This disclosure relates to an implant for an osteotomy, and tools for inserting an implant.
A calcaneal osteotomy is a form of surgery for correction of severe hind foot misalignment. During the procedure, the heel bone is cut and the tuberosity is moved medially toward the inside or laterally towards the outside, depending on the direction of the misalignment to be corrected. For example, if the patient has flat feet, the heel may be offset medially to shift the hind foot toward the inside to improve the weight distribution on the foot. On the other hand, if the patient has a high arched foot the calcaneal osteotomy may be performed to shift the hind foot laterally, to improve stability and reduce risk of sprain.
This procedure has often been performed by driving screws through the tuberosity into the anterior calcaneus. Some of the primary challenges associated with this approach are determining the amount of intra-operative offset that is achieved, the ability for fluoroscopy for targeting and placing the screws, and screw head prominence.
Implants have been developed for insertion during calcaneal osteotomy. For example, the assignee of this patent application, Wright Medical Technologies, has developed the DARCO® DPS plate, which provides support. This plate includes an anterior plate, a posterior plate, and an offset segment connecting the anterior and posterior plates. The DARCO® DPS plate is available with different amounts of offset between the anterior and posterior plates.
In some embodiments, a tool comprises a first body shaped to detachably receive a bone implant having a first portion with a first flat surface adapted to be attached to a bone and a second portion with a second flat surface oriented at a pre-determined angle relative to the first flat surface, the bone implant having at least one fastener hole penetrating each of the first and second portions. A second body has a surface or member, and is adjustably connected to the first body to selectably position the surface or member relative to the bone implant.
In some embodiments, an apparatus comprises a bone implant having a first portion with a first flat surface adapted to be attached to a bone and a second portion with a second flat surface oriented at a pre-determined angle relative to the first flat surface. The bone implant has at least one fastener hole penetrating each of the first and second portions. A cut guide is attachable to the bone implant using at least one of the fastener holes. The cut guide has a guide surface that is coplanar with the second flat surface when the cut guide is attached to the bone implant.
In some other embodiments, a method is provided that comprises: (a) fastening a bone implant to a bone, such that a first surface of the bone implant contacts a first portion of the bone; (b) connecting a tool to the bone implant, the tool having a movable contact member configured to engage a second portion of the bone which has been severed from the first portion of the bone; (c) adjusting the movable contact member until the second portion of the bone has a predetermined offset relative to the first surface of the bone implant; and (d) drilling a hole in the second portion of the bone for fastening the bone implant thereto, the drilling being performed using a drill guide in the tool.
This description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.
This disclosure provides an implant 150 (
In some embodiments, the implant 150 has a “door stop” or “L” bracket configuration, as best seen in
The anterior hole 153 is oriented at an obtuse angle θ2 relative to the bottom surface 151 for receiving a fastener 162. In some embodiments, the implant 150 is a plate having four holes 153; the posterior holes accept two (2) screws 161 inserted into the tuberosity 171, and the anterior holes accept two screws 162 placed into the cut surface 173 of the anterior calcaneus 172. Other embodiments (not shown) include one hole 153 for receiving one screw 161 inserted into the tuberosity and one hole for receiving one screw 162 inserted into the anterior calcaneus.
The plate 150 is positioned below the distal (anterior) portion 172 of the calcaneus 170 and therefore is not felt by the patient. Seating the implant 150 below the surface of the anterior calcaneus 172 also allows the surgeon to tamp down the edge or shelf created by the osteotomy, and smooth the transition. The configuration of the implant 150 does not dictate a specific offset amount between the tuberosity and the anterior calcaneus. One size of implant 150 as described herein can be used to provide a variety of offsets. Although the configuration of the implant 150 does not dictate the offset increments, in some embodiments, the inserter instrument sized to install the implant 150 may provide for discrete offset increments (e.g., 1 mm increments). In other embodiments, the inserter tool permits continuous control of the offset throughout a range (e.g., 6 mm to 12 mm).
