Systems and methods for treating bones

Abstract

The nut (106) for treating a bone includes a head (114) and a body, the body extending longitudinally from the head (114) to a free end. The body also includes a channel extending longitudinally from the free end into the body. The channel (136) is configured to engage the end of a bone screw. An external thread (120) extends from the outer surface of the body, around the body, and along the entire length of the body. An outer contour (150) of the external thread (120) is defined by a radially outermost edge (122) of the external thread (120). A first portion (142) of the outer contour (150), adjacent to the head (114), has a smaller diameter than a second portion (144) of the outer contour (150), extending from the first portion to the free end (134) of the body.

Description

[Background technology]

[0001] Fractures of long bones, such as the femur, may be treated using an intramedullary nail that is inserted into the medullary canal of the bone after reducing the fracture of the bone. In some cases, particularly in the case of distal condylar fractures, the bone may be treated using a retrograde nail that can be inserted into the medullary canal from the distal end of the bone. Set screws may be inserted into set holes that extend laterally through the bone and through the intramedullary nail to secure the intramedullary nail to the bone and / or provide additional stability to the bone. Summary of the Invention [Means for solving the problem]

[0002] The present disclosure relates to a nut for treating a bone comprising a head and a body extending longitudinally from the head to a free end, the body including a channel extending longitudinally inwardly from the free end and configured to engage an end of a bone screw, and an external thread extending from an outer surface of the body around the body and along an entire length of the body, the external thread having an outer contour defined by a radially outermost edge thereof, a first portion of the outer contour adjacent a head portion having a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body.

[0003] The present disclosure also relates to a system for treating a long bone, the system including an intramedullary nail insertable through the medullary canal of the bone and extending from a proximal end to a distal end, the intramedullary nail including a blind hole extending through the nail along an axis extending at an angle to a longitudinal axis of the nail, a set screw configured to be inserted into the bone and through the blind hole, the set screw including a head portion and a shaft extending from the head portion to a free end, the shaft including threads extending therealong, and a nut configured to be inserted into the bone, the set screw including a head portion and a shaft extending from the head portion to a free end, the shaft including threads extending therealong, and and a body extending from the head portion to a free end, the body having a channel extending longitudinally inward from the free end and configured to threadingly engage the free end of the set screw; an external thread extending from an outer surface of the body, along the entire length of the body and around the body; and a nut including an external thread outer contour defined by a radially outermost edge of the external thread, wherein a first portion of the outer contour adjacent the head portion has a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body.

[0004] The present disclosure also relates to a method for treating a bone, the method including inserting an intramedullary nail into a medullary canal of the femur through an insertion point at a distal end of the femur, driving a set screw through a first side of the femur such that a shaft of the set screw extends through a set hole extending through a distal portion of the intramedullary nail along an axis angled relative to a longitudinal axis of the intramedullary nail and a head portion of the set screw contacts a cortex along the first side of the femur, and inserting a nut through a second side of the femur opposite the first side of the femur such that a free end of the shaft of the set screw is threadably received within a channel of the nut. The nut includes a head and a body portion extending from the head to a free end, a channel extending longitudinally from the free end into the body, an external thread extending from an outer surface of the body, around the body and along the entire length of the body, an outer contour of the external thread defined by a radially outermost edge of the external thread, a first portion of the outer contour adjacent the head portion having a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body, such that when the nut is inserted through the bone and engaged with the set screw, the nut rotates to align the channel with the threads of the set screw. [Brief description of the drawings]

[0005] [Figure 1] 1 illustrates a longitudinal side view of a portion of a system according to an exemplary embodiment of the present disclosure. [Diagram 2] 2 shows a longitudinal section of a nut according to the system of FIG. 1; [Diagram 3] 1 illustrates a longitudinal side view of a portion of a system according to another exemplary embodiment of the present disclosure. [Figure 4] 1 shows a longitudinal cross-sectional view of a nut according to another exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] The present disclosure can be understood with reference to the following description and the accompanying drawings, in which like components are referred to with the same reference numerals. The present embodiments relate to the treatment of bones, and in particular to the treatment of long bones. The exemplary embodiments describe a system including an intramedullary nail configured to be inserted through the medullary canal of a long bone (e.g., a femur) in combination with a set screw insertable through a set hole extending laterally through the intramedullary nail and a nut configured to engage a threaded end of the set screw. The set screw and nut together act to provide additional stability, fixation, and / or compression, for example, at the distal end of the bone.

