Orthopedic Bone Screws

Abstract

The orthopedic bone screw includes a head and a threaded shaft extending from the head. The threads have a major diameter and a minor diameter. The shaft includes an unthreaded atraumatic tip opposite the head, the atraumatic tip having a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion that forms the tip of the orthopedic bone screw. The length of the cylindrical portion of the atraumatic tip is 25% to 150% of the major diameter of the threads.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 411,017, filed September 28, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to orthopedic bone screws, such as self-tapping and / or locking cortical bone screws. [Background technology]

[0003] Bone screws are configured to be driven into prepared holes in one or more bones (or bone fragments) to repair fractures, secure bone plates to the bone, and the like. Such holes are typically formed using a drill. Existing bone screws can be significantly angled around the opening of a pre-drilled hole in the bone, making it difficult to align the bone screw with the axis of the pre-drilled hole. This can make it difficult for the self-tapping bone screw to initiate threading into the bone and can increase the risk of stress fracture due to misalignment between the bone screw and the hole axis. Existing self-tapping bone screws can also require relatively high torque and / or compression force to initiate threading into a pre-drilled hole in the bone. Therefore, improved bone screws are needed. Summary of the Invention

[0004] The present disclosure relates to orthopedic bone screws having an atraumatic tip. In a representative example, the orthopedic bone screw comprises a head and a threaded shaft extending from the head, the threads having a major diameter and a minor diameter, the shaft comprising an unthreaded atraumatic tip opposite the head, the unthreaded atraumatic tip comprising a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion that forms the tip of the orthopedic bone screw, the length of the cylindrical portion of the atraumatic tip being 25% to 150% of the major diameter of the threads.

[0005] In another representative example, an orthopedic bone screw comprises a head and a threaded shaft extending from the head, the threads comprising a major diameter and a minor diameter, the shaft comprising an unthreaded atraumatic tip opposite the head, the unthreaded atraumatic tip comprising a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion forming the tip of the orthopedic bone screw, at least the cylindrical portion of the unthreaded atraumatic tip comprising a plurality of cutting flutes.

[0006] In another representative example, an orthopedic bone screw comprises a head and a shaft extending from the head, the shaft comprising threads, the shaft comprising an unthreaded atraumatic tip opposite the head, the unthreaded atraumatic tip comprising a cylindrical portion and a rounded end portion distal to the cylindrical portion, the unthreaded atraumatic tip having a length that is 50% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

[0007] The above and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side elevational view of an orthopedic bone screw according to one embodiment. [Figure 2] 2 is a cross-sectional view of the screw tip and shaft of the orthopedic bone screw of FIG. 1. FIG. [Figure 3] FIG. 2 is a diagram showing the external shape of the tip portion of the orthopedic bone screw of FIG. 1. [Figure 4] FIG. 2 is a cross-sectional view of a cross section of the threads of the orthopedic bone screw of FIG. 1. [Figure 5] 2 is a side elevational view of the distal portion of the orthopedic bone screw of FIG. 1, showing the curved surface of the cutting flutes edge-on; FIG. [Figure 6]5 is a side elevational view of the distal portion of the orthopedic bone screw of FIG. 1 rotated about its longitudinal axis relative to FIG. 5 to show the straight surfaces of the milled flutes edge-on. [Figure 7] FIG. 2 is a distal end view of the orthopedic bone screw of FIG. 1. [Figure 8] FIG. 2 is a head end view of the orthopedic bone screw of FIG. 1. [Figure 9] FIG. 10 is an elevational view of a head portion and a portion of a shaft of a locking bone screw according to another embodiment. [Figure 10] 2 is a schematic diagram showing the distal end of the orthopedic bone screw of FIG. 1 positioned through a bone plate and into a pre-drilled hole in a bone. [Figure 11] FIG. 1 illustrates the angle of an orthopedic bone screw within a hole drilled in bone. [Figure 12] FIG. 1 is a schematic diagram of an orthopedic bone screw inserted through bone with the atraumatic tip in contact with soft tissue. [Figure 13] FIG. 10 is a side elevational view of another embodiment of an orthopedic bone screw. [Figure 14] FIG. 14 shows the external shape of the tip portion of the orthopedic bone screw of FIG. 13. [Figure 15] FIG. 14 is a side elevational view of the distal portion of the orthopedic bone screw of FIG. 13, showing the curved surface of the cutting flutes edge-on. [Figure 16] 15 is a side elevational view of the tip portion of the orthopedic bone screw of FIG. 13 rotated about its longitudinal axis relative to FIG. 15 to show the straight surfaces of the milled flutes edge-on. [Figure 17] FIG. 14 is a distal end view of the orthopedic bone screw of FIG. 13. [Figure 18] FIG. 14 is a side elevational view of the tip portion of the orthopedic bone screw of FIG. 13 showing the angle formed by the crests of the threads in the runout region. [Figure 19] FIG. 14 is a side elevational view of another embodiment of the orthopedic bone screw of FIG. 13 having a shaft including threads with a different thread profile. [Figure 20] FIG. 20 is a cross-sectional view of a cross section of the threads of the orthopedic bone screw of FIG. 19. [Figure 21]FIG. 20 is a partial cross-sectional view of the bone screw of FIG. 19. [Figure 22] FIG. 20 is a partial cross-sectional view of the bone screw of FIG. 19, including an example of a reverse buttress thread. [Figure 23] FIG. 20 is a partial cross-sectional view of the bone screw of FIG. 19, including an example of an angled reverse buttress thread. [Figure 24] FIG. 20 is a partial cross-sectional view of the bone screw of FIG. 19 including an example of an angled buttress thread. [Figure 25] FIG. 20 is a partial cross-sectional view of the bone screw of FIG. 19 including an example Acme thread. DETAILED DESCRIPTION OF THE INVENTION

[0009] Terminology For purposes of this specification, certain aspects, advantages, and novel features of the disclosed embodiments are described herein. The disclosed methods, apparatus, and systems should not be construed as limiting in any way. Instead, the present disclosure is directed to all novel and non-obvious features and aspects of the various disclosed embodiments, alone and in various combinations and subcombinations with each other. The methods, apparatus, and systems are not limited to any particular aspect or feature or combination thereof, and the disclosed embodiments do not require that any one or more particular advantages be present or problems be solved.

