WO2008097795A1

WO2008097795A1 - Sliding hip helical implant

Info

Publication number: WO2008097795A1
Application number: PCT/US2008/052572
Authority: WO
Inventors: Alberto A. Fernandez Dell'oca
Original assignee: Synthes(U.S.A.); Synthes Gmbh
Priority date: 2007-02-02
Filing date: 2008-01-31
Publication date: 2008-08-14

Abstract

A device for treating fractures comprises a bone plate (110) sized and shaped for mounting on a target portion of bone, the bone plate including a lateral bore (112) extending therethrough which, when the plate is mounted on the bone in a desired orientation extends along an axis substantially parallel with an axis of a trochanter of the bone and a lateral implant (120) sized for insertion through the bore into the trochanter, the implant including a shaft (124) with a plurality of substantially helical blades (122) extending from a distal portion thereof in combination with a sleeve (126) slidably received over a proximal portion of the shaft, a keying element (140) of the sleeve engaging a mating feature (130) of the shaft to prevent relative rotation therebetween and a locking member (136) locking the sleeve in a desired position within the bore. Insertion apparatus (200, 300) allowing the lateral implant to be inserted to a desired depth is also disclosed.

Description

SLIDING HIP HELICAL IMPLANT

Background of the Invention

[0001] The present invention relates to devices for treating femoral fractures, in particular, fractures of the neck and the intertrochanteric region of the femur.

[0002] Many implants have been developed to treat intertrochanteric femoral fractures which are basically based on a hip nail or screw inserted from the side of the femur through the neck and into the femoral head which are afterwards fixed either to an intramedulary nail inside the femoral shaft or to a side plate on the outside of the femoral shaft.

[0003] In 1969 Zickel developed an intramedullary rod and cross nail assembly (disclosed in U.S. Pat. No. 3.433.220) consisting of a hip nail fixed to an intramedullary nail. This device, while permitting an adequate fixation and rotational control of the fracture, did not allow sliding of the bone fragments relative to one another along the hip nail. As a result, bone contact was insufficient to support the patient's weight increasing the risk of bending or breaking of the implanted hip nail. In combination with the shape of the hip nail, this often lead to excessive pressure over the femoral neck and head bone tissue causing "cut through" in which the nail pierces the surface of the femoral neck or head or to loose and improper alignment of bone fragments.

[0004] In response, collapsible implants were developed in which the hip nail or screw was allowed to slide through a bore in the side plate or intramedullary nail to permit migration of the bone fragments toward one another and consequent improvement in reduction of the fracture as weight is put on the fractured limb. This increased bone contact increases the pressure tolerable before the implant fails. An example of these implants is the Lawes intertrochanteric fracture fixation device (disclosed in US Pat. No. 5,176,681). However, the surface at which these devices contact bone tissue were not large enough to withstand the forces placed on the healing bone under the patients' weight increasing the risk of 'cut through' from the femoral head or improper alignment of the fragments. Moreover, such implants do not provide rotation of the femoral head around the hip screw.

[0005] Thereafter, complete helical blades were developed (such as Neufelds' Subtrochanteric Nail described in US Pat. No. 4.103.683; and Friggs' Fixation Plate disclosed in US Pat No. 4.978.349) which consist of a single helical blade inserted through the femoral neck into the femoral head so that, when inserted, the distal end of the blade lies in a vertical position passing through a vertical slot in the intramedullary nail while the proximal end lies in a horizontal position permitting the load over the femoral head to act on a larger and flat surface, diminishing pressure on the bone tissue and reducing the risk of 'cut out.' However these devices do not allow the implant to slide through the vertical slot in the intramedullary nail and, therefore, do not permit the bone fragment migration needed to achieve the desired fragment compression.

