tibial fixation plate

Abstract

A bone fixation plate is provided that includes a head section, a tail section, and a curved section. The head section is disposed at a proximal end of the fixation plate. The head section has top and bottom surfaces, at least one edge surface, at least one head aperture, and a head section centerline. The tail section disposed at the proximal end of the fixation plate includes top and bottom surfaces, caudal and cranial sides, at least one tail aperture, and a slotted tail aperture. The slotted tail aperture has a length axis that is greater than the width axis and is substantially parallel to the head section centerline. The curved section is between and continuous with the tail and head sections. The head section is oriented toward the caudal side of the fixation plate. The head section centerline is inclined at a head section angle greater than zero.

Description

[Technical Field]

[0001] This application claims priority to U.S. Patent Application No. 63 / 415,127, filed October 11, 2022, which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to bone fixation plates, and more particularly to bone fixation plates configured for fixation of the tibia of animals, including dogs. [Background technology]

[0003] Bone fixation plates can be used in tibial osteotomies and other procedures to fix two bone segments together. In a tibial plateau horizontal osteotomy (commonly referred to as "TPLO") procedure, for example, a curvilinear cut is made in the proximal tibia of a dog to separate the metaphysis from the proximal tibia. The metaphysis is then rotated to level the tibial plateau. Finally, the metaphysis is fixed to the proximal tibia with a fixation plate.

[0004] It is commonly desired by practitioners of tibial osteotomies to make a curved cut as high proximally as possible and as close to the joint between the tibia and the metaphysis. However, conventional bone fixation plates do not allow for such high proximal curved cuts. These high proximal curved cuts are not recommended, at least in part, due to the large size of the head portion of conventional bone fixation plates. Furthermore, the large head size and hole location limit the ability to manipulate the plate on the bone.

[0005] Additionally, the geometry of conventional bone fixation plates is straight from the head of the plate to the tail of the plate, which limits elevation of the caudal aspect of the proximal tibia and maximizing central coverage of the midshaft tibia. Furthermore, conventional bone fixation plates do not allow for placement of a skin retractor. As a result, longer incisions are required when utilizing conventional bone fixation plates.

[0006] Finally, conventional bone fixation plates are limited or have restrictive screw holes with respect to how screws inserted therein can be oriented. In other words, conventional bone fixation plates do not allow for multi-axial placement of screws. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides an improved bone fixation plate that facilitates lifting of the tail of the plate on the proximal tibia, allowing for a high proximal cut within the tibia while allowing a location for a skin retractor to engage the plate. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, a bone fixation plate is provided, including a head section, a tail section, and a curved section. The head section is disposed at a proximal end of the fixation plate. The head section has a first upper surface, a first bottom surface opposite the first upper surface, at least one edge surface extending between the first upper surface and the first bottom surface, and at least one head aperture extending between the first upper surface and the first bottom surface. The head section has a head section centerline that bisects the head section. The tail section, disposed at the proximal end of the fixation plate, includes a second upper surface, a second bottom surface opposite the second upper surface, a caudal side surface extending between the second upper surface and the second bottom surface, a cranial side surface extending between the second upper surface and the second bottom surface, at least one tail aperture extending between the second upper surface and the second bottom surface, and a slotted tail aperture extending between the second upper surface and the second bottom surface, thereby forming a fastener passage through the head section. The slotted tail aperture includes a longitudinal axis and a widthwise axis, the longitudinal axis extending a distance greater than the widthwise axis. The longitudinal axis is substantially parallel to the head section centerline. The curved section is disposed between and continuous with the tail section and the head section. The head section is oriented toward a caudal side of the fixation plate, and the head section centerline is disposed at a head section angle, the head section angle being greater than zero.

[0009] In any of the aspects or embodiments described above and herein, the at least one head aperture and the at least one tail aperture may each have an aperture center axis and may have a multi-axial configuration including multiple threaded sections with adjacent threaded sections separated from each other by relief pockets.

[0010] In any of the aspects or embodiments described above and herein, the multi-axial configuration of the at least one head aperture may be configured to allow a threaded fastener having a fastener central axis to be disposed within the at least one head aperture at an oblique angle with threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, the oblique angle being up to and including 15 degrees.

[0011] In any of the aspects or embodiments described above and herein, the at least one head aperture may have a first diameter proximate the first top surface and a second diameter proximate the first bottom surface, and the second diameter may be smaller than the first diameter.

