Self-retaining screws and screwdrivers

Abstract

The bone screw insertion device comprises an outer sleeve extending from a proximal end to a distal end and including a channel extending therethrough, and a drive member extending longitudinally through the channel in the outer sleeve from the proximal end to a distal end configured to engage a drive recess of the bone screw, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends across and covers a proximal portion of the bone screw that engages the drive member, and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the bone screw that engages the drive member.

Description

[Background technology]

[0001] Some fractures of long bones may be treated by placing the bone in a corrective alignment and inserting an intramedullary nail into the medullary canal of the aligned bone. The intramedullary nail may be fixed to the bone via a fixation screw inserted into a fixation hole extending laterally through the intramedullary nail. The fixation screw may include, for example, a headless screw (e.g., a screw having threads along its entire length) that may be inserted such that the screw is flush with the bone. However, in some cases, the headless screw may be inserted too far into the bone, which may interfere with the intramedullary nail, lose its foothold in the near cortex of the bone, and / or protrude too far from the far cortex of the bone. Summary of the Invention [Means for solving the problem]

[0002] The present disclosure also relates to a system for treating bone. The system includes a headless screw and an insertion device. The headless screw includes threads extending from a proximal end to a distal end and extending along an outer surface thereof. The headless screw includes a drive recess extending into its proximal end. The insertion device includes an outer sleeve extending from the proximal end to the distal end and including a channel therethrough and a drive member. The drive member extends longitudinally through the channel of the outer sleeve from the proximal end to the distal end. The proximal end of the drive member extends proximally of the proximal end of the outer sleeve to a distal end configured to engage the drive recess of the headless screw to rotationally drive the headless screw into bone. The outer sleeve is movable relative to the driving member between a first position in which the distal end of the outer sleeve extends across and covers a proximal portion of the headless screw when the headless screw is engaged with the driving member in an operable configuration, and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the headless screw.

[0003] In one embodiment, the headless screw further includes a retention recess extending distally from the drive recess.

[0004] In one embodiment, the insertion device further includes a retaining member extending longitudinally from the proximal end through the channel of the driving member to the distal end configured to engage the retaining recess such that the headless screw is retained on the insertion device during insertion of the headless screw into the bone.

[0005] In one embodiment, the retaining recess includes threads therealong and the distal end of the retaining member is correspondingly threaded, such that rotation of the retaining member about its longitudinal axis relative to the driving member engages the threads of the retaining member with the threads of the retaining recess to retain the headless screw on the insertion device.

[0006] In one embodiment, the proximal end of the retention member includes a knob extending proximally from the proximal end of the impaction member to rotate the retention member relative to the impaction member.

[0007] In one embodiment, the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first and second positions, the locking mechanism including a locking tab biased toward a locked configuration via a biasing element and a push button that compresses the biasing element to move the locking tab toward the unlocked configuration.

[0008] In one embodiment, the driving member includes a first groove extending into an outer surface of the driving member such that when the locking tab is received in the first groove, the outer sleeve is in a first position relative to the driving member, and a second groove extending into the outer surface of the driving member proximal to the first groove such that when the locking tab is received in the second groove, the outer sleeve is in a second position relative to the driving member.

[0009] In one embodiment, the core diameter of the proximal portion of the headless screw is larger than the core diameter along the remainder of the headless screw.

[0010] In one embodiment, the outer sleeve includes a gripping feature extending distally from a distal end thereof, the gripping feature configured to engage bone.

[0011] In one embodiment, the outer sleeve includes threads along its distal end configured to engage corresponding threads along a proximal portion of the headless screw.

[0012] In one embodiment, the outer sleeve includes a proximal portion and a distal portion connected to one another via a frictional interface, the distal portion being rotatable about its longitudinal axis.

[0013] In one embodiment, the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member.

[0014] In one embodiment, the proximal portion of the outer sleeve includes a depth indicator that indicates the depth to which the headless screw has been inserted into the bone. The present disclosure further relates to a bone screw insertion device. The device includes an outer sleeve extending from a proximal end to a distal end and including a channel therethrough and a drive member. The drive member extends longitudinally through the channel of the outer sleeve from the proximal end to a distal end configured to engage a drive recess of the bone screw. The outer sleeve is movable relative to the drive member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of the bone screw engaged with the drive member and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the bone screw engaged with the drive member.

[0015] In one embodiment, the system further includes a retention member extending longitudinally through the channel of the drive member from the proximal end to the distal end, the retention member configured to releasably engage with the retention recess of the bone screw.

[0016] In one embodiment, the distal end of the retention member is threaded to engage corresponding threads in the retention recess.

[0017] In one embodiment, the proximal end of the retention member includes a knob extending proximally from the proximal end of the impaction member to rotate the retention member relative to the impaction member.

[0018] In one embodiment, the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first and second positions, the locking mechanism including a locking tab biased toward a locked configuration via a biasing element and a push button that compresses the biasing element to move the locking tab toward the unlocked configuration.

[0019] In one embodiment, the driving member includes a first groove extending into an outer surface of the driving member such that when the locking tab is received in the first groove, the outer sleeve is in a first position relative to the driving member, and a second groove extending into the outer surface of the driving member proximal to the first groove such that when the locking tab is received in the second groove, the outer sleeve is in a second position relative to the driving member.

[0020] In one embodiment, the outer sleeve includes a gripping feature extending distally from a distal end thereof, the gripping feature configured to engage bone.

[0021] In one embodiment, the outer sleeve includes threads along an inner surface of a distal portion thereof configured to engage corresponding threads along a proximal portion of a headless screw received within the outer sleeve.

[0022] In one embodiment, the outer sleeve includes a proximal portion and a distal portion connected to one another via a frictional interface, the distal portion of the outer sleeve being rotatable about its longitudinal axis relative to the proximal portion of the outer sleeve.

[0023] In one embodiment, the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member.

[0024] In one embodiment, the proximal portion of the outer sleeve includes a depth indicator that indicates how deep the headless screw engaged with the driving member has been inserted into the bone. The present disclosure further provides a method for assembling the headless bone screw with the insertion device by inserting a distal end of the driving member of the insertion device into a correspondingly sized and shaped driving recess of the headless screw, inserting the headless bone screw with the insertion device in a first position adjacent the target region of the bone with the outer sleeve mounted over the driving member such that the distal end of the outer sleeve extends over and covers the proximal portion of the headless screw, and inserting the headless bone screw into the bone adjacent the target region of the bone with the insertion device in a first position with the outer sleeve mounted over the driving member such that the distal end of the outer sleeve extends over and covers the proximal portion of the headless screw. the headless bone screw is driven into the bone by rotating the driving member until the headless bone screw abuts the proximal cortex of the bone; drawing the outer sleeve proximally relative to the driving member from a first position to a second position in which a distal surface of the outer sleeve is longitudinally aligned with a proximal surface of the headless bone screw; and driving the headless bone screw further distally into the bone until a distal end of the outer sleeve contacts the proximal cortex of the bone providing tactile feedback to a user that the headless screw is flush with the bone.