The second (track groove) body 120 is adjustably connected to the core body 110 to selectably position the surface or member 122 relative to the bone implant 150. For example, as shown in
As shown in
A third (drill-through thumb screw) body 130 extends through the first (core) body 110. The third body 130 is detachably connectable to the bone implant 150 for retaining the bone implant against the core body 110, as shown in
The drill-through thumb screw 130 also has a ridge 133 for retaining the drill-through thumb screw 130 in the core body 110. During assembly of the tool 100, the drill-through thumb screw 130 is inserted into the core body 110, and two of the dowel pins 111 are inserted to retain the drill-through thumb screw 130. The drill-through thumb screw 130 of
The tool 100 further comprises a shaft 140 rotatably connected to the first (core) body 110. The shaft 110 has a male threaded portion 141 (
During insertion, the stop 122 of track/groove 120 abuts the cortex of the anterior calcaneus 172; and the bottom surface 151 of the implant 150 abuts the tuberosity 171 of the calcaneus. Thus, the offset distance between the tuberosity 171 and the anterior calcaneus 172 is directly controlled by rotating the shaft 140. This offset distance is equal to the vertical component of the distance between the member 122 of the groove/track body 120 and the bottom surface 151 of the implant 150. In some embodiments, the range of offsets is from D1=6 mm to D2=12 mm. The surgeon selects the appropriate offset for the individual patient, and rotates the shaft 140 to achieve the selected offset. In some embodiments, the shaft 140 has an enlarged portion 142 positioned adjacent the threaded portion 141, so as to limit a range of travel of the groove/track body 120 relative to the bone implant 150. For example, in some embodiments the stop 142 limits the maximum offset to 12 mm. This can prevent the surgeon from inadvertently offsetting the anterior calcaneus 172 beyond 12 mm relative to the tuberosity at any time during the osteotomy. In other embodiments (not shown), the track/groove body 120 is advanced using a ratchet, detents or other mechanism
In some embodiments, the shaft 140 has an end distal from the core body 110, with a connector 144 for connecting the shaft 140 to a tool handle (not shown). For example, the connector 144 may be an “AO QUICK CONNECT” connector. In some embodiments, the shaft 140 has a prescribed thread 141 to facilitate selection of a desired offset by the surgeon. For example, in some embodiments, the thread 141 provides one mm advance/retraction of the groove/track body 120 per full turn of the shaft. The handle facilitates turning of shaft 140, and clear identification of when the shaft 140 has turned through a complete 360 degree rotation. In other embodiments, the shaft 140 has a groove 145. During assembly of the tool 100, the shaft 140 is inserted through the threaded hole in the groove/track body 120 and into the core body 110. One of the pins 111 is then inserted into the core body 110 to retain the shaft in place.
The planar saw guide surface 201 of the cut guide 200 is coplanar with, or parallel to the plane containing the front surface 152 of the implant 150, when the cut guide 200 is attached to the implant. In some embodiments, the planar saw guide surface 201 of the cut guide 200 has a built in 0.127 to 0.381 mm offset from the front surface 152 of the implant 150 (when the cut guide is attached to the implant 150). The cut guide 200 is configured to form a cut from about 0.127 to 0.381 mm anterior of the front surface 152 of the implant 150, so that the anterior surface 152 of the installed implant 150 is about 0.127 to 0.381 mm away from the cut surface of the tuberosity. Subsequently, when the implant plate 150 is fastened to the anterior calcaneus 172 and the fasteners 162 are tightened, there is a 0.127 to 0.381 mm compression of the calcaneus against the tuberosity. In other embodiments, the planar saw guide surface 201 is coplanar with the second flat surface 152 of the bone implant 150, when the cut guide 200 is attached to the implant. The bone implant 150 has at least one fastener hole 153 penetrating each of the first and second portions. In some embodiments the implant has one anterior hole 153 and one posterior hole. In other embodiments, the implant 150 has two anterior holes 153 and two posterior holes. The cut guide 200 is attachable to the bone implant 150 using at least one of the same fastener holes 153 through which the anterior screws 162 (which fasten the implant 150 to the cut surface 173 of the anterior calcaneus 172).
The cut guide 200 has a mounting member 202 with a mounting hole for attaching the cut guide to the bone implant 150. The mounting hole receives the screw 204. The mounting hole is oriented at a predetermined angle relative to the guide surface, matching the orientation of the anterior hole(s) 153 of the implant 150. The predetermined angle relative to the second flat surface can be from about 30 degrees to about 60 degrees. In one embodiment, the predetermined angle is 45 degrees, matching the orientation of the anterior holes 153 in the implant 150. The cut guide 200 has a handle 205 comprising a shaft with a distal end fixed to cut guide 200 by dowel 203. In some embodiments, the distal end has a connector 206 for connecting the shaft to a tool handle (not shown). In other embodiments, the handle shaft contains a AO quick connection so an additional handle can be placed onto the shaft if desired.
