First Metatarsal Lateral Release Instruments and Techniques

Abstract

Instruments and techniques can be used to free the first metatarsal for realignment. In some implementations, the techniques involve surgically accessing the sesamoid ligament of the patient's foot and advancing a guide prong of a cutting instrument under the sesamoid ligament. This can trap the sesamoid ligament between the guide prong of the cutting instrument and a cutting surface of the cutting instrument that is concave relative to the distal end of the guide prong. The techniques further involve severing the sesamoid ligament with the cutting surface of the cutting instrument.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 313,131, filed February 23, 2022, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THEINVENTION The present disclosure relates to instruments and techniques for performing bone realignment procedures, and more particularly, to instruments and techniques for releasing bones to allow for their repositioning. [Background technology]

[0003] Bones in the human body, such as the bones of the foot, can be anatomically misaligned. For example, one common type of bone deformity is hallux valgus, a progressive foot deformity in which the first metatarsophalangeal joint is affected and is often associated with significant functional disability and foot pain. The metatarsophalangeal joint is laterally misaligned, with the first metatarsal bone abducting while the phalanges are adducting. This often leads to the development of soft tissue and a bony prominence on the medial side of the foot, called hallux valgus.

[0004] In some cases, surgical intervention is required to address hallux valgus and / or other bone deformities. Surgical intervention may include realigning one or more bones of the foot to improve patient comfort and increase patient mobility. Clinicians may use a variety of different surgical instruments, including one or more cutting instruments for cutting tissue and / or bone, during surgical procedures performed on the foot. Surgical instruments that can facilitate efficient, accurate, and reproducible clinical results are useful to practitioners performing bone realignment techniques. Summary of the Invention

[0005] In general, the present disclosure is directed to orthopedic cutting instruments, as well as associated systems and techniques that utilize such cutting instruments. In some examples, an orthopedic cutting instrument according to the present disclosure can be used to cut and release soft tissue, such as a ligament on the lateral side of the first metatarsal of the foot. This can help mobilize the first metatarsal for subsequent realignment, for example, by cutting soft tissue connected to the first metatarsal that would otherwise prevent repositioning of the bone during a realignment procedure.

[0006] For example, during a metatarsal realignment procedure, a clinician may surgically access the capsule of the metatarsophalangeal joint between the distal end of the first metatarsal and the proximal end of the proximal phalange. Using a scalpel, the clinician may incise to the outside of the capsule to expose soft tissue, such as one or more sesamoid ligaments on the outside of the first metatarsal. The clinician may then utilize a cutting instrument according to the present disclosure to cut the soft tissue accessed through the incision made in the capsule. The clinician may insert a head of the cutting instrument through the incision in the skin and capsule and use the head of the cutting instrument to selectively capture and cut the targeted soft tissue.

[0007] In some implementations, a cutting instrument according to the present disclosure is configured with a cutting surface and a guide protrusion extending outwardly relative to the cutting surface. The guide protrusion may be a region of relatively smaller cross-sectional area than the entire cutting head of the cutting instrument. For example, the guide protrusion may be defined by a protrusion having a cylindrical, rectangular, and / or other cross-sectional shape extending outwardly from the remainder of the cutting head. The guide protrusion may terminate in a blunt distal end that is not configured to cut tissue. A cutting surface recessed from the distal end of the guide protrusion may be provided.

[0008] In use, the clinician can advance the guide protrusion of the cutting head into an incision through the patient's skin toward the target soft tissue to be cut, such as one or more ligaments to be cut. The clinician can advance the guide protrusion under the soft tissue to be cut, for example, to position the guide protrusion between the soft tissue to be cut and underlying soft tissue and / or bone that is not intended to be cut. In this process, the clinician can trap the soft tissue to be cut between the guide protrusion and the cutting surface of the cutting instrument. The clinician can then further advance the cutting instrument to cut the captured soft tissue with the cutting surface. In this manner, the cutting instrument can enable the clinician to precisely target the soft tissue to be cut using the cutting instrument, helping to avoid inadvertent or untargeted cuts that may occur if the clinician simply pokes a scalpel into the general area of ​​the tissue intended to be cut.

[0009] In one example, a method of releasing a first metatarsal for realignment is described. The method includes surgically accessing a sesamoid ligament of a patient's foot and advancing a guide prong of a cutting instrument under the sesamoid ligament, thereby capturing the sesamoid ligament between the guide prong of the cutting instrument and a cutting surface of the cutting instrument that is concave relative to a distal end of the guide prong. The method also involves thereafter severing the sesamoid ligament with the cutting surface of the cutting instrument.

[0010] In another example, a method of realigning at least a portion of a first metatarsal is described. The method includes surgically accessing a sesamoid ligament of a patient's foot and advancing a guide prong of a cutting instrument under the sesamoid ligament, thereby capturing the sesamoid ligament between the guide prong of the cutting instrument and a cutting surface of the cutting instrument that is concave relative to a distal end of the guide prong. The method then includes cutting the sesamoid ligament with the cutting surface of the cutting instrument. The method also involves displacing at least a portion of the first metatarsal in at least one plane and fixing the displaced position of the portion of the first metatarsal by applying at least one bone fixation device.

[0011] In another example, an instrument configured to cut tissue to mobilize a first metatarsal of a foot is described. The instrument includes a handle extending from a first end to a second end and a cutting head on the second end of the handle. The example provides that the cutting head includes a cutting surface and a guide protrusion terminating at a distal end. According to the example, the cutting surface is concave relative to the distal end of the guide protrusion, and the cutting head is sized to be inserted into an intermetatarsal space between the first and second metatarsal of the foot.

[0012] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0013] [Figure 1A] FIG. 1A is a side view of an exemplary orthopaedic cutting instrument according to the present disclosure.

[0014] [Figure 1B] FIG. 1B is an enlarged perspective view of the cutting head of the cutting instrument of FIG. 1B.

[0015] [Figure 2A-2B] 2A and 2B are enlarged side and bottom views, respectively, of the cutting head of the cutting instrument of FIGS. 1A and 1B.

[0016] [Figure 2C] FIG. 2C is a perspective view of an exemplary configuration of a cutting instrument shown with a cutting head configured with two guide projections. [Figure 2D] FIG. 2D is a top view of an exemplary configuration of a cutting instrument shown with a cutting head configured with two guide projections.

[0017] [Figure 2E] FIG. 2E is a side view of the cutting instrument of FIGS. 1A and 1B illustrating an exemplary configuration in which the cutting head is angled relative to the handle.

[0018] [Figure 3A-3B] 3A and 3B are top and front views, respectively, of the foot showing an exemplary normal metatarsal alignment position.

[0019] [Figure 4] FIG. 4 shows the different anatomical planes of the foot.

[0020] [Diagram 5] FIG. 5 is a superior lateral view of the bone-ligament-capsule anatomy of the first MTP joint.

[0021] [Figure 6A-6B] Figures 6A and 6B are medial and lateral views, respectively, of the first metatarsophalangeal joint (MTP) with the extensor aponeurosis structures removed to show certain structural elements of the plantar capsular ligament-sesamoid complex.

[0022] [Figure 7] FIG. 7 is a lateral view of the first metatarsophalangeal (MTP) joint further illustrating the soft tissue anatomy in the joint.

