Multi-faceted cutting instrument for mobilizing small bones of the foot

Abstract

Orthopedic cutting instruments can be used to cut and release soft tissue and mobilize bone for subsequent bone realignment. In some instances, the cutting instrument is configured with a handle and a cutting head. The cutting head has multiple cutting surfaces, such as a distal cutting surface and a side cutting surface that extends at an angle away from the distal cutting surface. A mirror set of the cutting surfaces may be provided on the opposite side of the cutting head. The cutting surfaces may be positioned to allow controlled cutting of the soft tissue while limiting inadvertent deep penetration of the cutting instrument. Additionally, the cutting surfaces may be configured to allow for back and forth cutting movement of the cutting head, which may be useful when working within tight joint spaces.

Description

[Technical field]

[0001] (cross reference) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 313,124, filed February 23, 2022, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THEINVENTION The present disclosure relates to surgical cutting instruments and, more particularly, to a multi-faceted cutting instrument for releasing soft tissue between bones of the foot. [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] Another type of foot bone deformity is the adducted foot. MTA is a foot deformity in which the metatarsals are angled inward. MTA is typically characterized by a medial deviation of the metatarsals in the transverse plane. For example, MTA is often described as a structural deformity occurring at the Lisfranc joint (tarsometatarsal joint), where the metatarsals are deviated medially relative to the lesser foot.

[0005] In some cases, surgical intervention is required to address hallux valgus and / or MTA deformity. 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

[0006] 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 during a surgical procedure to cut and release soft tissue, such as ligaments, tendons, and / or muscles between bones. For example, during a bone realignment procedure, a joint space between adjacent bones can be surgically accessed. A cutting instrument can then be inserted into and / or across the joint space to cut soft tissue in and / or around the joint space. By cutting this soft tissue, bones that define the joint space can be released and mobilized, increasing the range of motion over which the bones can be moved to realign them during a surgical procedure.

[0007] In some implementations, the cutting instrument is configured with a handle that can be grasped by a clinician performing a procedure and a cutting head operably connected to the handle. The cutting head can have a number of different cutting surfaces or cutting facets arranged relative to one another to facilitate controlled cutting for a targeted surgical procedure. For example, the cutting head may be configured with a distal cutting surface and a pair of lateral cutting surfaces that extend at an angle away from the distal cutting surface. The distal cutting surface can define a straight cutting blade that is perpendicular to the longitudinal axis of the cutting instrument, and the lateral cutting surface can define a lateral cutting blade that extends obliquely relative to the longitudinal axis of the cutting instrument. The distal cutting blade can be used to cut tissue as the cutting instrument is advanced axially into the joint space. The lateral cutting blade can be used to cut tissue as the cutting instrument is moved back and forth (e.g., medially and laterally, distally and proximally) within the joint space.

[0008] In some configurations, the straight cutting blade defined by the tip cutting surface is relatively smaller than the maximum width of the cutting head measured between the side cutting blades. For example, the width of the cutting head may taper from the maximum width between the side cutting blades to a narrowed width defined by the tip cutting blade. At the same time, the tip cutting blade may define a minimum length, providing a larger cutting blade than simply a sharp tip. Configuring the cutting head with a relatively small tip cutting blade that spreads over the side cutting blades to define a larger cutting head width may be useful to help the clinician perform a controlled cut via the instrument. The relatively narrow tip cutting blade may allow the clinician to initiate axial advancement of the cutting head into the joint space and / or tissue to be cut. Subsequent expansion of the cutting head may create resistance to the axial advancement of the cutting head (e.g., as the relatively wider portion of the cutting head encounters a wider portion of the tissue to be cut). This configuration allows the clinician to effectively initiate the cut, while helping to prevent the clinician from pushing the instrument too deeply into the joint space, for example, which may cut tissue that was not otherwise intended to be cut during the surgical procedure.

[0009] Orthopaedic cutting instruments according to the present disclosure can be used in any desired surgical procedure. In some configurations, the cutting instruments may find particular utility in releasing soft tissue within a joint space of the foot prior to realigning one or more bones that define the joint space being released. The bones and corresponding joint spaces of the foot are small compared to many other larger bones and joint spaces of the body. This can make precision cutting in and around the joint space more delicate than when working in larger anatomical regions of the body.

[0010] In one embodiment, an orthopaedic cutting instrument is described that includes a handle and a cutting head. The handle has a length extending from a first end to a second end. The cutting head extends from the second end of the handle. According to this embodiment, the cutting head includes a leading cutting surface, a first side cutting surface, and a second side cutting surface. The first side cutting surface extends angled outward from the leading cutting surface on a first side of the cutting head. The second side cutting surface extends angled outward from the leading cutting surface in an opposite direction to the first side cutting surface on a second side of the cutting head.

[0011] In another embodiment, a method of preparing a joint is described. The method involves inserting a cutting head into a joint space defined between a first bone and a second bone and moving the cutting head within the joint space to cut soft tissue between the first bone and the second bone. The embodiment provides that the cutting head includes a leading cutting surface, a first lateral cutting surface, and a second lateral cutting surface. The first lateral cutting surface extends angled outward from the leading cutting surface on a first side of the cutting head. The second lateral cutting surface extends angled outward from the leading cutting surface in a direction opposite the first lateral cutting surface on a second side of the cutting head.

[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] 1A and 1B are top and side views, respectively, of an exemplary orthopaedic cutting instrument in accordance with the present disclosure; [Figure 1B] 1A and 1B are top and side views, respectively, of an exemplary orthopaedic cutting instrument in accordance with the present disclosure;

[0014] [Figure 1C] FIG. 1C is a top view of an exemplary configuration of a cutting head of the exemplary cutting instrument of FIGS. 1A and 1B, where one or more cutting blades of the cutting head define a curvature over the length of the blade. [Figure 1D]FIG. 1C is a top view of an exemplary configuration of a cutting head of the exemplary cutting instrument of FIGS. 1A and 1B, where one or more cutting blades of the cutting head define a curvature over the length of the blade.

[0015] [Diagram 2] FIG. 2 is an enlarged view of the cutting head of FIG. 1, illustrating an example configuration of the cutting head features.