[0006] To obtain the necessary sliding (minimizing the risk of breaking the implants while permitting compression of bone fragments), and to avoid the cutting-out problem of complete helical implants, partial helical implants were developed. Examples of these implants are the Two-part Angle Plate invented by Frigg US Pat. No. 5,300,074, and Bresinas' Helical Implant US Pat. No. 5,908,422. These devices include a helical blade at the front portion of the implant increasing a surface area over which the load is distributed and reducing the risk of 'cut-out and a distal shaft which slides through a bore in an intramedullary implant. However, the shaft utilized to permit sliding does not allow rotational control, which may result in the rotation of one bone fragment around another.

Summary of the Invention

[0007] It is an object of the present invention to provide a novel ostesynthetic device to treat proximal femoral fractures, which has minimal tendency to cut out through cancellous femoral bone tissue once inserted and which is rotationally stable while allowing sliding of the implant to permit the bone fragments to approach one another. The invention also provides a hip implant that permits its easy removal by a single lateral approach. The invention includes a side plate, a hip helical implant, a sliding sleeve, and a lateral set screw, as well as an insertion tool.

[0008] The present invention is further directed to a device for treating fractures comprising a bone plate sized and shaped for mounting on a target portion of bone, the bone plate including a lateral bore extending therethrough which, when the plate is mounted on the bone in a desired orientation extends along an axis substantially parallel with an axis of a trochanter of the bone and a lateral implant sized for insertion through the bore into the trochanter, the implant including a shaft with a plurality of substantially helical blades extending from a distal portion thereof in combination with a sleeve slidably received over a proximal portion of the shaft, a keying element of the sleeve engaging a mating feature of the shaft to prevent relative rotation therebetween and a locking member locking the sleeve in a desired position within the bore.

Brief Description of the Drawings

[0009] Fig. IA shows a perspective view of an assembled device according to an embodiment of the invention;

Fig. IB shows a top view of the device of Fig. IA;

Fig. 1C shows a side view of the device of Fig. IA;

Fig. ID shows a front view of the device of Fig. IA;

Fig. 2A shows a top view of the device of Fig. IA disassembled;

Fig. 2B shows a side view of the device of Fig. IA disassembled;

Fig. 3 A shows a side view of a bone plate for use with the device of Fig. IA;

Fig. 3B shows a front view of the bone plate of Fig. 3 A;

Fig. 3 C shows a perspective view of the bone plate of Fig. 3 A;

Fig. 4A shows a perspective view of a hip implant for use with the device of Fig. IA;

Fig. 4B shows a detail view of a portion of the hip implant of Fig. 4A; Fig. 4C shows an upper view of the implant of Fig. 4A;

Fig. 4D shows a detail view of a portion of the implant of Fig. 4A;

Fig. 5 A shows a front view of a sliding sleeve for use with the device of Fig. IA;

Fig. 5B shows a side view of the sliding sleeve of Fig. 5 A;

Fig. 5 C shows a perspective view of the sliding sleeve of Fig. 5 A;

Fig. 6 shows the components of an insertion tool for use with the device of Fig. 1;

Fig. 7 shows a side view of a slotted insert of the insertion tool of Fig. 6;

Fig. 8 shows a side view of the insertion tool of Fig. 6 assembled with the sliding sleeve of Fig. 5 A and the implant of Fig. 4A;

Fig. 9 shows a longitudinal cross-section of a guiding tool for use with the device of Fig. IA;

Fig. 10 shows a side view of the insertion tool of Fig. 6 assembled with the guiding tool of Fig. 9; and

Fig. 11 shows the assembly of Fig. 10 with slotted insert of Fig. 7 removed therefrom.

Detailed Description

[0010] The present invention, which may be further understood with reference to the following description and the appended drawing, relates to devices for treating fractures and, in particular, to internal fixation devices. It is noted that, although exemplary embodiments of the present invention are described below with respect to the treatment of fractures of the femur, the description is not meant to limit the application of the invention to such fractures as the invention may be employed in the treatment of fractures of other bones including, for example, the humerus.