[0007] The exemplary embodiment describes a nut including a head portion and a body portion including a channel configured to threadably receive the threaded end of a set screw. The nut of this embodiment also includes an external thread along an outer surface of the body. The outer profile of the nut defined by the radially outermost edge of the external thread narrows toward the head portion such that the nut can be rotated to align the channel threads with the set screw. The root diameter, defined as the diameter of the radially innermost portion of the outer surface of the body portion (i.e., the portion of the outer surface from which the external thread projects radially outward), increases toward the head portion of the nut to provide stability at the cortex when the nut is fully inserted. Although the exemplary embodiment specifically shows and describes a femoral retrograde nail system, it will be understood by one of ordinary skill in the art that the system of the present disclosure may be used to treat any of a variety of long bones, such as, for example, the humerus, regardless of the direction of approach. Additionally, although the exemplary embodiments show and describe set screws and nuts to provide stability and / or compression to the distal end of the bone, it will be understood by one of ordinary skill in the art that set screws and nuts can be used to provide additional stability / compression over any portion of the bone. As used herein, terms such as proximal and distal are intended to refer to directions corresponding to the proximal and distal ends of the bone, respectively, with distal referring to a direction away from the attachment point relative to the center of the body and proximal referring to a direction closer to the center of the body toward the attachment point, as would be understood by one of ordinary skill in the art.

[0008] 1 and 2, a system 100 according to an exemplary embodiment of the present disclosure includes an intramedullary nail 102 configured to be inserted through the medullary canal of a long bone (e.g., the femur) along with a set screw 104 and a nut 106 for securing a distal end 108 of the intramedullary nail 102 to the bone, for example, to provide stability and / or compression across the fracture. The set screw 104 is configured to be inserted from a first side of the bone through a set hole 110 extending laterally through a portion of the intramedullary nail 102.

[0009] The nut 106 includes a head 114 and a body 116 extending from the head 114. The body 116 is configured to engage a free end 118 of the set screw 104 from a second side opposite the first side of the bone to provide additional stability, fixation, and / or compression to a portion of the bone through which the set screw 104 extends. The body 116 includes external threads 120 extending radially outward along all or a portion of the length of its outer surface 124. An outer contour 150 of the body 116, defined by a radially outermost edge 122 of the external threads 120, narrows along a portion of the body 116 adjacent the head 114 to facilitate alignment with the set screw 104 as the nut 106 rotates about the longitudinal axis of the set screw 104.

[0010] Additionally, the root diameter, i.e., the diameter of the body 116 defined at the radially innermost point 152 on the outer surface 124 (i.e., the point at which the external threads 120 extend radially outward), is larger adjacent the head 114 such that the nut 106 provides stability at the cortex along the second side when the body 116 of the nut 106 is fully inserted into the bone. It will be appreciated by those skilled in the art that although the root diameter is larger adjacent the head 114, the increase in the root diameter is offset by the decrease in the outer contour 150 adjacent the head 114 such that cortical cracking along the second side of the bone is avoided.

[0011] The intramedullary nail 102 extends from a distal end 108 to a proximal end (not shown). In one exemplary embodiment, the intramedullary nail 102 is a femoral retrograde nail configured to be inserted into the medullary canal of the femur via an insertion point at the distal end of the bone. The intramedullary nail 102 in this embodiment is sized, shaped, and configured to correspond to the size and shape of the medullary canal of the target bone. In this embodiment, a stop hole 110 extends laterally through a distal portion 126 of the nail 102 and is configured to receive a set screw 104 therethrough to provide stability across the distal end of the femur, for example.

