Compound thread screw for intramedullary nail

Abstract

A bone screw for affixing an orthopedic implant such as an intramedullary nail to a patient's bone. The bone screw including an implant thread section including a first thread form configured to engage threads or other bone screw engaging features formed in a screw opening in the orthopedic implant and a bone thread section including a second thread form configured to engage bone. The second thread form is different from the first thread form. The second thread form including a major diameter that is substantially similar to the first thread form (e.g., at least a single turn of the second thread form has a major diameter substantially the same as a major diameter of the first thread form). In some examples, the second thread form includes a greater pitch than the first thread form and / or the second thread form includes a smaller minor diameter than the first thread form.

Description

[0001] Attorney Docket No. 8178.6168WO

[0002] COMPOUND THREAD SCREW FOR INTRAMEDULLARY NAIL

[0003] [1] The present disclosure relates generally to orthopedic implants, and more specifically to a compound screw configured to engage honey fragments and configured to provide mechanical load bearing. For example, the compound screw includes a screw thread configured to engage with bone fragments to provide interfragmentary compression concurrent with threadedly engaging with an orthopedic implant such as, for example, an intramedullary (IM) nail.

[0004] BACKGROUND

[0005] [2J Orthopedic implants may be used, for example, to stabilize an injury, to support a bone fracture, to fuse a joint, and / or to correct a deformity. Orthopedic implants may be attached permanently or temporarily and may be attached to the bone at various locations, including implanted within an intramedullary canal or other cavity of the bone, implanted beneath soft tissue and attached to an exterior surface of the bone, or disposed externally and attached by fasteners such as screws, pins, and / or wires. Some orthopedic implants allow the position and / or orientation of two or more bones, bone pieces, or bone fragments (terms used interchangeably herein without the intent to limit or distinguish) to be adjusted relative to one another. Orthopedic implants are generally machined or molded from isotropic materials, such as metals including, for example, titanium, titanium alloys, stainless steel, cobalt-chromium alloys, tantalum, etc.

[0006] [3] An intramedullary (“IM”) nail is one type of orthopedic implant. The primary function of the IM nail is to stabilize the fractured bone fragments, and thereby enable load transfer across the fracture site while maintaining anatomical alignment of the bone. Once implanted, an IM nail may be coupled to the patient’s bone by one or more bone screws passing through a one or more screw openings formed in the IM nail.

[0007] [4] One disadvantage of current systems is that the bone screws are designed and configured to engage the screw opening formed in the IM nail. That is, the screw openings formed in the IM nail include a screw thread or other bone screw engaging feature configured to prevent backing out of the inserted bone screw. The bone screw includes a thread pitch and / or major diameter configured to engage the screw thread or other bone screw engaging feature formed in the screw opening. As a result, the screw thread formed on the bone screw is not tailored or optimized to engage the patient’s bone. In particular, conventional screws are not configured to engage with bones that are fragmented, or which may have poor bone quality. Rather, the thread form of the Attorney Docket No. 8178.6168WO bone screw is configured to engage the screw thread or other bone screw engaging feature formed in the screw opening of the IM nail. If the screw threads were optimized to engage the patient’s bone, then the screw thread would not efficiently engage the IM nail.

[0008] [5] In addition, when addressing complicated fracture patterns, orthopedic surgeons frequently employ fixators to compress bone fragments together. In conventional systems, a surgeon utilizes separate systems to provide the functions of fracture reduction and securing a load bearing or load sharing device to the bone. Typically a surgeon may employ clamps or lag screws outside a plate or nail to reduce and / or compress fracture fragments. Then once reduction is complete, a plate or nail will be secured to the bone. In certain situations, a surgeon will provisionally place a plate on the bone prior to final reduction, use a lag screw or lagging technique to affix bone fragments to the plate, increase plate / bone fixation by adding more fixators, then replace the initial lag screw with a locking screw. In these conventional systems, the task of obtaining interfragmentary compression has nearly always been achieved separate from mechanical load bearing implant insertion.

[0009] [6] It would be beneficial to provide a bone screw that is configured with different screw threads configured to engage a patient’s bone and an orthopedic implant through which it passes. It is with respect to these and other considerations that the present disclosure may be useful.

[0010] BRIEF SUMMARY

[0011] [7] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.