[0012] In any of the aspects or embodiments described above and herein, the multi-axial configuration of the at least one tail aperture may be configured to allow a threaded fastener having a fastener center axis to be disposed within the at least one head aperture at an oblique angle with threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, the oblique angle being up to and including 15 degrees.

[0013] In any of the aspects or embodiments described above and herein, the at least one tail aperture can have a first diameter proximate the first top surface and a second diameter proximate the first bottom surface, and the second diameter can be smaller than the first diameter.

[0014] In any of the aspects or embodiments described above and herein, the tail section may have a tail section centerline that extends along an arcuate path.

[0015] In any of the aspects or embodiments described above and herein, the caudal surface can be disposed medial to the arcuate pathway and the cranial surface can be disposed lateral to the arcuate pathway.

[0016] In any of the aspects or embodiments described above and herein, the at least one tail aperture may include a first tail aperture and a second tail aperture, both of which may have an aperture center axis and may have a multi-axial configuration including a plurality of threaded sections with adjacent threaded sections separated from each other by relief pockets, and the first tail aperture may be disposed proximate a distal end of the fixation plate and the second tail aperture may be disposed between the first tail aperture and the slotted tail aperture.

[0017] In any of the aspects or embodiments described above and herein, both the first and second tail apertures may have a first diameter proximate the second top surface and a second diameter proximate the second bottom surface, and the second diameter may be smaller than the first diameter.

[0018] In any of the aspects or embodiments described above and herein, the multi-axial configuration of the first and second tail apertures may be configured to allow a respective threaded fastener having a fastener central axis to be disposed within the respective first or second tail aperture at an oblique angle with threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, the oblique angle being up to and including 15 degrees.

[0019] In any of the aspects or embodiments described above and herein, the curved section may curve caudally away from the tail section to cause the head section to project caudally from the tail section.

[0020] In any of the aspects or embodiments described above and herein, the fixation plate may further include at least one thread angle limiting protrusion (SAR protrusion) extending outward from the first bottom surface of the head section. The at least one SAR protrusion may be disposed proximate to the at least one head aperture. The SAR protrusion may be configured to limit the amount of fastener skew relative to a circumferential portion of each of the at least one head aperture.

[0021] In any of the aspects or embodiments described above and herein, the at least one head aperture may include a first head aperture having a first head aperture central axis. The first head aperture may have a multi-axial configuration including a plurality of threaded sections with adjacent threaded sections separated from each other by relief pockets. The multi-axial configuration may allow a threaded fastener having a fastener central axis to be disposed within the first head aperture at an angle such that the fastener central axis is oblique to the first head aperture central axis, with threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, the oblique angle being up to and including 15 degrees.

[0022] In any of the aspects or embodiments described above and herein, the at least one head aperture may include a first head aperture having a first head aperture central axis. The first head aperture may be configured to allow a threaded fastener having a fastener central axis to be disposed therein at an angle such that the fastener central axis is tilted relative to the first head aperture central axis. The fixation plate may further include at least one first thread angle limiting protrusion (SAR protrusion) extending outward from the first bottom surface of the head section. The at least one first SAR protrusion may be disposed proximate to the first head aperture and configured to limit the amount by which the fastener central axis of the threaded fastener can be tilted relative to the first head aperture central axis for at least a circumferential portion of the first head aperture.

[0023] In any of the aspects or embodiments described above and herein, the first head aperture may have a multi-axial configuration including multiple threaded sections having adjacent threaded sections separated from each other by relief pockets.

[0024] In any of the aspects or embodiments described above and herein, the multi-axial configuration of the first head aperture may be configured to allow the fastener central axis of the threaded fastener to be tilted at an angle up to and including 15 degrees relative to the first head aperture central axis, except for a portion of the first head aperture that coincides with the at least one first SAR projection.

[0025] In any of the aspects or embodiments described above and herein, the at least one first SAR projection may be a single SAR projection extending circumferentially around a portion of the first head aperture and extending outward a height amount from the first bottom surface of the head section.

[0026] In any of the aspects or embodiments described above and herein, the caudal section may have a caudal section centerline that extends along an arcuate path, with the caudal surface disposed medially of the arcuate path and the cranial surface disposed lateral to the arcuate path.