[0012] The eyelet hole 110 extends through the distal portion along an axis that is angled relative to the longitudinal axis of the nail 102. In one embodiment, the eyelet hole 110 extends through the distal portion 126 along an axis that is substantially perpendicular to the longitudinal axis of the nail 102. In another embodiment, the eyelet hole 110 extends through the distal portion 126 along an axis that is angled non-perpendicular to the longitudinal axis of the nail 102. Although the exemplary embodiment is described as having a single eyelet hole 110, one skilled in the art will appreciate that the intramedullary nail 102 may include two or more eyelet holes 110, each configured to receive a set screw 104 therethrough.

[0013] The set screw 104 may be a standard bone screw including a head portion 128 and a shaft 130 extending therefrom to a free end 118, as will be understood by those skilled in the art. The shaft 130 includes threads 132 along its outer surface such that the set screw 104 may be inserted into the bone and through the stop hole 110 by rotation of the set screw 104 about its longitudinal axis. As will be understood by those skilled in the art, the set screw 104 may be driven into the bone using, for example, a driver engageable with a driving recess in the head portion 128. As will be understood by those skilled in the art, the driver and head hole are correspondingly sized and shaped such that when both are engaged, rotation of the driver correspondingly rotates the set screw 104 to drive the set screw 104 into the bone. The set screw 104 may be inserted into the bone and through the stop hole 110 such that when the set screw 104 is fully inserted, the head portion 104 abuts the cortex of the bone along a first side of the bone. In one embodiment, the length of the set screw 104 is selected such that when the set screw 104 is fully inserted into the bone, the free end 118 of the shaft 130 protrudes approximately 2 mm from the far cortex.

[0014] As described above, the nut 106 includes a head 114 and a body 116 extending from the head 114 to a free end 134 configured to surround and engage the free end 118 of the set screw 104. Similar to the set screw 104, the head 114 of the nut 106 includes a driving recess engageable with a driver for driving the nut 106 into the bone (i.e., rotating the nut 106). The free end 134 may include a cutting edge 135 configured to facilitate inserting the nut 106 through the cortex of the bone. The body 116 includes a channel 136 extending longitudinally from the free end 134 into the body 116. The channel 136 is configured to receive the free end 118 of the set screw 104 therein and includes internal threads 138 along an inner surface 140 thereof. The internal threads 138 are sized and pitched to correspond to and threadingly engage the threads 132 of the set screw 104. In one embodiment, a portion 154 of the channel 136 extending through the body 116 adjacent the head 114 may have a larger diameter than a remainder 156 of the channel 136 extending through the body 116. According to one example, the threads 138 may extend along the remainder 156 such that the larger diameter portion 154 does not include threads. In another embodiment, the threads 138 may extend along the entire length of the channel 136. In another embodiment, the diameter of the channel 136 may be constant along its entire length.

[0015] As mentioned above, the body 116 of the nut 106 in this embodiment includes external threads 120 on an outer surface 124 along the entire length of the body 116. Thus, when the nut 106 is driven into the bone, the external threads 120 engage the bone. In particular, the nut 106 may be driven into a second side of the bone opposite the first side, and the longitudinal axis of the nut 106 may be substantially aligned with the longitudinal axis of the set screw 104 inserted through the stop hole such that the body 116 is threaded over the free end 118 of the set screw 104 when the nut 106 is driven into the bone.

[0016] An outer contour 150 of the nut 106 (shown by a dotted line in FIG. 2 ) is defined by the radially outermost edge 122 of the male thread 120, but the outer contour 150 narrows toward the head 114. In other words, the diameter of the outer contour 150 along the first portion 142 of the body 116 adjacent the head 114 is smaller than the diameter of the outer contour 150 along the second portion 144 of the body 116 extending from the first portion 142 to the free end 134. Because the outer contour 150 of the nut 106 (the path defined by the radially outermost points on the male thread 120) along the first portion 142 adjacent the head 114 defines a smaller diameter than the diameter of the outer contour 150 at the second portion 144, the female threads 138 of the channel 136 are aligned with the threads 132 of the set screw 104 when the nut 106 is rotated into the bone. In other words, as the first portion of the outer contour 150 of the nut 106 penetrates the bone, the first portion cuts a slightly wider path than the second portion 144, and this slightly increased diameter allows the nut 106 to move slightly relative to the insertion axis, allowing the nut 106 to adjust its position to more precisely align the axis of the channel 136 of the nut 106 with the axis of the shaft 130 of the set screw 104.