[0025] In one embodiment, the method further includes retaining the headless bone screw on the insertion device by threadingly engaging a threaded distal portion of a retention member with a correspondingly threaded retention recess of the headless bone screw, the retention member extending longitudinally through the drive member.

[0026] In one embodiment, drawing the outer sleeve proximally relative to the driving member from a first position to a second position includes moving a locking mechanism of the outer sleeve from a locked configuration to an unlocked configuration such that a locking tab of the locking mechanism is movable from a first groove along the driving member to a second groove along the driving member.

[0027] In one embodiment, the locking tab is biased towards the locked configuration via a bias.

[0028] In one embodiment, moving the locking mechanism from the locked configuration to the unlocked configuration includes depressing a push button to compress a biasing element such that the locking tab disengages from the first groove and the outer sleeve is movable proximally along the drive member to return to the biased configuration such that the locking tab engages the second groove in the second configuration.

[0029] In one embodiment, the method further includes removing the insertion device from the implanted headless bone screw by disengaging a threaded distal portion of the retention member from the retention recess and pulling the insertion device proximally out of the retention recess.

[0030] In one embodiment, the method further comprises retaining the headless bone screw on the insertion device by threading a distal end of the outer sleeve with a proximal portion of the headless screw.

[0031] In one embodiment, the outer sleeve includes a proximal portion and a distal portion connected via a frictional interface, and the distal portion is rotatable about its longitudinal axis such that the distal portion correspondingly rotates with the drive member relative to the proximal portion of the outer sleeve.

[0032] In one embodiment, the frictional interface provides feedback that indicates that the proximal portion of the headless screw is driving into the bone when the distal end abuts the nearby cortex of the bone. [Brief description of the drawings]

[0033] [Figure 1] 1 shows a longitudinal cross-sectional view of a system according to an exemplary embodiment of the present disclosure. [Diagram 2] 2 shows an enlarged view of a distal portion of an insertion device and a proximal portion of a headless screw according to the system described in FIG. 1. [Diagram 3] FIG. 2 shows a longitudinal section of a headless screw according to the system of FIG. 1 . [Figure 4] 2 shows a longitudinal cross-sectional view of a driving member of an insertion device according to the system of FIG. 1; [Diagram 5] FIG. 2 shows a side view of a retention member of an insertion device according to the system of FIG. [Figure 6] FIG. 2 shows a longitudinal cross-sectional view of the outer sleeve of the insertion device according to the system of FIG. 1. [Figure 7] FIG. 2 shows an enlarged cross-sectional view of a locking mechanism of the outer sleeve of the insertion device according to the system of FIG. [Figure 8] 2 shows a longitudinal cross-sectional view of a portion of the system of FIG. 1 with a distal portion of a headless screw inserted into bone. [Figure 9] 2 illustrates a longitudinal cross-sectional view of a portion of the system of FIG. 1 with the outer sleeve moved from a first position to a second position. [Figure 10] 2 illustrates a longitudinal cross-sectional view of a portion of the system of FIG. 1 with a headless screw inserted into bone in a desired configuration. [Figure 11] 1 shows a longitudinal cross-sectional view of a portion of a system according to another exemplary embodiment of the present disclosure in a first position. [Figure 12] 12 shows a longitudinal cross-sectional view of the system of FIG. 11 in a second position. [Figure 13] 12 shows a side view of an outer sleeve according to the system of FIG. 11. [Figure 14] FIG. 2 shows a partial longitudinal side view of a portion of a system according to another exemplary embodiment of the present disclosure in a first position. [Figure 15] 15 shows a partial longitudinal cross-sectional view of a portion of the system of FIG. 14 in a second position. [Figure 16]15 shows a partial longitudinal cross-section of an outer sleeve according to the system of FIG. 14. [Figure 17] 15 shows a side view of the driving member according to the system of FIG. 14. [Figure 18] FIG. 13 shows a perspective view of a system according to yet another exemplary embodiment of the present disclosure. [Figure 19] 19 shows a plan view from the proximal end of the outer sleeve according to the system of FIG. 18. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The present disclosure may be further understood with reference to the following description and the accompanying drawings, in which like elements are referred to with the same reference numerals. The present embodiments relate to the treatment of bones, and in particular fractures of long bones, such as the femur, tibia, humerus, etc., where once the bone is placed in a corrective alignment, an intramedullary nail is inserted through the medullary canal of the bone and secured thereto via a fixation screw. In particular, a headless screw, including threads along its entire length, may be inserted through a fixation opening extending laterally through the intramedullary nail, such that the headless screw is flush with the bone.

[0035] However, in some cases, the headless screw may be inserted too far into the bone, causing the screw to interfere with the intramedullary nail, lose foothold in the nearby cortex, and / or protrude too far from the far cortex. The exemplary embodiment describes a system including an insertion device for a headless screw that provides tactile feedback to the user when the screw is flush with the bone and prevents the screw from being inserted too far into the bone. It will be understood that the terms proximal and distal as used herein refer to directions toward (proximal) and away (distal) the user of the system described herein. It will be further understood that although the embodiments described herein are directed to a long bone intramedullary nail system, the insertion device and headless screw of the present disclosure may also be utilized in other bone fixation systems where the headless screw is to be inserted flush with the bone.

[0036] As shown in FIGS. 1-10 , a system 100 for treating a bone includes an insertion device 102 for inserting a headless screw 104 flush with the bone 10. The headless screw 104 extends longitudinally from a proximal end 106 to a distal end 108 and includes threads 110 along its entire length. The insertion device 102 may include a driving member 112 for driving the headless screw 104 into the bone 10, a retaining member 114 for engaging and retaining the headless screw 104 when the headless screw 104 is being driven into the bone 10, and an outer sleeve 116 for providing tactile feedback to a user (e.g., a surgeon) when the proximal end 106 of the headless screw 104 is flush with the bone. Each of the driving member 112, the retaining member 114, and the outer sleeve 116 is coupled to the handle member 124 such that the driving member 112, the retaining member 114, and the outer sleeve 116 are movable relative to one another to insert the headless screw 104 into bone, as described in further detail below.

[0037] As shown in FIG. 3 , the headless screw 104 extends along a longitudinal axis from a proximal end 106 to a distal end 108. The threads 110 extend along the entire length of the headless screw 104 such that the headless screw 104 is insertable into the bone 10 such that the proximal end 106 is flush with the nearby cortex of the bone 10. In some embodiments, the proximal portion 126 of the headless screw 104 may have a larger core diameter and / or a larger threaded diameter than the remaining portion 128 of the headless screw 104. The larger core diameter and outer diameter along the proximal portion 126 increases the insertion torque as the headless screw 104 is threaded (e.g., turned) into the bone and provides additional tactile feedback to the user that the proximal portion 126 of the headless screw 104 is engaging the bone 10. It will be understood by those skilled in the art that the core diameter of the proximal portion 126 may be defined via an outer surface of the proximal portion 126 along which the threads do not extend and / or via the radially inner ends of the threads extending along the proximal portion 126.

