 26c can be straight and shortened such that their row axes 46b are located on their respective sides 44, 45 closest to intersection boundary 119.

[0112] The second row 26b and the third row 26c can define a linear row length LC-2 that is half the row length LC of the base row 26a. Additionally, a transition portion 132 can extend along a respective transition length LT, which in this embodiment has an arc length RC-3 (see FIG. 14B) that is longer than the row length LC-2 of the second row 26b and the third row 26c. However, in other embodiments, such as those shown in FIGS. 15A and 15B, the row length LC-2 of the second row 26b and the third row 26c can be longer than the row length LC of the base row 26a, and the arc length RC-3 ( FIG. 15B) of the transition portion 132 can be shorter than the row length LC-2 of the second row 26b and the third row 26c. As described above, the plate threads 9 on either side of the intersection axis 97 can define a transition length LT measured from the row axis 46b of each of the second row 26b and the third row 26c to the intersection boundary 119.

[0113] As best shown in FIGS. 14B and 15B, which illustrate the basic version 6' of the triangular VA locking hole 6 shown in FIGS. 14A and 15A, the transition portion 132 defines a radius of curvature R11 (individually referred to herein as "transition radius" R11 and collectively referred to as "transition radius" R11), which may be constant along the second portion 26-2. As in the above-described embodiment, the distance R1-2 may be greater than the distance R1. The second corner 28b may extend tangentially from the transition portion 132 adjacent the second row 26b to the transition portion 132 adjacent the third row 26c. The second corner 28b may define a corner radius R9-2 that is smaller than the corner radius R9 of the first corner 28a and the third corner 28c. Additionally, as noted above, the helix angle of the plate threads 9 is reduced in the thread transition zone 130 to maintain a constant thread pitch P1 on both the outside and inside of the thread transition zone 130.

[0114] It should be understood that in embodiments in which the combination hole 90 has an arcuate convex transition zone 130, the transition radius R11 can range from substantially infinity (i.e., nearly straight) to substantially 0.0 mm (i.e., a short radius adjacent the second row 26b and the third row 26c). More specifically, the transition radius R11 can range from about 0.10 mm to about 20.0 mm, more specifically from about 0.50 mm to about 6.00 mm, and even more specifically from about 1.75 mm to about 4.25 mm. It should be understood that the dimensions R8, LA1, R9, R1, R1-2, LC, and LC-2 can be within the respective ranges described above.

[0115] According to a first non-limiting example embodiment shown in FIGS. 14A-15B, the reference circle radius R8 may be approximately 2.050 mm, the first axial separation distance LA1 may be approximately 4.0 mm to approximately 4.8 mm, the corner radii R9 of the first corner 28a and the third corner 28c may be approximately 1.95 mm, the distance R1 may be approximately 0.142 mm, the distance R1-2 may be approximately 2.800 mm, the base row 26a may have a row length LC of approximately 0.20 mm to approximately 0.35 mm, more specifically approximately 0.274 mm, the second row 26b and the third row 26c may each have a row length LC-2 of approximately 0.550 mm, and the transition portion 132 may have a radius R11 of approximately 4.943 mm.

[0116] According to a second non-limiting example of the embodiment shown in Figures 14A-15B, the dimensions R8, R9, LA1, LC, and R1 may be substantially the same as in the immediately preceding example, but the second row 26b and the third row 26c may each have a row length LC-2 of approximately 1.410 mm, the radius R11 of the transition portion 132 may be approximately 2.741 mm, and the distance R1-2 may be approximately 3.534 mm.

