WO2010122034A1

WO2010122034A1 - Foot positioning system and method

Info

Publication number: WO2010122034A1
Application number: PCT/EP2010/055218
Authority: WO
Inventors: Emmanuel Lizee
Original assignee: Tornier
Priority date: 2009-04-21
Filing date: 2010-04-20
Publication date: 2010-10-28

Abstract

Embodiments of a foot positioning system include a clamping device and an alignment device. The clamping device is applied around the talus and calcaneus; the alignment device is mounted to the clamping device; a foot orientation is selected relative to the tibia, which may be an arthrodesis position at a valgus angle; a first anterior rod and, advantageously, a lateral rod are aligned with the mechanical axis of the tibia in the coronal and sagittal planes, respectively; the alignment and clamping devices are locked; and the foot is rotated from the arthrodesis position to the drilling position in which a second anterior rod and the lateral rod of the alignment device are aligned with the mechanical axis of the tibia in the coronal and sagittal planes, respectively. The foot may be secured in the drilling position by inserting fixation pins through the alignment and clamping devices and into the tibia.

Description

FOOT POSITIONING SYSTEM AND METHOD

The present application claims the priority of provisional U.S. application No. 61/171 ,344 filed on April 21 , 2009, which is herein incorporated by reference. Embodiments of the present invention relate generally to bone positioning, and more specifically to systems and methods for ankle positioning for arthrodesis.

The orientation and positioning of the ankle during arthrodesis is often an important aspect of the procedure, and will also determine the ankle's position after surgery. Surgeons who perform ankle arthrodesis currently often orient and position the ankle using their unaided visual judgment and/or thal-and-error positioning methods. After a desired ankle position is achieved, surgeons also often experience difficulty in maintaining the desired position during drilling and other aspects of the procedure. Such basic positioning methods often increase the time of the procedure, lead to inconsistency in different procedures, and may result in less-than-optimal positioning.

Some arthrodesis procedures require the implantation of a bent or curved nail or support bar through the calcaneus, the talus, and into the tibia. For example, the implantation nail may include a valgus angle of approximately six degrees. However, although the implantation nail is bent, the hole drilled through the calcaneus, talus, and tibia must be relatively straight.

An embodiment of the present invention permits the ankle to be positioned between an arthrodesis position and a drilling position with a higher degree of precision.

To this end, embodiments of the invention provide systems and a method for positioning foot with respect to tibia for ankle arthrodesis, which are respectively defined in appended claims 1 , 16 and 24.

Additional advantageous features of the system according to embodiments of the invention, taken in isolation or in any technically feasible combination, are specified in dependent claims 2 to 15, 17 to 23 and 25 to 35. Thus, a foot positioning system according to embodiments of the present invention includes a clamping device and an alignment device. The clamping device may include an upper arm placed above the talus and a screw arm placed under the calcaneus. The screw arm is tightened until the clamping device is held to the ankle by a compression of the talus and calcaneus between the upper arm and the screw arm, according to embodiments of the present invention. Once attached in this manner, the clamping device moves with the ankle as the ankle is rotated with respect to the tibia. The alignment device includes one or more screws or pegs that slide within one or more slots on the clamping device, as well as alignment rods extending from the alignment device. The alignment device is placed onto the clamping device, and a desired foot position is found at least in part by aligning a bent valgus anterior rod and, advantageously, a lateral rod of the alignment device with the mechanical axis of the tibia. The angle of the bent valgus anterior rod corresponds substantially with the valgus angle of the selected arthrodesis implant nail, according to embodiments of the present invention.

The alignment device is attached (e.g. by a compression screw) to the clamping device, and then the ankle is rotated through an angle to align an unbent valgus anterior rod and the lateral rod of the alignment device with the mechanical axis of the tibia, to place the ankle in the drilling position. Once in the drilling position, one or more pins may be inserted through apertures in the alignment device and into the tibia, to secure the alignment device to the tibia. In addition, one or more pins may be inserted through an annular opening in the screw arm, through the calcaneus, the talus, and into the tibia, to further secure the alignment device to the foot and to prevent undesired rotation of the ankle during subsequent drilling and/or preparation steps.

While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

FIG. 1 illustrates a front perspective view of a clamping device, according to embodiments of the present invention. FIG. 2 illustrates a front perspective view of an alignment device, according to embodiments of the present invention. FIG. 3 illustrates a front perspective view of the clamping device of FIG. 1 being applied to a foot, according to embodiments of the present invention.

