INTRAMEDULLARY FEMORAL NAIL WITH A FLEXIBLE DISTAL END REGION
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a non-provisional of, and claims the benefit of the filing date of, pending U.S. provisional patent application number 63/565,633, filed March 15, 2024, entitled “Intramedullary Femoral Nail with A Flexible Distal End Region” the entirety of which application is incorporated by reference herein.
FIELD OF THE DISCLOSURE
[0002] The present disclosure is directed to orthopedic intramedullary (“IM”) nails for stabilizing one or more patient’s bones, bone portions, bone fragments, etc., and more specifically, to an IM nail such as, for example, a femoral IM nail, including a flexible distal end region. In use, the femoral IM nail is fixed (e.g., locked, secured, etc.) along a mid-point thereof in-between the rigid proximal end region and the flexible distal end region. Thus arranged, in use, anatomic fit of the IM nail is improved and the risk of stress risers, and the possibility of peri-prosthetic fractures, is reduced.
BACKGROUND
[0003] 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 patient’s bone, implanted beneath soft tissue and attached to an exterior surface of the patient’s 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 bone fragments, or two or more bones, to be adjusted relative to each other. Orthopedic implants are generally machined or molded from isotropic materials, such as metals including, for example, titanium, titanium alloys, stainless steel, cobalt-chromium alloys, and tantalum, although other materials such as, for example, polymers, composites, or the like, may be used.
[0004] An intramedullary (“IM”) nail is one type of orthopedic implant. The primary function of the IM nail is to stabilize the fracture fragments, and thereby enable load transfer across the fracture site while maintaining anatomical alignment of the patient’s bone. Currently, there are a large number of different commercially available IM nails in the marketplace.
[0005] One known type of an IM nail is a femoral IM nail. A femoral IM nail is arranged and configured to be inserted into the intramedullary canal of a patient’s femur. In use, the femoral IM nail may be inserted into the intramedullary canal via an incision made adjacent the patient’s greater trochanter.
[0006] However, manufacturing and implanting a femoral IM nail, which may extend substantially an entire length of the patient’s femur, can be a challenge. For example, challenges include, inter alia, creating a femoral IM nail, which anatomically fits the intramedullary canal of a varying patient population, creating a femoral IM nail, which can be implanted through the isthmus of the patient’s intramedullary canal, and creating a femoral IM nail, which is strong enough to support the patient’s femur.
[0007] Currently, femoral IM nails may include a bow utilized to implant the femoral IM nail into the patient’s femur. However, this often results in anterior impingement where the distal end or tip of the femoral IM nail rides against the anterior cortex of the patient’s femur instead of resting centrally within the metaphysis of the patient’s bone. In addition, in order to provide proper rotational support, these long IM nails are locked in the distal end region of the IM nail using one or more screws (e.g., the distal end region of the femoral IM nail includes one or more openings for receiving one or more locking screws). In use, the distal locking and anterior impingement may lead to stress risers in the distal region of the patient’s femur, which may increase the risk of distal peri- prosthetic fractures. Generally speaking, the distal end region of longer femoral IM nails often terminate in diaphysis bone, the introduction of a bone screw into the distal end region of the IM nail within the diaphysis bone may lead to bone fracture.
[0008] Alternatively, shorter femoral IM nails may be used to avoid, or at least reduce, creation of stress risers in the distal part of the patient’s femur, however utilization of shorter IM nails may lead to increased risk of stress risers, and hence peri- prosthetic fractures, in the mid-region of the patient’s femur where the shorter IM nail terminates. Generally speaking, stress risers occur where the implanted IM nail ends since the implant is stronger than the patient’s bone. Thus, the use of shorter IM nails tend to create stress risers in the mid-region of the patient’s femur where the shorter IM nail terminates, adjacent to the position of the distally implanted screw (e.g., since the IM nail terminates adjacent the screw opening, the implant does not support the area beneath the distally implanted screw).
[0009] It is with these considerations that the present disclosure is provided.
BRIEF SUMMARY
[0010] 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.