[0038] The proximal end 106 of the headless screw 104 includes a drive recess 118 that extends distally into the proximal end 106 of the headless screw 104 along the longitudinal axis of the headless screw 104. As shown in FIG. 3 , the drive recess 118 is configured to receive a correspondingly sized and shaped engagement portion 130 of the drive member 112 of the insertion device 102. The drive recess 118 is configured such that when the engagement portion 130 of the drive member 112 is received therein and rotated about its longitudinal axis, a torsional force is applied to the headless screw 104 to drive the headless screw 104 into the bone 10.

[0039] In one embodiment, the drive recess 118 includes a substantially circular central portion and a plurality of notches formed along a surface of the substantially circular central portion such that the notches extend radially outward from the longitudinal axis of the headless screw 104. Those skilled in the art will appreciate that the drive recess 118 can include any number of notches in any of a variety of configurations, so long as the notches are sized and shaped to engage corresponding portions of the engagement portion 130 of the drive member 112. Those skilled in the art will also appreciate that the drive recess 118 can have any of a variety of configurations, so long as the drive recess 118 is engageable with the drive member 112.

[0040] For example, in another embodiment, the drive recess 118 may have a hexagonal cross-section. In another example, the drive recess 118 may be star-shaped. However, one of ordinary skill in the art will understand that the drive recess 118 may have any of a variety of shapes so long as a torsional force can be applied to the headless screw 104.

[0041] The proximal end 106 of the headless screw 104 also includes a retaining recess 120 extending distally from the drive recess 118. The retaining recess 120 has a smaller cross-sectional area than the drive recess 118 and is configured to receive a threaded retaining portion 133 at the distal end 132 of the retaining member 114. In one embodiment, the retaining recess 120 may include threads 134 along an inner surface 136 thereof for engaging a correspondingly threaded engagement portion 133 of the retaining member 114. As described in further detail below, the engagement between the retaining member 114 and the retaining recess 120 helps to retain (e.g., maintain) the headless screw 104 in the insertion device 102 while the headless screw 104 is being driven into the bone 10.

[0042] As described above, the insertion device 102 includes a drive member 112, a retention member 114, and an outer sleeve 116. As shown in FIG. 4, the drive member 112 extends longitudinally from a proximal end 138 to an engagement portion 130 at its distal end 140 and includes a channel 142 extending longitudinally therethrough. The proximal end 138 is connected to a handle member 124 such that as the handle member 124 rotates about a longitudinal axis of the insertion device 102, the drive member 112 correspondingly rotates to drive the headless screw 104 engaged in the engagement portion 130 into the bone 10, as described in further detail below. Although the drive member 112 is shown and described as including a handle member 124 at the proximal end 138, in alternative embodiments, the proximal end 138 may be configured such that it may be coupled to one of the handle member 124 and a power driver such that the headless screw 104 may be manually driven or power driven into the bone, as desired.

[0043] 5, the retention member 114 extends longitudinally from a proximal end 144 to a distal end 132 and is sized and shaped to be received within a channel 142 of the drive member 112. In one embodiment, as described above, the distal end 132 includes a threaded retention portion 133 configured to engage corresponding threads 134 of the retention recess 120 of the headless screw 104. The proximal end 144 of the retention element 114 may be attached to a knob 146 that extends proximally of a proximal end 148 of the handle member 124, for example, when the retention member 114 is received within the channel 142.

[0044] The retaining element 114 is longitudinally movable relative to the driving member 112 between a non-retaining configuration and a retaining configuration. In the non-retaining configuration, the distal end 132 of the retaining member 114 is flush with or proximal to the distal end 140 of the driving member 112 such that the distal end 132 of the retaining member 114 does not extend distally beyond the distal end 140 of the driving member 112. Thus, even when the driving member 112 engages the driving recess 118 of the headless screw, the distal end 132 of the retaining member 114 does not engage the retaining recess 120 when in the non-retaining configuration. However, the retaining member 114 may be moved distally relative to the driving member 112 toward the retaining configuration such that the distal end 132 of the retaining member 114 extends distally beyond the distal end 140 of the driving member 112 to engage the retaining recess 120 of the headless screw 104.

[0045] Where distal end 132 includes a threaded retaining portion 133, retaining member 114 can be rotated about its longitudinal axis in a first direction to engage threaded engagement portion 133 with corresponding threads 134 of retaining recess 120. Retaining member 114 can be rotated, for example, via knob 146. To move retaining member 114 from the retaining configuration to the non-retaining configuration, retaining member 114 is rotated about its longitudinal axis in a second direction opposite the first direction until threaded retaining portion 133 is unscrewed from retaining recess 120.

[0046] As shown in FIG. 6 , the outer sleeve 116 extends longitudinally from a proximal end 150 to a distal end 122 and includes a channel 152 extending longitudinally therethrough. The outer sleeve 116 is slidably mounted over the driving member 112 such that the outer sleeve 116 is longitudinally movable relative to the driving member 112 between a first position and a second position. In the first position, the distal end 122 of the outer sleeve 116 extends distally beyond the distal end 140 of the driving element 112 such that the distal end 122 extends across and covers the proximal portion 126 of the headless screw 104 when the driving recess 118 of the headless screw 104 is engaged with the engagement portion 130 of the driving member 112. In the second position, the outer sleeve 116 is drawn proximally relative to the driving member 112 such that the distal end 122 is aligned with the proximal end 106 of the headless screw 104. Specifically, the distal surface 123 of the distal end 122 is longitudinally aligned with the proximal surface 107 of the proximal end 106 of the headless screw 104 .

[0047] The headless screw 104 is initially inserted into the body with the outer sleeve 116 in a first position until it reaches a target area of ​​the bone 10 where the headless screw 104 is to be driven. The headless screw 104 is inserted into the body with the proximal portion 126 covered to protect the surrounding tissue from the threads 110 extending along the proximal portion 126 which act as cutting flutes during implantation of the headless screw 104. Once the target area is reached, the outer sleeve 116 is retracted to a second position and the headless screw 104 is driven into the bone 10 until the distal face 123 of the outer sleeve 116 abuts the nearby cortex of the bone 10. The distance the outer sleeve 116 is retracted from the first position to the second position corresponds to the length of the proximal portion 126 of the headless screw 104. Thus, as the headless screw 104 is driven into the bone 10 and the distal face 123 abuts the nearby cortex of the bone 10, the abutment between the outer sleeve 116 and the bone 10 provides tactile feedback to the user indicating that the proximal end 106 is flush with the bone 10.