[0027] According to one aspect of the present disclosure, a bone fixation plate is provided, including a head section, a tail section, and a curved section. The head section is disposed at a proximal end of the fixation plate. The head section has a first upper surface, a first bottom surface opposite the first upper surface, at least one edge surface extending between the first upper surface and the first bottom surface, at least one head aperture extending between the first upper surface and the first bottom surface, and at least one thread angle limiting projection (SAR projection) extending outward from the first bottom surface of the head section. The at least one SAR projection is disposed proximate to the at least one head aperture. The SAR projection is configured to limit the amount of fastener skew relative to a circumferential portion of each of the at least one head aperture. The head section has a head section centerline that bisects the head section. The tail section is disposed at the proximal end of the fixation plate. The caudal section includes a second upper surface, a second bottom surface opposite the second upper surface, a caudal side extending between the second upper surface and the second bottom surface, a cranial side extending between the second upper surface and the second bottom surface, at least one caudal aperture extending between the second upper surface and the second bottom surface, and a slotted caudal aperture extending between the second upper surface and the second bottom surface. The curved section is disposed between and continuous with the caudal section and the cranial section. The head section is oriented toward the caudal side of the fixation plate, and a head section centerline is disposed at a head section angle, the head section angle being greater than zero.

[0028] The foregoing features and elements may be combined in various non-exclusive combinations unless expressly indicated otherwise. These features and elements, and their operation, will become more apparent in light of the following description and accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative in nature and non-limiting. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective top view of an embodiment of a fixation plate of the present disclosure. [Figure 2] FIG. 1 is a plan top view of an embodiment of a fixation plate of the present disclosure. [Figure 3] FIG. 3 is a plan top view of the embodiment of the fixation plate of the present disclosure shown in FIG. 2, including a cross-sectional cut line. [Figure 3A] 4 is a cross-sectional view of the fixation plate shown in FIG. 3 taken along section line AA. [Figure 3B] 4 is a cross-sectional view of the fixation plate shown in FIG. 3 taken along section line BB. [Figure 3C] 4 is a cross-sectional view of the fixation plate shown in FIG. 3 taken along section line CC. [Figure 4] FIG. 4 is an enlarged partial view of the fixation plate shown in FIG. 3, including a slotted tail aperture. [Figure 5] FIG. 1 is a perspective bottom view of an embodiment of a fixation plate of the present disclosure. [Figure 6] FIG. 10 is a plan bottom view of an embodiment of a fixation plate of the present disclosure. [Figure 7] FIG. 1 is a plan side view of an embodiment of a fixation plate of the present disclosure. [Figure 8] FIG. 1 is a plan proximal end view of an embodiment of a fixation plate of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0030] First, it should be noted that in the embodiments described herein, the standard anatomical terms used correspond to the standard anatomical positions of dogs or animals having hindlimb anatomical structures corresponding to those of dogs. The application of the embodiments of the present invention described herein is not limited to dogs or animals having hindlimb anatomical structures corresponding to those of dogs. However, it is contemplated that the present invention may be applied to humans or animals having lower limb anatomical structures corresponding to those of humans, although the standard anatomical positions of humans are different from the standard anatomical positions of dogs. Therefore, the standard anatomical terms used to describe the application of the present invention to dogs or animals having hindlimb anatomical structures corresponding to those of dogs do not correspond to the standard anatomical terms needed to describe the application of the present invention to humans or animals having lower limb anatomical structures corresponding to those of humans.

[0031] 1-8, a tibial fixation plate 20 ("fixation plate 20") is illustrated (see, for example, FIG. 3B) including a proximal end 22, a distal end 24, a caudal end 26, a cranial end 28, a superior surface 30, and a bottom surface 32. In use, the bottom surface 32 generally faces the tibia. The superior surface 30 is opposite the bottom surface 32. The fixation plate 20 can be described as having three distinct longitudinally disposed sections: a head section 34, a curved section 36, and a tail section 38. The head section 34 extends from the proximal end 22 of the fixation plate 20 toward the distal end 24 of the fixation plate 20. The tail section 38 extends from the distal end 24 of the fixation plate 20 toward the proximal end 22 of the fixation plate 20. The curved section 36 is disposed between and continuous with both the head section 34 and the tail section 38. A tail section-curved section boundary line 40 and a head section-curved section boundary line 42 are shown in FIG. 2 to illustrate the respective fixation plate 20 sections.