[0012] [8] A bone screw for affixing an orthopedic implant to a bone is described herein. The screw includes an implant thread section including a first thread form configured to engage a bone screw engaging feature formed in a screw opening in the orthopedic implant. The screw further includes a bone thread section including a second thread form configured to engage the bone. The section second thread form may be different from the first thread form, and the second thread form may include at least a single turn of the thread that has a major diameter that is substantially the same as a major diameter of the first thread form. The bone screw engages with bone fragments to provide interfragmentary compression while also threadedly engaging with an IM nail. Attorney Docket No. 8178.6168WO

[0013] [9] In any preceding or subsequent example, the second thread form comprises a greater pitch than the first thread form. In any preceding or subsequent example, the second thread form comprises a smaller minor diameter than the first thread form. In any preceding or subsequent example, the screw may include at least one cutting flute in a body of the screw. In any preceding or subsequent example, the bone thread section comprises the at least one cutting flute. In any preceding or subsequent example, the nail thread section comprises the at least one cutting flute.

[0014]

[0010] In any preceding or subsequent example, the screw includes an enlarged head portion including threads having an increased diameter for engaging bone.

[0015] IUJ In any preceding or subsequent example, the bone screw engaging feature comprises threads. In any preceding or subsequent example, the bone screw engaging feature has a plurality of fins configured to engage the first thread form of the nail thread section. In any preceding or subsequent example, the bone screw engaging feature has a locking ridge configured to engage the first thread form of the nail thread section. In any preceding or subsequent example, the second thread form of the bone thread section causes the bone to be compressed against the orthopedic implant.

[0016]

[0012] A method of implanting a bone screw in a bone with an IM nail is described herein. The method includes aligning the bone screw with a screw hole formed in the IM nail, with the bone screw including an implant thread section configured with a first thread form configured to engage the screw opening and a bone thread section configured with a second thread form configured to engage the bone. The second thread form may be different from the first thread form, and the second thread form may have a larger thread pitch than the first thread form. The method includes implanting the bone screw into the screw opening of the IM nail such that the second thread form engages the screw opening and rotating the bone screw so that the second thread form passes through the IM nail and into the bone on an opposing side of the IM nail. The first thread form engages the screw opening. The method includes compressing the bone against the intramedullary nail due to the varying pitches of the first and second thread forms.

[0017]

[0013] In any preceding or subsequent example of the method, the first thread form matches a thread form of the screw opening in the IM nail, and the second thread form comprises at least a single turn of the thread having a major diameter that is substantially the same as a major diameter of the first thread form. In any preceding or subsequent example of the method, the second thread form comprises a smaller minor diameter than the first thread form. In any preceding or subsequent example of the method, the screw opening of the IM nail is a threaded hole. Attorney Docket No. 8178.6168WO

[0018]

[0014] Examples of the present disclosure provide numerous advantages. For example, a bone screw in accordance with one or more features of the present disclosure provides different thread forms, one thread form specifically designed to engage a patient’s bone and another screw thread designed to engage an orthopedic implant. As such, improved engagement with the patient’s bone is achieved while maintaining secure engagement with the orthopedic implant. In addition, the bone screw provides additional benefits to surgeons attempting to secure a bone or bone fragments to an IM nail. The screw may simultaneously engage with the IM nail and the bone, the screw passing through the IM nail and engaging the bone on a distal side of the IM nail. Insertion of the bone screw drawing the bone toward the IM nail. Thus arranged, the bone screw would provide interfragmentary compression concurrent with mechanical load bearing. The number of steps required of a surgeon to repair the bone is reduced. The number of devices required to perform the steps is reduced. The compression of the bone to the IM nail is improved. Further features and advantages of at least some of the examples of the present disclosure, as well as the structure and operation of various examples of the present disclosure, are described in detail below with reference to the accompanying drawings.

[0019]

[0015] Further features and advantages of at least some of the examples of the present invention, as well as the structure and operation of various examples of the present invention, are described in detail below with reference to the accompanying drawings.

[0020] BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0021]

[0016] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced. By way of example, specific examples of the disclosed device will now be described, with reference to the accompanying drawings, in which:

[0022]

[0017] FIG. 1 illustrates a side perspective view of a bone with an intramedullary (IM) nail implanted therein.