[0016] [Figure 3A] 2A and 2B are front perspective and side views, respectively, of the cutting instrument of FIG. 1, illustrating an exemplary tapered profile of the cutting head; [Figure 3B] 2A and 2B are front perspective and side views, respectively, of the cutting instrument of FIG. 1, illustrating an exemplary tapered profile of the cutting head;

[0017] [Figure 4A] 1A and 1B are top and front views, respectively, of a foot showing an exemplary normal metatarsal alignment position. [Figure 4B] 1A and 1B are top and front views, respectively, of a foot showing an exemplary normal metatarsal alignment position.

[0018] [Diagram 5] 1 illustrates the different anatomical planes of the foot.

[0019] [Figure 6] 1 is a flow diagram of an exemplary bone realignment technique that may be implemented utilizing a cutting instrument in accordance with the present disclosure.

[0020] [Figure 7A] 1 illustrates an exemplary tissue cutting step that can be performed using a cutting instrument according to the present disclosure. [Figure 7B] 1 illustrates an exemplary tissue cutting step that can be performed using a cutting instrument according to the present disclosure. [Figure 7C] 1 illustrates an exemplary tissue cutting step that can be performed using a cutting instrument according to the present disclosure. [Figure 7D]1 illustrates an exemplary tissue cutting step that can be performed using a cutting instrument according to the present disclosure. [Figure 7E] 1 illustrates an exemplary tissue cutting step that can be performed using a cutting instrument according to the present disclosure.

[0021] [Figure 8A] 13 is a diagram of another exemplary joint space into which a cutting instrument can be inserted and moved to cut tissue to mobilize bones for realignment in accordance with the present disclosure; FIG. [Figure 8B] 13 is a diagram of another exemplary joint space into which a cutting instrument can be inserted and moved to cut tissue to mobilize bones for realignment in accordance with the present disclosure; FIG.

[0022] [Figure 8C] 1A-1C are diagrams of an exemplary technique using a cutting tool as a blocking tool.

[0023] [Figure 9A] 1A and 1B are perspective and top views, respectively, of an alternative exemplary configuration of a cutting head, the cutting head defining a bounded notch or cavity at a distal end thereof; [Figure 9B] 1A and 1B are perspective and top views, respectively, of an alternative exemplary configuration of a cutting head, the cutting head defining a bounded notch or cavity at a distal end thereof; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] 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 can be used to cut soft tissue connecting a bone to an adjacent bone, helping to mobilize the bone for a subsequent repositioning step. For example, the cutting instrument may be used to cut soft tissue during a metatarsal realignment and fusion procedure. While the instrument may find particular utility for cutting soft tissue, in practice, a clinician may use the instrument to cut and / or shape bone, shave cartilage, and / or perform any other procedure desired by the clinician without departing from the scope of the present disclosure.

[0025] 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., a 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.

[0026] Preparation and fusion of one or more TMT joints may be performed in accordance with the present disclosure for a variety of clinical reasons and indications. Preparation and fusion of a TMT joint may be performed to treat metatarsal adduction, hallux valgus, arthritis, and / or other bone and / or joint conditions.

[0027] Metatarsal adduction is a foot deformity characterized by a transverse plane deformity in which the metatarsals are adducted at the Lisfranc joint. The degree of metatarsal adduction deformity can be characterized by the metatarsal adduction angle. The metatarsal adduction angle can be defined as the angle between the long axis of the second metatarsal (representing the long axis of the metatarsal) and the long axis of the lesser tarsus. The measurement of the long axis of the lesser tarsus can be characterized by a line perpendicular to the transverse axis of the lesser tarsus, using the lateral articulation of the fourth metatarsal with the cuboid as a reference.

[0028] Hallux valgus, also called hallux abductus valgus, 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. The increase in the hallux adduction angle may tend to laterally displace the plantar aponeurosis and the tendons of the intrinsic and extrinsic muscles across the first metatarsophalangeal joint from the metatarsal to the hallux. As a result, the sesamoid may also be laterally displaced, for example, relative to the first metatarsophalangeal joint, resulting in subluxation of the joint between the sesamoid and the first metatarsal head. This may increase the pressure between the medial sesamoid and the crest of the first metatarsal head.

[0029] 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 tarsometatarsal ("TMT") joints, metatarsophalangeal ("MTP") joints, or other joints. Thus, references herein to the first metatarsal and medial cuneiform bones may be substituted with other bone pairs as described herein.

[0030] The anatomy of the foot and an exemplary technique utilizing a cutting instrument according to the present disclosure will be described in more detail with respect to Figures 4-8. However, an exemplary orthopaedic cutting instrument according to the present disclosure will first be described with respect to Figures 1-3.

[0031] 1A and 1B (collectively referred to as "FIG. 1") are top and side views, respectively, of an exemplary orthopaedic cutting instrument 10 according to the present disclosure. The cutting instrument 10 includes a handle 12 and a cutting head 14 operably connected to the handle. For example, in the configuration shown, the handle 12 has a major 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.

[0032] As described in more detail below, the cutting head 14 may be configured with a number of different cutting surfaces (which may also be referred to as cutting facets) that are controllably positioned relative to one another. The cutting head 14 may include a distal cutting surface and a lateral cutting surface that are interconnected together to form an overall cutting profile of the cutting head. In use, a clinician may advance the cutting head 14 in a number of different directions utilizing the different cutting surfaces of the cutting head depending on the particular direction in which the clinician is advancing the cutting head. This allows the clinician to precisely and efficiently cut tissue or other structures at a target location during a surgical procedure.

[0033] 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 tarsometatarsal joint space between a metatarsal and an opposing bone (cuneiform, cuboid) and / or the intermetatarsal space between adjacent metatarsals. A clinician may insert the cutting head 14 of the cutting instrument 10 into one or more of these target joint spaces when preparing a metatarsal (or a portion thereof) for subsequent realignment. For example, 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 the bone (e.g., metatarsal) that is intended to be realigned. Cutting the soft tissue using the cutting instrument 10 can mobilize the bone for subsequent realignment. 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 across the joint space.

[0034] 1A, the cutting head 14 is shown as including a distal cutting surface 20, a first side cutting surface 22, and a second side cutting surface 24. The distal cutting surface 20 may define the most distal cutting surface of the cutting head 14 (the first end 16 of the handle 12 defines the most proximal portion of the cutting instrument 10). The first side cutting surface 22 and the second side cutting surface 24 may be separated from each other in a width direction across the cutting head 14, e.g., the width of the cutting head is perpendicular to the length of the cutting instrument 10 and the material thickness of the cutting head. The first side cutting surface 22 may extend angled outward from the distal cutting surface 20 on a first width side of the cutting head. The second side cutting surface 24 may extend angled outward from the distal cutting surface 20 in a direction opposite the first side cutting surface 22 on a second width side of the cutting head 14.