[0017] The external threads 120 extend along a root diameter on the exterior surface 124 of the body 116 that also varies along its length. The root diameter is defined by a path connecting the radially innermost points 152 on each turn of the external threads 120. In this embodiment, the root diameter along a first portion 146 of the exterior surface 124 adjacent the head 114 is greater than the root diameter of a second portion 148 of the exterior surface 124 extending from the first portion 146 to the free end 134. Thus, when the nut 106 is fully inserted into the bone such that the head 114 abuts the second side of the bone, the expanded root diameter of the first portion 146 provides cortical stability at the insertion site of the nut 106. Although the first portion 146 of the outer surface 124 (adjacent the head 114) has a larger root diameter, the outer contour 150 along the first portion 142 adjacent the head 114 is reduced, reducing the risk of cortical cracking when the nut 106 is fully inserted.

[0018] 2, the first portion 142 of the outer contour 150 overlaps with the first portion 146 of the root diameter of the outer surface 124, but the length of the first portion 142 of the outer contour 150 is greater than the length of the first portion 146 of the outer surface 124. Thus, the nut 106 of this embodiment includes three different threaded portions. Threaded portion A is the portion of the body 116 that extends along the length of the body 116 that corresponds to the length of the second portion 144 of the outer contour 150, threaded portion B is the portion of the body 116 that extends along the length of the body 116 where the first portion 142 of the outer contour 150 and the second portion 148 of the outer surface 124 extend, and threaded portion C is the portion of the body that extends along the length of the body 116 that corresponds to the length of the first portion 146 of the outer surface 124.

[0019] In one embodiment, the length of threaded portion A may range from about 2 mm to 10 mm, the length of threaded portion B may range from about 2 mm to 15 mm, and the length of threaded portion C may range from about 1 mm to 5 mm. The depth of the male thread 120 extending along threaded portion A (i.e., the distance between the radially outermost edge 122 and the outer thread root) is greater than the depth of the male thread 120 along both threaded portions B and C. The depth of the male thread 120 extending along threaded portion B is less than the depth of the male thread 120 along threaded portion A, but greater than the depth of the male thread 120 along threaded portion C. Thus, the male thread 120 extending along threaded portion C has the shallowest depth relative to threaded portion A and threaded portion B.

[0020] Those skilled in the art will appreciate that the male thread 120 may be formed by cutting the wall of the nut along a trajectory defined by the outer contour 150 and the channel 136 and corresponding to the outer surface 124.

[0021] As discussed above, the system 100 may be used to treat fractures of a long bone, but in certain embodiments, may be used to treat fractures of the distal portion of the femur. The intramedullary nail 102 may be inserted through a distal end of the femur such that a distal portion 126 of the intramedullary nail 102 is received within the distal end of the femur and secured relative to the distal end of the femur via a set screw 104 inserted through a corresponding blind hole 110 extending laterally through the distal portion 126 of the nail 102. In one embodiment, the set screw 104 may be inserted through a first side of the femur such that the shaft 130 extends through the blind hole 110 and a head portion 128 of the set screw 104 abuts the cortex along the first side of the bone. Although the head portion 128 is described as abutting the bone, one skilled in the art will appreciate that a washer 112 may be positioned between the head portion 128 and the cortex of the bone.

[0022] The nut 106 may then be inserted through the second side of the bone and engaged with the free end 118 of the set screw 104 while being substantially aligned with the longitudinal axis of the bone screw 104. As the body 116 of the nut 106 is driven into the bone, the first portion 142 of the outer contour 150 allows the nut 106 to move slightly relative to its longitudinal axis to facilitate alignment of the female threads 138 along the inner surface 140 of the channel 136 of the nut 106 with the threads 132 of the set screw 104. The nut 106 may be fully inserted into the bone such that the head 114 of the nut 106 abuts the cortex along the second side of the bone. The increased root diameter along the first portion 146 of the outer surface 124 provides stability at the cortex when the nut 106 is fully inserted.