[0023] [Figure 8] FIG. 8 is a flow diagram of an exemplary bone realignment technique that may be implemented utilizing a cutting instrument in accordance with the present disclosure.

[0024] [Figure 9] 9 and 10 are posterior views of the foot showing exemplary incision locations lateral to the MTP joint capsule to access the underlying sesamoid ligament. [Figure 10] 9 and 10 are posterior views of the foot showing exemplary incision locations lateral to the MTP joint capsule to access the underlying sesamoid ligament. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present disclosure generally relates to orthopedic cutting instruments and associated systems (e.g., kits), as well as techniques incorporating one or more such cutting instruments. In some examples, a cutting instrument according to the present disclosure may be used to cut one or more ligaments and / or other soft tissues to mobilize the bone for subsequent realignment. For example, the cutting instrument may be used to perform a lateral release during a metatarsal realignment procedure. In these applications, the cutting instrument can be used to cut one or more ligaments and / or other soft tissues on the lateral side of the metatarsal, e.g., adjacent to the distal head of the metatarsal. For example, the instrument can be inserted through an incision that accesses the intermetatarsal space between a first metatarsal and an adjacent second metatarsal to cut one or more ligaments and / or other targeted tissues within the intermetatarsal space. This can mobilize the first metatarsal for subsequent realignment in one or more planes of the entire metatarsal or portions thereof (e.g., the distal portion of the metatarsal when performing an osteotomy to cut the metatarsal into proximal and distal portions). The instrument may be particularly useful for performing a lateral release of the first metatarsal, although in practice a clinician may use the instrument to cut any target soft tissue, including to release other bones and / or joints of the foot without departing from the scope of this disclosure.

[0026] In exemplary applications, the devices, systems, and techniques can be used during surgical procedures performed on one or more bones, such as bone alignment, osteotomies, fusion procedures, fracture repair, and / or other procedures in which one or more bones are set in a desired position. Such procedures can be performed on bones, such as bones of the foot or hand, where the bones are relatively small compared to bones in other parts of the human anatomy (e.g., adjacent bones separated by joints or different parts of a single bone). In one example, a procedure utilizing the devices and / or techniques of the present disclosure can be performed to correct alignment between a metatarsal bone (e.g., first metatarsal) and a cuneiform bone (e.g., medial cuneiform), such as hallux valgus correction. An example of such a procedure is the Lapidus procedure. In another example, the devices, systems, and / or techniques can be utilized when modifying the position of one portion of a bone relative to another portion of the same bone. An example of such a procedure is an osteotomy (e.g., metatarsal osteotomy) in which a bone is cut into at least two different bones and one portion (e.g., a distal portion) is realigned relative to another bone portion (e.g., a proximal portion) of the same bone.

[0027] Preparation and realignment of one or more bones or bone segments may be performed according to the present disclosure for various clinical reasons and indications. Preparation, realignment, and fusion of one bone (or a portion thereof) to another bone (or a portion thereof) may be performed to treat metatarsal hallux valgus and / or other bone and / or joint conditions. Hallux valgus, also called hallux valgus abductus, is a complex, progressive condition characterized by lateral deviation (valgus, abduction) of the great toe and medial deviation of the first metatarsophalangeal joint. Hallux valgus typically results in a progressive increase in the hallux adduction angle, i.e., the angle between the long axis of the first metatarsal and the proximal phalanges in the transverse plane. An increase in hallux adduction angle may tend to laterally displace the plantar aponeurosis and the tendons of the intrinsic and extrinsic muscles that cross the first metatarsophalangeal joint from the metatarsal to the hallux. As a result, the sesamoid may also be displaced laterally relative to the first metatarsophalangeal joint, for example, resulting in subluxation of the joint between the sesamoid and the first metatarsal head, which may increase pressure between the medial sesamoid and the crest of the first metatarsal head.

[0028] Although the techniques and devices are generally described herein in relation to the first metatarsal and medial cuneiform bones of the foot, these techniques and devices may be used with other adjacent bones (e.g., separated from one another by a joint) and / or adjacent bone portions (e.g., portions of the same bone separated from one another by a fracture or osteotomy). In various examples, the disclosed devices, systems, and / or techniques may be utilized with smaller bones of the foot, such as metatarsals (e.g., first, second, third, fourth, or fifth metatarsals), cuneiforms (e.g., medial, middle, lateral), cuboid, phalanges (e.g., proximal, middle, distal), and / or combinations thereof. The bones may be separated from one another by a tarsometatarsal ("TMT") joint, a metatarsophalangeal ("MTP") joint, an intermetatarsal space, or other joint or bone space. Thus, references herein to the first metatarsal and medial cuneiform bones may be substituted with other bone pairs as described herein.

[0029] The anatomy of the foot and an exemplary technique for utilizing a cutting instrument according to the present disclosure will be described in more detail with respect to Figures 3-10. However, an exemplary orthopaedic cutting instrument according to the present disclosure will first be described with respect to Figures 1 and 2.

[0030] FIG 1A is a side view of an exemplary orthopedic cutting instrument 10 according to the present disclosure. FIG 1B is an enlarged perspective view of a cutting head of the cutting instrument. In the illustrated example of FIGS. 1A and 1B, the cutting instrument 10 includes a handle 12 and a cutting head 14 operably connected to the handle. For example, in the illustrated configuration, the handle 12 has a main length extending from a first end 16 to a second end 18. The cutting head 14 is connected to and extends from the second end 18 of the handle 12. In various implementations, the handle 12 and the cutting head 14 may be manufactured as a unitary body (e.g., cut or cast as a single piece of material) or may be manufactured as separate components that are joined together to form a combined structure that does not separate during use.

[0031] As described in more detail below, the cutting head 14 can include a guide projection 20 and a cutting surface 22. The guide projection 20 extends outwardly relative to the cutting surface 22. As a result, the cutting surface 22 is concave relative to the distal end of the guide projection 20. In use, a clinician can advance the cutting head 14 of the cutting instrument 10 toward the target tissue to be cut, e.g., one or more ligaments to be cut. The clinician can use the guide projection 20 to guide the forward movement of the cutting instrument. The clinician can advance the cutting head 14 toward the targeted soft tissue for cutting, e.g., one or more ligaments, to position the guide projection 20 beneath the one or more ligaments to be cut. For example, the clinician can advance the guide projection 20 between the one or more ligaments to be cut and the underlying soft tissue and / or bone. This can capture the targeted tissue (e.g., one or more ligaments) within a notch 24 formed between the guide projection 20 and the cutting surface 22. With the targeted tissue captured within the notch 24, the clinician may push the cutting instrument 10 further forward causing the cutting surface 22 of the cutting instrument to slice through the tissue captured within the notch. In this manner, the cutting instrument 10 can enable the clinician to precisely cut targeted tissue, such as one or more ligaments, without inadvertently cutting surrounding tissue that is not targeted to be cut.