[0011] To improve the performance of ostesynthetic devices in the treatment of proximal femoral fractures (e.g., in the femoral neck or femoral head), embodiments of the present invention provide hip implants and side plates which minimize the risk of cut-through of the femoral head and neck after implantation, while permitting sliding and rotational control of the bone fragments. [0012] As shown in Figs. IA - ID and 2A - 2B, a device 100 according to an embodiment of the invention comprises a side plate 110 and a helical hip implant 120 including a helically twisted portion 122 at a distal end thereof and a shaft 124 extending proximally therefrom with a sliding sleeve 126 received on the shaft 124. The side plate 110 includes an oblique bore 112 for slidably accommodating the sliding sleeve 126 of the implant 120 when the implant 120 is inserted therethrough. The device 100 may further include a lateral screw 136 for securing the sliding sleeve 126 to the side plate 110.

[0013] The side plate 110, as shown in Fig. 3 A - 3C, includes a first portion 102 formed at an angle relative to a second portion 104, as shown in a side view of the side plate 110 in Fig. 3 A. Specifically, the portion 104 extends in a plane which, when the plate 110 is mounted on a bone in the desired orientation, extends substantially parallel to a longitudinal axis of the bone and the portion 102 angles away from the plane so that an end of the portion 102 coupled to the portion 104 is closer to an axis of the bone than is the opposite end of the portion 102. A bone-facing surface 106 of the second portion 104 may be substantially flat or slightly contoured to facilitate mounting on a shaft of a femur or other target bone. The angle of the first portion 102 is preferably selected to fit a bone-facing surface 108 of the portion 102 against a trochanter of the target bone and the oblique bore 112 is preferably formed through the first portion 102 at an angle which, when the plate 110 is mounted on the target bone in a desired orientation, will be substantially parallel to an axis of the trochanter. As shown in Figs. 3B and 3C₅ the first portion 102 may also include a threaded hole 116 for accommodating a lateral screw 136 while the second portion 104 may further include at least one transverse hole 114 through which bone screws may be mounted to secure the plate 110 to the target bone. The second portion 104 may further include a hole 118 for affixing the side plate 110 to a guiding tool, which may be used to insert the side plate 110 into the body as will be described below.

[0014] As shown in Figs. 4A - D, the helical portion 122 comprises two or more helically twisted blades 138. The helically twisted blades 138 extend around a longitudinal axis of the implant 120 along a substantially helical path with a helix angle Θ between 70° and 90°. The angle Θ is more preferably between approximately 75° and 85°. The shaft 124 extends proximally from the helical portion 122 to a proximal end 134. A first portion 128 of length of the shaft 124 may be substantially cylindrical, while an outer surface of a second portion 130 of the length of the shaft 124 may include a flat portion, as best shown in Figs. 4 A and 4B. The shaft 124 may be cannulated to include a channel 142 extending therethrough and a proximal end 134 thereof may be threaded, as shown in Fig. 4A, couple to an insertion shaft of an insertion tool as will be described in more detail below.