[0117] As discussed above, the transition radius R11 can range from substantially infinity (i.e., nearly straight) to substantially 0.0 mm (i.e., a short radius adjacent to rows 26b and 26c). Accordingly, it should be understood that the ratio of radius R8 to transition radius R11 can range from about 0.0:1 to about 1:0.0. More specifically, the ratio of R8 to R11 can range from about 1:1.0 to about 1:3.5, and even more specifically, from about 1:2.1 to about 1:2.7. Additionally or alternatively, the ratio of row length LC of base row 26a to row length LC-2 of the second and third rows can range, by way of non-limiting example, from about 1:0.1 to about 1:100, more specifically, from about 1:1.0 to about 1:20.0, more specifically, from about 1:2 to about 1:15, and even more specifically, from about 1:5 to about 1:8. In further embodiments utilizing arcuate and convex transition portions 132, the ratio of axial separation distance LA1 to radius R8 can be in the range of about 0.1:1 to about 4.0:1, more specifically in the range of about 0.125:1 to about 3.750:1, and even more specifically in the range of about 0.155:1 to about 3.414:1. Additionally, the ratio of row length LC-2 to radius R8 can be in the range of about 0.1:1 to about 2.0:1, more specifically in the range of about 0.125:1 to about 1.750:1, and even more specifically in the range of about 0.134:1 to about 1.536:1.

[0118] It should be understood that the combination bore 90 can employ a triangular VA locking bore 6 in which the transition zone 130 also transitions axially relative to the central bore axis 22 between the upper and lower surfaces 18, 20 of the plate 4, such that the bore 6 has multiple transition zone 130 profiles along the central bore axis 22. For example, the locking surface 24a can optionally include at least a first axial portion adjacent the upper plate surface 18 and defining a first transition zone 130 profile, such as any of those shown in FIGS. 13A-15B , and at least a second axial portion extending axially between the first axial portion and the lower plate surface 20 and defining a second transition zone 130 profile that differs from the first horizontal bore profile.

[0119] Additional details of the combination bore and the operation of the compression screw in that combination bore portion may be as more fully explained in the '761 and '047 references.

[0120] 18-20, in a further embodiment, the combination hole 90' ​​may be effectively defined by first and second VA locking holes 6 that intersect with one another. Such a combination hole 90' ​​may be referred to herein as a VA-VA combination hole 90'. In such an embodiment, the second surface 24b' is also a locking surface. Accordingly, the locking surface 24a may be referred to as the first locking surface 24a, and the second surface 24b' may be referred to as the second locking surface 24b'. As described above, the first locking surface 24a may define a first row 26a, a second row 26b, and a third row 26c, each separated from one another by a first corner 28a, a gap between the VA locking holes 6 (where the second corner would otherwise be), and a third corner 28c. The second locking surface 24b' can define a fourth row 26d, a fifth row 26e, and a sixth row 26f, separated from one another by a fourth corner 28d, a gap (where the fifth corner would otherwise be), and a sixth corner 28f, respectively. The threads 9 of the combination hole 90' ​​preferably extend along one or more thread paths (i.e., single-lead, double-lead, etc.) that traverse the locking surfaces 24a, 24b' in an uninterrupted manner between the upper and lower surfaces 18, 20 of the bone plate 4. The VA-VA combination hole 90' ​​can be defined by a polygonal-shaped VA locking hole 6, such as the triangular-shaped VA locking hole 6 shown, although any of the polygonal-shaped VA locking holes 6 described above can be incorporated into the VA-VA combination hole 90'.

[0121] The VA-VA combination bore 90' ​​of this embodiment can employ thread transition zones 130 similar to those described above with reference to Figures 13A-15B. For example, as shown in Figure 18, the VA-VA combination bore 90' ​​can define a linear, elongated transition zone 130 on each longitudinal side of an intersection boundary 119. In such an embodiment, the intersection boundary 119 can define an interface between the second row 26b and the sixth row 26f, and another interface between the third row 26c and the fifth row 26e. In other embodiments, as shown in Figures 19 and 20, the combination bore 90' ​​can employ arcuate, convex thread transition zones 130 and transition portions 132 similar to those described above. For example, the VA-VA combination bore 90' ​​of Figure 19 can employ a thread transition zone 130 in which the first and second locking surfaces 24a, 24b' each define an elongated, arcuate, convex transition portion 132 on each longitudinal side of the intersecting boundary 119, similar to the transition portion 132 described above with reference to Figures 14A-14E. Additionally, the VA-VA combination bore 90' ​​of Figure 20 can employ a thread transition zone 130 in which the first and second locking surfaces 24a, 24b' define elongated rows 26b, 26c, 26e, 26f and arcuate, convex transition portions 132 on each longitudinal side of the intersecting boundary 119, similar to the transition zone 130 described above with reference to Figures 15A and 15B. It should be understood that in other embodiments, the VA-VA combination bore 90' ​​may lack a thread transition region (such as thread transition region 130 described above with reference to Figures 13A-15B).