[0010] Although some operations of the disclosed embodiments are described in a particular sequential order for convenient presentation, it should be understood that this method of description encompasses rearrangement, unless a particular order is required by specific language described below. For example, operations described sequentially may in some cases be reordered or performed simultaneously. Moreover, for simplicity, the accompanying figures may not show the various ways in which the disclosed methods can be used in combination with other methods.

[0011] As used in this disclosure and claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Furthermore, the term "includes" means "comprises." Furthermore, the terms "coupled" and "associated" generally mean electrically, electromagnetically, and / or physically (e.g., mechanically or chemically) coupled or connected, and do not exclude the presence of intermediate elements between coupled or associated items unless the opposite is specified.

[0012] In some instances, values, procedures, or devices may be referred to as "lowest," "best," "smallest," etc. Such descriptions are intended to indicate that selections can be made from among many alternatives, and it will be understood that such selections are not necessarily better, lesser, or otherwise preferred than other selections.

[0013] Certain terms may be used herein, such as "top," "bottom," "upper," "bottom," "horizontal," "vertical," "left," and "right." These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. However, these terms do not imply absolute relationships, positions, and / or orientations. For example, with respect to an object, a "top" surface can become a "bottom" surface simply by flipping the object. Nevertheless, it is still the same object.

[0014] Unless otherwise indicated, all numbers expressing angles, dimensions, amounts of components, forces, moments, percentages, times, and the like used in the specification or claims should be understood to be modified by the term "about." Thus, unless otherwise specified, numerical parameters, implicitly or explicitly indicated, are approximations that may depend on the desired properties sought and / or limits of detection under testing conditions / methods well known to those skilled in the art. When directly and explicitly distinguishing an embodiment from the prior art discussed, the numbers of the embodiments are not approximations unless the word "about" is recited.

[0015] Although there are alternatives to the various components, dimensions, parameters, operating conditions, etc. described herein, this does not imply that the alternatives are necessarily equivalent and / or perform equally well, nor does it imply that the options are listed in order of preference unless otherwise stated.

[0016] As used herein, values ​​and / or relationships modified by the term "substantially" refer to ±10% of the stated value and / or relationship. "Substantially perpendicular" refers to an angle of 80° to 100° relative to a reference. "Substantially parallel" refers to an angle of ±10° relative to a reference.

[0017] Overview of the disclosed technology The present disclosure relates to orthopedic bone screws. Bone screws are typically provided in two major categories: cancellous bone screws, which are configured to anchor in the soft, spongy interior, or marrow, of bone, and cortical bone screws, which are configured to anchor in the denser, harder, external cortical bone. Cortical bone screws are typically configured as either locking or non-locking bone screws. Locking bone screws can have threads incorporated into the head of the screw configured to engage with corresponding threads formed in the inner diameter of a threaded hole in a bone plate or other orthopedic fixation device. Bone screws can also be self-tapping, where the bone screw is configured to cut threads into bone material when driven into the bone. Bone screws can also be non-self-tapping.

[0018] In certain instances, bone screws are configured to be driven into prepared holes in one or more bones (or bone fragments) to repair fractures, secure bone plates to the bone, and the like. Such holes are typically formed using a drill and are referred to herein as "pre-drilled holes." Existing bone screws can be significantly angled around the opening of the pre-drilled hole in the bone, making it difficult to align the bone screw with the axis of the pre-drilled hole. This can make it difficult to initiate the screw's threading into the bone and can also increase the risk of stress fracture due to misalignment between the bone screw and the hole axis. Existing self-tapping bone screws can also require relatively high torque and / or compression force to initiate threading into the pre-drilled hole in the bone.

[0019] The exemplary bone screws described herein include various features that address the shortcomings of existing bone screws discussed above. For example, the bone screws described herein include an unthreaded atraumatic tip having an unthreaded cylindrical portion and a rounded end. The unthreaded atraumatic tip can be received in a pre-drilled hole in a bone, and optionally through a threaded hole in a bone plate on the bone. The cylindrical portion of the unthreaded atraumatic tip can align the axis of the bone screw with the axis of the pre-drilled hole. This allows the bone screw to be driven into the pre-drilled hole in the bone with precise alignment. The length and diameter of the unthreaded atraumatic tip and / or the cylindrical portion of the atraumatic tip can be sized such that when the bone screw is seated in the pre-drilled hole, all or substantially all of the cutting grooves on the distal end of the bone screw are aligned and contact the surface of the pre-drilled hole. This can reduce the compressive force required to initiate driving of the bone screw into the bone.

[0020] Furthermore, the design of the unthreaded atraumatic tip can reduce soft tissue irritation. For example, the unthreaded atraumatic tip can include a runout region proximal to the cylindrical portion. The threads on the runout region can be sized and shaped in combination with the length of the cylindrical portion of the unthreaded atraumatic tip to be exposed beyond the exit opening of the pre-drilled hole and minimize the length of the threads that come into contact with soft tissue after the bone screw is driven into bone. The smooth, rounded end surface of the atraumatic tip can also reduce soft tissue irritation and associated postoperative complications.

[0021] Example 1: Orthopedic bone screw with an unthreaded atraumatic tip 1-3 illustrate an example of an orthopedic bone screw 100. The bone screw 100 includes a head 102 and a shaft 104 (also referred to as a shank) extending from the head 102. The shaft 104 includes an unthreaded, atraumatic tip 106. The bone screw 100 may define a longitudinal axis 105. For purposes of this description, the direction toward the head 102 of the screw will be referred to as the proximal direction, and the direction toward the unthreaded, atraumatic tip 106 will be referred to as the distal direction.

[0022] In the illustrated example, the shaft 104 may include a plurality of threads 110. The illustrated bone screw is configured as a cortical bone screw, with the threads 110 of the shaft 104 configured to engage cortical bone tissue. However, it should be understood that the various features described herein may be applicable to any type of orthopedic screw, including locking cortical bone screws (e.g., screws with threads on the head), locking and non-locking cancellous bone screws, etc.