[0048] The outer sleeve 116 in this embodiment is movable between a first position and a second position via a locking mechanism 154 including a locking tab 156 biased towards a locked configuration via a biasing element 158, as shown in FIG. 7, although one skilled in the art would understand that any mechanism that allows for the desired relative movement may be used. In the locked configuration, the locking tab 156 extends into the channel 152 of the outer sleeve 116 to engage one of a first groove 160 and a second groove 162 along the outer surface of the driving member 112. When the locking tab 156 is received in the first groove 160, the outer sleeve 116 is in a first position relative to the driving member 112. When the locking tab 156 is in the second groove 162, which is positioned proximal to the first groove 160, the outer sleeve 116 is in a second position relative to the driving member 112.

[0049] The locking tab 156 may be moved between the first groove 160 and the second groove 162, for example, by a push button 164 which, when pressed, moves the locking tab 156 out of the channel 152 and out of engagement with one of the grooves 160, 162 towards an unlocked configuration. Thus, when it is desired to move the outer sleeve 116 between the first and second positions, a user can simply press the push button 164 and slide the outer sleeve 116 longitudinally proximally or distally relative to the drive member 112. When the locking tab 156 is adjacent the other of the first groove 160 and the second groove 162, the locking tab 156 returns to its biased locked configuration and snap-engages the other of the first groove 160 and the second groove 162.

[0050] Although the locking mechanism 154 is shown positioned at the proximal end 150 of the outer sleeve 116, it will be understood by those skilled in the art that the locking mechanism 154 may be positioned along the length of the outer sleeve 116, so long as the locking mechanism 154 is accessible to a user during the implantation procedure and so long as the locking tabs 156 are received within the first groove 160 and the second groove 162 to allow the outer sleeve 116 to be moved relative to the driving member 112 between the first and second positions.

[0051] Those skilled in the art will also appreciate that, if desired, a user can depress button 164 to slide outer sleeve 116 proximally relative to drive member 112 to remove outer sleeve 116 from insertion device 102. It may be desirable to remove outer sleeve 116 if it is desired to implant headless screw 104 distally beyond the proximal cortex of bone 10. Those skilled in the art will also appreciate that outer sleeve 116 can be removed to drive a conventionally shaped bone screw including a head. The head of a conventional bone screw may include both a drive recess and a retaining recess substantially similar to drive recess 118 and retaining recess 120 described above.

[0052] According to an exemplary method of the present disclosure, the insertion device 102 is coupled to the headless screw 104 by inserting an engagement portion 130 of the driving member 112 into the driving recess 118 at the proximal end 106 of the headless screw 104 and engaging a distal end 132 of the retaining member 114 with the retaining recess 120 of the headless screw 104. In one embodiment, upon inserting the engagement portion 130 of the driving member 112 into the driving recess 118 of the headless screw 104, a threaded portion 133 of the retaining member 114 is engaged with the retaining recess 120 by rotating the retaining member about its longitudinal axis in a first direction and distally along the longitudinal axis relative to the driving member 112 and headless screw 104 such that the threaded retaining portion 133 threadably engages the threads 134 of the retaining recess 120.

[0053] The headless screw 104 is initially driven into the bone 10 with the outer sleeve 116 in a first position, i.e., with the distal end 122 extending over and covering the proximal portion 126 of the headless screw 104. The headless screw 104 is driven into the bone 10 by rotating the driving member 112 about its longitudinal axis until the distal end 122 of the outer sleeve 122 contacts the nearby cortex of the bone 10, as shown in FIG. 8 , providing the user with a first tactile feedback indicating that the distal portion 128 of the headless screw 104 has been inserted into the bone 10 to a desired initial depth (e.g., until the distal end of the proximal portion of the screw 104 is adjacent the nearby cortex of the bone).

[0054] The user then moves the outer sleeve 116 proximally relative to the driving member 112 to a second position such that the distal surface 123 of the outer sleeve 116 is aligned with the proximal surface 107 of the headless screw 104, as shown in FIG. 9 . As described above, the outer sleeve 116 may be locked in the second position relative to the driving member 112 via the locking mechanism 154. In one embodiment, the user may know that the distal portion 128 of the screw 104 is fully inserted into the bone after a predetermined number of full rotations of the headless screw 104 are completed. For example, the user may know that two full rotations of the headless screw 104 will result in the distal portion 128 of the headless screw 104 being fully inserted into the bone 10. That is, the screw 104 is inserted to a point where the distal end of the proximal portion 126 of the screw 104 is adjacent the proximal cortex of the bone 10.

[0055] Once the outer sleeve 116 is secured in the second position, the headless screw 104 is driven further into the bone 10 until the distal face 123 again abuts the nearby cortex, as shown in Fig. 10, indicating to the user via the second tactile feedback that the headless screw 104 has been inserted into the bone 10 such that the proximal end 106 is flush with the nearby cortex. If a predetermined number of turns to complete insertion of the headless screw 104 is known, the second tactile feedback can provide confirmation to the user that the proximal face 107 of the headless screw 104 is flush with the surface of the nearby cortex.

[0056] As described above, once the headless screw 104 is fully inserted into the bone 10, the insertion device 102 is disengaged from the headless screw 104 and removed from the body, optionally leaving the headless screw 104 embedded within the bone 10. Specifically, the retention member 114 is disengaged from the headless screw 104 by rotating the retention member 114 about its longitudinal axis in a second direction until the threaded retention portion 133 is fully unthreaded from the retention recess 120. The driving member 112 may then be disengaged from the driving recess 118 by simply pulling the insertion device 102 proximally away from the headless screw 104.

[0057] A system 200 for inserting a headless screw 204 into a bone 20 is shown in Figures 11-13. As described above, the system 200 may, for example, place a proximal end 206 of the headless screw 204 flush with the nearby cortex of the bone 20 to facilitate insertion of the screw 204 into a desired location. The system 200 may be substantially similar to the system 100, which includes an insertion device 202 including an outer sleeve 216 and a drive member 212 longitudinally slidable therein. Although not shown, one skilled in the art will appreciate that the insertion device 202 may also include a retaining member substantially similar to the retaining member 114 for retaining the headless screw 204 during insertion into the bone. Similar to the insertion device 102, the outer sleeve 216 is longitudinally movable relative to the driving member 212 between a first, initial position, as shown in FIG. 11, and a second position, as shown in FIG. 12, that indicates to a user that the headless screw 204 has been inserted into the bone 20 in a desired position, e.g., with the proximal end 206 flush with the bone 20.

[0058] However, in this embodiment, in the first position, the outer sleeve 216 extends over and covers the entire length of the headless screw 204 such that the position of the outer sleeve 216 relative to the driving member 212 in the first position is based on the selected length of the headless screw 204. Thus, prior to inserting the headless screw 204 into the bone, a user can select a headless bone screw 204 having a desired length and adjust the outer sleeve 216 to a desired first position that corresponds to the length of the selected headless bone screw 204, as described in more detail below.