[0122] It should be further understood that any of the above-described combination holes may be modified such that the VA locking hole 6 thereof employs a polygonal horizontal hole profile according to any of the polygonal hole shapes described herein.

[0123] 21A-29G, additional examples of bone plates including various triangular locking hole geometries, such as stand-alone locking holes and combination holes having locking holes intersected by compression holes, are described.

[0124] 21A-21G show an exemplary bone plate, particularly one for treating the medial distal portion of the tibia, having a "low flex" geometry and locking holes including stand-alone locking holes and combination holes using a triangular VA locking hole geometry, at least some and up to all of which are configured for use with standard locking screws having a shaft outer diameter of approximately 3.5 mm. According to one naming convention, the bone plate in this example can be classified as follows: LCP Medial Distal Tibia Plate 3.5, Low Flexion.

[0125] 22A-22G illustrate an exemplary bone plate, particularly a bone plate for treating the olecranon, having locking holes including stand-alone locking holes and combination holes using a triangular VA locking hole geometry, at least some and up to all of the locking holes configured for use with both standard and VA locking screws having shaft outer diameters of about 2.7 mm to about 3.5 mm. According to one naming convention, the bone plate in this example can be classified as follows: VA-LCP Olecranon Plate 2.7 / 3.5.

[0126] 23A-23G illustrate an exemplary bone plate, particularly one for treating the distal radius, having locking holes including stand-alone locking holes and combination holes using a triangular VA locking hole geometry, with at least some and up to all of the locking holes configured for use with both standard and VA locking screws having a shaft outer diameter of approximately 2.4 mm. According to one naming convention, the bone plate in this example can be classified as follows: VA-LCP Dual Row Distal Radius Plate 2.4.

[0127] 24A-24G show an example of an exemplary bone plate, particularly a bone plate for treating the lateral distal fibula, with locking holes including stand-alone locking holes and combination holes using a triangular VA locking hole geometry, at least some and up to all of the locking holes configured for use with both standard and VA locking screws having a shaft outer diameter of approximately 2.7 mm. According to one naming convention, the bone plate in this example can be classified as follows: VA-LCP Lateral Distal Fibula Plate 2.7

[0128] 25A-25G show an example of an exemplary bone plate, particularly a bone plate for treating a condyle, with locking holes including combination holes using a triangular VA locking hole geometry and stand-alone locking holes with different geometries, at least some and up to all of the locking holes configured for use with both standard and VA locking screws having shaft outer diameters of about 4.5 mm to about 5.0 mm. According to one naming convention, the bone plate in this example can be classified as follows: VA-LCP Condylar Plate 4.5 / 5.0.

[0129] 26A-26G show an example of an exemplary bone plate, particularly a bone plate for treating the proximal tibia, with a "low flex" geometry having locking holes including stand-alone locking holes and combination holes using a triangular VA locking hole geometry, at least some and up to all of the locking holes configured for use with both standard and VA locking screws having a shaft outer diameter of approximately 3.5 mm. According to one naming convention, the bone plate in this example can be classified as follows: VA-LCP Proximal Tibia Plate 3.5, Low Flexion.