At step 1204, the implant 150 with attached cut guide 200 is positioned on the calcaneus 170. At step 1206, the bone implant 150 is fastened to the bone 170, such that a first surface 151 of the bone implant 150 contacts a first portion 171 of the bone 170. In some embodiments, the implant 150 has two posterior holes, and this fastening step includes inserting two posterior screws 161 through the posterior hole(s) 153 in the implant and into the first portion 171 of the bone 170. In other embodiments, the implant has one posterior hole, and this step inserts one screw into that posterior hole. At step 1208, the bone is cut along a plane containing the guide surface 201 of the cut guide 200. At step 1210, the screw 204 is removed and the cut guide 200 is removed from the implant 150. The implant 150 remains attached to the tuberosity.
At step 1212, an insertion tool 100 is connected to the bone implant 150. The tool 100 has a track/groove body 120 with a movable contact member 122 configured to engage a second portion 172 of the bone 170 which has been severed from the first portion 171 of the bone. In some embodiments, the connection between the tool 100 and the implant 150 is made by inserting the threaded male end 132 of the drill-through thumb screw 130 into female threads of one of the anterior holes 153 of the implant 150. At step 1214, a (temporary) insertion pin 160 is optionally inserted through an opening 123 in the shelf 121 of the track/groove body 120 having the movable contact member 122, so that the threaded end 163 of the pin engages the bone 170 through the opening 123. In some embodiments, the pin 160 has a flange 164, and the pin 160 is inserted until the flange abuts the shelf 121.
At step 1216, the shaft 140 of the insertion tool is rotated, so as to adjust the movable contact member 122 until the second portion 172 of the bone 170 has a predetermined offset relative to the first surface 151 of the bone implant 150. In some embodiments, a shaft 140 having a fixed displacement relative to the bone implant 150 is rotated. The groove/track body 120 having the movable contact member 122 includes a female thread engaging the male thread 141 of the shaft 140. Rotating the shaft 140 adjusts the displacement of the movable contact member 122 relative to the bone implant 150. With the fixation pin 160 screwed into the bone, the rotation of shaft 140 and advancement/retraction of the track/groove body 120 changes the offset of the anterior calcaneus 172 relative to the tuberosity 171. At step 1218, in embodiments having two anterior holes 153, a drill guide (not shown) which is not engaged by the tool from the tool 100 is inserted in the open hole 153 of the implant 150 not covered by the tool 100. A hole is drilled in the second portion 172 of the bone 170 for fastening the bone implant 150 thereto. At step 1220, the drill guide is removed from the open hole and one of the anterior screws 162 is inserted through the anterior hole 153 and into the anterior calcaneus 172. In some embodiments, if compression is desired, non-locking screws are used. In other embodiments, locking screws are used. Also, in embodiments where the implant has only a single anterior hole 153 and a single posterior hole 153, steps 1218 and 1220 are skipped. At step 1222, the remaining anterior hole is drilled into the anterior calcaneus, through the drill guide 131 of the drill-through thumb screw 130. In some embodiments, instead of performing step 1222 while the tool 100 is attached, the tool 100 is removed, and steps 1218 and 1220 are repeated to form the remaining anterior screw hole.
At step 1224, drill-through thumb screw 130 containing the drill guide 131 is rotated, until threads 132 of the threaded body 130 disengage from the threads of the second (anterior) portion of the bone implant 150. The insertion tool 100 is removed. At step 1226, the final anterior fastener (e.g., a screw) 162 is inserted through the anterior hole 153 and into the anterior calcaneus 172. The screw 162 is inserted into the drilled hole in the second portion of the bone, so that the bone implant is fastened in a corner between a perimeter of the first portion of the bone and a cut face of the second portion of the bone.