FIG. 4 illustrates a front perspective view of the alignment device of FIG. 2 being applied to the clamping device, according to embodiments of the present invention.

FIG. 5 illustrates a front perspective view of a clamping device and an alignment device, according to embodiments of the present invention.

FIG. 6 illustrates a front elevation view of a valgus anterior alignment rod substantially aligned with a mechanical axis of a tibia, according to embodiments of the present invention.

FIG. 7 illustrates a side elevation view of another alignment rod substantially aligned with a mechanical axis of a tibia, according to embodiments of the present invention.

FIG. 8 illustrates a front elevation view of drilling position alignment rod substantially aligned with a mechanical axis of a tibia, according to embodiments of the present invention.

FIG. 9 illustrates a front perspective view of fixation pins inserted through the alignment device and the clamping device into the tibia, the calcaneus, and the talus, according to embodiments of the present invention. FIG. 10 illustrates a front perspective view of an alternative embodiment of a clamping device, according to embodiments of the present invention.

FIG. 11 depicts a flow chart illustrating a method for using an alignment device and clamping device, according to embodiments of the present invention.

While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. Embodiments of the present invention permit surgeons to more precisely move the subject's foot between a desired arthrodesis position and an alternative position in which drilling or other preparatory steps are performed. FIG. 1 illustrates a front perspective view of a clamping device 100, according to embodiments of the present invention. Clamping device 100 includes a general C-shape formed by the handle 102, the lower support bar 104, and the upper support bar 108. The lower support bar 104 may be secured to the handle 102 at one end 122 with a set screw 124. The lower support bar 104 may alternatively be rigidly and/or permanently coupled with the handle 102 at end 122, according to embodiments of the present invention. The lower support bar 104 may be threadably coupled at its other end 120 to a screw element 106. Screw element 106 may include a handle portion 1 14 configured to facilitate turning of screw element 106 within lower support bar 104. Screw element 106 may also include an endcap 1 16 configured for placement against an underside of the calcaneus. The endcap 1 16 may include nubs or cleats 1 18 to improve interaction with the calcaneus and minimize slippage of the screw element 106 with respect to the calcaneus, according to embodiments of the present invention. According to some embodiments of the present invention, the screw element 106 includes a threaded outer surface, and the end 120 of lower support bar 104 includes a threaded inner surface around the screw element 106, such that turning the screw element 106 (with handle 1 14, for example) advances the screw element 106 into or out of the lower support bar 104. According to some embodiments of the present invention, the handle 102 is rigidly coupled with the upper support bar 108 at joint 132; according to other embodiments of the present invention, the handle 102 is movably and/or adjustably coupled with the upper support bar 108 at joint 132. Upper support bar 108 includes a talus fork 1 10 and an alignment track 1 12, according to embodiments of the present invention. The talus fork 1 10 includes two tines configured for placement at the top of the talus, according to embodiments of the present invention. The talus fork 1 10 includes a general V-shape and/or U-shape to permit placement over the talus while minimizing tissue damage and potential slippage with respect to the talus, according to embodiments of the present invention. The talus fork 1 10 may further include nubs or cleats 130 on its underside for improved interaction with the talus and/or to minimize slippage of the talus fork 110 with respect to the talus, according to embodiments of the present invention.

The alignment track 112 is rigidly fixed to the upper support bar 108 and includes one or more slots 126 and/or holes 128 to receive corresponding screws, pegs, and/or protrusions of an alignment device, according to embodiments of the present invention. The alignment device is shown as generally semi-circular in shape, although based on the disclosure provided herein, one of ordinary skill in the art will appreciate that numerous shapes are possible. For example, the alignment track 112 may include a rectangular shape with slots 126 that extend at least partially along an arc of a circle.