[0130] 27A-27G show an example of an exemplary bone plate, particularly a bone plate for treating the proximal humerus, with locking holes including stand-alone locking holes and combination holes using a triangular locking hole geometry, at least some and up to all of the locking holes configured for use with standard locking screws. According to one naming convention, the bone plate in this example can be classified as follows: LCP Proximal Humerus Plate (Philos).

[0131] 28A-28G show an example of an exemplary bone plate, specifically a straight bone plate with a combination hole using a triangular locking hole geometry, where the locking holes are configured for use with standard locking screws having a shaft outer diameter of approximately 3.5 mm. According to one naming convention, the bone plate in this example can be classified as follows: LCP Plate 3.5, straight.

[0132] 29A-29G show an example bone plate, specifically an example showing a straight bone plate with stand-alone locking holes using a triangular locking hole geometry. According to one naming convention, the bone plate in this example can be classified as follows: 1 / 3 tubular locking.

[0133] Although the present disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations may be made herein without departing from the spirit and scope of the present invention as defined by the appended claims. Moreover, the scope of the present disclosure is not limited to the specific embodiments described herein. As one skilled in the art would readily appreciate from the process, any now-existing or later-developed machine, manufacture, composition of matter, means, method, or step that performs substantially the same function or achieves substantially the same result as the corresponding embodiment described herein can be utilized in accordance with the present disclosure.

[0134] [Embodiment] (1) A bone plate, a plate body defining a combination hole including a locking hole and a compression hole, the locking hole and the compression hole intersecting each other and each extending from an outer surface of the plate body to a bone-facing surface of the plate body, the locking hole and the compression hole extending away from each other along a longitudinal axis; the plate body further defines: 1) a locking surface defining the locking hole; 2) a second surface defining the compression hole; and 3) an interface edge along an intersection boundary between the locking surface and the second surface; The locking surface is a first row, a second row, and a third row positioned successively around a central axis of the locking hole, each row having a first side and a second side; a first recess extending from the second side of the first row to the first side of the second row; an additional recess extending from the second side of the third row to the first side of the first row; a transition zone between the first side of the second row and the second side of the third row, wherein the locking surface in the transition zone is elongated and extends to the intersection boundary; the bone plate further defines a plate thread traversing each of the rows and the first recess, the additional recess, and at least a portion of the transition zone, the crests of the plate threads extending linearly from the first side to the second side of each row. (2) The bone plate of embodiment 1, wherein the longitudinal axis intersects the first row, and the second row and the third row are spaced substantially equidistant from the longitudinal axis in a lateral direction perpendicular to the longitudinal axis. (3) each row defines a crest track axis that intersects the crest of each fully formed plate thread in said row, whereby the crest track axes of said first row, said second row, and said third row are 1) spaced substantially equidistant from said central axis and 2) positioned at substantially equal intervals about said central axis; 3. The bone plate of claim 2, wherein in a reference plane perpendicular to the central axis, the apex orbital axes of the first row, the second row, and the third row are spaced apart from the central axis by substantially equal radial distances measured along a radial direction perpendicular to the central axis. (4) The bone plate according to embodiment 3, wherein the apex orbital axes are linear and each oriented at an angle ranging from about 5 degrees to about 30 degrees relative to the central hole axis. (5) The bone plate of embodiment 3, wherein each row defines a row length measured from the first side to the second side along a respective direction perpendicular to the radial direction in the reference plane, the row lengths of the second row and the third row being equal, and the row length of the first row being different from the row lengths of the second row and the third row.

[0135] (6) The bone plate of embodiment 5, wherein the ratio of the length of the first row to the length of the second row and the third row is in the range of about 1:2 to about 1:15. (7) The bone plate of embodiment 6, wherein the ratio of the length of the first row to the length of the second row and the third row is in the range of about 1:5 to about 1:8. (8) The bone plate of embodiment 6, wherein the second row and the third row extend to the intersection boundary. (9) The bone plate of embodiment 3, wherein the locking surfaces further define transition portions extending from the second row and the third row, respectively, to the intersection boundary, the transition portions positioned opposite each other along the lateral direction, arcuately convex, and defining a transition radius, whereby the ratio of the radial distance to the transition radius is in the range of about 1:2.1 to about 1:2.7 at the reference plane. (10) The bone plate of embodiment 3, wherein the radial distance is less than the smallest distance measured from the central axis to the intersection boundary in a longitudinal direction oriented along the longitudinal axis.