[0032] While the cutting instrument 10 may be used for any desired surgical procedure, in some configurations, the cutting instrument is configured (e.g., sized and shaped) to facilitate cutting within a joint space between opposing bones of the foot. For example, the cutting head 14 of the cutting instrument 10 may be configured to be inserted into the intermetatarsal space between a first metatarsal bone and an adjacent second metatarsal bone. A clinician may insert the cutting head 14 of the cutting instrument 10 into a target joint space to cut soft tissue (e.g., muscle, tendon, ligament, and / or fascia) within the joint space. Such soft tissue may be connectively attached to one or more bones (e.g., metatarsals, sesamoids) that are intended to be realigned. Cutting the soft tissue using the cutting instrument 10 can mobilize the bone for subsequent realignment. For example, cutting the soft tissue using the cutting instrument 10 can mobilize the bone for subsequent rotation in the frontal plane and / or movement in the transverse plane. After realignment and other associated surgical steps, the realigned bone may be permanently fixed in the moved position using a fixation device to promote fusion of the realigned bone.

[0033] 2A and 2B (collectively referred to as "FIG. 2") are enlarged side and bottom views, respectively, of the cutting head 14 of the cutting instrument 10 from FIGS. 1A and 1B. FIG. 2 shows the cutting head 14 including a cutting surface 22 that defines a leading cutting edge 26. The leading cutting edge 26 can define a distal-most edge of the cutting surface 22 that contacts the tissue to be cut in use. The cutting head 14 is also shown as including a guide projection 20 that projects outwardly in a distal direction relative to the leading cutting edge 26. For example, the guide projection 20 can project outwardly relative to the leading cutting edge 26 to a distal end 28, which can define the distal-most end of both the cutting head 14 and the cutting instrument 10.

[0034] By configuring the cutting head 14 with an outwardly projecting guide projection 20, a clinician can use the guide projection to advance the guide projection in front of the cutting surface 22 to isolate one or more regions of soft tissue (e.g., ligament) from adjacent tissue structures. For example, the clinician can advance the distal end 28 of the guide projection 20 under one region of soft tissue targeted for cutting, e.g., by inserting the guide projection under one or more regions of soft tissue targeted for cutting and over an adjacent region not intended to be cut, thereby capturing and / or separating the targeted region of tissue from the adjacent regions. The cutting surface 22 follows the distal or tip of the guide projection 20. As a result, tissue that is initially separated from adjacent tissue by controlling the positioning of the guide projection 20 can then be cut by the cutting surface 22 by continuing to advance the cutting instrument forward, bringing the tip cutting edge 26 into contact with and cutting the tissue captured by the guide projection.

[0035] In general, the guide projections 20 may extend outward from the cutting surface 22 a sufficient distance to allow a clinician to separate the target tissue during use. However, it may be desirable to limit the length of the guide projections 20 that extend beyond the cutting surface 22 so that the target tissue captured by the guide projections is positioned close enough to the cutting surface to be easily cut without making the cutting instrument difficult to manipulate. The leading cutting edge 26 may be offset (e.g., set back) from the distal end 28 of the guide projections 20 by a distance 30, which may be measured from the distal end of the guide projections to the most distal location on the cutting edge. The distance 30 may be at least 1 mm, such as at least 3 mm, at least 5 mm, at least 7 mm, at least 9 mm, at least 11 mm, or at least 13 mm. Additionally or alternatively, the distance 30 may be less than 25 mm, such as less than 20 mm, less than 15 mm, or less than 10 mm. For example, the distance 30 may be in the range of 1 mm to 20 mm, such as 5 mm to 15 mm, 7 mm to 10 mm, or 8 mm to 10 mm. For example, the distance 30 may be approximately 9 mm, eg, ±10%.

[0036] The distance 30 may be relatively large relative to the overall length 32 of the cutting head 14 (e.g., in the Z direction as shown in FIG. 2). For example, the ratio of the length 32 of the cutting head 14 divided by the distance 30 may be less than 5.0, e.g., less than 4.0, less than 3.5, or less than 3.0. In some implementations, the ratio of the length 32 of the cutting head 14 divided by the distance 30 is in the range of 2.0 to 3.5, e.g., 2.5 to 2.75.

[0037] Guide projection 20 can define any cross-sectional shape (e.g., in the XY plane), including polygonal shapes (e.g., square, rectangular, hexagonal), arcuate shapes (e.g., circular, elliptical), and / or combinations of polygonal and arcuate shapes. Furthermore, the cross-sectional shape of guide projection 20 may be the same along the entire length of the guide projection, or may vary over the length of the guide projection. In the illustrated example of FIG. 2, guide projection 20 is shown as defining a cylindrical cross-sectional shape along at least a portion of its length.

[0038] The guide projection 20 may be sized to be inserted under and / or between small sized soft tissues, allowing the clinician to separate one or more regions of soft tissue to be cut from adjacent regions of soft tissue that are not to be cut. Thus, the guide projection 20 may typically have a relatively small cross-sectional size. In some implementations, the guide projection 20 has a major cross-sectional dimension 21 (e.g., diameter) of 5 mm or less, e.g., 4 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less. The guide projection 20 may define the same size throughout its length, or at least a portion of the guide projection 20 may have a different size (e.g., smaller size) than at least one other portion of the guide projection. For example, in the configuration of FIG. 2, the guide projection 20 is shown as having a tapered region 34 adjacent the distal-most end 28 of the guide projection. When so configured, the cross-sectional size of the guide projection 20 may be reduced moving from a proximal region of the guide projection toward a distal region of the guide projection. This can help provide a tapered distal end 28, which can be useful for guiding the guide projection 20 under and / or between areas of soft tissue.

[0039] In some configurations, the guide projection 20 terminates in an apex or sharp point at the distal end 28. In other configurations, the guide projection 20 terminates in a blunt distal end 28. For example, the distal end 28 of the guide projection 20 may not be sharp, but rather define a distal end 28 that defines a surface area extent (e.g., in the XY plane shown in FIG. 2). Configuring the guide projection 20 with a blunt distal end 28 can be useful to help prevent the guide projection 20 from penetrating and / or cutting tissue as the guide projection is guided under one or more target regions of the subject's soft tissue.

[0040] Generally, the cutting head 14 of the cutting instrument 10 can define a length 32 that extends from the proximal end to the distal end 28 of the cutting head. The cutting head 14 can also define a width (e.g., in the X direction shown in FIG. 2) that extends perpendicular to the length of the cutting head and the material thickness of the cutting head. For example, the cutting head 14 can define a width that extends from a first side edge 36A to a second side edge 36B. The cutting head 14 can further define a thickness (e.g., in the Y direction shown in FIG. 2) that extends perpendicular to both the length and width of the cutting head.

[0041] The guide projections 20 can be located at a number of different positions across the width of the cutting head 14. In some instances, the guide projections 20 form a side edge of the cutting head 14. For example, the guide projections 20 may form a second side edge 36B of the cutting head 14. When the cutting head 14 is inserted into the patient's anatomy, the second side edge 36B may be oriented at the top edge of the cutting head, the bottom edge of the cutting head, and / or may be oriented in yet another direction in three-dimensional space. In other configurations, the guide projections 20 may be located elsewhere along the width of the cutting head between the first side edge 36A and the second side edge 36B.

[0042] In configurations in which the guide projection 20 defines one side edge of the cutting head 14 and / or bounds one side of the cutting surface 22, the other side edge of the cutting head can have a variety of different configurations. In one example, the cutting surface 22 forms the side edge of the cutting head opposite the guide projection 20. In this configuration, the widthwise side edge of the cutting head may or may not be sharpened to provide a cutting edge extending along the widthwise side edge opposite the guide projection 20. In another example, the cutting head 14 includes a rail 38 that defines a first side edge 36A of the cutting head. When configured in this manner, the cutting surface 22 may be provided in an intermediate region between the guide projection 20 and the rail 38.