[0023] In certain examples, the thread 110 of the shaft 104 may be a single-lead thread. Referring to FIG. 4 , in certain examples, the thread 110 may be a buttress thread having a square or flat first surface 112 (e.g., oriented proximally toward the head 102) and an angled and / or curved second surface 114 (e.g., oriented distally toward the atraumatic tip 106). In the illustrated example, the first surface 112 of the thread 110 may subtend an angle θ with a reference axis 116 perpendicular to the longitudinal axis 105 of the bone screw. In certain examples, the angle θ may be between 0° and 10°, e.g., between 1° and 7° or 5°. The crest 118 of the thread 110 may also be rounded, as in the illustrated example, or may be pointed. As shown in FIG. 4 , the thread 110 may have a thread pitch P1. Buttress threads can increase the "push-out force" of a bone screw, which is the force required to push or pull the bone screw from the bone into which it is threaded. In some examples, the thread pitch P1 of any of the examples herein can be 0.5 mm to 1.2 mm, e.g., 0.5 mm to 1 mm or 0.8 mm.

[0024] 2 and 3, the thread 110 can have a major diameter designated D1 and a minor diameter designated D2. As best shown in FIGS. 2 and 6, the shaft 104 can include a runout region 130 (also referred to as a transition region) in which the thread height of the thread 110 gradually increases moving proximally from the atraumatic tip 106. As shown in FIG. 6, in certain examples, the runout region 130 can include a length L1. In certain examples, the runout region 130 can include one thread or multiple threads, such as two threads, three threads, four threads, or five threads (e.g., the runout region can include one or more turns of the thread around the circumference of the shaft). In the illustrated embodiment, the runout region 130 includes four threads 110.

[0025] 5 and 6, in the illustrated example, bone screw 100 is configured as a self-tapping bone screw and includes a plurality of milling grooves 120 formed in a distal end portion of the bone screw. Each of milling grooves 120 can include a first radially extending surface 122 and a second radially extending surface 124. First radially extending surface 122 can include a flat first portion 126 and a curved second portion 128 proximal to first portion 126. In a particular example, curved second portion 128 can have a radius r3, as shown in FIG. 5.

[0026] 6, the second radially extending surface 124 can be flat and / or planar and can define an angle α with the longitudinal axis 105 of the bone screw. In particular examples, the angle α can be between 1° and 10°, such as between 1° and 5°. In one particular example, the angle α can be 3°.

[0027] The cutting grooves 120 can extend along all or a portion of the unthreaded atraumatic tip 106. For example, in the illustrated embodiment, the cutting grooves 120 can originate at the spherical end surface 140 of the unthreaded atraumatic tip 106 and extend proximally along the unthreaded atraumatic tip 106 and enter the runout region 130.

[0028] 7, bone screw 100 includes three self-tapping grooves 120 spaced at 120° angular intervals, although the bone screw can have more or fewer grooves at any selected angular interval. The first and second surfaces 122, 124 of each groove 120 can define a 90° angle with respect to one another, although other configurations are possible. Providing three or more grooves 120 can reduce the torque required to initiate driving of the bone screw into both cancellous and cortical bone compared to existing bone screws.

[0029] 5 and 6, the unthreaded atraumatic tip 106 can be formed as an unthreaded (e.g., non-threaded) portion of the shaft 104 at the distal end of the bone screw and can also be referred to as an atraumatic pilot point or an atraumatic dog point. Referring to FIG. 6, the unthreaded atraumatic tip 106 can include a cylindrical portion 132 and a rounded end portion 134. The overall length L2 of the unthreaded atraumatic tip 106, including the cylindrical portion 132 and the rounded end portion 134, is shown in FIG. 6. The cylindrical portion 132 can have a diameter D3 (FIG. 3). In certain examples, the length L2 of the unthreaded atraumatic tip can be 60% to 100% of the diameter D3 of the cylindrical portion 132, such as 50% to 100% of the diameter D3, 50% to 80% of the diameter D3, 60% to 80% of the diameter D3, 70% to 80% of the diameter D3, 50% to 150% of the diameter D3, 70% to 150% of the diameter D3, 70% to 100% of the diameter D3, etc. In certain embodiments, the length L2 of the unthreaded atraumatic tip can be 75% of the diameter D3 of the cylindrical portion 132.

[0030] 6, the cylindrical portion 132 of the unthreaded atraumatic tip can have a length L3. In certain examples, the length L3 of the cylindrical portion 132 can be proportional to the major diameter D1 of the thread 110. For example, in certain examples, the length L3 of the cylindrical portion 132 can be 10% to 150% of the major diameter D1 of the thread 110, such as 10% to 100%, 10% to 80%, 10% to 60%, 10% to 40%, 20% to 150%, 20% to 100%, 20% to 80%, 20% to 60%, 20% to 40%, 25% to 150%, 25% to 100%, 25% to 80%, 25% to 60%, 25% to 40%, etc., of the major diameter D1 of the thread 110. In the illustrated example, the length L3 of the cylindrical portion 132 is 40% of the major diameter D1 of the thread 110. As will be explained in more detail below, sizing the cylindrical portion 132 within this range facilitates aligning the orthopedic bone screw with the axis of the pre-drilled hole in the bone when the cylindrical portion 132 is inserted into the pre-drilled hole. This configuration also results in each of the cutting flutes 120 contacting and aligning with the wall of the pre-drilled hole prior to driving the screw, which can significantly reduce the compression force required to initiate driving of the orthopedic bone screw into bone.

[0031] Referring again to FIG. 6 , in certain examples, the rounded end portion 134 can include multiple portions having different radii. For example, in the illustrated configuration, the rounded end portion 134 includes a first curved portion 136 and a second curved portion 138 that defines the end surface 140 of the unthreaded atraumatic tip 106. The first curved portion 136 can have a first radius r1, and the second curved portion can have a second radius r2 that is different from the first radius r1. In certain examples, the second radius r2 of the second curved portion 138 (and thus the end surface 140) is greater than the first radius r1 of the first curved portion 136. In certain examples, first radius r1 can be 10% to 90% of second radius r2, such as 10% to 75%, 10% to 50%, 10% to 40%, 20% to 50%, 20% to 40%, or 20% to 30% of second radius r2. Thus, in certain examples, first curved portion 136 can be configured as a fillet surface portion or transition surface between cylindrical portion 132 and end face 140 of unthreaded atraumatic tip 106 to avoid a ridge or sharp transition between the surfaces.