At step 1314, a (temporary) insertion pin 160 is optionally inserted through an opening 123 in the shelf 121 of the track/groove body 120 having the movable contact member 122, so that the threaded end 163 of the pin engages the bone 170 through the opening 123. In some embodiments, the pin 160 has a flange 164, and the pin 160 is inserted until the flange abuts the shelf 121. At step 1316, the shaft 140 of the insertion tool is rotated, so as to adjust the movable contact member 122 until the second portion 172 of the bone 170 has a predetermined offset relative to the first surface 151 of the bone implant 150. At step 1318, in embodiments having two anterior holes 153, a drill guide (not shown) which is not engaged by the tool from the tool 100 is inserted in the open hole 153 of the implant 150 not covered by the tool 100. A hole is drilled in the second portion 172 of the bone 170 for fastening the bone implant 150 thereto. At step 1320, the drill guide is removed from the open hole and one of the anterior screws 162 is inserted through the anterior hole 153 and into the anterior calcaneus 172. In some embodiments, if compression is desired, non-locking screws are used. In other embodiments, locking screws are used. Also, in embodiments where the implant has only a single anterior hole 153 and a single posterior hole 153, steps 1318 and 1320 are skipped.
At step 1322, an anterior hole 153 is drilled into the anterior calcaneus, through the drill guide 131 of the drill-through thumb screw 130. At step 1324, drill-through thumb screw 130 containing the drill guide 131 is rotated, until threads 132 of the threaded body 130 disengage from the threads of the second (anterior) portion of the bone implant 150. The insertion tool 100 is removed. At step 1326, the final anterior screw 162 is inserted through the anterior hole 153 and into the anterior calcaneus 172.
At step 1406, the implant 150 is positioned, such that a first surface 151 of the bone implant 150 contacts a first portion 171 of the bone 170, and the implant is used to make a line across the bone using a skin marker. At step 1408, the bone is cut, following the line made at step 1406. At step 1412, an insertion tool 100 is connected to the bone implant 150. In some embodiments, the connection between the tool 100 and the implant 150 is made by inserting the threaded male end 132 of the drill-through thumb screw 130 into female threads of one of the anterior holes 153 of the implant 150. At step 1414, a (temporary) insertion pin 160 is optionally inserted through an opening 123 in the shelf 121 of the track/groove body 120 having the movable contact member 122, so that the threaded end 163 of the pin engages the bone 170 through the opening 123. In some embodiments, the pin 160 has a flange 164, and the pin 160 is inserted until the flange abuts the shelf 121. At step 1416, the shaft 140 of the insertion tool is rotated, so as to adjust the movable contact member 122 until the second portion 172 of the bone 170 has a predetermined offset relative to the first surface 151 of the bone implant 150. At step 1418, in embodiments having two anterior holes 153, a drill guide (not shown) which is not engaged by the tool 100 is inserted in the open hole 153 of the implant 150 not covered by the tool 100. A hole is drilled in the second portion 172 of the bone 170 for fastening the bone implant 150 thereto. At step 1420, the drill guide is removed from the open hole and one of the anterior screws 162 is inserted through the anterior hole 153 and into the anterior calcaneus 172. Steps 1418 and 1420 are then repeated for placement of the open posterior screw 161 after the anterior screw 162 is placed into the anterior calcaneus 172, as indicated by the dashed arrow in
In embodiments where the implant has only a single anterior hole 153 and a single posterior hole 153, steps 1418 and 1420 are skipped. At step 1422, an anterior hole 153 is drilled into the anterior calcaneus, through the drill guide 131 of the drill-through thumb screw 130. At step 1424, drill-through thumb screw 130 containing the drill guide 131 is rotated, until threads 132 of the threaded body 130 disengage from the threads of the second (anterior) portion of the bone implant 150. The insertion tool 100 is removed. At step 1426, the final anterior screws 162 are inserted through the anterior holes 153 and into the anterior calcaneus 172. the drill guide is used to drill and the final posterior screw is placed.
The insertion tool 100 can be used in other ways. For example, the surgeon can preset the position of the groove/track body 200 to provide a desired offset between the anterior calcaneus 172 and the tuberosity 171. Then the surgeon can move the bone portions 171, 172 into position on the tool 100. When the bone portions 171, 172 abut the tool, they have been moved into the desired spatial relationship.
Although a particular example is described above in which the implant is used for a calcaneal osteotomy, one of ordinary skill in the art can readily apply the teachings herein to implants and insertion tools for osteotomies related to other bones besides the calcaneus.
Although the subject matter has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments, which may be made by those skilled in the art.
This application claims priority to U.S. Provisional Patent Application No. 61/695,149, filed Aug. 30, 2012, the entirety of which is incorporated by reference herein.
Number | Date | Country | |
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61695162 | Aug 2012 | US |