[0023] However, the nut 106 also prevents cracking at the cortex because the outer profile 150 of the male thread 120 along the first portion 142 adjacent the head 114 is smaller than the outer profile along the second portion 144. Although the exemplary embodiment specifically describes and illustrates the use of the system to treat a distal femur, one skilled in the art will understand that the stability and / or compression provided by the set screw 104 and nut 106 may be used to treat any of a variety of bones. One skilled in the art will also understand that the intramedullary nail 102, set screw 104, and nut 106 may be inserted / embedded into bone using any of a variety of methods known in the art.

[0024] According to another exemplary embodiment, as shown in FIG. 3, the system 100′ includes a first nut 106a′ and a second nut 106b′ that can be used to secure both ends of the set screw 104′ to enhance the constructive stability of the nail. Each of the first nut 106a′ and the second nut 106b′ can be substantially similar to the nut 106 of the system 100. The set screw 104′ can be substantially similar to the set screw 104, except that the set screw 104′ does not include a screw head such that both ends of the set screw 104′ can be received within the nuts 106a′ and 106b′. However, in this embodiment, the first nut 106a′ is inserted through the cortex along a first side of the bone until the head portion 114′ of the first nut 106′ contacts the cortex along the first side.

[0025] The free end of the set screw 104' is inserted into the head portion 114' of the first nut 106a' and through the body 116' of the nut 106a' such that the shaft 130' of the set screw 104' engages with threads along the interior of the body 116'. The set screw 104' is moved longitudinally relative to the first nut 106a' until its free end extends beyond the body to engage the bone and the head portion 128' of the set screw 104' abuts the head portion 114' of the first nut 106a'. In this embodiment, the channel extending through the body 116' of the first nut 106a' may have a larger diameter adjacent the head portion 114' so that the set screw 104' may be more precisely aligned with the axis of the channel when the set screw 104' is inserted into the body 116'.

[0026] In other words, a small amount of movement of the set screw 104' relative to the nut 106a' is permitted during the initial insertion of the set screw 104' in order to more accurately align the set screw 104' with the first nut 106a'. As described above, once the set screw 104' has been inserted into the bone through the first nut 106a', a second nut 106b' can be inserted transcortically along a second side of the bone opposite the first side to engage the free end of the set screw 104'. Those skilled in the art will appreciate that the insertion of the second nut 106b' to engage the free end 118' can be substantially similar to the insertion of the nut 106 described above with respect to the system 100.

[0027] 4, a nut 206 according to another exemplary embodiment may be substantially similar to the nut 106 previously described with respect to system 100. Like the nut 106, the nut 206 is configured to engage a free end of a set screw, which may be substantially similar to the set screw 104 previously described with respect to system 100. The nut 206 includes a head 214 and a body 216 extending longitudinally from the head 214 to a free end 234. A channel 236 extending longitudinally from the free end is configured to receive an end of the set screw therein. As with the nut 106, the outer contour 250 defined by the radially outermost point 222 of the male thread 220 extending along the outer surface 224 of the body 216 includes a first portion 242 adjacent the head 214 and a second portion 244 extending from the first portion 242, with the first portion 242 of the outer contour 250 having a smaller diameter than the second portion 244.

[0028] Also, as with the nut 106, the body 216 includes a first portion 246 adjacent the head 214 along which a root diameter (defined by a radially innermost point 252 of the external thread 220) along the outer surface 224 is greater than a root diameter along a second portion 248 extending from the first portion 246. However, in this embodiment, the first portion 242 of the outer contour 250 and the first portion 246 of the outer surface 224 substantially correspond (e.g., have substantially the same length and extend along the same portion of the body 216) such that the thread 220 along the body 216 includes two threaded portions, i.e., threaded portion A and threaded portion C, rather than three threaded portions as discussed above with respect to the nut 106.