[0059] The headless bone screw 204 may be substantially similar to the bone screw 104, extending longitudinally from a proximal end 206 to a distal end 208 and including threads extending along its entire length. The headless screw 204 also includes a drive recess 218 extending into the proximal end 206 and sized, shaped and configured to engage a correspondingly sized and shaped engagement portion 230 of the drive member 212. The headless screw 204 may also include a retaining recess (not shown) substantially similar to the retaining recess of the headless screw 104.

[0060] As described above, the insertion device 202 includes an outer sleeve 216 and a drive member 212 slidably housed therein. The outer sleeve 216 may be substantially similar to the outer sleeve 116, extending from a proximal end to a distal end 222 and including a channel 252 extending therethrough. However, the channel 252 includes a shoulder 253 positioned along a distal portion thereof, which, as described in further detail below, functions as a stop to prevent further distal movement of the drive member 212 when the drive member 212 is in a second position relative to the outer sleeve 216. The distal face 223 of the outer sleeve 216 may also include a plurality of teeth 266 projecting therefrom and configured to engage the bone 20 when the distal face 223 is pressed against it. The teeth 266 hold the insertion device 202 in a target position along the bone 20 so that the headless screw 204 may be driven therein.

[0061] The drive member 212 may be substantially similar to the drive member 112 extending from a proximal end to a distal end 240 that includes an engagement portion 230 sized, shaped, and configured to engage a drive recess 218 of the headless screw 204. However, in this embodiment, the drive member 212 further includes a plurality of grooves 260 extending longitudinally along its distal portion. Each of the grooves 260 extends around the circumference of the drive member and is configured to receive a locking tab 256 of a locking mechanism 254 to secure the outer sleeve 216 and the drive member 212 in a desired first position relative to one another, as described in further detail below. Each groove 260 defines a selected length of the headless screw 204. For example, a first groove 260a may represent a 30mm screw, a second immediately proximal groove 260b may represent a 35mm, a third groove 260c immediately proximal to the second groove 260b may represent a 40mm screw, and so on.

[0062] In this embodiment, the locking mechanism 254 can include a sliding push button 264 slidable along the length of the outer sleeve 216 and relative to the driving member 212, with a locking tab 256 thereof engaging a desired one of the grooves 260 of the driving member 212. Similar to the locking tab 156, the locking tab 256 can be biased toward a locked configuration via a biasing element, such as a spring. Thus, when the push button 264 is pressed, the biasing element is compressed to disengage the locking tab 256 toward an unlocked configuration, causing the push button 264 to also slide along the length of the outer sleeve 216, such that the locking tab 256 can be moved to a desired position along therewith corresponding to a desired one of the grooves 260, as shown in FIG. 13 . The push button 264 can then be released such that the locking tab 256 returns to its biased configuration and engages the desired one of the grooves 260 corresponding to a selected length of the headless screw 204. In this embodiment, the outer sleeve 216 includes markings 268 along it to indicate a position that corresponds to the desired length of the headless screw 204 .

[0063] Once the length of the headless screw 204 has been selected and the push button 264 has been adjusted to secure the outer sleeve 216 and the diving member 212 in a corresponding first position, the headless screw 205 may be inserted into the bone. The engagement portion 230 of the driving member 212 is inserted into the driving recess 218 such that in the first position, the outer sleeve 216 extends over and covers the entire length of the headless screw 204. In one embodiment, the distal tip of the headless screw 204 and the distal surface 223 of the outer sleeve 216 are longitudinally aligned in the first position. The insertion device 202 is then pressed distally against the target portion of the bone 20 such that the teeth 266 along the distal surface 223 of the outer sleeve 216 engage the bone 20.

[0064] Once in the target position, the drive member 212 is rotated about its longitudinal axis relative to the outer sleeve 216 and moved distally relative thereto such that the headless screw 204 is driven from the outer sleeve 216 and into the bone 20. The headless screw 204 may be driven into the bone 20 until a portion of the locking mechanism 254 abuts the shoulder 253, indicating to the user that the drive member 212 and the outer sleeve 216 are in a second position relative to one another, i.e., the headless screw 204 is in a desired configuration within the bone 20 and the proximal face 207 of the headless screw 204 is flush with the nearby cortex of the bone.

[0065] As shown in FIGS. 14-17, the system 300 may be substantially similar to the systems 100, 200 described above and includes an insertion device 302 for inserting a headless screw 304 into a desired location within a bone 30 (e.g., a proximal face 307 of the headless screw 304 is substantially flush with a surface of the proximal cortex of the bone 30). As with the systems described above, the insertion device 302 includes an outer sleeve 316 in which a drive member 312 is longitudinally movable between a first initial position, as shown in FIG. 14, and a second position, as shown in FIG. 15, that indicates to a user that the headless screw 304 is in a desired location within the bone. As with the outer sleeve 116, when a distal face of the outer sleeve 316 abuts the proximal cortex of the bone 30, abutment between the outer sleeve 316 and the bone 30 provides tactile feedback to a user indicating that the headless screw 304 has been inserted into the desired location within the bone 30. In addition to tactile feedback indicating the desired position of the headless screw 304, the insertion device 302 also provides audible feedback, as described in more detail below.

[0066] The headless screw 304 is substantially similar to the headless screw 104, as described above with respect to the system 100. As shown in FIG. 16 , the outer sleeve 316 is also substantially similar to the outer sleeve 116, extending from a proximal end 350 to a distal end 322 and including a channel 352 extending therethrough. The outer sleeve 116 also includes a locking mechanism 354 at the proximal end 350 including a locking tab 356 biased towards a locked configuration via a biasing element 358. As shown in FIG. 17 , the drive member 312 is substantially similar to the drive member 112, configured to extend longitudinally through the channel 352 of the outer sleeve 316 and is longitudinally and rotationally movable relative thereto to drive the headless screw 304 into the bone 30 via an engagement portion 330 at its distal end 340. In a further configuration, the drive member 312 may have a channel extending therethrough configured to accommodate a retention member (not shown), the retention member being substantially similar to the retention member 114 shown in FIG. 5.

[0067] Similar to the insertion device 102, the locking tab 356 of the locking mechanism 354 engages with a first groove 360 ​​of the drive member 312 in a first position and a second groove 362 of the drive member 312 in a second position. However, in this embodiment, the insertion device 302 is moved from the first position ( FIG. 14 ) toward the second position ( FIG. 15 ) as the headless screw 304 is driven into the bone toward the desired configuration. Specifically, the locking tab 356 is moved from the first groove 360 ​​toward the second groove 362 as the headless screw 304 is driven into the bone toward the desired location.