[0015] The sliding sleeve 126, as shown in Figs. 5 A - 5C, is sized to accommodate the shaft 124 and to fit within the oblique bore 112 of the side plate 110. The sliding sleeve 126 may be beveled at a distal end 144 to make gradual a transition from the diameter of the shaft 124 to the increased diameter of the sleeve 126. The diameter of the channel 142 is preferably selected to closely match the outer diameter of the shaft 124 so that the shaft 124 slides smoothly therethrough. As the diameter of the helical portion 122 is greater than that of the shaft 124, the helical portion 122 can not pass into the channel 142. The sliding sleeve 126 may also include a shoulder 146 at a proximal end thereof with a diameter greater than that of the oblique bore 112. Thus, distal end 144 of the sliding sleeve 126 may be inserted into the oblique bore 112 from the proximal side of the plate 110 until the shoulder 146 engages the portion of the plate surrounding the bore 112. The sleeve 126 can not be slid distally through the bore 112. The channel 142 of the sliding sleeve 126 may also be keyed to the shaft 124 to prevent rotation of the shaft 124 relative to the sliding sleeve 126 about an axis thereof. For example, a flat surface 140 on an inner surface of the channel 142 engages the flat surface 132 on the second portion 130 of the shaft 124 so that the angular orientation of the shaft 124 within the lumen 142 is fixed. It will be understood by those in the art that a variety of other key systems may be used so long as the shaft 124 and the sliding sleeve 126 are able to slide relative to one another without rotating relative to one another about their longitudinal axes. For example, the shaft 124 and the lumen 142 of the sliding sleeve 126 may be hexagonal or otherwise shaped to prevent relative rotation. [0016] As shown in Figs. 6 - 9, an exemplary system according to the present invention may further include an insertion device 200 and a guiding tool 300. The guiding tool 300, as shown in Fig. 9 is assembled with the side plate 110 prior to insertion of the side plate 110 into the body to provide a guide . The assembled insertion tool 200 may be slidably received within the guiding tool 300. The insertion device 200, as shown in Fig. 6, comprises an insertion shaft 202, a driving sleeve 204, and a slotted insert 206. The insertion tool 200 may be coupled to the helical hip implant 120, as shown in Fig. 8. The insertion shaft 202 includes an elongated body 208 and an annular shoulder 210 extending radially outward from a proximal end of the body 208. The insertion shaft 202 may be cannulated with a channel 212 extending therethough. The insertion shaft 202 also further includes a threaded distal end 214 sized to threadably receive the threaded proximal end 134 of the helical hip implant 120.

[0017] The driving sleeve 204, includes a lumen 216 sized to slidably receive therein the shaft 124 of the helical hip implant 120 and the elongated body 204 of the insertion shaft 202, which preferably have diameters substantially equal to one another. When assembling the insertion tool 200, the driving sleeve 204 may be slid over the insertion shaft 202 prior to coupling the insertion shaft 202 with the helical hip implant 120. The driving sleeve 204 is slidable over the shaft 124 of helical hip implant 120 until a distal end 220 of the insertion shaft 202 abuts the shoulder 146 of the sliding sleeve 126. The driving sleeve 204 may continue to move distally along the helical hip implant 120 pushing the sliding sleeve 126 distally therealong until the distal end 144 of the sliding sleeve abuts the helical portion 122. At this point, the sliding sleeve 126 and the driving sleeve 204 can move no further distally over the shaft 124. The length of the insertion shaft 202 is preferably selected relative to the lengths of the shaft 124, the sliding sleeve 126 and the driving sleeve 204 so that, at the point when the sliding sleeve 126 and the driving sleeve 206 are moved to their distal-most position on the helical hip implant 120, a gap between a proximal end 222 of the driving sleeve 206 and the annular shoulder 210 along the longitduinal axes of these shafts is at least equal to a distance by which it is desired to drive the helical hip implant 120 into the femur. That is, the annular shoulder 210 must be free to advance distally by a distance required to drive the helical hip implant 120 through the bore 112 to a desired depth in the bone.

[0018] The slotted insert 206 is preferably formed as a slotted spacer with a length selected to be substantially equal to the distance by which it is desired to drive the helical hip implant 120 into the bone. As best shown in Fig. 7, slot 218 along the length of the slotted insert 206 allows the insert to be slid over and removed from the insertion shaft 210 between the proximal end 222 of the driving sleeve 204 and the annular shoulder 210 to maintain the desired separation therebetween, as shown in Fig. 8. Thus, the slot 218 should be sized to fit over the insertion shaft 202, but should also be smaller in diameter than the driving sleeve 204.