[0011] In some examples, an intramedullary (“IM”) nail, more preferably, a femoral IM nail, is disclosed. The IM nail including a body including a proximal end region and a distal end region. The body including an overall length, which is arranged and configured to extend substantially an entire length of the patient’s bone (e.g., femur) (generally referred to as a long IM nail). The proximal end region having a first stiffness. The distal end region having a second stiffness, which is less than the first stiffness of the proximal end region. In addition, the IM nail includes a means or mechanism for fixing or locking the IM nail to the patient’s bone along a midshaft or region of the patient’s bone. Thus arranged, the IM nail may be secured (e.g., locked) along the midshaft or region of the patient’s bone, approximate the position of a conventional shorter IM nail, which, in use, may extend approximately half-way into the patient’s bone and which does not extend the entire length of the patient’s bone. In addition, by incorporating midportion locking with a distal end region having a decreased stiffness to provide increased flexibility in the distal region as compared to the proximal region, occurrences of stress risers, which may be caused by implantation of femoral IM nails, is reduced.
[0012] Thus arranged, a femoral IM nail with a stiffer proximal end region, a more flexible (e.g., less stiff) distal end region, and a locking mechanism in the mid-portion thereof is disclosed, the “nail long, lock short design” is arranged and configured to provide an improved anatomic fit within the intramedullary canal of the patient’s femur while reducing stress risers and instances of peri-prosthetic fractures.
[0013] In some examples, the body may include an intermediate region positioned between the distal and proximal end regions. In some examples, the intermediate region may include one or more openings to receive a fastener such as, for example, a locking screw.
[0014] In some examples, the increased flexible distal end region (e.g., less stiff distal end region) may be achieved using different combinations of materials. For example, the proximal end region of the IM nail may be manufactured from a different, more stiff material or design than the more flexible distal end region of the IM nail.
[0015] In some examples, the more flexible distal end region (e.g., less stiff distal end region) may be achieved using varying cross sections between the proximal and distal end regions (e.g., the distal end region may incorporate a larger inner-diameter (“ID”) and/or a smaller outer diameter (“OD”). [0016] In some examples, the femoral IM nail may include a “clothespin” or split nail design extending from adjacent the screw opening formed in the mid-shaft to the distal end region.
[0017] In some examples, the distal end region may include a cut pattern such as, for example, a helical cut pattern, to provide increased flexibility.
[0018] In some examples, the distal end region includes a flexibility or stiffness that substantially matches the modulus of elasticity of bone.
[0019] In some examples, the distal end region is arranged and configured to flex during implantation to match the curvature of the patient’s intramedullary canal (e.g., the distal end region self-conforms to the anatomical curvature of the patient’s bone to avoid, or at least minimize, anatomic impingement).
[0020] In some examples, the flexibility or stiffness of the IM nail changes continuously. For example, the flexibility or stiffness of the body of the IM nail may gradually change over a length of the IM nail. For example, the flexibility or stiffness may change over the entire length of the IM nail starting with the proximal end region through the intermediate region and along the distal end region. Alternatively, the flexibility or stiffness may change over a length corresponding to 90 percent of the length of the IM nail. Alternatively, the flexibility or stiffness may change over the entire length extending from the intermediate region to the distal end region, or commencing with the distal end region. [0021] In another example, an intramedullary (“IM”) nail, more preferably, a femoral
IM nail, is disclosed. The IM nail including a body including a proximal end region, a distal end region, an intermediate region positioned between the proximal end region and the distal end region, one or more screw holes formed in the proximal end region for securing the IM nail within a patient’s bone, and one or more screw holes formed in the intermediate end region for securing the IM nail within a patient’s bone, wherein the proximal end region includes a first stiffness and the distal end region includes a second stiffness, the second stiffness being less than the first stiffness; the one or more screw holes formed in the intermediate end region is positioned at a location of between 10cm and 20cm from a proximal end of the body; and the first stiffness is between 420N/m2 and 180N/m2 and the second stiffness is between 10N/m2 and 100N/m2.
[0022] In some examples, the body of the IM nail includes an overall length of between 26cm and 50cm.
[0023] In some examples, the proximal end region includes a length of between 8cm and 10cm and the distal end region includes a length of between 16cm and 42cm.
[0024] In another example, an intramedullary (“IM”) nail, more preferably, a femoral IM nail, is disclosed. The IM nail including a body including a proximal end region; a distal end region; an intermediate region positioned between the proximal end region and the distal end region; means for securing the intermediate region of the body within a patient’s bone; and means for increasing a flexibility of the distal end region as compared to a flexibility of the proximal end region. [0025] Examples of the present disclosure provide numerous advantages. For example, by designing and providing femoral IM nails incorporating an increased flexible distal end region with mid-shaft locking, an improved anatomic fit within the patient’s femur may be achieved. In addition, the occurrence of stress risers caused by implantation of conventional femoral IM nails may be reduced leading to a reduction in the number of peri-prosthetic fractures. For example, by enabling surgeons to lock the IM nail proximally to hold rotation (e.g., enable a surgeon to insert a screw into the proximal end region of the IM nail to prevent rotation) and to enable surgeons to secure the IM nail along the mid-region while permitting the IM nail to extend well beyond the distal screw with a flexible distal end region, reduction in stress-risers, and hence peri-prosthetic fractures, can be achieved.