[0068] In this embodiment, the ramp 370 extends between the first groove 360 ​​and the second groove 362. The ramp 370 increases in diameter from a distal end 372 connected to the first groove 360 ​​to a proximal end 374 adjacent the second groove 362. The distal end 372 has substantially the same diameter as the first groove 360, while the proximal end 374 has a larger diameter than the second groove 362. Thus, when the driving member 312 is moved distally relative to the outer sleeve 316 to drive the headless screw 304 into bone, the locking tab 356 slides along the ramp 370 out of the first groove 360 ​​and the biasing element of the locking mechanism 354 compresses to be received within the second groove 362 as the locking tab 356 slides along the ramp 370 until the locking tab 356 is moved proximally beyond the proximal end 374 of the ramp 370.

[0069] Once the locking tab 356 moves proximally beyond the proximal end 374 of the ramp 370, the locking tab 356 returns to the biased configuration such that the locking tab "clicks" into the second groove 362, providing audible feedback to the user. The audible feedback indicates to the user that the headless screw 304 has been fully inserted into the bone in the desired configuration, such that the proximal face 307 of the headless screw 304 is substantially flush with the surface of the bone 30.

[0070] As shown in FIGS. 18-19, a system 400 according to another exemplary embodiment may be substantially similar to the systems 100-300 described above and includes an insertion device 402 for driving a headless screw 404 into a desired location in a bone. The insertion device 402 includes a drive member 412 that extends through an outer sleeve 416. However, rather than including a separate retaining member, the outer sleeve 416 in this embodiment includes threads 453 along a distal end of a channel 452 extending through the outer sleeve for engaging threads 410 along a proximal portion 426 of the headless screw 404 to retain the screw 404 while it is being driven into the bone. Additionally, the outer sleeve 416 includes a depth indicator 476 for indicating the insertion depth of the proximal portion 426 of the headless screw 404 so that a user may drive the headless screw 404 into a desired location in a bone, for example, so that a proximal face 407 of the screw 404 is flush with the bone.

[0071] Similar to outer sleeves 116-316, outer sleeve 416 extends from a proximal end 450 to a distal end 422 and includes a channel 452 extending therethrough. However, outer sleeve 416 further includes a proximal portion 478 and a distal portion 480 having a frictional interface 481, such as, for example, a ratchet mechanism. Channel 452 penetrates both proximal portion 478 and distal portion 480. As described above, channel 452 includes a distal threaded portion 453 for engaging and holding headless screw 404 during insertion of screw 404 into bone. Similar to outer sleeve 216, distal surface 423 of outer sleeve 416 includes teeth 466 or other gripping features configured to grip or engage bone when outer sleeve 416 is pressed distally thereagainst.

[0072] 19 , the proximal portion 478 includes a depth indicator 476 along a proximal face 477 such that the depth indicator 476 is visible to a user of the insertion device 402. The depth indicator 476 indicates to a user the insertion depth of the proximal portion 426 of the headless screw 404. It will be understood by one of ordinary skill in the art that the length of the proximal portion 426 of the headless screw 404 is known to the user of the device 402.

[0073] For example, in one embodiment, the proximal portion 426 of the headless screw 404 may have a length of approximately 6.25 mm such that a user knows the headless screw 404 is fully embedded when the depth indicator indicates the corresponding insertion depth. As described in further detail below, the proximal portion 478 also includes a mating feature 482 that is sized and shaped to mate with a corresponding mating feature 484 of the driving member 412 such that when the mating features 482, 484 engage one another, the proximal portion 478 and the driving member 412 are keyed together such that the proximal portion 478 and the driving member 412 cannot rotate relative to one another.

[0074] The drive member 412 is substantially similar to the drive members described above, including an engagement portion 430 at its distal end 440 for engaging a drive recess 418 of the headless screw 404. The drive member 412 extends through a channel 452 of the outer sleeve 416 and includes a mating feature 484 such that when the mating feature 484 engages a mating feature 482 of a proximal portion 478 of the outer sleeve 416, the proximal portion 478 and the drive member 412 are keyed together. In one embodiment, the mating feature 482 of the proximal portion 478 may include a longitudinal groove extending along a surface of a portion of the channel extending therethrough, and the corresponding mating feature 484 of the drive shaft 412 includes a correspondingly sized and shaped protrusion extending outwardly from the drive shaft 412 and received within and slidable along the longitudinal groove of the mating feature 482. It will be understood by those skilled in the art that the mating features 482, 484 can have any of a variety of configurations, so long as the mating features 482, 484 key the driving member 412 and the proximal portion 478 relative to one another to prevent rotation of the driving member 412 relative to the proximal portion 478 while allowing distal movement of the driving member 412 relative to the proximal portion 478.

[0075] At the user, the headless screw 404 is assembled with the insertion device 402 prior to insertion. Specifically, the outer sleeve 416 is threaded over the proximal portion 426 of the headless screw 404, and the engagement portion 430 of the drive member 412 is inserted into a correspondingly sized and shaped drive recess 418 of the headless screw 404. The headless screw 404 is then inserted into the body and positioned over a target area of ​​the bone. The drive member 412 is then rotated to drive the headless screw 404 into the bone. Because the drive member 412 is keyed to the proximal portion 478 of the outer sleeve 416, rotation of the drive member 412 also causes rotation of the proximal portion 478. Additionally, because the proximal and distal portions 478, 480 of the outer sleeve 416 have a frictional interface, the distal portion 480 is also correspondingly rotated along with the impaction member 412 until the outer sleeve 416 is pressed distally against the bone surface.

[0076] When the headless screw 404 is driven far enough into the bone so that the outer sleeve 416 is pressed against the bone, the teeth 466 along the distal face 423 of the bone prevent further rotation of the distal portion 480 of the outer sleeve 416. Thus, as the user continues to rotate the driving member 412 to drive the headless screw 404 further into the bone, a ratchet mechanism between the proximal portion 478 and the distal portion 480 engages, providing audible feedback to the user as the proximal portion 478 rotates relative to the distal portion 480. The audible feedback indicates that countersinking has begun to drive the proximal portion 426 of the headless screw 404 into the bone.

[0077] In one embodiment, when the distal surface 423 of the outer sleeve 416 first contacts the bone, the depth indicator 476 may indicate 0 mm of insertion. However, as the user continues to rotate the drive member 412, the proximal portion 478 of the outer sleeve 416 also rotates relative to the distal portion 480 providing audible feedback while the depth indicator 476 indicates how far the screw 404 has traveled. As the headless screw 404 is driven further into the bone, the headless screw 404 is also unthreaded from the threaded distal portion 453 of the outer sleeve 416. Once the depth indicator 476 indicates that the desired insertion depth has been achieved, i.e., the desired length of the proximal portion 426 of the headless screw 404 has been inserted into the bone, the user may remove the insertion device 402 from the body with the headless screw 404 remaining embedded in the bone at the desired location.