[0136] (11) The plate thread defines a fully formed thread profile including the crest and further including a root and a flank extending from the root to the crest; 11. The bone plate of claim 10, wherein at least some of the plate threads extend to the intersection boundary, whereby the interface edges on either side of the longitudinal axis in the lateral direction include edges of the fully formed thread profile. (12) The bone fixation system of claim 10, wherein the plate threads traverse the locking surface such that a thread height measured from the crest to the root is substantially constant along at least one partial revolution about the central axis from the intersection boundary on one side of the longitudinal axis to the intersection boundary on the opposite side of the longitudinal axis. (13) A bone plate, a plate body defining an outer side, a bone-facing surface opposite the outer side, and combination holes including a locking hole and a compression hole, the locking hole and the compression hole intersecting each other and each extending from the outer side to the bone-facing surface, the locking hole and the compression hole extending away from each other along a longitudinal axis; the plate body further defines: 1) a locking surface that defines the locking hole; and 2) a second surface that defines the compression hole; The locking surface is a plurality of rows positioned successively around a central axis of the locking hole in a polygonal pattern; a plurality of recesses respectively positioned between at least some of the rows; the bone plate further defining a plate thread traversing each of the rows, the crests of the plate threads extending linearly from the first side of each row to the second side of each row. (14) The plate body defines an intersecting boundary between the locking surface and the second surface, and a first portion of the intersecting boundary on a first side of the longitudinal axis is separated from a second portion of the intersecting boundary on a second side of the longitudinal axis by a gap open to the locking hole and the compression hole; the longitudinal axis intersects a first row of the plurality of rows and extends centrally through the gap; 14. The bone plate of claim 13, wherein the plurality of rows includes at least a second row and a third row, the second row and the third row being spaced substantially equidistant from the longitudinal axis in a lateral direction perpendicular to the longitudinal axis. (15) The plate thread defines a fully formed thread profile including the crest and further including a root and a flank extending from the root to the crest; 15. The bone plate of claim 14, wherein at least some of the plate threads extend to the intersection boundary, whereby interface edges between the locking surface and the second surface along the first and second portions of the intersection boundary include edges of the fully formed thread profile.

[0137] (16) The bone plate of embodiment 15, wherein the plate threads traverse the locking surface such that a thread height, measured from the crest to the root, is substantially constant along at least one partial revolution about the central axis from the second portion of the intersection boundary to the first portion of the intersection boundary. (17) The bone plate of embodiment 13, wherein the bone plate is formed from a material selected from the group consisting of stainless steel, titanium, titanium-aluminum-niobium (TAN) alloy, titanium-aluminum-vanadium (TAV) alloy, titanium-molybdenum alloy, cobalt-chromium alloy, and nitinol. (18) The bone plate of embodiment 17, wherein the flanks of the plate threads define a plate thread angle ranging from about 20 degrees to about 60 degrees. (19) The bone plate of embodiment 18, wherein the flank of the plate thread has a first portion defining the thread angle and a second portion defining a second thread angle, the second portions of the flank being located between the first portion and the crest, respectively, the thread angle being in the range of about 25 degrees to about 40 degrees, and the second thread angle being in the range of about 40 degrees to about 75 degrees. (20) The plate thread defines a fully formed thread profile including the crest, a root, and a flank extending from the root toward the crest; the root, the crest, and the flank collectively deviate from a nominal thread profile, the nominal thread profile being V-shaped and defining a crest reference point at an apex of a first side of the nominal thread profile and a root reference point at an apex of a second side opposite the first side; 19. The bone plate of claim 18, wherein a thread height measured from the crest to the root is less than a reference height measured from the crest reference point to the root reference point, whereby the ratio of the thread height to the reference height is in the range of 0.50:1 to 1.00:1.