[0035] FIG. 2 is an enlarged view of the cutting head 14 of FIG. 1, illustrating an exemplary configuration of cutting head features. FIG. 2 illustrates a leading cutting surface 20 defining a leading cutting edge 26, a first side cutting surface 22 defining a first side cutting edge 28, and a second side cutting surface 24 defining a second side cutting edge 30. The first side cutting surface 22, and the first side cutting edge 28 defined thereby, are shown to extend at an angle away from the leading cutting surface 20, and the leading cutting edge 26 defined thereby, in a width direction (e.g., the positive X direction shown in FIG. 2). The second side cutting surface 24, and the second side cutting edge 30 defined thereby, are shown to extend at an angle away from the leading cutting surface 20, and the leading cutting edge 26 defined thereby, in a generally opposite width direction (e.g., the negative X direction shown in FIG. 2). As a result, the overall width of the cutting head 14 in the configuration of FIG. 2 increases as one moves proximally from the distal cutting blade 26 along the portion of the cutting head defined by the first and second side cutting blades 28, 30 of the cutting head.

[0036] Configuring the cutting head 14 with a relatively narrow distal cutting surface 20 (and distal cutting blade 26 defined thereby) followed by a relatively wider region of the cutting head defined by the first and second side cutting surfaces 22, 24 (and side cutting blades 28, 30 defined thereby) can be useful to facilitate controlled penetration of the cutting head by the clinician during use. The relatively narrow distal cutting surface 20 allows the clinician to apply a concentrated force to the relatively small distal cutting blade 26 to introduce the cutting instrument into the joint space and / or to apply a cutting force to the tissue to be cut. The relatively wider trailing region of the cutting head 14 expands the cutting area created by the cutting head. This can increase the cutting area of ​​the cutting head 14, increasing the amount of tissue cut while at the same time increasing resistance against the cutting head. This can help prevent the clinician from inadvertently plunging the cutting head 14 too far into the joint space during a procedure and cutting muscle, tendon, and / or other tissue that would otherwise not be desired to be cut during the procedure.

[0037] In some implementations, the cutting head 14 defines a maximum width 32 at a location rearward (proximal) of the tip cutting surface 20, between the first side cutting surface 22 and the second side cutting surface 24. This maximum width 32 of the cutting head 14 can be compared to a length 34 of the tip cutting blade 26, e.g., a straight cutting blade extending widthwise at the distal tip of the cutting head 14. The length 34 of the tip cutting blade 26 can be set to be less than the maximum width 32 of the cutting head 14, thereby configuring the cutting head 14 with a relatively narrow distal cutting tip that expands widthwise in the proximal direction.

[0038] While the specific dimensions of the cutting head 14 may vary depending on the intended application, in some examples, the tip cutting blade 26 defines a length 34 in a range of 1 mm to 15 mm, e.g., 2 mm to 10 mm, or 3 mm to 7 mm. For example, the tip cutting blade 26 may define a length 34 of about 5 mm (e.g., ±10 percent). In addition, the maximum width 32 of the cutting head 14 between the first side cutting surface 22 and the second side cutting surface 24 may range from 5 mm to 25 mm, e.g., 7 mm to 20 mm, or 9 mm to 13 mm. For example, the maximum width 32 of the cutting head 14 may be about 11 mm (e.g., ±10 percent).

[0039] Depending on the relative widthwise dimensions of the cutting head 14 at different locations along its length, the ratio of the length 34 of the tip cutting blade 26 divided by the maximum width 32 of the cutting head may range from 0.25 to 0.75, such as from 0.35 to 0.5. For example, the ratio of the length 34 of the tip cutting blade 26 divided by the maximum width 32 of the cutting head may be less than 0.5, such as less than 0.45, or less than 0.4.

[0040] In the configuration of FIG. 2, the first side cutting surface 22 extends angled outward from the tip cutting surface 20, and the second side cutting surface 24 extends angled outward from the tip cutting surface 20 in a different direction than the first side cutting surface. For example, the tip cutting edge 26 defined by the tip cutting surface 20 may extend from a first end 26A to a second end 26B. The first side cutting edge 28 may intersect with the first end 26A of the tip cutting edge 26 and extend outward therefrom. The second side cutting edge 30 may intersect with the second end 26B of the tip cutting edge 26 and extend outward therefrom. The angles at which the first and second side cutting surfaces 22, 24 extend away from the tip cutting surface 20 may be defined by the intersection angles between the tip cutting surface and the first and second side surfaces, respectively.

[0041] As mentioned above, the tip cutting surface 20 may terminate at a distal-most end of the tip cutting blade 26, which may be referred to as a linear cutting blade due to the straight or non-curved linear shape of the blade (when so configured). In addition, the first side cutting surface 22 may terminate at an outermost edge forming a first side cutting blade 28, which may also be referred to as a first angled side blade. The second side cutting surface 24 may also terminate at an outermost edge to form a second side cutting blade 30, which may also be referred to as a second angled side blade. The first side cutting blade 28 may intersect with the tip cutting blade 26 to define a first intersecting angle 36A. The second side cutting blade 30 may intersect with the tip cutting blade 26 to define a second intersecting angle 36B. In some examples, one or more cutting blades of the cutting head 14 may define a curvature (e.g., a concave or convex curvature).

[0042] In some configurations, such as shown in FIG. 2, the first intersection angle 36A and the second intersection angle 36B can have the same value to provide a symmetrical expansion of the cutting head 14 extending away from the tip cutting blade 26. In other configurations, the first intersection angle 36A can be different (e.g., greater or smaller) than the second intersection angle 36B to provide an asymmetrical expansion of the cutting head 14. In various examples, the first intersection angle 36A and / or the second intersection angle 36B can range from 10 degrees to 75 degrees, such as from 15 degrees to 45 degrees, or from 25 degrees to 35 degrees. For example, the first intersection angle 36A and / or the second intersection angle 36B can be about 30 degrees (e.g., ±10%).