[0032] In certain examples, the diameter D3 of the cylindrical portion 132 can be within a range of ±10% of the minor diameter D2 of the thread 110, such as within a range of ±5%, ±4%, ±3%, etc. of the minor diameter D2 of the thread 110 ( FIG. 2 ). In certain examples, the diameter D3 of the cylindrical portion 132 can be substantially equal to the minor diameter D2 of the thread 110. In certain examples, the diameter D3 of the cylindrical portion 132 can be 90% to 100% of the minor diameter D2 of the thread 110, such as 95% to 100% of the minor diameter D2 of the thread 110.

[0033] In certain examples, the length L3 of the cylindrical portion 132 of the unthreaded atraumatic tip 106 can be 100% to 500%, such as 100% to 400%, 100% to 300%, 100% to 200%, etc., of the thread pitch P1 of the threads 110. In certain examples, the length L3 of the cylindrical portion 132 can be 175% of the thread pitch P1 of the threads 110.

[0034] In certain examples, the length L3 of the cylindrical portion 132 of the unthreaded atraumatic tip 106 can be 10% to 200% of the diameter D3 of the cylindrical portion 132, such as 25% to 200%, 25% to 100%, 25% to 75%, etc. In certain examples, the length L3 of the cylindrical portion 132 can be 50% of the diameter D3 of the cylindrical portion 132.

[0035] In certain examples, the overall length L2 of the unthreaded atraumatic tip 106 (e.g., the length L3 of the cylindrical portion 132 plus the axial length of the rounded end portion 134) can be 100% to 600%, e.g., 100% to 500%, 100% to 400%, 100% to 300%, 200% to 600%, 200% to 500%, 200% to 400%, or 200% to 300% of the thread pitch P1 of the threads 110. In certain examples, the overall length L2 of the unthreaded atraumatic tip 106 can be 250% of the thread pitch P1 of the threads 110.

[0036] 8 , in the illustrated example, the head 102 can define a drive socket 142. In a particular example, the drive socket 142 can be configured to accept a multi-lobe drive bit (e.g., coupled to a power driver such as a drill). In the illustrated example, the drive socket includes six angularly spaced recesses configured to accept a hexa-lobe driver bit. However, the drive socket 142 can be configured to accept a driver bit having any configuration (e.g., a hexagonal driver bit, a Phillips driver bit, etc.).

[0037] In certain examples, features described herein, such as an unthreaded atraumatic tip, may be applicable to locking cortical screws that include head threads for engaging internal threads in a bone plate hole or other orthopedic fixation. FIG. 9 shows a representative example of a locking cortical screw 200 that includes a shaft 204 having a first thread 210 and a head 202 that includes a second thread 208. In certain examples, the second thread 208 of the head 202 can be a multi-lead thread. For example, in the illustrated configuration, the second thread 208 is configured as a dual-lead thread (also referred to as a "two-lead" and "double-start" thread). In certain examples, the dual-lead second thread 208 includes two thread grooves that start 180° apart around the circumference of the proximal and distal ends of the head 202. In other embodiments, the second thread may be a single-lead thread, a triple-lead thread, or the like, depending on the specific characteristics desired.

[0038] In certain examples, the first thread 210 on the shaft 204 can have a first thread pitch P1, and the second thread 208 on the head can have a second thread pitch P2. In certain examples, the thread pitch P1 of the first thread 210 can be different from the pitch P2 of the second thread 208. For example, in certain examples, the thread pitch P2 of the second thread 208 on the head 202 can be greater than the pitch P1 of the first thread 210 on the shaft 204. As a result of this configuration, when the bone screw 200 is driven into bone through a bone plate or other fixation member having a threaded hole, and the second thread 208 on the head 202 engages the threads of the bone plate, the head 202 can move a greater linear distance per rotation of the bone screw than the shaft 204. This can have the effect of moving or "lifting" the bone plate away from the surface of the bone as the screw is tightened, reducing compressive loads and / or pressure applied to the underlying bone surface. This can reduce the risks associated with periosteal necrosis. In some examples, the dual lead thread pitch P2 of any of the examples herein can be 0.5 mm to 1.2 mm, for example, 0.5 mm to 1 mm or 0.8 mm.

[0039] Orthopedic bone screws, such as the examples described herein, can be manufactured from any of a variety of biocompatible metallic materials, such as stainless steel (e.g., SAE Type 316LS stainless steel), titanium alloys, cobalt chromium alloys, magnesium alloys, and / or tantalum alloys, any of a variety of polymeric materials, including resorbable polymers such as polylactides, including poly-L-lactic acid (PLLA), and the like.

[0040] In use, the bone screw 100 can be used to secure two or more bone segments / fragments together and / or to secure a bone plate or other orthopedic fixation device to a bone. For example, referring to FIG. 10 , a hole 144 can be drilled into a bone 146 at a selected location and angle. The diameter of the pre-drilled hole can be selected based on the major diameter of the threads of the orthopedic bone screw being used. If the use of a bone plate is indicated, the bone plate 148 can be placed on the bone 146 such that a selected screw hole opening 150 of the bone plate 148 overlaps and aligns with the pre-drilled hole 144 of the bone 146. The bone screw 100 can be inserted into the screw hole opening 150 of the bone plate 148 and driven into the pre-drilled hole 144 of the bone. The unthreaded atraumatic tip 106 can be received in the pre-drilled hole. In instances where the bone screw is configured as a self-tapping bone screw, the self-tapping groove 120 on the distal end of the shaft 104 can cut threads into bone tissue as the screw is driven into the bone. In cases where the bone screw is configured as a locking screw, the threads on the head can engage corresponding internal threads in the threaded hole opening 150 of the bone plate 148 upon final tightening to secure the bone screw 100 to the bone plate 148.