[0023]

[0018] FIG. 2 is a first view of a screw in accordance with one or more features of the present disclosure, the screw including an implant thread section configured with a first thread form configured to engage a screw opening formed in the IM nail and a bone thread section configured with a second thread form configured to engage the bone.

[0024]

[0019] FIG. 3 is a second view of the screw shown in FIG. 2.

[0025]

[0020] FIG. 4 is a perspective view of the screw shown in FIG. 2. Attorney Docket No. 8178.6168WO

[0026]

[0021] FIG. 5 is an alternate perspective view of the screw shown in FIG. 2.

[0027]

[0022] FIG. 6 illustrates a top cross-sectional view of the screw shown in FIG. 2 passing through the screw opening formed in the IM nail, the screw threadedly engaging internal threads formed in the screw opening.

[0028]

[0023] FIG. 7 illustrates an alternate top cross-sectional view of the screw shown in FIG. 2 passing through the screw opening formed in the IM nail, the screw threadedly engaging a locking ridge formed in the screw opening.

[0029]

[0024] FIG. 8 is a block diagram depicting a method to install a screw in a bone with an IM nail.

[0030]

[0025] It should be understood that the drawings are not necessarily to scale and that the disclosed examples are sometimes illustrated diagrammatically and in partial views. In certain instances, details which are not necessary for an understanding of the disclosed methods and devices or which render other details difficult to perceive may have been omitted. It should be further understood that this disclosure is not limited to the particular examples illustrated herein. In the drawings, like numbers refer to like elements throughout unless otherwise noted.

[0031] DETAILED DESCRIPTION

[0032]

[0026] Various features or the like of a bone screw and corresponding method of use, will now be described more fully herein with reference to the accompanying drawings, in which one or more features of the screw will be shown and described. It should be appreciated that the various features may be used independently of, or in combination, with each other. It will be appreciated that the screw as disclosed herein may be embodied in many different forms and may selectively include one or more concepts, features, or functions described herein. As such, the screw should not be construed as being limited to the specific examples set forth herein. Rather, these examples are provided so that this disclosure will convey certain features to those skilled in the art.

[0033]

[0027] A bone screw is described herein that includes features configured to engage bone and features configured to engage an orthopedic implant such as, for example, an intramedullary (IM) nail, to provide mechanical load bearing. In some examples, the bone screw includes a first, proximal, or implant (e.g., nail) section, segment, or region (terms used interchangeably herein without the intent to limit or distinguish) and a second, distal, or bone section, segment, or region (terms used interchangeably herein without the intent to limit or distinguish). The proximal section is configured with a first thread form configured (e.g., optimized) to engage a bone screw Attorney Docket No. 8178.6168WO engaging feature formed in a screw opening formed in an orthopedic implant such as, for example, the IM nail. The distal section is configured with a second thread form configured to engage and interact with the bone screw engaging feature formed in the screw opening formed in the IM nail as the screw is being passed therethrough. In addition, the second thread form in the distal section of the screw is configured (e.g., optimized) to specifically engage bone including bone having a poor-quality. Thus arranged, the second thread form is different from the first thread form. In some examples, the second thread form comprises a larger pitch as compared to the first thread form. In addition, and / or alternatively, the second thread form includes a larger difference between the major and minor diameters thereof as compared to the major and minor diameters of the first thread form.

[0034]

[0028] In some examples, the screw can engage with bone or bone fragment to provide interfragmentary compression while also threadedly engaging with the IM nail. That is, for example, the second thread form formed in the distal section of the screw may include a smaller minor diameter as compared to the minor diameter of the first thread form formed in the proximal section of the screw. In addition, the major diameter of the first and second thread forms may be substantially similar. Moreover, the pitch of the second thread form formed in the distal section of the screw may be larger than the pitch of the first thread form formed in the proximal section of the screw. Thus arranged, the screw functions substantially similar as a typical screw being inserted through a screw opening formed in an IM nail. However, once the screw tip passes through the IM nail and into a bone fragment on the distal side of the IM nail, the modified thread form on the distal section of the screw acts to draw the bone fragment toward the nail at an increased rate. The increased rate is caused by the difference in pitch between the first and second thread forms. This advanced rate of ‘pull’ or advanced rate of screw insertion creates interfragmentary compression.

[0035]

[0029] While the present disclosure will describe and illustrate a bone screw in use with an IM nail, it should be appreciated that the bone screw may be used in conjunction with other orthopedic implants such as, for example, bone plates. As such, the present disclosure should not be limited for use with IM nails unless explicitly claimed.