[0043] The first and / or second side cutting surfaces 22, 24 may extend angled outward from the distal cutting surface 22 along the entire length of the cutting head 14. When so configured, the overall width of the cutting head 14 may increase continuously from the distal-most end of the cutting head defined by the distal cutting blade 26 to the proximal-most end of the cutting head. In other configurations, the first and / or second side cutting surfaces 22, 24 may extend angled outward from the distal cutting surface 20 over a portion of the length of the cutting head 14 before changing direction to extend parallel to the length and / or back toward the longitudinal center of the cutting head. In these latter configurations, the cutting head 14 may define a relatively narrow distal region, a relatively narrow proximal region, and a relatively wider intermediate region between the distal and proximal regions.

[0044] 2, the first side cutting surface 22 defines a first side cutting edge 28 that extends angled outwardly at a first intersecting angle 36A and further includes a first straight side edge 38 proximally adjacent the angled first side cutting edge. In addition, the second side cutting surface 24 defines a second side cutting edge 30 that extends angled outwardly at a second intersecting angle 36B and further includes a second straight side edge 40 proximally adjacent the angled second side cutting edge.

[0045] In the configuration shown, the first straight side blade 38 and the second straight side blade 40 are each parallel to one another and to a longitudinal axis 42 defined by the cutting head 14. In some configurations, the first straight side blade 38 is longer than the first side cutting blade 28 and / or the second straight side blade 40 is longer than the second side cutting blade 30. In other configurations, as shown, the first straight side blade 38 is shorter than the first side cutting blade 28 and / or the second straight side blade 40 is shorter than the second side cutting blade 30. For example, the first straight side blade 38 and the second straight side blade 40 can each have a length (measured along the face of the blade) that is less than 75% of the total length of the first side cutting blade 28 and the second side cutting blade 30, respectively, such as less than 50% of the total length, less than 40% of the total length, or less than 25% of the total length.

[0046] Regardless of whether the cutting head 14 is configured with the first straight side blade 38 and / or the second straight side blade 40, the cutting head may include one or more concave surfaces that narrow the overall width of the cutting head. In the configuration of FIG. 2, the cutting head 14 narrows from a region of maximum width 32 to a shank 44 located proximal to the distal cutting surface 20, the first side cutting surface 22, and the second side cutting surface 24. The transitions between the first side cutting surface 22 and the second side cutting surface 24 and the proximal shank 44 (along one or more intermediate regions, such as the first straight side 38 and the second straight side 40, if included) may be abrupt (e.g., a 90° angle cut) or may taper at a more gradual angle. In either case, the cutting head 14 may define an angled concave surface that tapers toward the shank 44.

[0047] In the embodiment of FIG. 2, the cutting head 14 defines a first concave surface 46 that extends angled inward from the first side cutting surface 22 to the shank 44. The cutting head 14 also defines a second concave surface 48 that extends angled inward from the second side cutting surface 24 to the shank 44. For example, the cutting head 14 may define a first concave blade 50 that extends between the first side cutting blade 28 (with the first straight side blade 38 interposed therebetween, when so configured) and the first blade 44A that bounds the shank 44. The cutting head 14 may also define a second concave blade 52 that extends between the second side cutting blade 30 (with the second straight side blade 40 interposed therebetween, when so configured) and the second blade 44B that bounds the shank 44.

[0048] The first concave surface 46 can define a first concave intersection angle 54 with the first side cutting surface 22. Similarly, the second concave surface 48 can define a second concave intersection angle 56 with the second side cutting surface 24. The first concave intersection angle 54 and the second concave intersection angle 56 can each be in a range of 5° to 90°, such as, for example, 10° to 75°, 15° to 40°, or 25° to 35°. For example, the first concave intersection angle 54 and the second concave intersection angle 56 can each be approximately 30° (e.g., ±10%).

[0049] The specific dimensions of the cutting instrument 10, including the one or more cutting surfaces of the cutting head 14, may vary depending on the desired application. In some implementations, the first lateral cutting surface 22 and the second lateral cutting surface 24 are sized to facilitate cutting within a relatively small joint space. The first lateral cutting surface 22 and the second lateral cutting surface 24 may each be characterized by a longitudinal length 58 extending parallel to the longitudinal axis 42 of the cutting head 14. In some configurations, the length 58 is greater than 3 mm, e.g., greater than 5 mm, and / or less than 25 mm, e.g., less than 15 mm, or less than 10 mm. For example, the length 58 may range from 5 mm to 15 mm, e.g., from 6 mm to 9 mm. The length 58 of the first lateral cutting surface 22 may be the same as or different from the length 58 of the second lateral cutting surface 22.

[0050] In some configurations, the cutting head 14 defines an overall length (e.g., from the distal end of the tip cutting surface 20 to the second end 18 of the handle 12 as shown in FIG. 1) that ranges from 10 mm to 100 mm, e.g., 15 mm to 45 mm. The handle 12 can have any desired length between the first end 16 and the second end 18, but in some instances can exhibit a length that ranges from 50 mm to 200 mm, e.g., 100 mm to 150 mm.

[0051] Generally, features of the cutting head 14 described as cutting surfaces may define regions 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 a material to be cut, the reduced thickness of the cutting surface may facilitate cutting. Each cutting surface 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, referring to FIG. 1B, the thickness of the cutting head 14 in the Y direction shown in the figure may be tapered across the region of each cutting surface defined by the cutting head (e.g., including the tip cutting surface 20, the first side cutting surface 22, and the second side cutting surface 24). The size and configuration of each cutting surface may vary as described herein. In some implementations as shown, the tip cutting surface 20 defines a trapezoid having a long base at the distal-most end of the cutting head 14, a short base located proximally, a first leg joining the long base to the short base, and a second leg joining the long base to the short base.

[0052] 1A, 1B, and 2, the cutting blades of the cutting head 14 are shown as straight or non-curved. In particular, the leading cutting blade 26 of the leading cutting surface 20, the first side cutting blade 28 of the first side cutting surface 22, and the second side cutting blade 30 of the second side cutting surface 24 are each shown as straight blades that do not have any curvature along the length of the blade. In other configurations, one or more of the cutting blades of the cutting head 14 may define a curvature over the length of the blade.