[0078] It will be apparent to those skilled in the art that modifications and variations can be made to the structure and method of the present invention without departing from the spirit and scope of the present invention. Thus, it is intended that the present invention cover the modifications and variations of the present invention provided they come within the scope of the appended claims and their equivalents.

[0079] [Embodiment] (1) A system for treating a bone, comprising: a headless screw including threads extending from a proximal end to a distal end and extending along an outer surface thereof, said headless screw including a drive recess extending into said proximal end thereof; 11. An insertion device comprising: an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; and a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end, the proximal end of the drive member extending proximally of the proximal end of the outer sleeve to a distal end configured to engage the drive recess of the headless screw for rotationally driving the headless screw into bone, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of the headless screw when the headless screw is engaged in an operative configuration with the drive member, and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the headless screw. (2) The system of embodiment 1, wherein the headless screw further includes a retention recess extending distally from the driving recess. (3) The system of embodiment 2, wherein the insertion device further includes a retaining member extending longitudinally through the channel of the driving member from a proximal end to a distal end configured to engage the retaining recess such that the headless screw is retained on the insertion device during insertion of the headless screw into the bone. (4) The system of embodiment 3, wherein the retaining recess includes threads therealong, the distal end of the retaining member is correspondingly threaded, and rotation of the retaining member about its longitudinal axis relative to the driving member causes the threads of the retaining member to engage with the threads of the retaining recess to retain the headless screw on the insertion device. (5) The system of embodiment 4, wherein the proximal end of the retaining member includes a knob extending proximally of the proximal end of the driving member to rotate the retaining member relative to the driving member.

[0080] (6) The system of embodiment 1, wherein the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first position and the second position, the locking mechanism including a locking tab biased toward a locked configuration via a biasing element, and a push button compressing the biasing element to move the locking tab toward an unlocked configuration. (7) The system of embodiment 6, wherein the driving member includes a first groove extending into an outer surface of the driving member such that when the locking tab is received in the first groove, the outer sleeve is in the first position relative to the driving member, and a second groove extending into the outer surface of the driving member proximal to the first groove such that when the locking tab is received in the second groove, the outer sleeve is in the second position relative to the driving member. (8) The system of embodiment 1, wherein a core diameter of the proximal portion of the headless screw is larger than a core diameter along a remainder of the headless screw. (9) The system of embodiment 1, wherein the outer sleeve includes a gripping feature extending distally from the distal end thereof, the gripping feature configured to engage the bone. (10) The system of embodiment 1, wherein the outer sleeve includes threads along the distal end thereof configured to engage corresponding threads along the proximal portion of the headless screw.

[0081] (11) The system of embodiment 10, wherein the outer sleeve includes a proximal portion and a distal portion connected to one another via a frictional interface, the distal portion being rotatable about its longitudinal axis. (12) The system of claim 11, wherein the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member. (13) The system of claim 11, wherein the proximal portion of the outer sleeve includes a depth indicator that indicates how deeply the headless screw has been inserted into the bone. (14) A bone screw insertion device, comprising: an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end configured to engage a drive recess of a bone screw, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of the bone screw that engages the drive member and a second position in which the distal end of the outer sleeve is longitudinally aligned with a proximal end of the bone screw that engages the drive member. (15) The system of claim 14, further comprising a retention member extending longitudinally through the channel of the drive member from a proximal end to a distal end, the retention member configured to releasably engage a retention recess of a bone screw.

[0082] (16) The system of embodiment 15, wherein the distal end of the retention member is threaded to engage corresponding threads in the retention recess. (17) The system of embodiment 16, wherein the proximal end of the retention member includes a knob extending proximally from the proximal end of the impaction member to rotate the retention member relative to the impaction member. (18) The system of embodiment 14, wherein the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first position and the second position, the locking mechanism including a locking tab biased toward a locked configuration via a biasing element, and a push button compressing the biasing element to move the locking tab toward an unlocked configuration. (19) The system of embodiment 18, wherein the driving member includes a first groove extending into an outer surface of the driving member such that when the locking tab is received in the first groove, the outer sleeve is in the first position relative to the driving member, and a second groove extending into the outer surface of the driving member proximate the first groove such that when the locking tab is received in the second groove, the outer sleeve is in the second position relative to the driving member. (20) The system of embodiment 14, wherein the outer sleeve includes a gripping feature extending distally from the distal end thereof, the gripping feature configured to engage the bone.

[0083] (21) The system of claim 14, wherein the outer sleeve includes threads along an inner surface of a distal portion thereof configured to engage corresponding threads along the proximal portion of a headless screw received within the outer sleeve. (22) The system of embodiment 21, wherein the outer sleeve includes a proximal portion and a distal portion connected to one another via a frictional interface, and the distal portion of the outer sleeve is rotatable about its longitudinal axis relative to the proximal portion of the outer sleeve. (23) The system of claim 22, wherein the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member. (24) The system of claim 22, wherein the proximal portion of the outer sleeve includes a depth indicator that indicates a depth to which the headless screw engaged with the driving member has been inserted into the bone. (25) A method for implanting a bone screw, comprising: assembling the insertion device and headless bone screw by inserting a distal end of a drive member of the insertion device into a correspondingly sized and shaped drive recess of the headless screw; inserting the headless bone screw with the insertion device in a first position adjacent a target area of ​​the bone with an outer sleeve mounted on the driving member such that a distal end of the outer sleeve extends over and covers a proximal portion of the headless screw; driving the headless bone screw into the bone by rotating the drive member until the distal end of the outer sleeve abuts the proximal cortex of the bone; drawing the outer sleeve proximally relative to the drive member from the first position to a second position in which a distal surface of the outer sleeve is longitudinally aligned with a proximal surface of the headless bone screw; and driving the headless bone screw further distally into the bone until the distal end of the outer sleeve contacts the nearby cortex of the bone providing tactile feedback to the user that the headless screw is flush with the bone.

[0084] (26) The method of claim 25, further comprising retaining the headless bone screw on the insertion device by threadingly engaging a threaded distal portion of a retention member with a correspondingly threaded retention recess of the headless bone screw, the retention member extending longitudinally through the drive member. (27) The method of embodiment 25, wherein pulling the outer sleeve proximally relative to the driving member from the first position to the second position includes moving a locking mechanism of the outer sleeve from a locked configuration to an unlocked configuration such that a locking tab of the locking mechanism is movable from a first groove along the driving member to a second groove along the driving member. (28) The method of claim 27, wherein the locking tab is biased toward the locking configuration via a bias. (29) The method of embodiment 28, wherein moving the locking mechanism from the locked configuration to the unlocked configuration includes depressing a push button to compress the biasing element such that the locking tab disengages from the first groove, the outer sleeve is movable proximally along the driving member, and the locking tab returns to the biased configuration to engage the second groove in the second configuration. 30. The method of claim 26, further comprising removing the insertion device from the implanted headless bone screw by disengaging the threaded distal portion of the retention member from a retention recess and pulling the insertion device proximally out of the retention recess.