[0019] The guiding tool 300, as shown in Fig. 9, comprises an elongated body 302, a proximal shoulder 304 and a distal shoulder 306. The guiding tool 300 may be coupled to the side plate 110 via an affixing screw 310. The shoulder 304 is formed laterally of the elongated body 302 at a proximal end thereof. The shoulder 306 is formed at a distal end of the guiding tool 300 at an angle so that the shoulder 306 may abut the side plate 110 with a channel 308 extending therethrough alined and communicating with the oblique bore 112 of the side plate 110. The affixing screw 310 fixes the side plate 110 to the guiding tool 300 via, for example, a threaded hole 312 in the shoulder 306 which, when the channel 308 is alined with the bore 112, aligns with the hole 118 in the side plate 110. The channel 308 is sized so that it may slidably receive the driving sleeve 204 of an insertion tool 200 that has been coupled to the helical hip implant 120 as will be described in more detail below.

[0020] A surgical technique according to an exemplary embodiment of the present invention comprises assembling the insertion tool 200 with the helical hip implant 120 and the sliding sleeve 126, and assembling the guiding tool 300 with the side plate 110. The insertion tool 200 is assembled with the helical hip implant 120 and the sliding sleeve 126 by sliding the sliding sleeve 126 over the shaft 124 of the helical hip implant 120 until the distal end 144 of the sliding sleeve 126 abuts the helical portion 122. The driving sleeve 204 of the insertion device 200 may be slid over the remaining shaft 124 and the threaded end 214 of the insertion shaft 202 may be slid through the proximal end 222 of the driving sleeve until the threaded end 214 comes into contact with the threaded opening 134 at the proximal end of the shaft 124. The shaft 124 and the insertion shaft 202 are then rotated about their longitudinal axes relative to one another so that the threaded end 214 and the threaded cannulation 134 engage one another, coupling the insertion shaft 202 and the shaft 124. The slotted insert 206 may then be introduced over the insertion shaft 202 via the slot 218 such that the slotted insert 206 is positioned between the shoulder 210 of the insertion shaft 202 and the proximal end 222 of the driving sleeve 204, as shown in Fig. 8.

[0021] The guiding tool 300 may be assembled with the side plate 110 by inserting the affixing screw 310 through the threaded hole 312 on the shoulder 306 of the guiding tool 300 and the hole 118, which may also be threaded, in the side plate 110. The shoulder 306 abuts the side plate 110 so that the channel 308 of the guiding tool 300 aligns with the oblique bore 112 of the side plate 110, as shown in Fig. 9. After the guiding tool 300 has been assembled with the side plate 110, the side plate 110 is inserted into the body to a target site on the femur or other target bone. When the side plate 110 has been appropriately positioned alongside the femur with the first portion 102 of the side plate 110 abutting the trochanter and the second portion 104 extending along the femur and with the oblique bore 112 aligned with an axis substantially parallel to an axis of the trochanter, the side plate 110 may be coupled to the femur (e.g., by inserting bone screws through one or more transverse holes 114). A wire, such as a Kirschner wire (K- wire), may then be inserted into the channel 308 of the hollow guiding tool 300 until it is in a desired position in the femoral head. As would be understood by those skilled in the art, the k-wire acts as a guidewire so that a hole may be drilled thereover following the direction of the k-wire.

[0022] After the side plate 110 has been inserted and positioned, the assembly of the insertion device 200 with the helical hip implant 120 and the sliding sleeve 126 is inserted through the channel 308 of the guiding tool 300 following the direction of the guiding tool 300 over the K- wire until a distal end 224 of the slotted insert 206 abuts the shoulder 304 of the guiding tool 300, as shown in Fig. 10. To move the assembly forward, the shoulder 210 of the insertion shaft 202 may be hammered until the slotted insert 206 abuts the shoulder 304 of the guiding tool 300. Once the assembly is in the first configuration, the slotted insert 206 may be removed and the shoulder 210 may again be hammered until the shoulder 210 abuts the shoulder 304 of the handle, driving the helical hip implant 120 through the bore 112 to a desired portion in the trochanter, as shown in Fig. 11.