[0053] For example, Figures 1C and 1D are top views of other exemplary configurations of the cutting head 14 of the cutting instrument 10, where one or more cutting blades of the cutting head 14 define a curvature over the blade length. In particular, Figure 1C illustrates an exemplary configuration of the cutting head 14 in which the leading cutting blade 26 of the leading cutting surface 20, the first side cutting blade 28 of the first side cutting surface 22, and the second side cutting blade 30 of the second side cutting surface 24 each define a curvature over the blade length. Figure 1D illustrates an exemplary configuration of the cutting head 14 in which the leading cutting blade 26 of the leading cutting surface 20 defines a curvature over the blade length, while the first side cutting blade 28 of the first side cutting surface 22 and the second side cutting blade 30 of the second side cutting surface 24 are each shown as straight blades that do not have a curvature over the blade length. When configured to have a curved blade, the blade may define a convex radius of curvature in which a portion of the blade extending outwardly along the length of the blade at an intermediate portion of the blade is associated with a portion of the blade at the longitudinal ends of the blade.

[0054] Figures 3A and 3B (collectively referred to as Figure 3) are front perspective and side views, respectively, of the cutting instrument 10, illustrating an exemplary tapered profile of the cutting head 14. As shown in Figure 3, the cutting surface of the cutting head 14 tapers across the thickness of the material defining the cutting head, thereby forming a flat surface with a relatively sharp edge (e.g., apex) for cutting tissue.

[0055] In some implementations, the cutting head 14 defines a cutting plane on one side of the cutting head. For example, a first plane 60 can be defined by the length and width of the cutting head 14 on one side of the cutting head (e.g., in the XZ plane shown in FIG. 3A), and a second plane 62 can be defined by the length and width of the cutting head 14 on the opposite side of the cutting head. The cutting plane defined by the cutting head 14 can extend at an angle across the thickness of the cutting head (e.g., in the Y direction shown in FIG. 3A) toward the opposite plane.

[0056] In some examples, the cutting head 14 defines a cutting surface that extends in a single direction across the thickness of the cutting head (e.g., in the negative Y direction from the first planar surface 60 toward the second planar surface 62) and does not have a cutting surface that extends in the opposite direction (e.g., in the positive Y direction from the second planar surface 62 toward the first planar surface 60). In these configurations, the cutting surface may be defined on the first planar side 60 of the cutting head 14, and the second planar side 62 of the cutting head may lack a cutting surface. This configuration may be referred to as a one-sided tapered configuration.

[0057] 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 set of cutting surfaces tapered in a first direction across the thickness of the cutting head (e.g., in a negative Y direction from the first plane 60 to the second plane 62) and a second set of cutting surfaces tapered in a second direction across the thickness of the cutting head (e.g., in a positive Y direction from the second plane 62 to the first plane 60). The two sets of cutting surfaces may intersect each other at a location between the first plane 60 and the second plane 62, e.g., at a location that is substantially centered across the thickness of the cutting head. For example, the two sets of cutting surfaces may intersect each other to define an intersection apex 64. This configuration may be referred to as a double-sided tapered configuration.

[0058] When configured to have cutting surfaces on both sides of the cutting head 14, the two sides of the cutting head may or may not have a mirror image arrangement of cutting surfaces. For example, an exemplary arrangement of cutting surfaces on one side of the cutting head 14 is described above with respect to FIG. 2. The other side of the cutting head 14 may be configured with a set of cutting surfaces identical to the cutting surfaces prepared on the first side of the cutting head. This can provide a mirror image (e.g., symmetrical) arrangement in which the cutting surfaces on both sides of the cutting head have the same size, shape, and / or arrangement, but are tapered in opposite directions to each other. The blades of the cutting surfaces on the two sides of the cutting head 14 can intersect each other across the thickness of the cutting head. In other configurations, the cutting head 14 may have cutting surfaces on both sides of the cutting head that have different sizes, shapes, and / or arrangements from each other, providing an asymmetric arrangement of cutting surfaces.

[0059] The cutting head 14 in the embodiment of FIG. 3 is shown as having cutting surfaces on both sides of the cutting head that are symmetrically arranged. For example, referring to FIG. 3A, the cutting head 14 is shown as having a first leading cutting surface 20A on a first planar side 60 of the cutting head and a second leading cutting surface 20B on a second planar side 62 of the cutting head. The cutting head 14 is also shown as having a first side cutting surface 22A on the first planar side 60 of the cutting head and a first side cutting surface 22B on the second planar side 62 of the cutting head. The cutting head 14 is further shown as having a second side cutting surface 24A on the first planar side 60 of the cutting head and a second side cutting surface 24B on the second planar side of the cutting head. The opposing pairs of cutting surfaces intersect each other across the thickness of the cutting head to form cutting blades (e.g., a leading cutting blade, a first side cutting blade, and a second side cutting blade). In some proposals, the opposing pairs of cutting surfaces intersect each other at a midline across the cutting thickness.

[0060] The particular angle at which each cutting surface of the cutting head 14 tapers toward the outermost edge may vary based on, for example, the size and configuration of the cutting head. With reference to FIG. 3B, the cutting head 14 may define a taper angle 66, which is the angle at which the cutting surface tapers across the thickness of the cutting head. In some examples, the taper angle 66 may range from 5 degrees to 45 degrees, such as 5 degrees to 25 degrees, or 10 degrees to 20 degrees. When configured to have cutting surfaces on both sides of the cutting head 14 to provide a first taper angle 66 and a second taper angle 68, the two taper angles may be the same or different from one another. Furthermore, all cutting surfaces on a single planar side of the cutting head 14 may taper at the same taper angle, while in other configurations, different cutting surfaces on one side of the cutting head 14 may taper at different angles relative to one another. In some implementations, the total thickness 70 of the cutting head 14 between the first plane 60 and the second plane 62 may be in the range of 0.5 mm to 10 mm, such as 0.75 mm to 5 mm, 1 mm to 2.5 mm, or 1.25 mm to 1.75 mm.

[0061] 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.

[0062] 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 surface 20 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).

[0063] 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 72, such as knobs, ribs, knurling, and / or other features that facilitate gripping of the handle without slipping. While the handle 12 may generally be designed to be manually grasped by the hand of a clinician, 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.

[0064] In the configuration shown, the handle 12 is shown extending collinearly with the cutting head 14. That is, the longitudinal axis defined by the handle 12 is shown extending collinearly with the longitudinal axis 42 defined by the cutting head 14. In other configurations, the handle 12 (either the entire handle or a portion thereof) may be offset from and / or angled relative to the longitudinal axis 42 defined by the cutting head 14.