[0041] The example bone screws and various features described herein, both alone and in various combinations, can provide several significant advantages over existing bone screws. For example, the unthreaded atraumatic tip 106 can facilitate precise alignment of the screw with a pre-drilled hole in the bone. As shown in FIG. 11 , the diameter of the pre-drilled hole can be selected by the surgeon based on the diameter of the bone screw being used. The diameter of the pre-drilled hole can be the same as or slightly larger than the diameter D3 of the unthreaded atraumatic tip. Thus, when the bone screw is inserted into the pre-drilled hole, the unthreaded atraumatic tip can be guided by the wall of the pre-drilled hole. Therefore, bone screws having an unthreaded atraumatic tip, particularly a cylindrical portion of the unthreaded atraumatic tip with the length-to-thread-large-diameter relationship described herein, can facilitate alignment of the bone screw with the pre-drilled hole. In particular, the inventors have discovered that an unthreaded atraumatic tip having a cylindrical portion with a length described herein, as shown in FIG. 11, can limit the angle of the bone screw relative to the pre-drilled hole within a specific angle range (e.g., 1° to 20°, e.g., 1° to 10°). This, combined with the configuration of the cutting grooves and runout region on the distal end of the bone screw, can facilitate more precise alignment of the cutting grooves with the bone surface inside the pre-drilled hole. Each of the cutting grooves can also contact the bone before drilling is initiated by the geometry of the unthreaded atraumatic tip. As a result, the axial compressive load (force) required to engage the self-tapping grooves with bone material as the screw is driven into the bone is surprisingly reduced. In exemplary testing, the inventors determined that the axial compressive load of a bone screw configured as described herein was reduced by more than 50%, from 8.1 N to 3.5 N, compared to existing bone screws without an unthreaded atraumatic tip. The relatively large number of threads combined with the gradual increase in thread height in the runout region can also achieve a significant reduction in the torque required to advance the bone screw into bone.

[0042] Referring to FIG. 12 , in certain orthopedic surgical procedures, bone screws can extend through bone and to the opposite side a selected length. In such procedures, the smooth, rounded end surface of the unthreaded, atraumatic tip can advantageously reduce irritation of surrounding soft tissue. Furthermore, spacing the runout region axially (e.g., proximally) from the tip of the bone screw by the length of the unthreaded, atraumatic tip (and / or cylindrical portion) can reduce the likelihood of threads protruding from the head to the exit of a pre-drilled hole on the opposite side of the bone. This can reduce both the length and height profile of the threads that come into contact with soft tissue, further reducing the likelihood of soft tissue irritation and associated postoperative complications. In other words, the example bone screws described herein do not have sharp edges that extend into soft tissue once the screw is driven into the bone.

[0043] Furthermore, for cortical locking screws, by making the thread pitch P2 of the second thread on the head greater than the thread pitch P1 of the first thread on the shaft, the bone screw can reduce the compressive force applied to the bone by the bone plate when the bone screw is tightened. For example, because the second thread pitch P2 is greater than the first thread pitch P1, when the second thread engages the bone plate, the head moves a greater distance than the shaft per revolution of the bone screw. This can have the effect of lifting the bone plate away from the bone when the bone screw is tightened. By lifting the bone plate away from the bone surface, compressive forces on the periosteum are alleviated, which can reduce pressure-related necrosis, as described above. The resulting structure can also facilitate a strong and independent connection between the bone screw and the bone plate (e.g., via the second thread on the head) and between the bone screw and the bone (e.g., via the first thread on the shaft).

[0044] Example 2: Orthopedic bone screw with small diameter thread transition 13-18 show another example of an orthopedic bone screw 300. The bone screw 300 can be configured similarly to the bone screws 100 and 200, and in FIGS. 13-18, like reference numerals indicate like features as shown in the previous examples. For example, the bone screw 300 can include a head 302, a shaft 304, and an atraumatic tip portion 306. The shaft 304 can include a first thread 310 similar to the other first threads described above. The head 302 can include a second thread 308 similar to the second thread 208. For example, the second thread 308 can be a multi-lead thread, such as a dual-lead thread. The unthreaded atraumatic tip portion 306 can comprise a cylindrical portion 332, a rounded end portion including a first curved portion 336, and a second curved portion 338 that defines an end surface 340 of the unthreaded atraumatic tip 306, similar to the example described above.

[0045] 14 and 15 , in certain instances, the diameter D3 of the cylindrical portion 332 of the unthreaded atraumatic tip portion 306 can be slightly smaller than the minor diameter D2 of the first thread 310, as described above. In some instances, a surgeon may drill a pilot hole in the bone having a diameter equal to or substantially equal to the diameter D3 of the cylindrical portion 332 to limit the angle of the bone screw and ensure that the self-tapping threads engage the wall of the hole. Therefore, in some instances, it may be advantageous to gradually increase the minor diameter of the first thread 310 within the thread runout region 330. For example, FIG. 14 schematically illustrates the minor diameter of the first thread 310, indicated by lines 311 and 313. Lines 311 and 313 are shown widening within the thread runout region 330 as the minor diameter increases from the diameter D3 of the cylindrical portion 332 to the nominal / specified minor diameter D2. This can prevent a stepwise increase in shaft diameter when the diameter D3 of the cylindrical portion 332 is smaller than the specified minor diameter D2 of the first thread 310, thereby reducing the torque required to initiate threading and drive the screw into bone. This can also facilitate the use of threads with minor diameters larger than the diameter of the atraumatic tip portion, improving the axial strength of the bone screw. In certain examples, the minor diameter D2 of the first thread 310 can be 1% to 10% larger than the diameter D3 of the cylindrical portion 332, such as 1% to 8%, 1% to 5%, etc. In certain examples, the diameter D3 of the cylindrical portion 332 can be 2.8 mm and the specified minor diameter D2 of the first thread 310 can be 2.9 mm, with the gradual increase in the minor diameter of the thread eliminating the 0.1 mm step in the thread runout region 330. The transition of the minor thread diameter from diameter D3 of cylindrical portion 332 to the designated minor diameter D2 can occur over the entire length of thread runout region 330, or over a portion thereof. The rate of increase of the minor thread diameter can be constant along the length of thread runout region 330, as shown in FIG. 14, or can be non-constant, such as exponential.

[0046] 15 and 16 , cutting groove 320 can include first radially extending surface 322 and second radially extending surface 324. First radially extending surface 322 can include a flat first portion 326 and a curved second portion 328 proximal to first portion 326, similar to the example above. Flat first portion 326 (also referred to as the “flat surface portion”) can be within unthreaded atraumatic tip 306 (e.g., coextensive with unthreaded atraumatic tip 306). Curved second portion 328 (also referred to as the “curved surface portion”) can be within runout region 330 (e.g., coextensive with runout region 330).