[0043] The rail 38 may be a structure configured to slide against tissue placed in contact with the rail, for example, without cutting the tissue. For example, the rail 38 may define a non-cutting surface that bounds the cutting surface 22 on one side edge. The rail 38 may define any polygonal and / or arcuate cross-sectional shape (e.g., in the XY plane shown in FIG. 2). The rail 38 may extend distally to a distal end 40. In some examples, the distal end 40 of the rail 38 is collinear with at least a portion of the leading cutting edge 26 of the cutting surface 22. In other words, the distal end 40 of the rail 38 may be positioned such that there is substantially no offset between at least a portion of the leading cutting edge 26 at the distal end of the rail (e.g., the portion immediately adjacent the rail). In other configurations, the leading cutting edge 26 of the cutting surface 22 may be offset (e.g., proximally or distally) relative to the distal end 40 of the rail 38.

[0044] For example, the leading cutting edge 26 of the cutting surface 22 may be concave relative to the distal end 40 of the rail 38, in addition to being concave relative to the distal end 28 of the guide projection 20, for example. When so configured, the rail 38 may function as a second guide projection in addition to the guide projection 20, albeit on the opposite side of the cutting head. In these implementations, the rail 38 may have any of the configurations and offset dimensions described above with respect to the guide projection 20. In configurations in which the leading cutting edge 26 of the cutting surface 22 is concave relative to the distal end 40 of the rail 38, the cutting edge may be concave the same or a different distance from the distal end of the rail compared to the distal end of the guide projection 20. For example, the leading cutting edge 26 may be concave a relatively smaller distance from the distal end 40 of the rail 38 than the concave distance 30 between the distal end 28 of the guide projection 20 and the cutting surface. In some such examples, the distal-most location of the leading cutting edge 26 is spaced from the distal end 40 of the rail 38 by a distance of less than 7 mm, such as less than 5 mm, less than 3 mm, or less than 2 mm.

[0045] In alternative configurations of the cutting head 14, the opposing surfaces of the guide projection 20 and rail 38 may be taped to form opposing cutting edges (in addition to or instead of providing the cutting surface 22). In one such configuration, the guide projection 20 and rail 38 may be movable relative to one another (e.g., about a pivot point to provide a scissoring action) to cut tissue captured between the two surfaces. However, in the configuration shown, the guide projection 20 and rail 38 are located in fixed (non-movable) positions relative to one another.

[0046] As mentioned above, the rail 38 may have any of the configurations and offset dimensions described above with respect to the guide projections 20. Thus, in some implementations, the cutting head 14 of the cutting instrument 10 may be configured with two guide projections 20 that bound opposing side edges of the cutting head 14. FIGS. 2C and 2D are perspective and top views, respectively, of the cutting instrument 10 shown with the cutting head 14 configured with a first guide projection 20A and a second guide projection 20B. The cutting head 14 includes a cutting surface 22 that extends between the first guide projection 20A and the second guide projection 20B. When so configured, the first guide projection 20A can form a first side edge 36A of the cutting head 14, and the second guide projection 20B can form a second side edge 36B of the cutting head.

[0047] Configuring the cutting head 14 with two spaced apart guide protrusions 20A and 20B can be useful to help define a boundary space between the two guide protrusions to which the distal cutting edge 26 is concave. In use, a clinician can advance the guide protrusions 20A and 20B between one or more ligaments to be cut and the underlying soft tissue and / or bone. This can capture the targeted tissue (e.g., one or more ligaments) within the notch 24 formed between the first guide protrusion 20A, the second guide protrusion 20B, and the cutting surface 22. By offsetting the cutting surface 22 relative to the first guide protrusion 20A and the second guide protrusion 20B, the two guide protrusions can help the clinician navigate the cutting head 14 relative to the target tissue to be cut, while providing a non-cutting boundary structure on either side of the distal cutting edge 26 to help prevent inadvertent cutting of tissue while navigating the cutting head.

[0048] The first guide protrusion 20A and the second guide protrusion 20B can each protrude outwardly in a distal direction relative to the leading cutting edge 26. The first guide protrusion 20A and the second guide protrusion 20B can each have any of the configurations and dimensions described herein for the guide protrusion 20. In the illustrated example of FIG. 2C and FIG. 2D, the first guide protrusion 20A and the second guide protrusion 20B are shown as being symmetrically sized and shaped. That is, the first guide protrusion 20A and the second guide protrusion 20B have the same size and shape. In other examples, the first guide protrusion 20A can be asymmetrically sized and / or shaped relative to the second guide protrusion 20B (e.g., such that the first guide protrusion 20A has a different size and / or shape than the second guide protrusion 20B).

[0049] 2A and 2B, the cutting head 14 can define an intersection angle 42 between the guide projection 20 and the cutting surface 22, the intersection angle 42 indicating the angle at which the guide projection extends relative to the cutting surface. In the example shown, the intersection angle 42 is shown to be approximately 90°. In other examples, the intersection angle 42 can be a different value. For example, the intersection angle 42 can be in the range of 45° to 135°, such as 75° to 105°.

[0050] Generally, the cutting surface 22 of the cutting head 14 may define a region of the cutting head having a reduced thickness compared to the remainder of the cutting head. When the cutting head 14 is placed in contact with tissue to be cut, the reduced thickness of the cutting surface may facilitate cutting. The cutting surface 22 may be formed by tapering the thickness of the cutting head 14 in the region of the cutting surface (e.g., from a region of relatively greater thickness toward the center of the cutting head to a region of relatively lesser thickness at the outermost edge of the cutting surface). For example, with reference to FIG. 2, the thickness of the cutting head 14 in the Y direction shown in the figure may be tapered across the region defining the cutting surface 22.

[0051] In some implementations, the cutting head 14 defines a cutting surface 22 on one side of the cutting head. With reference to FIG. 1B, for example, a first plane 44A can be defined by the length and width of the cutting head 14 on one side of the cutting head, and a second plane 44B can be defined by the length and width of the cutting head 14 on the opposite side of the cutting head. The cutting surface 22 can extend at an angle (e.g., in the Y direction shown in FIG. 1B) across the thickness of the cutting head toward the opposite plane.

[0052] In some examples, the cutting head 14 defines a cutting surface that extends in a single direction (e.g., in the negative Y direction from the first planar surface 44A to the second planar surface 44B) through the thickness of the cutting head, without an opposing cutting surface that extends in the opposite direction (e.g., in the positive Y direction from the second planar surface 44B to the first planar surface 44A). In these configurations, the cutting surface 22 may be defined on the first planar side 44A of the cutting head 14, and the second planar side 44B of the cutting head may lack a cutting surface. This configuration may be referred to as a one-sided tapered configuration.

[0053] However, in other configurations, the cutting head 14 may define cutting surfaces on both sides of the cutting head. For example, the cutting head 14 may include a first cutting surface 22 tapered in a first direction across the thickness of the cutting head (e.g., in a negative Y direction from the first plane 44A to the second plane 44B) and a second cutting surface tapered in a second direction across the thickness of the cutting head (e.g., in a positive Y direction from the second plane 44B to the first plane 44A). The two sets of cutting surfaces may intersect at a location between the first plane 44A and the second plane 44B, e.g., at a location substantially centered across the thickness of the cutting head, to define a leading cutting edge 26. This configuration may be referred to as a double-sided tapered configuration.