[0026] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] By way of example, specific examples of the disclosed device will now be described, with reference to the accompanying drawings, in which:
[0028] FIG. 1 is a perspective view of an example of a femoral intramedullary
(“IM”) nail in accordance with one or more features of the present disclosure; [0029] FIG. 2 is a perspective view of an alternate example of a femoral intramedullary (“IM”) nail in accordance with one or more features of the present disclosure;
[0030] FIG. 3 is a perspective view of an alternate example of a femoral intramedullary (“IM”) nail in accordance with one or more features of the present disclosure;
[0031] FIG. 4 is a perspective view of an alternate example of a femoral intramedullary (“IM”) nail in accordance with one or more features of the present disclosure;
[0032] FIGS. 5A and 5B illustrate various views of an alternate example of a femoral intramedullary (“IM”) nail in accordance with one or more features of the present disclosure; and
[0033] FIGS. 5C-5F illustrate various views of an alternate example of a femoral intramedullary (“IM”) nail in accordance with one or more features of the present disclosure.
[0034] 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.
DETAILED DESCRIPTION
[0035] Various features of IM nails will now be described more fully hereinafter with reference to the accompanying drawings, in which one or more features of the IM nails 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 an IM nail as disclosed herein may be embodied in many different forms and should not be construed as being limited to the examples set forth herein. Rather, these examples are provided so that this disclosure will convey certain features of the IM nails to those skilled in the art.
[0036] Disclosed herein are various IM nails including one or more features arranged and configured to be implanted within the intramedullary canal of a patient’s bone. As will be described in greater detail herein, in various examples, the IM nails may be arranged and configured as a femoral IM nail, which is arranged and configured to be implanted within the intramedullary canal of a patient’s femur. The IM nails (e.g., femoral IM nails) are arranged and configured to include a proximal end region and a distal end region wherein the proximal end region includes a first stiffness and the distal end region includes a second stiffness, which is less than the first stiffness, to provide a distal end region having increased flexibility relative to the proximal end region (e.g., the femoral IM nail includes one or more features or means that are arranged and configured to increase the flexibility of the distal end region as compared to the proximal end region). In addition, the femoral IM nail includes one or more openings for receiving, for example, a locking screw, in the mid-portion thereof (e.g., locking screw may be implanted in-between the more rigid proximal end region and the more flexible distal end region). Thus arranged, by utilizing the so-called “nail long, lock short concept,” the femoral IM nails are arranged and configured to provide an improved anatomic fit within the intramedullary canal of the patient’s femur while reducing stress risers and instances of peri-prosthetic fractures.
[0037] As will be shown and described herein, the IM nail may be arranged and configured as a femoral IM nail arranged and configured for implantation into a patient’s femur. However, one or more features of the present disclosure may be used in other applications such as, for example, in connection with implantation into other parts of the patient’s body such as, for example, a patient’s tibial, a patient’s humerus, etc. As such, the present disclosure should not be limited to a specific type of IM nail unless specifically claimed.
[0038] With reference to FIGS. 1-4, various examples an IM nail 100 in accordance with one or more features of the present disclosure are illustrated. As will be readily appreciated by one of ordinary skill in the art, in use, the IM nail 100 is arranged and configured to be implanted within an intramedullary canal of a patient’s bone. As will be described herein, preferably the IM nail 100 is arranged and configured to be implanted within an intramedullary canal of a patient’s femur and thus may be referred to herein as a femoral IM nail, although this is but one configuration and it is envisioned that features described herein can be used with IM nails implantable in other areas of the patient’s body and thus the present disclosure should not be limited to any particular type of IM nail unless specifically claimed.
[0039] As illustrated, the IM nail 100 includes a body 102 such as, for example, a cannulated body. The body 102 includes a proximal end portion or region 110 and a distal end portion or region 130 (terms portion or region used interchangeably without the intent to limit or distinguish). In some examples, as illustrated, the body 102 may include an intermediate region 150 positioned between the proximal and distal end regions 110, 130.