[0036]

[0030] FIG. 1 illustrates a side perspective view of a bone with an IM nail inserted and a screw affixed.

[0037]

[0031] The IM nail 106 is illustrated as being inserted into the medullary cavity of a bone. The IM nail 106 may be implanted into the cavity to share a mechanical load with the bone. Typically, Attorney Docket No. 8178.6168WO the IM nail 106 is inserted into a bone that has experienced a fracture or other injury. The IM nail 106 is configured with one or more screw openings through the body of the IM nail 106. The screw openings including a bone screw engaging feature configured to engage threads formed on a bone screw. In some examples, the bone screw engaging feature formed in the screw opening may be configured as internal threads to engage external threads formed on the bone screw. Alternatively, the bone screw engaging feature formed in the screw opening may be configured with a plurality of fins, a locking ridge, etc. In use, the screw opening may include any now known or hereafter developed bone screw engaging feature for engaging with threads formed on the bone screw. In some examples, the screw opening is disposed perpendicular to the longitudinal axis of the IM nail 106. That is, when the IM nail 106 is arranged vertically, such as in a femur of a standing person, the screw opening is horizontal. Alternatively, the screw opening may be configured at other angles with respect to the IM nail 106. In any configuration, the screw opening substantially passes through the axial radius of the IM nail 106 and forms an opening to receive a screw 200.

[0038]

[0032] A screw 200 is illustrated in FIG. 1 as engaging with the IM nail 106 and the bone 102. The specifics of the screw 200 is described in greater detail with respect to FIG. 2 - FIG. 5.

[0039]

[0033] FIG. 2 is a first view of a screw 200 in accordance with one or more features of the present disclosure. In some examples, the screw 200 may engage with bone fragments to provide interfragmentary compression while also threadedly engaging with the IM nail 106.

[0040]

[0034] The screw 200 is illustrated with a nail thread section 202 and a bone thread section 208. The screw 200 may also include an optional enlarged thread section 216 adjacent the head portion of the screw 200, the enlarged thread section 216 is arranged and configured to engage the bone. The increased diameter threads of the enlarged thread section 216 provides increased purchase in the near cortex of the patient’s bone (e.g., the bone cortex closest to the head of the screw 200). The enlarged thread section 216 may offset any deficiencies or compromise (wallowed out) of the cortical hole during implantation of the screw 200 through the screw opening in the IM nail. In some examples, the screw 200 is configured to pass through bone, through a screw opening formed in the IM nail 106 and into bone 102 on the distal side of the IM nail 106.

[0041]

[0035] The nail thread section 202 is located on a shank or central portion of the screw 200 and has a thread form that is configured to engage with a bone screw engaging feature formed in a screw opening that passes through an IM nail 106. As such, the nail thread section 202 on the proximal section of the screw 200 includes a thread form optimized to engage the screw engaging Attorney Docket No. 8178.6168WO feature formed in the screw opening formed in the IM nail. For example, the thread form of the screw in the nail thread section 202 has a nail section major diameter 204 and a nail section minor diameter 206 that matches the bone screw engaging feature (e.g., internal threads, locking ridge, fins, etc.) formed in the screw opening of the IM nail 106.

[0042]

[0036] The distal section of the screw 200 is illustrated with a bone thread section 208 optimized to engage bone. As such, the bone thread section 208 on the distal section of the screw 200 includes a thread form optimized for engagement with bone. For example, the bone thread section 208 may include a greater variation between the minor diameter and major diameter of the screw. The major diameter is the diameter of the screw at the crest of the thread while the minor diameter is the diameter of the screw at the root of the thread. The nail thread section 202, which is optimized for engagement with the IM nail, include a smaller variation between the minor diameter and major diameter of the screw.

[0043]

[0037] The bone thread section 208 may also include a greater pitch than the pitch of the nail thread section 202. The pitch of a thread section is the distance between adjacent threads, such as from a bone section major diameter 210 of one thread to the bone section major diameter 210 of an adjacent thread moving directly up or down the screw 200 longitudinally. In some examples, a 5mm diameter screw 200 may have a bone thread section 208 with a pitch of .069 inches and a nail thread section 202 with a pitch of .050 inches. Different pitches may be configured for different thread forms in the IM nail 106 and for different bone types or bone quality. For example, a bone thread section 208 pitch may be .50, .55, .60, .65, .70, .75, or .80 inches, or any other suitable pitch. The nail thread section 202 pitch may be .40, .45, .50, .55, .60, .65, or .70 inches, or any other suitable pitch, but generally smaller than the bone thread section 208 pitch.