[0047] In some examples, the second radially extending surface 324 of each milling groove 320 can be parallel or substantially parallel to the longitudinal axis 305. Stated another way, the surface 324 can be flat and parallel to the longitudinal axis 305 at the atraumatic tip portion and the runout region. This can increase the cutting angle of the self-tapping thread (e.g., at the runout region 330) and improve thread initiation when driving the bone screw into bone. Furthermore, the second radially extending surface 324 can also be offset from the longitudinal axis 305 when viewed end-on. For example, as shown in FIG. 16 , when an observer's viewpoint is aligned with the longitudinal edge of one of the second radially extending surfaces 324, the second radially extending surface 324 can be offset from the longitudinal axis 305 by a distance d along the positive y-axis in FIG. 16 . In some examples, the offset distance d can be radially offset relative to the longitudinal axis 305. In certain examples, the distance d can be 5% to 25% of the diameter D3 of the cylindrical portion 332, such as 5% to 20%, 5% to 15%, 10% to 25%, 10% to 15%, etc. An end view of the bone screw 300 showing the cutting grooves 320 is shown in FIG.

[0048] In certain examples, the crests of the threads can define an angle with the longitudinal axis of the bone screw as the height of the threads increases within the runout region 330. Stated another way, the threads can increase in height within the runout region 330 such that a line tangent to the threads within the runout region can define a particular angle. For example, FIG. 18 shows three threads 310 within the runout region 330 whose height increases proximally such that a line tangent to the threads 310 forms an angle β with the longitudinal axis 305. In certain examples, the angle β can be between 5° and 30°, e.g., between 5° and 20°, between 5° and 15°, or 10°. Increasing the height of the threads according to the angle ranges described herein can reduce the height of the leading threads of each cutting flute. This can increase the cutting depth of the threads when the screw is driven into bone, reducing the force required during initial driving into bone and reducing the risk of fracture.

[0049] Any of the screw examples described herein can include other thread profiles on the shaft. For example, FIGS. 19-21 show another example of an orthopedic bone screw 300 in which a first thread 310 has symmetrical flanks that form an angle θ1. Referring to FIG. 20, the crest / apex of the thread can have a radius r4, and the root of the thread can have a radius r5 that is greater than radius r4. The walls of the thread can subtend an angle θ2 with the central axis 315 of the thread. In some examples, the angle θ2 can be between 0° and 90°, e.g., between 10° and 60°, between 10° and 50°, between 10° and 40°, between 10° and 30°, etc. In some examples, the proximal wall of the thread can have an angle θ2 such that the angle of the proximal wall in the withdrawal direction (e.g., proximally toward the head) is between 10° and 60°, less than 60°, or any of the other angle ranges described herein. In some examples, angle θ1 can be 60° and angle θ2 can be 30°, as in the case of a metric MJ thread profile. The thread can have a thread height h and a pitch P1. In certain examples, radius r4 can be 4% to 12% of the thread height h, such as 6% to 10% or 8% of the thread height h. In certain examples, radius r5 can be 10% to 100% of the thread height h, such as 20% to 50% or 33% of the thread height h. Certain examples of orthopedic bone screws having the thread profiles shown in Figures 19-21 have demonstrated improved pull-out strength in testing.

[0050] In yet other examples, the first thread 310 (or the first thread of any of the other screw examples herein) can be configured as a "reverse" buttress thread, with the flat surface oriented distally toward the atraumatic tip and the curved surface oriented proximally toward the head of the screw. An example of a bone screw 300 having a first thread 310 configured as a reverse buttress thread is shown in FIG. 22. In FIG. 22, the proximal surface of the first thread 310 (facing the pull-out direction toward the head) is curved. In other examples, both the proximal and distal surfaces of the buttress thread can be flat / planar. For example, FIG. 23 shows an example of a bone screw 300 in which the first thread 310 has a flat proximal surface 333 that is inclined (e.g., 30°-70°, 40°-70°, 45°-60°, etc.) relative to the longitudinal axis 305. The first thread 310 can also have a flat distal surface 335 that is perpendicular or substantially perpendicular to the longitudinal axis 305. The thread 310 can also have a rounded (also referred to as "curved" and "rounded") crest. Figure 24 shows a bone screw 300 in which the first thread 310 is a buttress thread with an opposite configuration, in which the distal surface 335 is inclined relative to the longitudinal axis 305 and the proximal surface 333 is perpendicular or substantially perpendicular to the longitudinal axis.

[0051] FIG. 25 illustrates another thread profile that can be implemented on the first thread of any of the example bone screws described herein. The walls (also referred to as "flanks") of the first thread 310 can define an angle θ3 between 1° and 20°, e.g., between 1° and 15°, between 1° and 10°, between 1° and 5°, between 3° and 20°, between 3° and 15°, between 3° and 10°, or between 3° and 5°. In some examples, the first thread 310 of FIG. 25 can be configured as an "acme" thread having an angle between opposing thread flanks of 29°, a "trapezoidal" thread having an angle between opposing thread flanks of 30°, or a "square" thread having 90° thread flanks, measured relative to the longitudinal axis 305 of the shaft. The thread 310 can be rounded at the root where the thread originates from the shaft and rounded or filleted along the top surface.

[0052] Additional Examples of the Disclosed Techniques It should be understood that any of the features of the orthopedic bone screws described herein can be used in various combinations with any of the other orthopedic bone screws described herein. For example, a reduced diameter thread transition can be implemented in bone screw 100 and / or bone screw 200, as well as bone screw 300. Additionally, any of bone screws 100, 200, and / or 300 can include milled flutes having flat / planar surfaces that are parallel or substantially parallel to and offset from the screw shaft axis when viewed end-on, similar to surface 324 of bone screw 300.

[0053] In view of the above-described embodiments of the disclosed subject matter, the present application discloses the following additional examples: It should be noted that one feature of an example alone, or two or more features of an example taken in combination, and optionally in combination with one or more features of one or more additional examples, are additional examples included in the disclosure of the present application.