[0040] As will be readily appreciated by one of ordinary skill in the art, the proximal end region 110 may include an opening 112 arranged and configured to receive a fastener such as, for example, a compression screw, a lag screw, or both, a helical blade, etc. In use, the fastener is arranged and configured to be implanted through the opening 112 in the proximal end region 110 of the IM nail 100 and into the patient’s femoral head to stabilize, for example, femoral neck fractures.
[0041] In accordance with one or more features of the present disclosure, the distal end region 130 is arranged and configured with a stiffness that is less than the stiffness of the proximal end region 110.
[0042] In addition, the IM nail 100 includes a means or mechanism for securing or locking the IM nail 100 to the patient’s bone along a midshaft or region of the patient’s bone. In use, the means or mechanism for securing the IM nail can be any now known or hereafter developed locking mechanism including, for example, cabling. In some examples, the IM nail 100 may include one or more screw openings, holes, etc. 152 (terms used interchangeably herein without the intent to limit or distinguish) arranged and configured to receive a fastener, screw, etc. (terms used interchangeably herein without the intent to limit or distinguish) in situ. For example, the intermediate region 150 may include one or more screw openings 152. Alternatively, it is envisioned that the intermediate region 150 may be omitted and the screw opening 152 may be formed at the distal end of the proximal end region 110 or at a proximal end of the distal end region 130.
[0043] In some examples, one or more of the screw openings 152 can be circular. Alternatively, one or more of the screw openings 152 can be elongated. In addition, and/or alternatively, one or more of the screw openings 152 can be arranged and configured as a locking screw opening. Alternatively, one or more of the screw openings 152 can be arranged and configured as a variable angled screw opening.
[0044] That is, as will be generally understood by one of ordinary skill in the art, the one or more screw openings 152 may be in the form of a locking screw opening, which may include a plurality of threads formed on an inner surface thereof for mating with threads formed on an outer surface of the screw. Thus arranged, the screw may be said to be locked to the IM nail 100 via the engagement between the threads of the screw and the threads in the locking screw opening. That is, in use, the screw may be threaded through one of the locking screw openings 152 of the IM nail 100 and into the patient’s bone.
The screw is secured to the IM nail 100 via threads formed on the screw that cooperate with the threaded locking screw opening formed in the IM nail 100. This secures the IM nail 100 with respect to the patient’s bone and provides rigid fixation between the IM nail 100 and the screw. That is, because threads formed on the screw interdigitate with threads formed in the locking screw openings of the IM nail 100, the IM nail 100 and the screws form a stable system or construct, and the stability of the fracture can be dependent on or aided by the stiffness of the construct. Locking a screw into the IM nail 100 can achieve angular and axial stability and eliminate the possibility for the screw to toggle, slide, or be dislodged, reducing the risk of postoperative loss of reduction.
[0045] Alternatively, in some examples, the screw opening 152 may be in the form of a variable angled screw opening. In use, as will be appreciated by one of ordinary skill in the art, variable angled openings are arranged and configured to receive a non-locking or variable angled (e.g., polyaxial) locking bone screw. In use, the variable angled screw openings are arranged and configured to enable the screw inserted therein to achieve a greater range of insertion angles as compared to, for example, a locking screw that is threadably coupled to the IM nail 100. For example, the angular position of the screw may be rotated through a range of approximately ± 6 degrees, although the range of allowable polyaxial rotation can vary, including greater and less than the fifteen degrees. In use, the variable angled screw openings may be provided in any suitable manner, configuration, etc. now known or hereafter developed for enabling polyaxial positioning or angling of the screw relative to the IM nail 100.
[0046] In some examples, the variable angled screw opening may include a plurality of fins or tabs that extend radially inward from an inner surface of the variable angled screw opening and into an interior region of the variable angled screw opening, and which are configured to engage or cooperate with the screw. In use, the fins or tabs engage threads or the like formed on the screw in order to secure the screw at a desired position and at a desired angular orientation within the variable angled screw opening.
[0047] In addition to providing one or more screw openings 152 in the body 102 of the IM nail 100, in accordance with one or more features of the present disclosure, as previously mentioned, the distal end region 130 of the IM nail 100 includes a stiffness that is less than the stiffness of the proximal end region 110. For example, in accordance with one or more features of the present disclosure, the distal end region 130 preferable includes a stiffness that substantially mimics patient’s bone (e.g., the distal end region 130 includes a flexibility that substantially matches the modulus of elasticity of bone). As such, in some examples, the distal end region is arranged and configured to flex during implantation to match the curvature of the patient’s intramedullary canal to avoid, or at least minimize the likelihood of anatomic impingement.