[0044]

[0038] In addition to a greater pitch, the bone thread section 208 may have a smaller bone section minor diameter 212 than a comparable nail section minor diameter 206. In some examples, the bone section minor diameter 212 may be .118 inches while the nail section minor diameter 206 may be .167 inches. Any other suitable minor thread diameters may be used such as .10, .11, .12, .13, .14, .15, .16, .17, .18, .19, or .20 inches, as long as the bone section minor diameter 212 is smaller than the nail section minor diameter 206.

[0045]

[0039] In addition to a greater pitch, the bone thread section 208 may have a similar bone section major diameter 210 as a comparable nail section major diameter 204. In some examples, the bone section minor diameter 212 and the nail section minor diameter 206 may be .197 inches. Attorney Docket No. 8178.6168WO Any other suitable major thread diameters may be used such as .17, .18, .19, .20, .21, .22, .23, .24, or .25 inches, as long as the bone section minor diameter 212 is the same as the nail section minor diameter 206.

[0046]

[0040] In some examples, the bone thread section 208 may have a thread form in which only a limited number of turns of the bone section major diameter 210 of the nail thread section 202 is the same as the nail section major diameter 204, such as one or two turns. In this example, the bone section minor diameter 212 is smaller than the nail section minor diameter 206, but the bone section major diameter 210 of at least the single turn is the same as the nail section major diameter 204. When in this configuration the height of the thread from the root to the crest is greater in the bone thread section 208 than in the nail thread section 202.

[0047]

[0041] The greater pitch of the bone thread section 208 and the larger variation of the bone thread section 208 between the minor diameter and major diameter of the screw causes the screw 200 to engage with bone material and even poor-quality bone material more efficiently than the nail section major diameter 204. However, the portion of the bone thread section 208 that has a bone section major diameter 210 that is the same as the nail section major diameter 204 causes the screw 200 to engage with the bone screw engaging feature formed in the screw opening in the IM nail 106 as the screw 200 passes through the screw opening. This causes the bone thread section 208 to be pulled through the screw opening as the screw 200 is turned even before the nail thread section 202 arrives in the screw opening.

[0048]

[0042] Further, when the bone thread section 208 on the distal section of the screw 200 passes through the IM nail 106 and into a bone fragment on the distal side of the IM nail, the bone thread section 208 on the distal section of the screw 200 begins pulling the bone fragment toward the IM nail 106 at an increased rate. The difference in the rate is determined by the difference in pitch between the bone thread section 208 and the nail thread section 202. For each turn of the screw, the greater pitch causes the screw to move further though the bone than the screw 200 moves through the screw opening. The advanced rate of ‘pull’ or advanced rate of screw insertion causes interfragmentary compression. The bone 102 section or fragment is compressed against the IM nail 106 to create increased stability and load sharing.

[0049]

[0043] The optional enlarged thread section 216 is illustrated with an enlarged thread major diameter that is larger than either the bone thread section 208 or the nail thread section 202. In the illustrated example, the enlarged thread minor diameter is the same as the bone section major diameter 210. The enlarged thread section 216 may have a thread form configured to engage a Attorney Docket No. 8178.6168WO bone section that is on the proximal side (e.g., near cortex) of the bone from the IM nail 106. Because the bone section major diameter 210 is greater than the nail thread section 202 that preceded the screw 200, the screw 200 will gain a greater engagement, or bite, into the proximate bone 102 section.

[0050]

[0044] The screw 200 is illustrated with a screw head 222 at a driver side of the screw 200. That is, the screw head 222 is configured to receive a driving tool, such as hex driver, a screwdriver, or any other type of driver that mates with the screw head 222.

[0051]

[0045] The screw is illustrated with three cutting flutes 224. A cutting flute 224 is an interruption of the thread pattern often with a section of the minor thread diameter cut out to create a cutting edge on the body of the screw 200. The cutting flute 224 causes the screw 200 to self-tap into the bone 102 more efficiently. The cutting flute 224 removes a section of the bone 102 to allow the threads to create a groove in the bone 102 in which to seat the threads.