[0029] Threaded portion A extends along a portion of body 216 that corresponds to second portion 244 of outer contour 250 and second portion 248 of exterior surface 224. Threaded portion C, on the other hand, extends along a portion of body 216 that corresponds to first portion 242 of outer contour 250 and first portion 246 of exterior surface 224. In one embodiment, the length of threaded portion A may range from about 5 mm to 20 mm, and the length of threaded portion C may range from about 1 mm to 20 mm. The depth of male thread 220 along threaded portion A is greater than the depth of thread 220 along threaded portion C. Although nut 206 includes only two threaded portions A, C, one skilled in the art will appreciate that, as with nut 106, the reduced diameter of first portion 242 of outer contour 250 facilitates alignment with a set screw (e.g., set screw 104) when nut 206 is inserted into bone, and the increased diameter of first portion 246 of outer surface 224 promotes stability at the cortex with the associated cortical cracking. It will be appreciated by one skilled in the art that nut 206 may be used in much the same manner as nut 106.

[0030] Those skilled in the art will understand that modifications and variations can be made to the structure and methods of these embodiments without departing from the spirit or scope of these embodiments. Thus, it is intended that the present invention cover the modifications and variations of these embodiments, provided they come within the scope of the appended claims and their equivalents.

[0031] [Embodiment] (1) A nut for treating a bone, comprising: a head and a body extending longitudinally from the head to a free end, the body including a channel extending longitudinally therein from the free end and configured to engage an end of a bone screw; a male thread extending from an outer surface of the body, around the body and along the entire length of the body, an outer contour defined by a radially outermost edge of the male thread, a first portion of the outer contour adjacent the head portion having a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body. (2) The nut of embodiment 1, wherein a diameter of a thread root of a first portion of the outer surface through which the male thread extends is larger than a diameter of a thread root of a second portion of the outer surface extending from the first portion of the outer surface to the free end of the body. (3) The nut of embodiment 2, wherein a length of the first portion of the outer surface is less than a length of the first portion of the outer contour. (4) The nut of embodiment 3, wherein the external thread includes three threaded portions: a first threaded portion corresponding to a portion of the external thread extending along the length of the body along which the second portion of the outer contour extends; a second threaded portion corresponding to a portion of the external thread extending along the length of the body where the first portion of the outer contour and the second portion of the exterior surface overlap; and a third threaded portion of the external thread corresponding to the length of the body along which the first portion of the exterior surface extends. (5) The nut of embodiment 4, wherein a depth of the male thread along the first threaded portion is greater than a depth of the male thread along the second threaded portion, and the depth of the male thread along the second threaded portion is greater than a depth of the male thread along the third threaded portion.

[0032] (6) The nut of embodiment 2, wherein a length of the first portion of the outer contour corresponds to a length of the first portion of the outer surface, and a length of the second portion of the outer contour corresponds to a length of the second portion of the outer surface. (7) The nut of embodiment 6, wherein the male thread includes two threaded portions: a first threaded portion of the male thread corresponding to the second portion of the outer contour and the second portion of the outer surface; and a second threaded portion of the male thread corresponding to the first portion of the outer contour and the first portion of the outer surface. (8) The nut of embodiment 7, wherein a depth of the male thread along the first threaded portion is greater than a depth of the male thread along the second threaded portion. (9) The nut of claim 1, further comprising internal threads extending along an inner surface of the channel for engaging corresponding threads of the bone screw. (10) A system for treating a long bone, comprising: an intramedullary nail insertable through a medullary canal of a bone and extending from a proximal end to a distal end, the intramedullary nail including a blind hole extending through the nail along an axis extending at an angle relative to a longitudinal axis of the nail; a set screw configured to be inserted into the bone and through the set hole, the set screw including a head portion and a shaft extending from the head portion to a free end, the shaft including threads extending therealong; 1. A system comprising: a nut configured to be inserted into bone, the nut including: a head and a body extending from the head to a free end, the body including a channel extending longitudinally inward from the free end and configured to threadingly engage the free end of the set screw; an external thread extending from an outer surface of the body, along an entire length of the body and around the body; and an outer contour of the external thread defined by a radially outermost edge of the external thread, a first portion of the outer contour adjacent the head portion having a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body.