[0065] In configurations where the handle 12 and cutting head 14 are formed as a single unit 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.

[0066] 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), and / or other conditions that may manifest as misalignment of one or more bones in the foot.

[0067] 4A and 4B 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.

[0068] 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 MT joint 134. The angle between adjacent metatarsals is referred to as the intermetatarsal angle ("IMA").

[0069] 4A and 4B, 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.

[0070] FIG. 5 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).

[0071] 6 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 FIG. 6, the cutting instrument 10 may be utilized to cut soft tissue to help mobilize the bone for subsequent bone realignment. In the exemplary technique, the end of the bone to be realigned and the end of the bone opposite across the tarsometatarsal joint may each be prepared and a fixation device may be placed across the joint to promote fusion of the realigned bone across the joint. In other implementations, such as osteotomy, where a single bone is cut into two pieces, one portion of the bone (e.g., a distal portion) may be realigned relative to the other portion (e.g., a proximal portion).

[0072] Exemplary cutting steps utilizing the cutting instrument 10 that may be performed are described with reference to Figures 7 and 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.

[0073] The exemplary technique of FIG. 6 includes making an incision (602) through the patient's skin to surgically access the joint space. The incision may be made through the skin, such as through 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 elsewhere on the foot. The incision may be made to provide surgical access to one or more of 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. Additionally or alternatively, the incision may be made to access one or more other joints, such as the MTP joints and / or the intermetatarsal joint space between adjacent metatarsals. To surgically access the joint, the patient may be placed supine on the operating room table and administered general anesthesia or monitored anesthesia care. Hemostasis may be obtained by application of a thigh tourniquet or mid-sural tourniquet. In some instances, imaging of the foot can be used to assist the clinician in identifying the location of the target joint where the incision can be centered when later cutting through the skin.

[0074] After surgically accessing one or more target joints, the technique of Figure 6 involves cutting (604) tissue in and / or around the one or more joints using a cutting instrument 10. For example, the cutting instrument 10 can be inserted into the surgically accessed joint space to cut soft tissue within the joint space to help free and mobilize the bone for subsequent repositioning. Figures 7A-7E show exemplary tissue cutting steps that can be performed using the cutting instrument 10 to free the first metatarsal bone 102 for subsequent realignment.

[0075] 7A, an exemplary cutting step using a cutting instrument 10 is shown in which the cutting head 14 of the cutting instrument 10 is inserted into the tarsometatarsal joint space 126. The distal cutting surface 20 (FIG. 2) of the cutting head 14 may be advanced inferiorly (plantarly) into the tarsometatarsal joint space. The clinician may sweep the cutting instrument 10 medially and laterally (e.g., anteriorly and posteriorly) within the joint space to cut tissue using first and second lateral cutting surfaces defined by the cutting head 14.

[0076] Before or after inserting the cutting instrument 10 into the tarsometatarsal joint space 126, the clinician may insert the cutting head 14 of the cutting instrument 10 into the intermetatarsal space between the first metatarsal bone 102 and the second metatarsal bone 104, as shown in FIG. 7B. The clinician may advance the distal cutting surface 20 of the cutting head 14 plantarally into the intermetatarsal space between the first metatarsal bone 102 and the second metatarsal bone 104. The clinician may introduce the cutting head 14 to the proximal base of the first metatarsal bone 102 and sweep the instrument distally (away from the middle cuneiform bone and downward toward the distal end of the intermetatarsal space). Additionally or alternatively, the clinician may introduce the cutting head 14 into the intermetatarsal space at a location distal to the proximal head of the first metatarsal bone 102 and sweep the cutting instrument proximally over the intermetatarsal space. The clinician may also sweep the cutting head 14 proximally and distally (e.g., posteriorly and anteriorly) within the intermetatarsal space. In either case, the first lateral cutting surface 22 and / or the second lateral cutting surface 24 may cut tissue within the joint space.

[0077] In some applications, the clinician may insert the cutting head 14 to an initial depth within the joint space and / or joint spaces to first open the joint space and then advance the cutting head 14 deeper into one or more joint spaces. For example, the clinician may first insert the cutting head 14 into the tarsometatarsal joint space 126 (e.g., as shown in FIG. 7A ) and then insert the cutting head 14 into the intermetatarsal joint space (e.g., as shown in FIG. 7B ). The clinician may then advance the cutting head 14 deeper (further into the plantar part of the foot) in the tarsometatarsal joint space 126 and / or the intermetatarsal space.

[0078] For example, Figures 7C and 7D show the cutting head 14 advanced deeper into the tarsometatarsal joint space 126 and the intermetatarsal joint space, respectively. The clinician can advance the leading cutting surface 20 of the cutting head 14 to a desired depth within one or both joint spaces. In some applications, the clinician can reciprocate the cutting head 14 up and down to cut tissue using both the leading cutting surface 20 (when advancing downward) and the first and second concave cutting surfaces 46, 48 (when retracting upward). The clinician can also sweep the cutting head 14 from side to side within one or both joint spaces at a desired depth to cause the first lateral cutting surface 22 and / or the second lateral cutting surface 24 to cut tissue within the joint space.

[0079] In some applications, the clinician advances the cutting head 14 into a first joint space (e.g., the tarsometatarsal joint 126), then removes the cutting head from the joint space, and then inserts the cutting head into a second joint space (e.g., the intermetatarsal joint space). In other applications, the clinician may use one of the lateral cutting surfaces of the cutting head 10 to cut tissue and sweep around the proximal lateral corner of the first metatarsal to transition from the first joint space to the second joint space. FIG. 7E is an illustration of the cutting instrument 10 performing an exemplary proximal-lateral cutting sweep around the proximal lateral corner of the first metatarsal 102. After performing any desired cuts within one or more joint spaces, the cutting instrument 10 may be removed from the joint space for subsequent steps of the surgical procedure.