[0054] The particular angle at which the cutting surface 22 of the cutting head 14 tapers toward the leading cutting edge 26 can vary based on, for example, the size and configuration of the cutting head. With reference to FIG. 1B, the cutting head 14 can define a taper angle 46, which is the angle at which the cutting surface tapers across the thickness of the cutting head. In some examples, the taper angle 46 can range from 5 degrees to 45 degrees, such as from 5 degrees to 25 degrees, or from 10 degrees to 20 degrees. When configured with cutting surfaces on both sides of the cutting head 14, the two surfaces can taper toward one another at the same angle or different angles.

[0055] In some examples, the cutting surface 22 tapers at a single taper angle 46 across the cutting surface. In other configurations, the cutting surface 22 tapers at a number of different angles across the cutting surface. For example, as seen in FIG. 1B, the cutting surface 22 may define a first taper region having a first taper angle 46 and a second taper region having a second taper angle 48. The second taper angle 48 may be different from the first taper angle 46 (e.g., may be greater or less than the first taper angle). In the example shown, the region defining the second taper angle 48 is positioned proximal or posterior to the region defining the first taper angle 46. Further, in this example, the second taper angle 48 is shown as being less or shallower than the first taper angle 46. In general, configuring the cutting surface 22 with one or more tapered services may be beneficial to facilitate cutting of the target soft tissue. Depending on the overall thickness of the cutting head 14, the cutting surface 22 may be a distal region of the cutting head that is not tapered relative to the remainder of the cutting head. These implementations may be used, for example, when the overall thickness of the cutting head is relatively small and the non-tapered cutting surface 22 still provides sufficient cutting of the target soft tissue.

[0056] With further reference to FIG. 2A, the distal cutting edge 26 of the cutting surface 22 may extend straight across the width of the cutting head (e.g., in the X direction as shown in the figure) or may define a curvature. In the configuration shown, the distal cutting edge 26 of the cutting surface 22 defines a curvature along the width of the cutting head, which is shown as a convex curvature in which the central or intermediate region of the distal cutting surface is concave in a proximal direction relative to the region of the distal cutting edge adjacent the lateral edge. In other examples, the distal cutting edge 26 of the cutting surface 22 may define a convex curvature in which the central or intermediate region of the distal cutting surface extends outward distally relative to the region of the distal cutting edge adjacent the lateral edge. In yet other configurations, the distal cutting edge 26 may be angled proximally or distally from the first lateral edge 36A to the second lateral edge 36B.

[0057] The specific dimensions of the cutting instrument 10, including the cutting head 14, may vary depending on the desired application. In some implementations, the longitudinal length 32 of the cutting head 14 may range from 5 mm to 50 mm, e.g., 10 mm to 35 mm, or 20 mm to 30 mm. The width 50 of the cutting head 14 between the first side edge 36A and the second side edge 36B may range from 5 mm to 13 mm, e.g., 6 mm to 10 mm, or about 8 mm (e.g., ±10%). Depending on the configuration, the width 52 of the cutting surface 22 (which defines the length of the distal cutting edge 26) may be less than the full width of the cutting head, e.g., at least less than 1 mm, at least less than 2 mm, or at least less than 3 mm. For example, the width 52 of the cutting head 14 where the cutting surface 22 meets may range from 2 mm to 10 mm, e.g., 3 mm to 7 mm, or about 5 mm (e.g., ±10%). In some implementations, the maximum thickness of the cutting head 14 ranges from 0.5 mm to 4 mm, such as from 1 mm to 3 mm, or about 2 mm (eg, ±10 percent).

[0058] Generally, the cutting instrument 10, including the handle 12 and the cutting head 14, may be formed from any desired material or combination of materials. Typically, the cutting head 14 is manufactured from a metal to provide a sharp cutting surface, such as steel (e.g., stainless steel), titanium, etc., but may also be formed from ceramic or other sharp materials. The handle 12 may be formed from a variety of materials, including one or more metals and / or polymeric materials.

[0059] In some configurations, the handle 12 and the cutting head 14 are formed (e.g., via casting, milling) as a unitary structure defined by a single type of material. In other configurations, the handle 12 and the cutting head 14 may be formed as separate structures joined together to couple the cutting head to the handle for subsequent use. In some such configurations, the handle 12 may be formed from a different material (e.g., a polymeric material) than the cutting head 14 (which may be formed from a metallic material), for example, for increased gripping ability and / or comfort and retention. For example, the handle 12 may define a receiving cavity at the second end 18, and the end of the cutting head 14 opposite the distal cutting edge 26 may be inserted into the receiving cavity to interconnect the handling cutting head. Fastening means (e.g., adhesives, screws, bolts, welding) may be used to permanently affix the cutting head to the handle. In other configurations, the cutting head 14 may be removably attached to the handle 12 to allow the handle to be used with different interchangeable cutting heads (e.g., each having the same configuration or having different configurations from each other).

[0060] The handle 12 may generally be configured to be manually grasped by the hand of a clinician using the cutting instrument 10. The handle 12 may have an enlarged cross-sectional size (e.g., width, thickness) relative to the cutting head 14 to provide a larger surface for grasping. In some configurations, the handle 12 includes surface texturing, such as knobs, ribs, knurling, and / or other features that facilitate gripping of the handle without slipping. The handle 12 may generally be designed to be manually grasped by the hand of a clinician, while in other configurations, the handle 12 may be designed to be inserted into a powered hand instrument that can drive movement of the cutting head 14 via the handle. The handle 12 may have any desired length between the first end 16 and the second end 18, while in some instances, it may exhibit a length ranging from 50 mm to 200 mm, such as from 100 mm to 150 mm.

[0061] In the depicted configurations of Figures 1A, 1B, 2A and 2B, the handle 12 is shown extending collinearly with the cutting head 14. That is, the long axis defined by the handle 12 is shown extending collinearly with the long axis defined by the cutting head 14 (e.g., in the XZ plane shown in Figure 1A and in the YZ plane shown in Figure 2B). In other configurations, the handle 12 (either the entire handle or a portion thereof) may be offset from and / or angled relative to the long axis defined by the cutting head 14.

[0062] For example, FIG. 2E is a side view of the cutting instrument 10 illustrating an exemplary configuration in which the cutting head 14 is angled relative to the handle 12. When so configured, the longitudinal axis 60 defined by the cutting head 14 may be angled relative to the longitudinal axis 62 defined by the handle 12 to define an angle 64 between the two axes. The cutting head 14 may be angled in a direction such that the first plane 44A and / or the second plane 44B are positioned out of plane with the handle 12 (e.g., in the XZ plane shown in FIG. 2E). In some examples, the angle 64 may range from 5 degrees to 45 degrees, e.g., from 10 degrees to 25 degrees. The angle 64 may be defined by a sharp transition or an angled intersection between the handle 12 and the cutting head 14. Alternatively, the instrument 10 may define a radius of curvature between the handle 12 and the cutting head 14 that defines the angle 64. Configuring the cutting instrument 10 with an angular offset between the handle 12 and the cutting head 14 can be useful to assist the clinician in guiding the cutting instrument 10 into the incision site and / or targeting the tissue to be cut using the instrument.