[0052]

[0046] In some examples, the screw 200 may be configured as a locking screw via the threads on the screw 200 and corresponding internal threads formed in the screw opening. That is, as will be appreciated by one of ordinary skill in the art, the screw 200 is threaded through internal threads of the screw opening in the IM nail 106 and into the patient’s bone on the distal side.

[0053]

[0047] Alternatively, in some examples, alternate bone screw engaging features may be used to secure the screw to the screw opening formed in the IM nail. For example, a locking ridge or projection 702 may be provided within the screw opening for engaging the bone screw. For example, the locking ridge 702 may be provided on a distal edge of the screw hole, although this is but one configuration. The locking ridge interacts with the threads of the screw 200 to provide increased locking strength.

[0054]

[0048] In another example, the bone screw engaging feature may include a plurality of fins positioned within the screw opening to secure the screw to the screw opening formed in the IM nail. In yet another example, a plastic insert may be provided in the screw opening in the IM nail 106. The plastic insert may wedge the screw 200 against the threads opposite the plastic creating metal-to-metal drag. The plastic insert may press the screw 200 against a metal locking component opposite the plastic. A metal insert may be used to lock the screw 200 in place after insertion. Any suitable type of bone screw engaging feature may be employed to prevent the screw 200 from backing out of the bone 102 and IM nail 106.

[0055]

[0049] The total length of the screw 200 may be any suitable length depending on the size of the bone 102 to be engaged. For example, the screw 200 may be approximately 1.5 inches long Attorney Docket No. 8178.6168WO to 4.5 inches long. The screw 200 may be approximately 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, or 4.5 inches long. The bone thread section 208 may make up a portion of the total length, such as .75 inches or 1 .15 inches. The length of the bone thread section 208 may be determined by the thickness of the bone 102 beyond the IM nail 106. For example, the nail thread section 202 may be .6, .7, .8, .9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, or 3.1 inches.

[0056]

[0050] FIG. 3 is a second view of a screw 200 shown in FIG. 2 in accordance with one or more features of the present disclosure. The view of the reverse side of the screw 200 of FIG. 1 illustrates that the threads in each section are continuous except for the portions interrupted by a cutting flute. Only a single cutting flute 224 is illustrated on the back view of the screw 200.

[0057]

[0051] FIG. 4 is a perspective view of a screw 200 shown in FIG. 2 in accordance with one or more features of the present disclosure. The perspective view illustrates that the nail section major diameter 204 is equal to the bone section major diameter 210 of the at least one thread turn. The perspective view illustrates the cutting flutes 224 interruption of the thread pattern.

[0058]

[0052] The screw head 222 is illustrated with a hex connection 402 cutout. In the example, a driver or machined connection that is hexagonally shaped may be mated into the hex connection 402 to allow the screw 200 to be turned and driven into an IM nail or into bone 102. Any other suitable connection type may be machined into the screw head 222 to allow a driver to be connected for driving the screw 200.

[0059]

[0053] FIG. 5 is an alternate perspective view of the screw 200 shown in FIG. 2 in accordance with one or more features of the present disclosure. The perspective view illustrates that the nail section major diameter 204 is equal to the bone section major diameter 210 of the at least one thread turn.

[0060]

[0054] The perspective view further illustrates the cutting flutes 224 interruption of the thread pattern and cutout into the body of the screw 200.

[0061]

[0055] FIG. 6 illustrates a top cross-sectional view of the screw shown in FIG. 2 passing through the screw opening formed in the IM nail, the screw threadedly engaging internal threads formed in the screw opening.

[0062]

[0056] The IM nail 106 is illustrated as a circular rod with a cannulated bore 604 running longitudinally down the center. As described with respect to FIG. 1, the IM nail 106 may be configured with a threaded, cylindrical screw opening through the body of the IM nail 106. The screw opening is disposed perpendicular to the longitudinal axis of the IM nail 106. That is, when Attorney Docket No. 8178.6168WO the IM nail 106 is arranged vertically, such as in a femur of a standing person, the cylindrical screw opening is horizontal.