[0080] As discussed above, the cutting instrument 10 can be used to cut tissue in a variety of different joint spaces, including different joint spaces within the foot. Figures 8A and 8B are diagrams of another exemplary joint space into which the cutting instrument 10 can be inserted and moved to cut tissue to mobilize bones for realignment. In particular, as seen in Figure 8A, the cutting instrument is shown as being insertable into the intermetatarsal space between the third metatarsal bone 106 and the fourth metatarsal bone 108. For example, a clinician may insert the cutting head 14 of the cutting instrument 10 into a proximal portion of the intermetatarsal space between the third metatarsal bone 106 and the fourth metatarsal bone 108 to cut soft tissue within the joint space. A clinician may cut the soft tissue within the joint space to free and mobilize the third metatarsal bone 106 from the fourth metatarsal bone 108 to facilitate subsequent realignment of the third metatarsal bone 108 and / or the second metatarsal bone 104, such as in an adductor foot correction procedure.

[0081] With reference to FIG. 8A, the clinician may advance the distal cutting surface 20 of the cutting head 14 plantarally into the intermetatarsal space between the third metatarsal bone 106 and the fourth metatarsal bone 108. The clinician may introduce the cutting head 14 at the proximal base of the third metatarsal bone 106. As shown in FIG. 8B, the clinician may continue to press the distal cutting surface of the cutting head 20 down to a desired depth within the intermetatarsal space. With the cutting head 14 at the desired depth within the intermetatarsal space, the clinician may sweep the cutting instrument 10 distally (down toward the distal end of the intermetatarsal space, away from the cuboid bone) and / or proximally (up toward the cuboid bone) (e.g., back and forth) to cut tissue at the intermetatarsal space using the lateral cutting surface of the cutting instrument.

[0082] With the soft tissue suitably freed from the intermetatarsal space, the clinician can remove the cutting instrument 10 from the intermetatarsal space. Additionally or alternatively, the clinician may leave the cutting instrument 10 in the intermetatarsal space with the handle 12 protruding outwardly from the intermetatarsal space. For example, the clinician may additionally or alternatively utilize the cutting instrument 10 as a blocking device to help control the subsequent preparation of the end of the third metatarsal 106. The cutting instrument 10 can function to help prevent the clinician from inadvertently cutting the fourth metatarsal 108 with a saw while attempting to prepare the end of the third metatarsal 106, optionally using a cutting guide. Such a blocking arrangement of the cutting instrument 10 is shown in FIG. 8C.

[0083] With further reference to the exemplary technique of FIG. 6, the technique includes preparing (606) an end of a first bone at an end of a second bone facing the first bone across the joint space for fusion. For example, the clinician may prepare the end of the metatarsal bone to be realigned (first metatarsal 102, second metatarsal 104, third metatarsal 106, fourth metatarsal 108, and / or fifth metatarsal 112) and the end of the opposing bone (medial cuneiform 118, middle cuneiform 120, lateral cuneiform 122, and / or cuboid 124) across the tarsometatarsal joint. One or both of the end faces of the metatarsal bone and the opposing bone can be prepared before and / or after moving the metatarsal bone relative to the cuneiform bone. Thus, unless otherwise specified, the order of preparation and / or movement of the bones is not limited.

[0084] 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.

[0085] 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.

[0086] The exemplary technique of FIG. 6 also includes realigning (608) at least one bone relative to at least one other bone. For example, one or more metatarsals may be realigned in one or more planes before and / or after preparing one or more end faces of the bones that define the joint. For example, the clinician may move the first metatarsal 102, the second metatarsal 104, the third metatarsal 106, and / or one or more other bones. Moving the bones may include moving the bones in at least one plane. For example, the metatarsals may be moved in at least a transverse plane to close the intermetatarsal angle between the moved bones in the adjacent bones. Additionally or alternatively, the metatarsals may be in a frontal plane (e.g., to reposition a sesamoid bone substantially centered under the metatarsal). In some examples, the metatarsals may be moved in multiple planes, such as a transverse plane and / or a frontal plane and / or a sagittal plane (e.g., each of a transverse plane, a frontal plane, and a sagittal plane). The clinician may or may not utilize a bone positioning device to facilitate the movement of the bone portions. The moved position of the metatarsal may result in realignment of the metatarsal relative to one or more other adjacent bones.

[0087] After realignment (or instead of performing a separate realignment step), the exemplary technique of FIG. 6 can include compressing one or more bone surfaces together (610). When performed, the prepared end surfaces of the bones that face the joint may be compressed together. 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.

[0088] After suitably realigning one or more of the first, second, third, fourth, and / or fifth metatarsals, the technique of FIG. 6 includes fixing (612) the displaced position of one or more displaced metatarsals. 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 one or more metatarsals (e.g., by inserting fixation pins through one or more displaced metatarsals and 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. 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 faces of the opposing prepared bones to provide a fusion joint.

[0089] The cutting instrument 10 has been generally described as an instrument configured with a distal cutting surface 20, a first side cutting surface 22, and a second side cutting surface 24, where the first and second sides extend at an angle outwardly from the distal cutting surface. In an alternative configuration of the cutting instrument 10, the instrument may be configured with a concave notch at the tip of the cutting head 14. If so configured, the instrument may have a concave distal cutting surface, where the first side cutting surface 22 and the second side cutting surface 24 extend at an angle inwardly relative to the concave cutting surface.

[0090] For example, Figures 9A and 9B (collectively "Figure 9") are perspective and top views, respectively, of an alternative exemplary configuration of the cutting head 14 of the cutting instrument 10, where the cutting head defines a bounded notch or cavity 80 at a distal end thereof. In this embodiment, the cutting head 14 has a concave distal cutting surface 82. The first side cutting surface 22 extends angled inwardly from the distal end of the cutting head 14 to the concave distal cutting surface 82. The second side cutting surface 24 also extends angled inwardly from the distal end of the cutting head 14 to the concave distal cutting surface 82. When so configured, the cavity 80 can define an inverse shape profile of the shape profile of the cutting head 14 described above with respect to Figures 1-3.

[0091] 9 illustrates a concave distal cutting surface 82 defining a cutting blade 84, a first side cutting surface 22 defining a first side cutting blade 28, and a second side cutting surface 24 defining a second side cutting blade 30. The first side cutting surface 22, and the first side cutting blade 28 defined thereby, are shown as extending at an angle away from the concave distal cutting surface 82, and the cutting blade 84 defined thereby, in a width direction moving from proximal to distal along the length of the cutting head 14. Similarly, the second side cutting surface 24, and the second side cutting blade 30 defined thereby, are shown as extending at an angle away from the concave distal cutting surface 82, and the cutting blade 84 defined thereby, in a width direction moving from proximal to distal along the length of the cutting head 14. As a result, the overall width of the cutting head 14 in the configuration of FIG. 9 increases as one moves distally from the cutting blade 84 of the cutting head along the portion of the cutting head defined by the first and second side cutting blades 28, 30.