[0033] (11) The system of claim 10, wherein the blind hole extends through a distal portion of the intramedullary nail. (12) The system of claim 10, wherein a thread root diameter of a first portion of the exterior surface through which the male thread extends is greater than a thread root diameter of a second portion of the exterior surface extending from the first portion of the exterior surface to the free end of the body. (13) The system of claim 12, wherein a length of the first portion of the exterior surface is less than a length of the first portion of the outer contour. (14) The system of embodiment 13, wherein the external thread includes three threaded portions: a first threaded portion corresponding to a portion of the external thread extending along a length of the body along which the second portion of the outer contour extends; a second threaded portion corresponding to a portion of the external thread extending along a length of the body where the first portion of the outer contour and the second portion of the exterior surface overlap; and a third threaded portion of the external thread corresponding to a length of the body along which the first portion of the exterior surface extends. (15) The system of embodiment 14, wherein a depth of the male thread along the first threaded portion is greater than a depth of the male thread along the second threaded portion, and the depth of the male thread along the second threaded portion is greater than a depth of the male thread along the third threaded portion.

[0034] (16) The system of claim 12, wherein a length of the first portion of the outer contour corresponds to a length of the first portion of the exterior surface, and a length of the second portion of the outer contour corresponds to a length of the second portion of the exterior surface. (17) The system of embodiment 16, wherein the male thread includes two threaded portions: a first threaded portion of the male thread corresponding to the second portion of the outer contour and the second portion of the outer surface; and a second threaded portion of the male thread corresponding to the first portion of the outer contour and the first portion of the outer surface. (18) The system of embodiment 17, wherein a depth of the male thread along the first threaded portion is greater than a depth of the male thread along the second threaded portion. (19) A method for treating a bone, comprising: inserting an intramedullary nail into the medullary canal of the femur through an insertion point at the distal end of the femur; extending a shaft of a set screw through a set hole extending through a distal portion of the nail along an axis angled relative to a longitudinal axis of the nail, and driving the set screw through a first side of the femur such that a head portion of the set screw contacts a cortex along the first side of the femur; inserting a nut through a second side of the femur opposite the first side of the femur so that a free end of the shaft of the set screw is threadingly received in a channel of the nut, the nut including a head and a body portion extending from the head to a free end, the channel extending longitudinally from the free end into the body, an external thread extending from an outer surface of the body around the body along an entire length of the body, an outer contour of the external thread defined by a radially outermost edge of the external thread, a first portion of the outer contour adjacent the head portion having a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body, such that when the nut is inserted through the bone and engaged with the set screw, the nut rotates to align the channel with the thread of the set screw. 20. The method of claim 19, wherein the nut is fully inserted until the head of the nut contacts the cortex along the second side of the femur, compressing the distal end of the bone.

[0035] (21) The method of claim 20, wherein a root diameter of a first portion of the exterior surface through which the male screw thread extends is greater than a root diameter of a second portion of the exterior surface extending from the first portion of the exterior surface to the free end of the body, thereby providing stability at the cortex when the nut is fully inserted.

Claims

1. A nut for treating a bone, comprising: a head and a body extending longitudinally from the head to a free end, the body including a channel extending longitudinally therein from the free end and configured to engage an end of a bone screw; and an external thread extending from an outer surface of the body, around the body and along the entire length of the body, an outer contour defined by a radially outermost edge of the external thread, a first portion of the outer contour adjacent the head having a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body.

2. 2. The nut of claim 1, wherein a root diameter of a first portion of said outer surface through which said male thread extends is greater than a root diameter of a second portion of said outer surface extending from said first portion of said outer surface to said free end of said body.

3. The nut of claim 2 , wherein a length of the first portion of the exterior surface is less than a length of the first portion of the outer contour.