[0063] With further reference to Figures 1 and 2, in configurations where the handle 12 and cutting head 14 are formed as a unitary body and there is no distinct transition between the handle and the cutting head, the handle 12 may be considered to have an optional second end 18 between the handle and the cutting head 14, and the handle transitions into the cutting head without any distinct change in size or shape between the handle and the cutting head.

[0064] As briefly described above, the cutting instrument 10 can be used during a variety of different procedures, including as part of a bone alignment procedure. In some instances, the cutting instrument 10 is utilized during a procedure in which one or more bones of the foot are realigned. To further understand such exemplary techniques, the anatomy of the foot is described with respect to Figures 4A and 4B. Bone misalignment may be caused by metatarsal adduction, hallux valgus (bunion), arthritis, and / or other conditions that may manifest as misalignment of one or more bones in the foot.

[0065] 3A and 3B are top and front views, respectively, of a foot 100 showing normal metatarsal alignment. The foot 100 is made up of multiple bones, including a first metatarsal 102, a second metatarsal 104, a third metatarsal 106, a fourth metatarsal 108, and a fifth metatarsal 112. The first metatarsal 102 is on the innermost side of the foot, and the fifth metatarsal 112 is on the outermost side of the foot. The metatarsals are connected distally to phalanges 114, and more specifically, each is connected to a respective proximal phalange. The joints 116 between the metatarsals and the corresponding opposing proximal phalanges are referred to as metatarsophalangeal ("MTP") joints. The first MTP joint is labeled as joint 116 in FIG. 1A, but the second, third, fourth, and fifth MTP joints are also shown in series adjacent to the first MTP joint.

[0066] The first metatarsal 102 is proximally connected to the medial cuneiform 118, the second metatarsal 104 is proximally connected to the middle cuneiform 120, and the third metatarsal 106 is proximally connected to the lateral cuneiform 122. The fourth and fifth metatarsals 108, 112 are proximally connected to the cuboid 124. The joints between the metatarsals and the opposing bones (cuneiform, cuboid) are referred to as tarsometatarsal ("TMT") joints. FIG. 4A shows the first TMT joint 126, the second TMT joint 128, the third TMT joint 130, the fourth TMT joint 132, and the fifth TMT joint 134. The angle between adjacent metatarsals is referred to as the intermetatarsal angle ("IMA").

[0067] 3A and 3B, foot 100 is illustrated as having generally normally aligned metatarsals. Normal metatarsal alignment may be characterized by, among other attributes, a small intermetatarsal angle between the first and second metatarsals (e.g., 9 degrees or less, e.g., 5 degrees or less). In addition, the lesser metatarsal may be generally parallel to a long axis that bisects the foot proximally to distally.

[0068] FIG. 4 illustrates different anatomical planes of the foot 100, including the frontal plane 140, the transverse plane 142, and the sagittal plane 144. The frontal plane 140, also known as the coronal plane, is generally considered to be any vertical plane that divides the body into anterior and posterior parts. In the foot 100, the frontal plane 140 is a plane that extends vertically and perpendicular to an axis that extends from proximal to distal along the length of the foot. The transverse plane 142, also known as the horizontal, axial, or transaxial plane, is considered to be any plane that divides the body into superior and inferior parts. In the foot 100, the transverse plane 142 is a plane that extends horizontally and perpendicular to an axis that extends from dorsal to plantar (superior to inferior) across the foot. Additionally, the sagittal plane 144 is a plane that is parallel to the sagittal suture that divides the body into left and right halves. In foot 100, sagittal plane 144 is a plane that extends vertically and intersects an axis that extends from proximally to distally along the length of the foot. In patients suffering from certain bony misalignments, one or more of the metatarsals may be medially deviated in the transverse plane (e.g., in addition to or instead of being rotated in the frontal plane and / or deviated in the sagittal plane relative to clinically defined normal anatomical alignment for a standard patient population).

[0069] FIG. 5 is a superior lateral view of the bone-ligament-capsule anatomy of the first MTP joint 116. As seen in FIG. 5, the first MTP joint 116 includes the distal head of the first metatarsal, the proximal head of the proximal phalanx, and the medial and lateral sesamoids. The sesamoid complex may be characterized as including two sesamoid bones, eight ligaments, and seven muscles. The sesamoid joint with the first metatarsal head is continuous with that of the MTP joint. Most of the capsular ligament stabilizing structures are concentrated on the plantar surface of the joint.

[0070] The dorsal surface of the MTP joint is innervated by the extensor hallucis longus tendon (EHL), which lies dorsally in the midline. The extensor hallucis brevis (EHB) tendon is just plantar and lateral to the EHL. The sagittal aponeurosis cap extends from the tendon sheath to encase the ligaments, forming a confluence of thickened capsular tissue that extends from the plantar side to both the medial and lateral collateral ligaments in the midline. These capsular ligamentous structures are generally aligned with the equator of the joint, extending from the epicondyle region of the first metatarsal head to the base of the proximal phalanx.

[0071] A small bony ridge or crest separates the two sesamoids as they lie in their respective grooves. A dense plantar pad covers the sesamoids and secures them to the proximal phalanx. The medial sesamoid is ovoid and usually slightly distal and larger than the lateral one. The sesamoids are encased by the two heads of the flexor hallucis brevis tendon.

[0072] 6A and 6B are medial and lateral views, respectively, of the first metatarsophalangeal joint (MTP) with the extensor aponeurotic structures removed to show certain structural elements of the plantar capsular ligament-sesamoid complex. As shown, the collateral ligament complex of the capsular ligament-sesamoid complex is found on the medial and lateral sides and includes the primary collateral ligament 150 and the accessory sesamoid ligament 152. The abductor hallucis 154 tendon inserts into the medial sesamoid and fuses with the capsular structures on the medial side of the joint. The transverse head 156 and oblique head 158 of the adductor hallucis send fibers to the lateral sesamoid, capsule, and plantar plate. The medial and lateral heads of the flexor hallucis brevis 160 insert into the sesamoids found along the plantar surface of the metatarsal. The flexor hallucis longus tendon 162 is also shown.

[0073] FIG. 7 is a lateral view of the first metatarsophalangeal (MTP) joint further illustrating the soft tissue anatomy at the joint. As shown in FIG. 7, the first TMT is formed between the first metatarsal 102 and the proximal phalange 114, with the lateral sesamoid bone 168 positioned below the joint. The lateral metatarsophalangeal ligament 170, also referred to as the proper collateral ligament, is shown extending from the lateral epicondyle 174 to the proximal phalange. The lateral supervisory ligament 172, also referred to as the collateral collateral ligament, is shown extending from the lateral epicondyle 174 to the lateral sesamoid bone 168. The lateral phalangeal-sesamoid ligament 176 is shown extending from the lateral sesamoid bone 168 to the proximal phalange 114. The lateral metatarso-sesamoid ligament is shown extending from the lateral sesamoid bone 168 to the first metatarsal 102. Also shown in FIG. 7 are the adductor oblique muscle 180, the adductor transverse head 182, and the deep transverse metatarsal ligament 184.