FIG. 2 illustrates a front perspective view of an alignment device 200, according to embodiments of the present invention. Alignment device 200 includes a base 202, alignment rods 204, 206, 208, pin mounts 212, 214, and screw 218, according to embodiments of the present invention. Rods 204 and 208 are anterior rods that form an angle with respect to each other, while rod 206 is a lateral rod, according to embodiments of the present invention. The angle between rod 204 and rod 208 may be imparted by bending rod 204 and/or rod 208 at or near the base 202. Alternatively, rods 204 and 208 may be straight or substantially straight rods which are mounted on the base 202 at an angle with respect to each other. Alternatively, rods 204, 208 may be a single rod mounted to the base 202 which is split into two rod halves that form an angle with respect to each other. FIG. 6 illustrates an angle 602 between rod 204 and rod 208 substantially in the coronal plane, according to embodiments of the present invention. Angle 602 may be six degrees, according to embodiments of the present invention. Alternatively, angle 602 may be any desired angle corresponding to a preferred arthrodesis angle or a preferred drilling angle or another preferred angle for the foot with respect to the tibia for a surgical step, according to embodiments of the present invention.

Pin mounts 212, 214 may protrude from a top surface of the base 202, and may include pegs 216 which extend from the bottom surface of the base 202. Pegs 216 may be configured to fit within and interact with the one or more slots 126 of the clamping device 100, according to embodiments of the present invention. Pin mounts 212, 214 may each include fixation pin holes 220 through which one or more fixation pins may be placed for fixation to the tibia. Multiple fixation pin holes 220 may be provided at different vertical levels on pin mounts 212, 214 in order to provide different placement options for the fixation pins, and/or placement options for multiple fixation pins through each pin mount 212, 214, according to embodiments of the present invention.

A screw 218 may also extend through a slot 210 in the base 202; screw 218 may be configured for threadable engagement with the one or more holes 128 in the clamping device 100. One or more compression screws 218 may be included to removably couple the alignment device 200 with the clamping device 100, according to embodiments of the present invention. When screw 218 is placed through slot 210 and engaged with hole 128 and tightened, alignment device 200 does not rotate or translate with respect to clamping device 100, according to embodiments of the present invention. Based on the disclosure provided herein, one of ordinary skill in the art will realize that one or more screws 218 may be used on the base 202 and/or the alignment track 1 12, and may be used to interface with one or more holes 128 and/or slots 210, 126, and/or one or more nuts and/or washers (not shown) to couple the alignment device 200 with the clamping device 100. The alignment device 200 may also be adjusted relative to and affixed to the clamping device 100 in other ways. The clamping device 100 may be used for either left side or right side application (and may thus be used on either side of either foot), according to embodiments of the present invention. The alignment device 200 may include different left and right designs for use depending upon which foot and also which side of the foot on which the clamping device 100 is used, such that the anterior alignment rods extend in front of the tibia and the lateral alignment rod extends to the side of the tibia, according to embodiments of the present invention.

FIG. 3 illustrates a front perspective view of the clamping device 100 being applied to a foot 300, according to embodiments of the present invention. The foot 300 includes a calcaneus 302 and a talus 304. The talus fork 1 10 is placed over the talus 304 (e.g. over the talus dome and at least partially below the tibia 306), and the screw element 106 is placed below the calcaneus 302. The handle 1 14 of the screw element 106 is turned to move the endcap 1 16 closer toward the fork 110 until the endcap 116 contacts the bottom of the calcaneus 302, according to embodiments of the present invention. In external applications, the screw element 106 is turned to move the endcap 116 closer to toward the fork 110 until the endcap 116 contacts the bottom of the subject's foot directly under the calcaneus (e.g. the subject's skin under the calcaneus 302). The screw element 106 may be tightened as desired by the surgeon. For example, the screw element 106 may be tightened to create sufficient compression between the talus fork 110 and the screw element 106 such that adjusting the angle of the foot with respect to the tibia 306 using handle does not result in any significant slippage of the talus fork 110 with respect to the talus 304 or of the endcap 116 with respect to the calcaneus 302. According to some embodiments of the present invention, the endcap 116 is free to rotate with respect to the screw element 106, such that rotating the screw element 106 does not force rotation of the endcap 116, in order to prevent or minimize soft tissue damage. FIGS. 4 and 5 illustrate the alignment device 200 being applied to or mounted to the clamping device 100, according to embodiments of the present invention. Pegs 216 and screw 218 are configured to interface with slots 126 and holes 128, such that pegs 216 slide within slots 126 to permit the base 202 to slide with respect to the alignment track 112 through different radial angular orientations, as illustrated by arrow 502, according to embodiments of the present invention. Once the clamping device 100 has been secured around the talus 304 and calcaneus 302, the foot 300 may be oriented in a desired or preferred arthrodesis position with respect to the tibia 306. While the foot 300 is oriented in the arthrodesis position, the anterior rod 208 of the alignment device 200 may be aligned with the mechanical axis of the tibia 306 in a substantially coronal plane (as illustrated in FIG. 6), and the lateral rod 206 may be aligned with the mechanical axis of the tibia 306 in a substantially sagittal plane (as illustrated in FIG. 7). Once the foot 300 is in the arthrodesis position, and the anterior rod 208 and lateral rod 206 aligned with the mechanical axis of the tibia 306, the alignment device 200 may be coupled with the clamping device 100 such that the position and/or angular orientation of the alignment device 200 is no longer permitted to change with respect to the clamping device 100. This may be accomplished by, for example, tightening one or more compression screws 218 through slot 210 and into one or more holes 128. This step may be referred to as "locking" the alignment device 200 with respect to the clamping device 100.