4. 4. The nut of claim 3, wherein the external thread comprises three threaded portions: a first threaded portion corresponding to a portion of the external thread extending along the length of the body along which the second portion of the outer contour extends; a second threaded portion corresponding to a portion of the external thread extending along the length of the body where the first portion of the outer contour and the second portion of the outer surface overlap; and a third threaded portion of the external thread corresponding to the length of the body along which the first portion of the outer surface extends.

5. 5. The nut of claim 4, wherein a depth of said male thread along said first threaded portion is greater than a depth of said male thread along said second threaded portion, and said depth of said male thread along said second threaded portion is greater than a depth of said male thread along said third threaded portion.

6. 3. The nut of claim 2, wherein a length of the first portion of the outer contour corresponds to a length of the first portion of the outer surface, and a length of the second portion of the outer contour corresponds to a length of the second portion of the outer surface.

7. 7. The nut of claim 6, wherein the male thread includes two threaded portions: a first threaded portion of the male thread that corresponds to the second portion of the outer contour and the second portion of the outer surface, and a second threaded portion of the male thread that corresponds to the first portion of the outer contour and the first portion of the outer surface.

8. 8. The nut of claim 7, wherein a depth of the male threads along the first threaded portion is greater than a depth of the male threads along the second threaded portion.

9. The nut of claim 1 further comprising internal threads extending along an inner surface of the channel for engaging corresponding threads of the bone screw.

10. A system for treating a bone, comprising: an intramedullary nail insertable through a medullary canal of a bone and extending from a proximal end to a distal end, the intramedullary nail including a blind hole extending through the nail along an axis extending at an angle relative to a longitudinal axis of the nail; a set screw configured to be inserted into the bone and through the set hole, the set screw including a head portion and a shaft extending from the head portion to a free end, the shaft including threads extending therealong; 1. A system comprising: a nut configured to be inserted into a bone, the nut including: a head and a body extending from the head to a free end, the body including a channel extending longitudinally inward from the free end and configured to threadingly engage the free end of the set screw; an external thread extending from an outer surface of the body, along an entire length of the body and around the body; and an outer contour of the external thread defined by a radially outermost edge of the external thread, wherein a first portion of the outer contour adjacent the head has a smaller diameter than a second portion of the outer contour extending from the first portion to the free end of the body.

11. The system of claim 10 , wherein the blind hole extends through a distal portion of the nail.

12. 11. The system of claim 10, wherein a root diameter of a first portion of the exterior surface through which the external thread extends is greater than a root diameter of a second portion of the exterior surface extending from the first portion of the exterior surface to the free end of the body.

13. The system of claim 12 , wherein a length of the first portion of the exterior surface is less than a length of the first portion of the outer contour.

14. 14. The system of claim 13, wherein the male thread includes three threaded portions: a first threaded portion corresponding to a portion of the male thread extending along the length of the body along which the second portion of the outer contour extends; a second threaded portion corresponding to a portion of the male thread extending along the length of the body where the first portion of the outer contour and the second portion of the exterior surface overlap; and a third threaded portion of the male thread corresponding to the length of the body along which the first portion of the exterior surface extends.

15. 15. The system of claim 14, wherein a depth of the male thread along the first threaded portion is greater than a depth of the male thread along the second threaded portion, and wherein the depth of the male thread along the second threaded portion is greater than a depth of the male thread along the third threaded portion.

16. 13. The system of claim 12, wherein a length of the first portion of the outer contour corresponds to a length of the first portion of the outer surface, and a length of the second portion of the outer contour corresponds to a length of the second portion of the outer surface.

17. 17. The system of claim 16, wherein the male thread includes two threaded portions: a first threaded portion of the male thread corresponding to the second portion of the outer contour and the second portion of the outer surface, and a second threaded portion of the male thread corresponding to the first portion of the outer contour and the first portion of the outer surface.

18. 20. The system of claim 17, wherein a depth of the male threads along the first threaded portion is greater than a depth of the male threads along the second threaded portion.

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