[0023] When the shoulder 210 abuts the shoulder 304, the user knows that the helical hip implant 120 as at the desired depth in the bone. This may be confirmed by x-ray or other visualization system, which should show the helical portion 122 in the femoral head. Once the helical hip implant 120 is in the second configuration, the insertion device 200 and the guiding tool 300 may be disassembled and removed. The insertion shaft 202 may be rotated relative to the helical hip implant 120 such that the threaded end 214 disengages from the threaded cannulation 134 of the shaft 124. Once the insertion shaft 202 has been disengaged from the helical hip implant 120, the insertion shaft 202 and the driving sleeve 204 may be removed from the guiding tool 300. The guiding tool 300 may then be disassembled from the side plate 110 by removing the affixing screw 310 from the hole 118 of the side plate and the threaded hole 312, leaving the side plate 110, the helical hip implant 120 and the sliding sleeve 126 implanted in the body. The shoulder 146 of the sliding sleeve 126 abuts a surface of the side plate 110, preventing the entire sliding sleeve 126 from passing through the oblique bore 112. To secure the sliding sleeve 126 to the side plate 110, the lateral screw 136 may be inserted into the threaded hole 116 of the side plate. A distal end of the lateral screw 136 engages a surface of the sliding sleeve 126 such that the sliding sleeve 126 is locked in place.

[0024] Since the sliding sleeve 126 is securely locked in place within the oblique bore 112 and the helical portion 122 of the helical hip implant 120 is lodged in the femoral head, the helical hip implant 120 may slide within the sliding sleeve 126, without rotating relative to the sliding sleeve 126. The device 100 allows relative axial sliding between the side plate 110 and the helical hip implant 120 while preventing relative rotation between the trochanter and the shaft of the femur. Thus, fragments of the femur may move axially relative to one another (along the axis of the bore 112) when the patient is walking, supporting the patient's weight and preventing cut- through of the cancellous tissue within the femoral neck or head as well as any breaking or bending of the helical hip implant 120.

[0025] It will be apparent to those skilled in the art that various modifications and variations can be made in the structure and methodology of the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A device for treating fractures comprising: a bone plate sized and shaped for mounting on a target portion of bone, the bone plate including a lateral bore extending therethrough which, when the plate is mounted on the bone in a desired orientation extends along an axis substantially parallel with an axis of a trochanter of the bone; a lateral implant sized for insertion through the bore into the trochanter, the implant including a shaft with a plurality of substantially helical blades extending from a distal portion thereof; a sleeve slidably received over a proximal portion of the shaft, a keying element of the sleeve engaging a mating feature of the shaft to prevent relative rotation therebetween; and a locking member locking the sleeve in a desired position within the bore.

2. The device of claim 1, wherein the keying element includes a flat surface and the mating feature of the sleeve includes a corresponding flat surface.

3. The device of claim 1 , wherein the locking member comprises a set screw for engaging the sleeve.

4. The device of claim 3, wherein the set screw is a lateral set screw for insertion substantially parallel to the bore.

5. The device of claim 1, wherein a proximal end of the lateral implant includes a feature for coupling to an insertion member.

6. The device of claim 5, wherein the feature for coupling to an insertion member includes a threaded recess sized to couple to a corresponding threaded projection of an insertion member.

7. The device of claim 1, wherein a helix angle of the blades is between 70° and 90°.

8. The device of claim 7, wherein a helix angle of the blades is between 75° and 85°.

9. The device of claim 1 , wherein the plate includes a first portion which, when mounted on the bone in a desired location and orientation, extends substantially parallel to a longitudinal axis of the bone and a second portion angled relative to the first portion to engage a trochanter of the bone.