[0074] The cutting head 14 may be used as part of the technique shown and / or described with respect to Figures 5-7 to cut soft tissue such as one or more ligaments and / or muscles to help mobilize the bone (e.g., first metatarsal 102) for realignment. Figure 8 is a flow diagram of an exemplary bone realignment technique that may be performed utilizing a cutting instrument 10 according to the present disclosure. As described, in some examples of the technique of Figure 8, the cutting instrument 10 may be utilized to cut soft tissue on the lateral side of the first metatarsal 102 to help mobilize the bone for subsequent bone realignment.

[0075] Exemplary cutting steps utilizing the cutting instrument 10 that may be performed are described with reference to Figure 8. Additional details regarding exemplary surgical techniques, including exemplary instrumentation that may be used during the techniques, can be found in U.S. Patent No. 9,622,805, issued April 18, 2017, entitled "BONE POSITIONING AND PREPARING GUIDE SYSTEMS AND METHODS," U.S. Patent Application Publication No. 2020 / 0015856, published January 16, 2020, entitled "COMPRESSOR-DISTRACTOR FOR ANGULARLY REALIGNING BONE PORTIONS," and U.S. Patent Application Publication No. 2021 / 0361330, published November 25, 2021, entitled "DEVICES AND TECHNIQUES FOR TREATING METATARSUS ADDUCTUS," the entire contents of each of which are incorporated herein by reference.

[0076] The exemplary technique of FIG. 8 includes making an incision (802) through the patient's skin to surgically access the soft tissue to be cut, such as one or more sesamoid ligaments of the foot. The incision may be made through the skin, such as on the dorsal side of the foot, to access the MTP joint and / or the intermetatarsal joint space between adjacent metatarsals. For example, the incision may be made from the dorsal side of the foot by cutting into the first metatarsophalangeal joint capsule. The clinician may, for example, cut from the dorsal side of the foot, on the lateral side of the first metatarsophalangeal joint capsule. The cut may be positioned and made deep enough to expose the targeted, underlined soft tissue (e.g., ligaments) for subsequent cutting during the procedure. The clinician may use a scalpel or other bladed cutting instrument to perform the access cut. FIGS. 9 and 10 are dorsal views of a foot 100 showing an exemplary incision location 146 lateral to the MTP joint capsule 148 to access the underlying lateral sesamoid ligament. As shown in these examples, exemplary incision locations 146 include a proximal-to-distal incision on the outside of the MTP joint capsule 148, and / or a medial-to-lateral incision extending from the outside of the MTP joint capsule 148 to the inside of the capsule (e.g., intersecting with the proximal-to-distal incision).

[0077] 8, an exemplary technique involves advancing the guide protrusion 20 of the cutting instrument 10 into an access incision made through the patient's skin and using the guide protrusion to capture one or more target areas of soft tissue to be cut (804). For example, a clinician can introduce the cutting head 14 of the cutting instrument 10 into an incision made outside the MTP joint capsule. The clinician can advance the guide protrusion 20 (and subsequently the remainder of the cutting head 14) to the target soft tissue by, for example, advancing the cutting head into the incision plantarally and / or proximally up the intermetatarsal space and / or distally down the intermetatarsal space.

[0078] Regardless of the particular direction of movement, the clinician can use the guide projection 20 to separate one or more regions of soft tissue targeted for cutting from one or more adjacent regions of soft tissue that are not intended to be cut. For example, the clinician can guide the distal end 28 of the guide projection 20 under one or more ligaments and / or muscles to capture the ligaments and / or muscles in the notch 24 between the guide projection and the cutting surface 22. This can position the guide projection 20 between the captured ligaments and / or muscles and the underlying structure (e.g., soft tissue, bone). In some examples, the clinician can use the first guide projection 20A and the second guide projection 20B to separate one or more regions of soft tissue targeted for cutting from adjacent regions of soft tissue on either side of the cutting head that are not intended to be cut. The clinician can guide the distal end of the first guide projection 20A and the second guide projection 20B under one or more ligaments and / or muscles to capture the ligaments and / or muscles in the notch 24 between the two guide projections and the cutting surface 22. It should be understood that references to positioning the guide projection under a particular tissue do not require a particular orientation relative to gravity, but instead are intended to refer to positioning the guide projection between the targeted tissue and the underlying material.

[0079] The particular soft tissue targeted for cutting by the clinician may vary depending on the particular procedure being performed and the degree of bone mobilization and release desired by the clinician. In some applications, the clinician advances the guide projection 20 of the cutting instrument 10 at least beneath the accessory supervisory ligament 172. Additionally or alternatively, the clinician may advance the guide projection 20 of the cutting instrument 10 beneath the intrinsic collateral ligament 170. Additionally or alternatively, the clinician may advance the guide projection 20 of the cutting instrument 10 beneath one or more of the lateral metatarsophalangeal ligament 176, the lateral sesamoid ligament 178, the adductor capitis 180, the adductor capitis transverseis 182, and / or the deep transverse metatarsal ligament 184. The clinician may simultaneously capture one or more of the target regions of soft tissue within the notch 24, or may capture different target regions of soft tissue through different cutting paths.

[0080] With one or more regions of soft tissue targeted for cutting separated by the guide projections 20 and captured within the notch 24, the clinician may proceed to cut (806) the captured tissue using the cutting surface 22 of the cutting instrument 10. The clinician may further advance the cutting instrument 10 in the direction in which the instrument was advanced to initially capture the soft tissue, causing the leading cutting edge 26 of the cutting surface 22 to contact and / or cut through the tissue captured within the notch.

[0081] For example, if the clinician initially advances the guide projection 20 of the cutting instrument 10 in a first direction (e.g., plantar, dorsal, proximal, distal, plantar-proximal, plantar-distal) to capture the target soft tissue, the clinician may advance the cutting instrument further in that first direction to subsequently cut the captured soft tissue. In practice, the clinician may initially feel resistance to pushing as the cutting surface 22 compresses the captured soft tissue, and the resistance is reduced or released when the cutting surface has finished cutting the soft tissue. This may be accompanied by an audible sound, such as a pop, indicating that the tissue has been cut.

[0082] In some instances, the clinician may advance the cutting head 14 in one direction to cut one or more regions of soft tissue (e.g., one or more ligaments, muscles), and then rotate and advance the cutting head in a different direction to capture and cut one or more other regions of soft tissue. For example, the clinician may first advance the cutting head 14 in a generally proximal direction (e.g., to capture and cut at least the anterior ligament 172 and the intrinsic collateral ligament 170), and then rotate the cutting head 14 in a different direction, such as a generally distal direction (e.g., to capture and cut other soft tissue). The clinician may or may not perform this rotation and flip movement without removing the cutting head 14 from the incision. After performing any desired cuts, the cutting instrument 10 may be removed for subsequent steps of the surgical procedure.

[0083] In the exemplary technique of FIG. 8, the technique includes moving (808) at least a portion of the first metatarsal 102 in at least one plane. For example, before or after performing a soft tissue release using the cutting instrument 10 as described above, at least a portion of the first metatarsal 102 may be realigned in one or more planes. For example, at least a portion of the metatarsal may be moved at least in the transverse plane to close the inter-metatarsal angle between the moved bones on the adjacent bones. Additionally or alternatively, at least a portion of the metatarsal may be moved in the frontal plane (e.g., to reposition the sesamoid bone substantially centered under the metatarsal). In some instances, the portion of the metatarsal may be moved in multiple planes, such as the transverse and / or frontal and / or sagittal planes (e.g., each of the transverse, frontal, and sagittal planes). The clinician may or may not utilize a bone positioning device to facilitate the movement of the bone portion. The moved position of the metatarsal may result in a realignment of the metatarsal relative to one or more other adjacent bones.