Claims

1. 1. A bone plate comprising: a plate body defining a combination hole including a locking hole and a compression hole, the locking hole and the compression hole intersecting each other and each extending from an outer surface of the plate body to a bone-facing surface of the plate body, the locking hole and the compression hole extending away from each other along a longitudinal axis; the plate body further defines: 1) a locking surface defining the locking hole; 2) a second surface defining the compression hole; and 3) an interface edge along an intersection boundary between the locking surface and the second surface; The locking surface is a first row, a second row, and a third row positioned successively around a central axis of the locking hole, each row having a first side and a second side; a first recess extending from the second side of the first row to the first side of the second row; an additional recess extending from the second side of the third row to the first side of the first row; a transition zone between the first side of the second row and the second side of the third row, the locking surface in the transition zone extending linearly to the intersection boundary; the bone plate further defines a plate thread traversing each of the rows and the first recess, the additional recess, and at least a portion of the transition zone, the crests of the plate threads extending linearly from the first side to the second side of each row.

2. 2. The bone plate of claim 1, wherein the longitudinal axis intersects the first row, and the second row and the third row are spaced substantially equidistant from the longitudinal axis in a lateral direction perpendicular to the longitudinal axis.

3. each row defining a crest track axis that intersects the crest of each fully formed plate thread in said row, whereby the crest track axes of said first row, said second row, and said third row are 1) spaced substantially equidistant from said central axis; and 2) located at substantially equal intervals about said central axis; 3. The bone plate of claim 2, wherein in a reference plane perpendicular to the central axis, the apex trajectory axes of the first row, the second row, and the third row are spaced from the central axis by substantially equal radial distances measured along a radial direction perpendicular to the central axis.

4. The bone plate of claim 3, wherein the apex track axes are linear and each oriented at an angle ranging from about 5 degrees to about 30 degrees relative to the central bore axis.

5. 4. The bone plate of claim 3, wherein each row defines a row length measured from the first side to the second side along a respective direction perpendicular to the radial direction in the reference plane, the row lengths of the second row and the third row being equal, and the row length of the first row being different from the row lengths of the second row and the third row.

6. 6. The bone plate of claim 5, wherein a ratio of the row length of the first row to the row length of the second row and the third row ranges from about 1:2 to about 1:

15.

7. 7. The bone plate of claim 6, wherein the ratio of the row length of the first row to the row length of the second row and the third row ranges from about 1:5 to about 1:

8.

8. The bone plate of claim 6 , wherein the second row and the third row extend to the intersection boundary.

9. 4. The bone plate of claim 3, wherein the locking surfaces further define transition portions extending from the second row and the third row, respectively, to the intersection boundary, the transition portions positioned opposite one another along the lateral direction, being arcuately convex, and defining transition radii, whereby a ratio of the radial distance to the transition radius ranges from about 1:2.1 to about 1:2.7 at the reference plane.

10. The bone plate of claim 3 , wherein the radial distance is less than a minimum distance measured from the central axis to the intersection boundary in a longitudinal direction oriented along the longitudinal axis.

11. the plate thread defines a fully formed thread profile that includes the crest and further includes a root and a flank extending from the root to the crest; 11. The bone plate of claim 10, wherein at least some of the plate threads extend to the intersecting boundary, whereby the interface edges on either side of the longitudinal axis in the lateral direction include edges of the fully formed thread profile.

12. 11. The bone plate of claim 10, wherein the plate threads traverse the locking surfaces such that the thread height, measured from crest to root, is substantially constant along at least one partial revolution about the central axis from the intersection boundary on one side of the longitudinal axis to the intersection boundary on an opposite side of the longitudinal axis.

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