[0048] In some examples, the stiffness of the distal end region 130, defined here as the flexural rigidity, may be between 100N/m2 and 10N/m2. The stiffness of the proximal end region 110 may be between 420N/m2 and 180N/m2.
[0049] Thus arranged, in accordance with features of the present disclosure, by fixating (e.g., locking) the IM nail 100 along a mid-portion thereof and by providing a more flexible (e.g., less stiff) distal end region 130 as compared to the proximal end region 110, the occurrence of stress risers caused by conventional implantation of femoral IM nails can be reduced. That is, in accordance with one or more features of the present disclosure, a femoral IM nail 100 is provided. The femoral IM nail 100 includes a stiffer proximal region, a more flexible distal region, and a mechanism for locking the IM nail along a mid-portion thereof This so-called “nail long, lock short concept,” has been found to improve anatomic fit while reducing stress-risers, which may lead to peri- prosthetic fractures.
[0050] In accordance with features of the present disclosure, the body 102 of the IM nail 100 may have an overall length of between 26cm and 50cm. The proximal end region 110 may have a length of between 8cm and 10cm. The distal end region 130 may have a length of between 16cm and 42cm. The intermediate region 150, if included, may have a length of between 5cm and 10cm. Thus arranged, the screw opening 152, if provided, for fixing the IM nail 100 to the patient’s bone may be positioned at a location of between 10cm and 20cm from the proximal end.
[0051] With reference to FIG. 1, in some examples, in accordance with features of the present disclosure, the distal end region 130 may be rendered more flexible (e.g., less stiff) than the proximal end region 110 by any suitable means, method or mechanism now known or hereafter developed. For example, a more flexible distal end region can be achieved by utilizing different combination of materials such as, for example, different materials may be used to manufacture the proximal and distal end regions (e.g., the proximal end region of the IM nail may be manufactured from a different material than the more flexible distal end region of the IM nail, the material used to manufacture the distal end region having a lower stiffness than the material used to manufacture the proximal end region). Choice of materials include, but is not limited to, titanium, titanium alloys, NiTi, polymers such as, for example, PEEK, carbon fiber, etc. [0052] Alternatively, the proximal and distal end regions may be manufactured with varying cross sections such as, for example, by manufacturing the distal end region with a larger inner diameter and a smaller outer diameter as compared to the proximal end region. That is, in some examples, the more flexible distal end region may be achieved using varying cross sections between the proximal and distal end regions (e.g., the distal end region may incorporate a larger inner-diameter (“ID”) and a smaller outer diameter (“OD”)).
[0053] In some examples, the stiffness of the body 102 of the IM nail 100 may be arranged and configured to change continuously. For example, the stiffness of the body 102 of the IM nail 100 may change gradually over the entire overall length of the IM nail as one moves from the proximal end region to the distal end region. Alternatively, the stiffness may change over a substantial length corresponding to, for example, 90 percent of the length of the IM nail, although this is but one example and the stiffness may change over a length corresponding to 75 percent, 60 percent, 50 percent, or the like. Alternatively, the stiffness may change over the entire length extending, adjacent to and distally, from the screw opening 152, if provided, to the distal end region. Alternatively, the stiffness may change over the length of the distal end region.
[0054] Alternatively, with reference to FIG. 2, in some examples, the distal end region 130 may include an elongated slot 132 formed therein. The elongated slot 132 extending from the distal most tip 134 toward the proximal end region 110. As illustrated, in some examples, the elongated slot 132 may extend to a position substantially adjacent to the screw openings 152 formed in the mid-shaft or intermediate region 150 of the body 102 of the IM nail 100. Thus arranged, the elongated slot 132 divides the distal end region 130 into first and second arms or segments 136, 138, which are arranged and configured to flex relative to each other and thereby provide increased flexibility within the distal end region 130 (e.g., the femoral IM nail includes a “clothespin” or split nail design extending from adjacent the screw opening 152 formed in the mid-shaft (e.g., intermediate region 150) to the distal most tip 134).