[0084] In some instances, such as during an osteotomy procedure, a clinician may realign a distal portion of the first metatarsal relative to an adjacent proximal portion. In these applications, a clinician may surgically access the first metatarsal (e.g., make an incision through the patient's skin) at a location between the TMT joint and the MTP joint. The clinician may cut the first metatarsal to form a proximal portion that extends back to the TMT joint and a distal portion that extends to the MTP joint. The incision may be made through the skin, such as on the dorsal side of the foot, on the medial side of the foot, on the dorsal-medial side of the foot, on the lateral side of the foot, or even elsewhere on the foot. The clinician may then realign the distal portion of the first metatarsal in one or more planes.

[0085] In other instances, the clinician may realign the entire length of the first metatarsal. In these instances, the clinician may make an incision to access the first TMT joint 126. Again, the incision may be made through the skin, such as on the dorsal side of the foot, the medial side of the foot, the dorsal-medial side of the foot, the lateral side of the foot, or even elsewhere on the foot. In either case, the clinician may prepare the end of the first metatarsal and the end of the medial cuneiform bone across the first TMT joint 126 for fusion. One or both of the end faces of the metatarsal and the opposing bone may be prepared before and / or after moving the metatarsal relative to the cuneiform bone. Thus, unless otherwise specified, the order of preparation and / or movement of the bones is not limited.

[0086] Generally, a clinician can prepare the ends of each bone that forms the TMT joint to promote fusion of the bone ends across the joint following realignment. Bone preparation can include using a tissue removal instrument to apply force to the end faces of the bones to create a bleeding bone surface to promote subsequent fusion. Exemplary tissue removal instruments that can be used include, but are not limited to, saws, rotary drilling instruments, rongeurs, reamer, osteotome, spatula, and the like. In certain implementations, the cutting instrument 10 is used to prepare the ends of one or both bone surfaces in addition to or instead of using a different cutting instrument. Such use of the cutting instrument 10 can be in addition to or instead of cutting soft tissue as described herein.

[0087] Regardless of the type of tissue removal instrument used, the tissue removal instrument may be applied to the end surface of the bone that is being prepared for removal of cartilage and / or bone. For example, the tissue removal instrument may be applied to the end surface to remove cartilage (e.g., all cartilage) down to the subchondral bone. Additionally or alternatively, the tissue removal instrument may be applied to cut, fenestrate, mortar, and / or otherwise reshape the end surface of the bone and / or to create a bleeding bone surface to promote fusion. When a cutting operation is performed to remove the end of the bone, the cut may be performed freehand and with the aid of a cutting guide having a guide surface positionable over the portion of the bone to be cut. When a bone preparation guide is used, the cutting instrument may be inserted against the guide surface of the bone preparation guide (e.g., between a slot defined between two guide surfaces) to guide the cutting instrument for removal of the bone.

[0088] After realignment (or in lieu of a separate realignment step), the clinician may or may not compress together one or more bone surfaces of the opposing bone portions (e.g., end surfaces of the proximal and distal portions of the first metatarsal, end surfaces of the first metatarsal and medial cuneiform bones). The clinician may compress the end surfaces together by manual pressure and / or using a compression tool physically attached to both the first and second bone portions.

[0089] After suitably realigning at least a portion of the first metatarsal, the technique of FIG. 8 involves fixing the displaced position (810). In some instances, a temporary fixation step is performed in which one or more temporary fixation pins are placed to hold the displaced position of the metatarsal (e.g., by inserting fixation pins through the displaced metatarsal or portion thereof into one or more adjacent bones). A permanent fixation device can be applied across the joint separating the prepared epiphysis to hold the displaced position of the epiphysis for subsequent fusion. For example, one or more permanent fixation devices can be applied across a joint (osteotomy) formed by cutting the first metatarsal into a distal metatarsal portion and a proximal metatarsal portion. As another example, one or more permanent fixation devices can be applied across the first TMT joint 126 separating the first metatarsal from the medial cuneiform bone. Exemplary permanent fixation devices include, but are not limited to, pins (e.g., intramedullary nails, K-wires, Steinmann pins), plates, screws, staples, and combinations thereof. With time and healing, the realigned bones can then fuse to the end surfaces of the opposing bones to provide a fused joint.

[0090] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. 1. An instrument configured to cut tissue to mobilize a first metatarsal of a foot, comprising: (a) a handle extending from a first end to a second end; (b) a cutting head on the second end of the handle, (i) a cut surface; (ii) a cutting head including a guide projection terminating at a distal end; Equipped with the cutting surface is concave relative to the distal end of the guide projection; the cutting head is sized to be inserted into the intermetatarsal space between the first and second metatarsal bones of the foot; Equipment.

2. The instrument of claim 1 , wherein the cutting surface defines a distal-most edge, the distal-most edge of the cutting surface being spaced from the distal end of the guide projection by a distance of at least 3 mm.

3. The device of claim 2, wherein the distance is in the range of 5 mm to 15 mm.

4. 4. The tool of claim 2 or 3, wherein the ratio of the length of the cutting head divided by the distance is in the range of 2 to 3.

5.

5. the cutting head defines a length extending from the distal end to the proximal end and a width perpendicular to the length, the width extending from a first side edge of the cutting head to a second side edge of the cutting head; the guide projection forms the second side edge of the cutting head; 3. The device of claim 1 or 2.

6. the guide protrusions include a first guide protrusion and a second guide protrusion; the first guide projection forms the first side edge of the cutting head; the second guide projection forms the second side edge of the cutting head; 6. The device of claim 5.

7. 3. The instrument of claim 1 or 2, wherein the cutting head further includes a rail defining the first side edge of the cutting head, the rail terminating at a distal end, and the cutting surface also being concave relative to the distal end of the rail.

8. The instrument of claim 1 or 2, wherein the guide projection defines a cylindrical cross-sectional shape along at least a portion of its length.

9. The instrument of claim 1 or 2, wherein the distal end of the guide projection is blunt, and the guide projection includes a taper toward the blunt distal end.

10. The instrument of claim 1 or 2, wherein the cutting head defines a thickness, the thickness of the cutting head tapering across the cutting surface.

11. The cutting surface includes a leading cutting surface and a trailing cutting surface; the cutting head tapers across the distal cutting surface at a first taper angle; the cutting head tapers across the trailing cutting surface at a second taper angle that is less than the first taper angle; 11. The device of claim 10.

12. The device of claim 1 or 2, wherein the cutting surface terminates in a cutting edge.

13. The instrument of claim 12 , wherein the cutting edge defines a curvature along the width of the cutting head.

14. 3. The instrument of claim 1 or 2, wherein the cutting head is positioned out of plane with the handle so as to define an angle between a longitudinal axis defined by the cutting head and a longitudinal axis defined by the handle.

15. the cutting head defines a length extending from the distal end to the proximal end, a width perpendicular to the length, and a thickness perpendicular to the length and the width; the width of the cutting head is in the range of 5 mm to 13 mm; The thickness of the cutting head is in the range of 0.5 mm to 4 mm.

3. The device of claim 1 or 2.

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