[0092] Configuring the cutting head 14 with a cavity 80 bounded by three cutting blades can be useful to provide a recessed space that a clinician can use to capture and cut tissue. As the clinician advances the cutting head 14 towards the target tissue to be cut, the clinician can position tissue within the cavity 80 of the cutting head 14 before further advancing the cutting head and using one or more cutting surfaces (e.g., cutting blades) of the cutting head to cut the tissue captured within the cavity.

[0093] The first side cutting blade 28 can intersect with the cutting edge 84 of the concave distal cutting surface 82 to define a first intersection angle 86A. The second side cutting blade 30 can intersect with the cutting edge 84 of the concave distal cutting surface 82 to define a second intersection angle 86B. In some configurations, such as shown in FIG. 9, the first intersection angle 86A and the second intersection angle 86B can have the same value to provide a symmetrical expansion of the cutting head 14 extending distally outward from the cutting blade 84. In other configurations, the first intersection angle 86A can be different (e.g., greater or smaller) than the second intersection angle 86B to provide an asymmetrical profile of the cutting head 14. In various examples, the first intersection angle 86A and / or the second intersection angle 86B can be at least 90 degrees, e.g., at least 110 degrees, at least 125 degrees, or at least 135 degrees. For example, the first intersection angle 86A and / or the second intersection angle 86B may be in the range of 90 degrees to 160 degrees, such as 110 degrees to 145 degrees, or 115 degrees to 135 degrees.

[0094] A cutting head 14 configured according to the embodiment of Figure 9 may utilize any of the construction details (e.g., shapes, dimensions) described above for the cutting head 14 in connection with Figures 1-3. For example, the concave distal cutting surface 82 and corresponding cutting blade 84 may be implemented using any of the construction details described for the tip cutting surface 20 and tip cutting blade 26, respectively.

[0095] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. 1. An orthopedic cutting instrument comprising: (a) a handle having a length extending from a first end to a second end; (b) a cutting head extending from the second end of the handle, (i) a tip cut surface; (ii) a first side cutting surface extending angularly outward from the tip cutting surface on a first side of the cutting head; (iii) a second side cutting surface extending angularly outward from the tip cutting surface in a direction opposite the first side cutting surface on a second side of the cutting head; a cutting head including: An apparatus comprising:

2. the cutting head defines a maximum width at a location between the first side cutting surface and the second side cutting surface; the distal cutting surface terminates in a cutting edge having a length; the length of the cutting blade is less than the maximum width of the cutting head; 10. The device of claim 1.

3. The instrument of claim 2 , wherein the cutting blade defines a straight cutting edge.

4. 4. The device of claim 2 or 3, wherein the ratio of the length of the cutting blade divided by the maximum width of the cutting head is in the range of 0.25 to 0.

75.

5. 4. The device of claim 2 or 3, wherein the ratio of the length of the cutting blade divided by the maximum width of the cutting head is less than 0.

5.

6. The length of the cutting blade is in the range of 3 mm to 7 mm; The maximum width of the cutting head is in the range of 9 mm to 13 mm.

4. The device according to claim 2 or 3.

7. the distal cutting surface terminates in a cutting edge extending from a first end to a second end; the first side cutting surface defines a first angled side edge that intersects the first end of the cutting blade; the second side cutting surface defines a second angled side edge that intersects with the second end of the cutting edge; 3. The device of claim 1 or 2.

8. the first side cutting surface further defines a first straight side edge, the first angled side edge intersecting the first end of the cutting edge on one side and the first straight side edge on the other side; the second side cutting surface further defines a second straight side edge, the second angled side edge intersecting the second end of the cutting edge on one side and the second straight side edge on the other side; 8. The device of claim 7.

9. The instrument of claim 8 , wherein the first straight side blade and the second straight side blade are each parallel to a longitudinal axis of the cutting head.

10. The cutting head Shank and a first concave surface extending angularly inward from the first cutting surface to the shank; a second concave surface extending angularly inward from the second cutting surface to the shank; The device of claim 1 or 2, further comprising:

11. 3. The instrument of claim 1 or 2, wherein the cutting head defines a thickness, the thickness of the cutting head tapering across the tip cutting surface, the first side cutting surface, and the second side cutting surface.

12. 3. The instrument of claim 1 or 2, wherein the distal cutting surface defines a trapezoid having a long base, a short base, a first leg joining the long base to the short base, and a second leg joining the long base to the short base, the long base of the trapezoid defining the distal-most end of the cutting head.

13. the cutting head has a width and a length defining a first side of the cutting head and a second side of the cutting head, the first side of the cutting head being separated from the second side of the cutting head by a thickness of the cutting head; the tip cutting surface, the first side cutting surface, and the second side cutting surface are each defined on the first side of the cutting head; the second side of the cutting head is devoid of a cutting surface; 3. The device of claim 1 or 2.

14. the cutting head has a width and a length defining a first side of the cutting head and a second side of the cutting head, the first side of the cutting head being separated from the second side of the cutting head by a thickness of the cutting head; the cutting surfaces include a first cutting surface on the first side of the cutting head and a second cutting surface on the second side of the cutting head, the first and second cutting surfaces intersecting each other across the thickness of the cutting head to form a cutting edge; the first side cutting surface includes two first side cutting surfaces, one on the first side of the cutting head and one on the second side of the cutting head, the two first side cutting surfaces intersecting each other across the thickness of the cutting head to form a first side cutting blade; the second side cutting surface includes two second side cutting surfaces, one on the first side of the cutting head and one on the second side of the cutting head, the two second side cutting surfaces intersecting each other across the thickness of the cutting head to form a second side cutting blade; 3. The device of claim 1 or 2.

15. the cutting head has a width and a length defining a first side of the cutting head and a second side of the cutting head, the first side of the cutting head being separated from the second side of the cutting head by a thickness of the cutting head; the tip cutting surface, the first side cutting surface, and the second side cutting surface are each defined on the first side of the cutting head; the cutting head defining a mirror image arrangement of cutting surfaces on the second side of the cutting head; 3. The device of claim 1 or 2.

Images