[0063]

[0057] The screw opening in the IM nail 106 may be threaded to engage with at least the nail thread sections 202 of the screw 200. The screw 200 is illustrated in FIG. 6 as threaded into the screw opening of the IM nail 106 and extending beyond the IM nail 106 into bone 102.

[0064]

[0058] As illustrated, the nail section major diameter 204 of the screw 200 extends into the screw opening thread 602 in the IM nail 106. The nail section minor diameter 206 allows the screw opening thread 602 to extend into the thread of the screw 200. The thread of the screw 200 and the screw opening thread 602 of the IM nail 106 are thus engaged. In the example, the screw opening thread 602 engages the screw 200 on both sides of the IM nail 106, both before and after the cannulated bore 604. In other examples, the screw opening thread 602 may only be on one side of the cannulated bore 604, such as the entering side or the exiting side of the IM nail 106.

[0065]

[0059] The bone thread section 208 of the screw 200 of FIG. 2 illustrated that at least one turn of the thread in the bone thread section 208 has a similar major diameter as the thread of the nail thread section 202. Thus, the bone section major diameter 210 allows the bone thread section 208 to similarly engage with the screw opening thread 602. Because the pitch and the bone section minor diameter 212 may be different than the thread form of the nail thread section 202, the engagement may not be as secure or efficient as the engagement between the screw opening thread 602 and the nail thread section 202 of the screw 200. However, the engagement is sufficient to allow the screw 200 to be propelled through the IM nail 106 when the screw 200 is turned.

[0066]

[0060] FIG. 7 illustrates a top cross-sectional view of a screw 200 shown in FIG. 2 passing through the screw opening formed in the IM nail 106, the screw 200 threadedly engaging a locking ridge 702 formed in the screw opening.

[0067]

[0061] In a similar manner as described in FIG. 6, the IM nail 106 is illustrated as a circular rod with a cannulated bore 604 running longitudinally down the center. The screw 200 is threaded into the IM nail 106 and extending beyond the IM nail 106 into bone 102.

[0068]

[0062] The screw 200 is threaded onto a locking ridge 702. The nail section minor diameter 206 allows the locking ridge 702 to extend into the thread of the screw 200. The thread of the screw 200 and the locking ridge 702 of the IM nail 106 are thus engaged. Additional details on the configuration of the locking ridge, along with additional details on threaded screw openings and screw openings including a plurality of fins, is provided in PCT application published as Attorney Docket No. 8178.6168WO WO2023224905A1 published on November 23, 2023, and entitled “Intramedullary Tibial Nail with Variable Angle Screw Openings,” the entirety of which is incorporated herein by reference.

[0069]

[0063] The locking ridge 702 may be at the entrance to the screw opening of the IM nail 106, the exit of the screw opening, or at any position alone the length of the screw opening. The locking ridge 702 may engage with the nail thread section 202 of the screw 200 or the bone thread section 208 of the screw as described herein.

[0070]

[0064] The locking ridge 702 may be used in conjunction with a screw opening thread 602. For example, the screw opening thread 602 may be limited to the entrance to the screw opening while the locking ridge 702 is located on the exit of the screw opening. The locking ridge 702 serves to function as a locking mechanism for the screwed connection.

[0071]

[0065] FIG. 8 is a block diagram depicting a method to install a screw 200 in a bone with an IM nail 106.

[0072]

[0066] In block 802, method 800 aligns a screw 200 with a screw opening of an IM nail 106. In an example, an alignment tool may be used to achieve a proper alignment. The screw 200 may first be driven through a proximate section of bone 102 before reaching the IM nail 106.

[0073]

[0067] In block 804, method 800 drives the screw 200 such that the screw 200 engages with the screw opening of the IM nail 106. Initially, the bone thread section 208 of the screw 200 engages the screw opening drawing the screw through the screw opening and into the patient’s bone on the distal side of the IM nail. Eventually, the thread form of the nail thread section 202 engages the screw opening, which may cause metal to metal contact with the screw opening thread 602. In addition, the bone thread section 208 of the screw 200 engages the bone on an opposing side of the IM nail.

[0074]

[0068] In block 806, method 800 drives a bone thread section 208 of the screw into a bone on an opposing side of the IM nail. The thread form of the bone thread section 208 allows engagement with potentially poor bone quality of the bone.

[0075]

[0069] In block 808, method 800 compresses the bone against the IM nail. The thread form of the bone thread section 208 causes the bone to be compressed against the body of the IM nail 106.