10. The device of claim 1 , wherein the bore is formed in the second portion of the plate.

11. A system, comprising: a bone plate sized and shaped for mounting on a target portion of bone, the bone plate including a lateral bore extending therethrough which, when the plate is mounted on the bone in a desired orientation extends along an axis substantially parallel with an axis of a trochanter of the bone; a lateral implant sized for insertion through the bore into the trochanter, the implant including a shaft with a plurality of substantially helical blades extending from a distal portion thereof; a sleeve slidably received over a proximal portion of the shaft, a keying element of the sleeve engaging a mating feature of the shaft to prevent relative rotation therebetween; and a locking member locking the sleeve in a desired position within the bore; and an insertion apparatus for inserting the lateral implant into the bone through the bore, the insertion apparatus including: an insertion shaft engaging a proximal end of the lateral implant and including an annular shoulder at a proximal end thereof; and a guiding sleeve sized such that, when a distal end of the guiding sleeve abuts the plate, a distance separating the shoulder of the shaft and a proximal end of the guiding sleeve substantially equals a depth to which the implant is to be driven into the bone; and a guiding tool coupleable to a proximal side of the bone plate, the guiding tool including an elongated body defining a lumen extending therethrough and a shoulder at a distal end thereof, the shoulder extending laterally from the body at an angle selected to engage a proximal surface of the bone plate so that the lumen aligns with the bore, the lumen being sized such that the shaft of the insertion apparatus, the sliding sleeve and the implant may slide therethrough.

12. The system of claim 11, wherein the handle includes a second shoulder at a proximal end thereof, the lumen extending through the shoulder.

13. The system of claim 11, further comprising a spacer slidable over the shaft between the shoulder and the proximal end of the guiding sleeve.

14. The system of claim 11, wherein a length of the guiding sleeve is selected so that, when the distal end of the guiding sleeve abuts the plate, the proximal end of the guiding sleeve extends out of the lumen of the aiming block.

15. A method, comprising the steps of: coupling a bone plate to a target bone with a first portion of the plate engaging a shaft of the bone and a second portion, angled relative to the first portion, engaging a trochanter of the bone, the second portion of the plate including a bore extending laterally therethrough along an axis alined which, when the plate is coupled to a bone in a target orientation, is substantially parallel to a trochanter axis; inserting a lateral implant through the bore into the trochanter, a distal portion of the implant including a plurality of substantially helical blades extending therefrom, a proximal portion of the implant being slidably and non-rotatably received within a sleeve; and locking the sleeve in a desired position within the bore using a locking member permitting the implant to move relative to the bone plate along a longitudinal axis of the implant without rotating relative thereto.

16. The method of claim 15, further comprising coupling a guiding tool to the plate, the guiding tool including an elongated body defining a lumen extending therethrough, the guiding tool further including at a distal end thereof, a shoulder extending laterally from the elongated body angled to engage a proximal surface of the bone plate such that the lumen aligns with the bore, the lumen being sized such that the shaft of the insertion apparatus, the sliding sleeve and the implant may slide therethrough into the bore.

17. The method of claim 16, further comprising coupling a distal end of an insertion shaft to a proximal end of the implant, the insertion shaft including an annular shoulder at a proximal end thereof, a length of the insertion shaft selected relative to a length of the guiding tool so that, when a distal end of the guiding tool abuts the plate, a distance between the shoulder of the insertion shaft and a proximal end of the guiding sleeve equals a depth to which the implant is to be driven into the bone.

18. The method of claim 17, further comprising temporarily installing a spacer over the a proximal portion the insertion shaft between the shoulder and the proximal end of the guiding tool to prevent relative movement therebetween.

19. The method of claim 18, further comprising removing the spacer when it is desired to drive the implant into the bone.

20. The method of claim 17, further comprising the step of sliding the implant, the sliding sleeve and the insertion shaft through the lumen of the guiding tool until the spacer abuts a proximal end of the guiding tool.

21. The method of claim 18, further comprising the step of driving the implant into the bone by a depth substantially equal to the distance between the shoulder of the insertion apparatus and the proximal end of the guiding tool.