[0054] [Example 1] The orthopedic bone screw comprises a head and a threaded shaft extending from the head, the threads comprising a major diameter and a minor diameter, the shaft comprising an unthreaded atraumatic tip opposite the head. [Example 2] The orthopedic bone screw of any embodiment herein, in particular embodiment 1, wherein the unthreaded atraumatic tip comprises a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion that forms the tip of the orthopedic bone screw.

[0055] [Example 3] The orthopedic bone screw of any embodiment herein, particularly embodiment 2, wherein the length of the cylindrical portion of the atraumatic tip is between 25% and 150% of the major diameter of the thread.

[0056] [Example 4] The orthopedic bone screw comprises a head and a threaded shaft extending from the head, the threads having a major diameter and a minor diameter, the shaft having an unthreaded atraumatic tip opposite the head, the unthreaded atraumatic tip comprising a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion that forms the tip of the orthopedic bone screw, the length of the cylindrical portion of the atraumatic tip being 25% to 150% of the major diameter of the threads.

[0057] [Example 5] The orthopedic bone screw of any embodiment herein, particularly embodiment 4, wherein the diameter of the cylindrical portion of the unthreaded atraumatic tip is 90% to 100% of the minor diameter of the threads.

[0058] [Example 6] The orthopedic bone screw of any example herein, particularly Example 4 or Example 5, wherein the total length of the unthreaded atraumatic tip is 50% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

[0059] [Example 7] The orthopedic bone screw of any embodiment herein, in particular any one of embodiments 1 to 6, wherein the threads comprise a thread pitch and the length of the cylindrical portion of the unthreaded atraumatic tip is 100% to 500% of the thread pitch.

[0060] [Example 8] The orthopedic bone screw of any embodiment herein, in particular any one of embodiments 1 to 7, wherein the shaft further comprises a runout region proximal to the unthreaded atraumatic tip, the threads having a thread height that gradually increases moving proximally from the unthreaded atraumatic tip.

[0061] [Example 9] The orthopedic bone screw of any embodiment herein, particularly embodiment 8, wherein the diameter of the cylindrical portion of the unthreaded atraumatic tip is smaller than the minor diameter of the threads, and the minor diameter of the threads increases within a runout region of the threads from the diameter of the cylindrical portion of the unthreaded atraumatic tip to the specified minor diameter.

[0062] [Example 10] The orthopedic bone screw of any embodiment herein, particularly any one of embodiments 1 to 9, wherein the unthreaded atraumatic tip further comprises a fillet surface portion between the cylindrical portion and the rounded end portion.

[0063] [Example 11] The orthopedic bone screw of any embodiment herein, particularly embodiment 10, wherein the rounded end portion of the unthreaded atraumatic tip comprises a spherical end surface.

[0064] [Example 12] The orthopedic bone screw of any embodiment herein, particularly embodiment 11, wherein the fillet surface portion comprises a first radius and the spherical end face comprises a second radius greater than the first radius.

[0065] [Example 13] 13. The orthopedic bone screw of any embodiment herein, in particular any one of embodiments 1 to 12, wherein the shaft threads are first threads with a first thread pitch and the head further comprises second threads having a second thread pitch, the second thread pitch being greater than the first thread pitch.

[0066] [Example 14] 14. The orthopedic bone screw of any embodiment herein, in particular any one of embodiments 1 to 13, wherein the orthopedic bone screw is configured as a self-tapping bone screw and comprises an unthreaded atraumatic tip and cutting grooves formed in the threads of the shaft.

[0067] [Example 15] The orthopedic bone screw of any embodiment herein, particularly embodiment 14, further comprising a runout region proximal to the unthreaded atraumatic tip, the cutting grooves extending into the runout region.

[0068] [Example 16] The orthopedic bone screw of any embodiment herein, in particular embodiment 12, wherein the cutting flutes comprise a first radially extending surface and a second radially extending surface, the first radially extending surface comprising a flat surface portion in the unthreaded atraumatic tip and a curved surface portion in the runout region, and the second radially extending surface is flat at the unthreaded atraumatic tip and in the runout region and is parallel or substantially parallel to a longitudinal axis of the orthopedic bone screw.

[0069] [Example 17] The orthopedic bone screw of any embodiment herein, in particular any one of embodiments 1 to 16, wherein the length of the cylindrical portion of the unthreaded atraumatic tip is 25% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

[0070] [Example 18] The orthopedic bone screw of any embodiment herein, in particular any one of embodiments 1 to 17, wherein the diameter of the cylindrical portion of the unthreaded atraumatic tip is ±5% of the minor diameter of the threads.

[0071] [Example 19] 19. A method comprising driving the orthopedic bone screw of any one of Examples 1 to 18 into a bone.

[0072] [Example 20] The orthopedic bone screw comprises a head and a threaded shaft extending from the head, the threads comprising a major diameter and a minor diameter, the shaft comprising an unthreaded atraumatic tip opposite the head, the unthreaded atraumatic tip comprising a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion forming the tip of the orthopedic bone screw, at least the cylindrical portion of the unthreaded atraumatic tip comprising a plurality of cutting grooves.

[0073] [Example 21] The orthopedic bone screw of any embodiment herein, particularly embodiment 20, further comprising a runout region proximal to the unthreaded atraumatic tip, the cutting grooves extending into the runout region.

[0074] [Example 22] The orthopedic bone screw of any embodiment herein, in particular embodiment 20 or embodiment 21, wherein the length of the cylindrical portion of the atraumatic tip is 25% to 150% of the major diameter of the thread.

[0075] [Example 23] The orthopedic bone screw of any embodiment herein, particularly any one of embodiments 20 to 22, wherein the overall length of the unthreaded atraumatic tip is 50% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

[0076] [Example 24] The orthopedic bone screw of any embodiment herein, in particular any one of embodiments 20 to 23, wherein the threads comprise a thread pitch and the length of the cylindrical portion of the unthreaded atraumatic tip is 100% to 500% of the thread pitch.