The arthrodesis position of the foot 300 with respect to the tibia 306 is typically at a valgus angle, such as a valgus angle of six degrees. Because a hole for an arthrodesis nail must typically be drilled in a straight line through the foot 300 and into the tibia 306, the foot 300 must often be repositioned from the arthrodesis position into a drilling position. Once the alignment device 200 has been locked to the clamping device 100 as described above, the foot 300 may be moved from the arthrodesis position to the drilling position by aligning the anterior rod 204 with the mechanical axis of the tibia 306 in a substantially coronal plane, as illustrated in FIG. 8, and by aligning the lateral rod 206 with the mechanical axis of the tibia 306 in a substantially sagittal plane, similar to the illustration in FIG. 7, according to embodiments of the present invention. As seen in FIG. 6, the angle through which the foot 300 is rotated between the arthrodesis and drilling positions substantially corresponds to the angle 602 between anterior rods 204 and 208. Thus, the angle 602 may be customized for a particular surgeon and/or a particular operation, arthrodesis nail, or patient. According to some embodiments of the present invention, multiple alignment devices 200 are provided, each having a different angle 602, and each being capable of being locked to the clamping device 100.

Once the foot 300 is in the drilling position, it may be fixed in the drilling position by placing one or more fixation pins 902 inserted through the one or more fixation pin holes 220 and into the tibia, and/or by placing a long fixation pin 904 through the screw element 106 and into the calcaneus, talus, and tibia, as illustrated in FIG. 9, according to embodiments of the present invention. The screw element 106 may be cannulated in order to permit insertion of long fixation pin 904 and/or insertion of a drill bit therethrough, according to embodiments of the present invention. According to some embodiments of the present invention, the holes for the fixation pins 902, 904 are drilled. According to some embodiments of the present invention, the fixation pin 904 itself is a drill bit. Once the long fixation pin 904 has been placed as illustrated in FIG. 9, the screw element 106 and endcap 116 may be loosened and removed, and another instrument (not shown) may be used to bore around the fixation pin 904, according to embodiments of the present invention. Once the necessary drilling and other preparations have been made for the arthrodesis nail, the arthrodesis nail may be installed. FIG. 10 illustrates a front perspective view of an alternative embodiment of a clamping device 1000, which is similar to clamping device 100 in which the upper support bar 108 is replaced with upper support bar 1002, according to embodiments of the present invention. Providing a curvature to upper support bar 1002 may help minimize soft tissue damage in installation of the clamping device 1000, according to embodiments of the present invention. FIG. 11 depicts a flow chart illustrating a method 1400 for using an alignment device and clamping device, according to embodiments of the present invention. A clamping device 100 is applied around a talus 304 and calcaneus 302 (block 1402), as illustrated in FIG. 3. The alignment device 200 is mounted to the clamping device (block 1403) as illustrated in FIGS. 4 and 5. A foot 300 orientation, such as an arthrodesis position of foot 300 with respect to tibia 306, is selected (block 1404). This arthrodesis foot orientation may be at a six degree valgus angle, according to embodiments of the present invention. The valgus angle anterior rod 208 of the alignment device 200 is aligned with the mechanical axis of the tibia 306, and the lateral rod 206 of the alignment device 200 is aligned with the mechanical axis of the tibia 306 (block 1406), as illustrated in FIGS. 6 and 7. The alignment device 200 is locked with respect to the clamping device (block 1408). The foot 300 may be rotated from the selected arthrodesis position to a drilling or other surgical position by aligning the zero degree anterior rod 204 with the mechanical axis of the tibia 306 and the lateral rod 206 with the mechanical axis of the tibia 306 (block 1410), as illustrated in FIG. 8, and securing fixation pins 902, 904 through the alignment device 200 and clamping device 100 and into the tibia 306 (block 1412), as illustrated in FIG. 9.

Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the appended claims, together with all equivalents thereof.

Claims

1. A system for positioning a foot with respect to a tibia for ankle arthrodesis, the system comprising: - a clamping device (100; 1000) adapted to be fixedly held to the foot, and

- at least one alignment device (200) adapted to be adjustably mounted and fixedly locked to the clamping device such that, when the clamping device is held to a foot (300), a first alignment rod (208) of this alignment device is aligned with a mechanical axis of the tibia (306) in a first anatomical plane, in particular in a coronal plane, and wherein the at least one alignment device (200) further includes a second alignment rod (204) which forms a predetermined angle (602) with respect to the first alignment rod (208) in the first anatomical plane.

2. The system according to claim 1 , wherein the at least one alignment device (200) further includes a third alignment rod (206) adapted to be aligned with the mechanical axis of the tibia (306) in a second anatomical plane, in particular a sagittal plane, when the clamping device (100; 1000), held to the foot (300) and locked with respect to this alignment device, is moved to align successively the first and the second alignment rods (208, 204) with the mechanical axis of the tibia in the first anatomical plane.

3. The system according to claim 1 or claim 2, wherein the clamping device (100; 1000) and the at least one alignment device (200) are adapted to be mounted to each other in a sliding manner along at least one sliding slot (126, 210).

4. The system according to claim 3, wherein the at least one sliding slot

(126, 210) extends at least partially along an arc of a circle.

5. The system according to one of claims 1 to 4, wherein the clamping device (100; 1000) and the at least one alignment device (200) are adapted to be locked to each other by a threadable engagement.

6. The system according to claim 5, wherein the threadable engagement includes at least one screw (218) adapted to be tightened in an associated hole

(128).

7. The system according to any one of claims 1 to 5, wherein the clamping device (100; 1000) includes first (104) and second (108; 1002) support bars adapted to receive and compress between them the calcaneus (302) and the talus (304) of the foot (300).

8. The system according to claim 7, wherein the first support bar (104) is coupled to a screw element (106), wherein the screw element is adapted to be tightened to move an endcap (1 16) of the screw element toward the second support bar (108; 1002) until the endcap contacts the bottom of the calcaneus (302) or until the endcap contacts the bottom of the skin below the calcaneus.

9. The system according to claim 8, wherein the endcap (1 16) is free to rotate with respect to the screw element (106).

10. The system according to any one of claims 7 to 9, wherein the second support bar (108; 1002) is provided with a general V-shape or U-shape fork (1 10) adapted to be placed over the talus (304).

1 1 . The system according to any one of claims 7 to 10, wherein the second support bar (1002) is curved.

12. The system according to any one of claims 7 to 1 1 , wherein the clamping device (100; 1000) further includes a handle (102) which links the first (104) and second (100; 1000) support bars.

13. The system according to any one of claims 1 to 12, wherein one of the first and second alignment rods (208, 204) is straight, the other being bent with an angle corresponding to the predetermined angle (602).

14. The system according to any one of claims 1 to 13, wherein the predetermined angle (602) is equal to six degrees.

15. The system according to any one of claims 1 to 14, wherein the system comprises a plurality of alignment devices (200) each having a respective predetermined angle (602) different from the other alignment devices (200) of the plurality of alignment devices (200).

16. A method for positioning a foot with respect to a tibia for ankle arthrodesis, the method comprising steps in which: - a clamping device is fixedly held to a foot, - an alignment device is adjustably mounted then fixedly locked to the clamping device such that, when the foot is in an arthrodesis position with respect to a tibia, a first alignment rod of the alignment device is aligned with a mechanical axis of the tibia in a predetermined anatomical plane, in particular in a coronal plane,

- the foot is moved from the arthrodesis position to a surgical preparation position, in which a second alignment rod of the alignment device is aligned with the mechanical axis of the tibia in the predetermined anatomical plane, the second alignment rod forming a predetermined angle with respect to the first alignment rod in the predetermined anatomical plane, and

- when the foot is in the surgical preparation position, the foot and the tibia are surgically prepared.