[0055] Alternatively, with reference to FIG. 3, in some examples, the distal end region 130 may include first and second extensions 140, 142. While the distal end region 130 has been shown and described as being manufactured as first and second extensions, this is but one configuration and the distal end region may include more or less extensions. In use, the first and second extensions 140, 142 are arranged and configured to flex relative to each other and thereby provide increased flexibility as compared to the proximal end region 110.
[0056] Alternatively, with reference to FIG. 4, in some examples, the distal end region 130 may include a plurality of segments 160. For example, the distal end region 130 may include a plurality of discrete segments 160 coupled to each other. For example, the distal end region 130 may include a plurality of independent and separate segments 160, which may then be coupled to each other. Thus arranged, the distal end region 130 includes a series of segments 160 that are designed to move relative to each other.
Alternatively, the distal end region 130 may include, for example, a laser cut formed therein, such as, for example, a helical cut pattern, to provide the increased flexibility (e.g., the distal end region 130 includes one or more cuts, grooves, or the like formed therein to facilitate flexing or bending thereof). In some examples, the laser cut may be provided in a spiral configuration (e.g., the distal end region may be manufactured from a single piece of material with a spiral cut along its length). Thus arranged, in some examples, the IM nail may be manufactured as a unitary or integral piece. Subsequently, a spiral groove may be cut or formed within the distal end region of the body to provide the increased flexibility.
[0057] With reference to FIGS. 5A and 5B, an alternate example of an IM nail in accordance with one or more features of the present disclosure is illustrated. In accordance with features of this example, the distal end region 130 of the IM nail 100 may be rendered more flexible (e.g., less stiff) than the proximal end region 110 by incorporating a taper 175 into the body 102 of the distal end region 130 of the IM nail 100. In accordance with one or more features of the present disclosure, the taper 175 may be provided in a single plane of the body 102 of the IM nail 100, preferably in the anterior plane of the body 102. This is in contrast to providing a circumferential taper as previously described. As illustrated, the anterior portion of the body 102 of the IM nail 100 may be flattened out along the distal end region 130 to produce the anterior taper (e.g., FIG. 5B (and FIG. 5F) schematically illustrating the wedge shape portion, which was removed from the IM nail to create the taper).
[0058] In some examples, as illustrated in FIGS. 5C-5F, the distal end region 130 may include one or more holes, slots, or combinations thereof. Nevertheless, the occurrence of stress-risers adjacent the location of the implanted screws is reduced due to the increase in flexibility of the distal end region 130. In some examples, the distal end region 130 may be provided with increased flexibility by incorporating a taper 175 and/or using different materials, printing a three-dimensional flexible structure, etc.
[0059] In some examples, the body 102 of the distal end region 130 may include a constant outer diameter. Meanwhile, the inner diameter of the body 102 of the distal end region 130 may be constant or increase distally.
[0060] In accordance with one or more features of the present disclosure, which may be used in combination with any of the examples of the IM nails described herein, or separately and used in combination with any suitable IM nail now known or hereafter developed, the IM nail may be provided as a system or kit with interchangeable portions. For example, the proximal end portion or region and the distal end portion or region may be provided as separate components, which are arranged and configured to be coupled together. Moreover, it is envisioned that more than two components may be provided, for example, the system or kit may include intermediate region.
[0061] Thus arranged, the number of unique nails may be reduced. For example, the system or kit may include a single proximal end portion or region, which is arranged and configured to couple any number of different distal end portion or regions. In some embodiments, the system or kit may include a plurality of different distal end portions or regions including, for example, conventionally known stiff shafts and one or more of the prescribed described flexible shafts. In addition, and/or alternatively, the distal end portions or regions may be provided with different characteristics such as, for example, different flexibilities, different lengths, different curvatures, or combinations thereof. In some examples, the IM nail be coupled into its final implantable configuration within the operating room providing the surgeons with increased flexibility in selecting the final implant.
[0062] In use, the proximal end portion or region may be arranged and configured to couple to the intermediate region and/or distal end portion or region by any suitable coupling mechanism now known or hereafter developed including, for example, corresponding threads.
[0063] The foregoing description has broad application. Accordingly, 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.
[0064] The term "a" or "an" entity, as used herein, refers to one or more of that entity. As such, the terms "a" (or "an"), "one or more" and "at least one" can be used interchangeably herein. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms "including," "comprising," or "having" and variations thereof are open-ended expressions and can be used interchangeably herein. 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. [0065] All directional references (e.g., proximal, distal, upper, underside, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) 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., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative 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. 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 sizes reflected in the drawings attached hereto may vary.