[0077] [Example 25] The orthopedic bone screw comprises a head and a shaft extending from the head, the shaft comprising a thread, the shaft comprising an unthreaded atraumatic tip opposite the head, the unthreaded atraumatic tip comprising a cylindrical portion and a rounded end portion distal to the cylindrical portion, the unthreaded atraumatic tip having a length that is 50% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

[0078] [Example 26] The orthopedic bone screw of any embodiment herein, particularly embodiment 25, wherein the cylindrical portion of the unthreaded atraumatic tip has a length that is 25% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

[0079] [Example 27] The orthopedic bone screw of any embodiment herein, particularly embodiment 25 or embodiment 26, wherein the length of the cylindrical portion of the unthreaded atraumatic tip is 25% to 150% of the major diameter of the threads.

[0080] In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are merely examples and should not be construed as limiting the scope of the disclosure. Rather, the scope of the disclosure is at least as broad as the following claims and the equivalents of the recited features. Accordingly, the inventors claim all that comes within the scope and spirit of these claims.

Claims

1. 1. An orthopedic bone screw, comprising: The head and a shaft extending from the head and comprising a thread, the thread comprising a major diameter and a minor diameter; the shaft having an unthreaded atraumatic tip opposite the head, the atraumatic tip having a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion that forms a tip end of the orthopedic bone screw; An orthopedic bone screw wherein the length of the cylindrical portion of the atraumatic tip is 25% to 150% of the major diameter of the thread.

2. The orthopedic bone screw of claim 1, wherein the diameter of the cylindrical portion of the unthreaded atraumatic tip is 90% to 100% of the minor diameter of the threads.

3. 3. The orthopedic bone screw of claim 1 or 2, wherein the overall length of the unthreaded atraumatic tip is between 50% and 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

4. 4. The orthopedic bone screw according to any one of claims 1 to 3, wherein the threads comprise a thread pitch and the length of the cylindrical portion of the unthreaded atraumatic tip is between 100% and 500% of the thread pitch.

5. 5. The orthopedic bone screw of any one of claims 1 to 4, wherein the shaft further comprises a runout region proximal to the unthreaded atraumatic tip, the threads having a thread height that gradually increases moving proximally from the unthreaded atraumatic tip.

6. the diameter of the cylindrical portion of the unthreaded atraumatic tip is smaller than the minor diameter of the threads; the minor diameter of the threads increases within a runout region of the threads from the diameter of the cylindrical portion of the unthreaded atraumatic tip to a specified minor diameter; 6. The orthopedic bone screw of claim 5.

7. 7. The orthopedic bone screw of claim 1, wherein said unthreaded atraumatic tip further comprises a fillet surface portion between said cylindrical portion and said rounded end portion.

8. 8. The orthopedic bone screw of claim 7, wherein said rounded end portion of said unthreaded atraumatic tip comprises a spherical end surface.

9. The orthopedic bone screw of claim 8 , wherein said fillet surface portion comprises a first radius and said spherical end face comprises a second radius greater than said first radius.

10. the thread of the shaft is a first thread having a first thread pitch; the head further comprises a second thread having a second thread pitch; the second thread pitch is greater than the first thread pitch; 10. An orthopedic bone screw according to any one of claims 1 to 9.

11. 11. The orthopedic bone screw of any one of claims 1 to 10, wherein the orthopedic bone screw is configured as a self-tapping bone screw and includes the unthreaded atraumatic tip and cutting grooves formed in the threads of the shaft.

12. 12. The orthopedic bone screw of claim 11, further comprising a runout region proximal to said unthreaded atraumatic tip, said cutting grooves extending into said runout region.

13. the cutting groove comprises a first radially extending surface and a second radially extending surface; the first radially extending surface comprising a flat surface portion in the unthreaded atraumatic tip and a curved surface portion in the runout region; the second radially extending surface is flat at the unthreaded atraumatic tip and at the runout region and is parallel or substantially parallel to the longitudinal axis of the orthopedic bone screw.

13. The orthopedic bone screw of claim 12.

14. 14. The orthopedic bone screw of any one of claims 1 to 13, wherein the length of the cylindrical portion of the unthreaded atraumatic tip is 25% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

15. 15. The orthopedic bone screw of any one of claims 1 to 14, wherein the diameter of the cylindrical portion of the unthreaded atraumatic tip is ±5% of the minor diameter of the threads.

16. 16. A method comprising the step of driving an orthopaedic bone screw according to any one of claims 1 to 15 into a bone.

17. 1. An orthopedic bone screw, comprising: The head and a shaft extending from the head and comprising a thread, the thread comprising a major diameter and a minor diameter; the shaft having an unthreaded atraumatic tip opposite the head, the atraumatic tip having a cylindrical portion distal to the threads and a rounded end portion distal to the cylindrical portion that forms a tip end of the orthopedic bone screw; An orthopedic bone screw, wherein at least the cylindrical portion of the unthreaded atraumatic tip comprises a plurality of cutting grooves.

18. 18. The orthopedic bone screw of claim 17, further comprising a runout region proximal to said unthreaded atraumatic tip, said cutting grooves extending into said runout region.

19. 19. The orthopedic bone screw of claim 17 or 18, wherein the length of the cylindrical portion of the atraumatic tip is between 25% and 150% of the major diameter of the thread.

20. 20. The orthopedic bone screw of any one of claims 17 to 19, wherein the overall length of the unthreaded atraumatic tip is 50% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

21. 21. The orthopedic bone screw of any one of claims 17 to 20, wherein the threads comprise a thread pitch and the length of the cylindrical portion of the unthreaded atraumatic tip is between 100% and 500% of the thread pitch.

22. 1. An orthopedic bone screw, comprising: The head and a shaft extending from the head and including a thread; the shaft includes an unthreaded atraumatic tip opposite the head, the unthreaded atraumatic tip including a cylindrical portion and a rounded end portion distal to the cylindrical portion; An orthopedic bone screw, wherein the unthreaded atraumatic tip has a length that is 50% to 100% of the diameter of the cylindrical portion of the unthreaded atraumatic tip.

23. 23. The orthopedic bone screw of claim 22, wherein the cylindrical portion of the unthreaded atraumatic tip has a length that is 25% to 100% of a diameter of the cylindrical portion of the unthreaded atraumatic tip.

24. 24. The orthopedic bone screw of claim 22 or 23, wherein the length of the cylindrical portion of the unthreaded atraumatic tip is 25% to 150% of the major diameter of the threads.

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