17. A method, comprising: applying a clamping device around a talus and a calcaneus of a foot; mounting an alignment device to the clamping device, wherein the alignment device comprises a first rod and a second rod, wherein an angle is formed between the first rod and the second rod; positioning the foot in an arthrodesis foot orientation with respect to a tibia; locking the alignment device to the clamping device when the first rod is aligned with a mechanical axis of the tibia in a substantially coronal plane and when the foot is in the arthrodesis foot orientation; rotating the foot through the angle in the substantially coronal plane until the second rod is aligned with the mechanical axis of the tibia in the substantially coronal plane, to place the foot in a surgical preparation orientation with respect to the tibia; and fixing a position of the alignment and clamping devices with respect to the tibia when the foot is in the surgical preparation orientation.

18. The method of claim 17, wherein the alignment device comprises a third rod, wherein locking the alignment device to the clamping device further comprises locking the alignment device to the clamping device when the third rod is aligned with the mechanical axis of the tibia in a substantially sagittal plane, and wherein the third rod is also aligned with the mechanical axis of the tibia in the substantially sagittal plane when the foot is in the surgical preparation orientation.

19. The method of one of claims 17 and 18, wherein the angle is six degrees.

20. The method of one of claims 17 to 19, further comprising drilling a hole into the tibia using as a guide fixation pin holes on the alignment device.

21 . The method of one of claims 17 to 20, further comprising inserting a fixation pin through the alignment device and into the tibia, wherein the fixation pin substantially fixes the movement of the alignment device with respect to the tibia.

22. The method of one of claims 17 to 21 , wherein the clamping device comprises a talus fork and an endcap, and wherein applying the clamping device around the talus and the calcaneus comprises inserting the talus fork between the tibia and the talus and adjusting a distance between the talus fork and the endcap until the talus and the calcaneus are compressed between the talus fork and the endcap.

23. The method of one of claims 17 to 22, wherein the clamping device comprises a cannula, the method further comprising inserting an arthrodesis nail through the cannula and into the calcaneus, the talus, and the tibia.

24. A system for ankle arthrodesis, the system comprising: a clamping device configured to be fixedly attached to a foot, such that the foot is movable with respect to a tibia when the clamping device is applied to the foot; an alignment device adjustable relative to the clamping device, the alignment device comprising a first angle indicator and a second angle indicator, wherein an angle formed between the first angle indicator and the second angle indicator substantially corresponds to an angle through which the foot is rotated about the tibia in a substantially coronal plane between an arthrodesis orientation and a surgical preparation orientation; and a locking mechanism configured to lock a position of the alignment device with respect to the clamping device.

25. The system of claim 24, wherein at least one of the first and second angle indicators is a rod.

26. The system of one of claims 24 or 25, wherein the foot comprises a talus and a calcaneus, and wherein the clamping device comprises: a talus fork configured for placement between the tibia and the talus; and an endcap configured for placement against a bottom of the calcaneus or a bottom of skin under the calcaneus.

27. The system of claim 27, wherein a distance between the talus fork and the endcap is adjustable.

28. The system of one of claims 26 or 27, wherein the endcap rotates freely with respect to other components of the clamping device.

29. The system of one of claims 24 to 28, wherein the clamping device comprises a slot, wherein the alignment device comprises a protrusion, and wherein the alignment device is adjustable relative to the clamping device by sliding the protrusion within the slot.

30. The system of one of claims 24 to 29, wherein the alignment device comprises a slot, wherein the clamping device comprises a protrusion, and wherein the alignment device is adjustable relative to the clamping device by sliding the protrusion within the slot.

31. The system of one of claims 29 or 30, wherein the slot extends at least partially along an arc of a circle.

32. The system of claim 31 , wherein a center of the circle substantially coincides with a mechanical axis of the tibia.

33. The system of one of claims 24 to 32, wherein the alignment device comprises a third angle indicator, and wherein the third angle indicator is configured for alignment with a mechanical axis of the tibia in a substantially sagittal plane in both the arthrodesis orientation and the surgical preparation orientation of the foot.

34. The system of one of claims 24 to 33, wherein the angle is six degrees.

35. The system of one of claims 24 to 34, wherein the angle corresponds to a valgus angle of approximately six degrees.