[0085] 31. The method of claim 25, further comprising retaining the headless bone screw on the insertion device by threading the distal end of the outer sleeve with the proximal portion of the headless screw. (32) The method of embodiment 31, wherein the outer sleeve includes a proximal portion and a distal portion connected via a frictional interface, the distal portion being rotatable about its longitudinal axis such that the distal portion correspondingly rotates with the driving member relative to the proximal portion of the outer sleeve. 33. The method of claim 31, wherein the frictional interface provides feedback indicating that the proximal portion of the headless screw is driving into the bone when the distal end abuts the nearby cortex of the bone.

Claims

1. 1. A system for treating a bone, comprising: a headless screw including threads extending from a proximal end to a distal end and extending along an outer surface thereof, said headless screw including a drive recess extending into said proximal end thereof; an insertion device including an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; and a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end, the drive member extending from a position proximal to the proximal end of the outer sleeve to a distal end of the drive member configured to engage the drive recess of the headless screw to rotationally drive the headless screw into bone, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends across and covers a proximal portion of the headless screw when the headless screw is operatively engaged with the drive member, and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the headless screw; The headless screw further includes a retention recess extending distally from the drive recess.

2. 2. The system of claim 1, wherein the insertion device further comprises a retaining member extending longitudinally through the channel of the drive member from a proximal end to a distal end configured to engage the retaining recess such that the headless screw is retained on the insertion device during insertion of the headless screw into the bone.

3. 3. The system of claim 2, wherein the retaining recess includes threads therealong, the distal end of the retaining member is correspondingly threaded, and rotation of the retaining member about its longitudinal axis relative to the driving member causes the threads of the retaining member to engage with the threads of the retaining recess to retain the headless screw on the insertion device.

4. The system of claim 3 , wherein the proximal end of the retention member includes a knob extending proximally from the proximal end of the impaction member to rotate the retention member relative to the impaction member.

5. A system for treating bone, comprising: a headless screw including threads extending from a proximal end to a distal end and extending along an outer surface thereof, said headless screw including a drive recess extending into said proximal end thereof; an insertion device including an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; and a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end, the drive member extending from a position proximal to the proximal end of the outer sleeve to a distal end of the drive member configured to engage the drive recess of the headless screw to rotationally drive the headless screw into bone, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends across and covers a proximal portion of the headless screw when the headless screw is operatively engaged with the drive member, and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the headless screw; the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first position and the second position, the locking mechanism including a locking tab biased toward a locked configuration via a biasing element and a push button compressing the biasing element to move the locking tab toward an unlocked configuration; the driving member includes a first groove extending into an outer surface of the driving member such that when the locking tab is received in the first groove, the outer sleeve is in the first position relative to the driving member, and a second groove extending into the outer surface of the driving member proximal to the first groove such that when the locking tab is received in the second groove, the outer sleeve is in the second position relative to the driving member.

6. The system of claim 1 , wherein a core diameter of the proximal portion of the headless screw is larger than a core diameter along a remainder of the headless screw.

7. The system of claim 1 , wherein the outer sleeve includes a gripping feature extending distally from the distal end thereof, the gripping feature configured to engage the bone.

8. A system for treating a bone, comprising: a headless screw including threads extending from a proximal end to a distal end and extending along an outer surface thereof, said headless screw including a drive recess extending into said proximal end thereof; an insertion device including an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; and a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end, the drive member extending from a position proximal to the proximal end of the outer sleeve to a distal end of the drive member configured to engage the drive recess of the headless screw to rotationally drive the headless screw into bone, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends across and covers a proximal portion of the headless screw when the headless screw is operatively engaged with the drive member, and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the headless screw; the outer sleeve including threads along the distal end thereof configured to engage corresponding threads along the proximal portion of the headless screw; The system, wherein the outer sleeve includes a proximal portion and a distal portion connected to one another via a frictional interface, the distal portion being rotatable about its longitudinal axis.

9. 9. The system of claim 8, wherein the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member.

10. The system of claim 8 , wherein the proximal portion of the outer sleeve includes a depth indicator that indicates how deeply the headless screw has been inserted into the bone.

11. 1. A bone screw insertion device comprising: an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end configured to engage a drive recess of a bone screw, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of the bone screw engaged by the drive member and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the bone screw engaged by the drive member; the bone screw insertion device further comprising a retention member extending longitudinally through the channel of the drive member from a proximal end to a distal end, the retention member configured to releasably engage a retention recess of a bone screw.

12. The bone screw insertion device of claim 11 , wherein the distal end of the retaining member is threaded to engage corresponding threads in the retaining recess.

13. The bone screw insertion device of claim 12 , wherein the proximal end of the retention member includes a knob extending proximally from the proximal end of the drive member to rotate the retention member relative to the drive member.

14. A bone screw insertion device comprising: an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end configured to engage a drive recess of a bone screw, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of the bone screw engaged by the drive member and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the bone screw engaged by the drive member; the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first position and the second position, the locking mechanism including a locking tab biased toward a locked configuration via a biasing element and a push button compressing the biasing element to move the locking tab toward an unlocked configuration; 11. A bone screw insertion device comprising: a first groove extending into an outer surface of the drive member proximal to the first groove such that when the locking tab is received in the first groove, the outer sleeve is in the first position relative to the drive member; and a second groove extending into the outer surface of the drive member proximal to the first groove such that when the locking tab is received in the second groove, the outer sleeve is in the second position relative to the drive member.

15. The bone screw insertion device of claim 11 , wherein the outer sleeve includes a gripping feature extending distally from the distal end thereof, the gripping feature configured to engage bone.

16. A bone screw insertion device comprising: an outer sleeve extending from a proximal end to a distal end and including a channel therethrough; a drive member extending longitudinally through the channel of the outer sleeve from a proximal end to a distal end configured to engage a drive recess of a bone screw, the outer sleeve being movable relative to the drive member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of the bone screw engaged by the drive member and a second position in which the distal end of the outer sleeve is longitudinally aligned with the proximal end of the bone screw engaged by the drive member; the outer sleeve including threads along an inner surface of a distal portion thereof configured to engage corresponding threads along the proximal portion of a headless screw received within the outer sleeve; A bone screw insertion device, wherein the outer sleeve includes a proximal portion and a distal portion connected to one another via a frictional interface, the distal portion of the outer sleeve being rotatable about its longitudinal axis relative to the proximal portion of the outer sleeve.

17. 17. The bone screw insertion device of claim 16, wherein the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the drive member to prevent the proximal portion from rotating relative to the drive member.

18. The bone screw insertion device of claim 16 , wherein the proximal portion of the outer sleeve includes a depth indicator that indicates how deeply the headless screw engaged with the drive member has been inserted into bone.

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