[0076]

[0070] While the present disclosure refers to certain examples, numerous modifications, alterations, and changes to the described examples are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is Attorney Docket No. 8178.6168WO intended that the present disclosure not be limited to the described examples, but that it has the full scope defined by the language of the following claims, and equivalents thereof. The discussion of any example is meant only to be explanatory and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these examples. In other words, while illustrative examples of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.

[0077]

[0071] The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure are grouped together in one or more examples or configurations for the purpose of streamlining the disclosure. However, it should be understood that various features of the certain examples or configurations of the disclosure may be combined in alternate examples, or configurations. Any example or feature of any section, portion, or any other component shown or particularly described in relation to various examples of similar sections, portions, or components herein may be interchangeably applied to any other similar example or feature shown or described herein. Additionally, components with the same name may be the same or different, and one of ordinary skill in the art would understand each component could be modified in a similar fashion or substituted to perform the same function.

[0078]

[0072] Moreover, the following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate example of the present disclosure.

[0079]

[0073] As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one example” of the present disclosure are not intended to be interpreted as excluding the existence of additional examples that also incorporate the recited features.

[0080]

[0074] The phrases “at least one,” “one or more,” and “and / or,” as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. The terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) Attorney Docket No. 8178.6168WO are only used for identification purposes to aid the reader’s understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of this disclosure. Connection references (e.g., engaged, attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative to movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. All rotational references describe relative movement between the various elements. Identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority but are used to distinguish one feature from another. The drawings are for purposes of illustration only and the dimensions, positions, order and relative to sizes reflected in the drawings attached hereto may vary.

Claims

Attorney Docket No. 8178.6168WOCLAIMSWhat is claimed is:

1. A bone screw for affixing an orthopedic implant to a bone, the screw comprising: an implant thread section including a first thread form configured to engage a bone screw engaging feature formed in a screw opening in the orthopedic implant; and a bone thread section including a second thread form configured to engage the bone; wherein the second thread form is different from the first thread form; and wherein the second thread form comprises at least a single turn of the thread that has a major diameter that is substantially the same as a major diameter of the first thread form.

2. The screw of claim 1, wherein the second thread form comprises a greater pitch than the first thread form.

3. The screw of claim 1, wherein the second thread form comprises a smaller minor diameter than the first thread form.

4. The screw of claim 1, further comprising at least one cutting flute in a body of the screw.

5. The screw of claim 4, wherein the bone thread section comprises the at least one cutting flute.

6. The screw of claim 4, wherein the nail thread section comprises the at least one cutting flute.

7. The screw of claim 1, wherein the screw is locked into position when screwed into the screw opening.

8. The screw of claim 1, wherein the bone screw engaging feature comprises threads.

9. The screw of claim 1, wherein the bone screw engaging feature comprises a plurality of fins configured to engage the first thread form of the nail thread section.

10. The screw of claim 1, wherein the bone screw engaging feature comprises a locking ridge configured to engage the first thread form of the nail thread section.

11. The screw of claim 1, wherein the second thread form of the bone thread section causes the bone to be compressed against the orthopedic implant.Attorney Docket No. 8178.6168WO12. A method of implanting a bone screw in a bone with an intramedullary nail, comprising: aligning the bone screw with a screw hole formed in the intramedullary nail, the bone screw including an implant thread section configured with a first thread form configured to engage the screw opening and a bone thread section configured with a second thread form configured to engage the bone, the second thread form being different from the first thread form and the second thread form comprising a larger thread pitch than the first thread form; implanting the bone screw into the screw opening of the intramedullary nail such that the second thread form engages the screw opening; rotating the bone screw so that the second thread form passes through the intramedullary nail and into the bone on an opposing side of the intramedullary nail, the first thread form engaging the screw opening; and compressing the bone against the intramedullary nail due to the varying pitches of the first and second thread forms.

13. The method of claim 12, wherein the first thread form matches a thread form of the screw opening in the intramedullary nail, and wherein the second thread form comprises at least a single turn of the thread having a major diameter that is substantially the same as a major diameter of the first thread form.

14. The method of claim 13, wherein the second thread form comprises a smaller minor diameter than the first thread form.

15. The method of claim 12, wherein the screw opening of the intramedullary nail is a threaded hole.

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