[0032] The caudal section 38 of the fixation plate 20 is defined by a top surface 30, a bottom surface 32, a caudal edge surface 44, and a cranial edge surface 46. In a portion of the caudal section 38, the caudal edge surface 44 and the cranial edge surface 46 may be disposed equidistant from one another. In some embodiments, the caudal edge surface 44 and the cranial edge surface 46 may converge toward one another at the distal end 24 of the fixation plate 20. In some embodiments, the caudal section 38 may include a distal end surface extending between the caudal edge surface 44 and the cranial edge surface 46 at the distal end 24 of the fixation plate 20. The embodiment of the fixation plate 20 shown in FIGS. 1-3 illustrates one implementation of the fixation plate 20 in which the caudal edge surface 44 and the cranial edge surface 46 converge toward one another proximate the distal end 24. The present disclosure is not limited to this configuration of the caudal section 38.

[0033] Some of the drawings are shown with orthogonal axes X, Y, and Z to facilitate explanation herein. The tail section 38 may be described as extending along a non-linear tail section centerline (TS centerline 48) that includes a lengthwise component (Y-axis direction) and a widthwise component (X-axis direction); for example, the tail section may be described as being curved. The thickness 50 (see FIG. 3B) of the tail section 38 extends along the Z-axis (Z-axis perpendicular to the XY plane). The extent to which the tail section 38 may be non-linear (e.g., arcuately extending—curved—in the XY plane) may vary for particular embodiments but is typically selected to create beneficial alignment between the tibia and the tail section 38. FIG. 2 illustrates a vertical line 52 (parallel to the Y-axis) that intersects the center point of the first tail aperture 58A.

[0034] In the embodiment shown in FIGS. 1-3 , for example, the tail section 38 extends along an arcuate path (i.e., the TS centerline 48) that deviates from a vertical line 52 parallel to the Y-axis. Alternatively, the tail section 38 may extend along a non-linear path that includes a compound curvature, e.g., a collection of arcuate subsections with different curvatures. As another example of a non-linear path, the tail section 38 may extend along a path that includes one or more arcuate subsections and one or more linear sections. These examples of non-linear tail section paths are provided to illustrate possible tail section centerline path configurations and are not intended to be limiting. The Y-axis component of the TS centerline 48 path is substantially greater than the X-axis component. The non-linear tail section 38 configuration of the tail section 38 is oriented such that the caudal side 26 of the tail section 38 is "inside" the arcuate path and the cranial side 28 of the tail section 38 is "outside" the arcuate path. In the XY plane, the TS centerline 48 in the XY plane is equidistant from the caudal edge surface 44 and the cranial edge surface 46. The TS section centerline 48 may be configured as a plane, e.g., the caudal section 38 (and TS centerline 48) extends in the XY plane without any curvature / deviation in the Z-axis direction (except for elements such as the recessed channel in the caudal section 38 as described herein).

[0035] 1-3C illustrate one embodiment of a fixation plate 20 of the present disclosure including an open notch 54 disposed in the tail section 38 at the distal end 24. The open notch 54 may be configured to facilitate engagement of the fixation plate 20 with a surgical tool, such as a Hohmann tissue retractor, or other surgical tool. The present disclosure does not require an open notch 54 disposed at the distal end 24 of the fixation plate 20.

[0036] The tail section 38 of the fixation plate 20 includes a tail positioning aperture 56, a first tail aperture 58A, a second tail aperture 58B, and a slotted tail aperture 60. The first tail aperture 58A is disposed adjacent the distal end 24 of the fixation plate 20, and the slotted tail aperture 60 is disposed adjacent the curved section 36. The second tail aperture 58B is disposed between the first tail aperture 58 and the slotted tail aperture 60. The first and second tail apertures 58A, 58B, and the slotted tail aperture 60 may be centered on the TS centerline 48. The embodiment shown in FIGS. 1-3 illustrates the tail positioning aperture 56 disposed between the first tail aperture 58A and the second tail aperture 58B. The present disclosure is not limited to disposing the caudal positioning aperture 56 between the first caudal aperture 58A and the second caudal aperture 58B. The caudal positioning aperture 56 is configured to receive a fixation member (not shown; e.g., a pin, screw, or other mechanical structure) for temporarily positioning the fixation plate 20 on the subject's tibia and / or to facilitate a user's visualization of the desired trajectory of a fastener inserted through the head aperture (described below). The caudal apertures 58A, 58B allow the caudal section 38 to be fixed to a bone segment; for example, in a tibial plateau horizontal osteotomy or "TPLO" procedure, the caudal section 38 of the fixation plate 20 is attached to the distal / epiphyseal segment of the tibia.

[0037] The first and second tail apertures 58A, 58B (and the head apertures described in more detail below) each have a multi-axial configuration having a central axis 158A, 158B (see, e.g., FIG. 3B) that extends through the thickness 50 of the tail section 38 (e.g., along the Z-axis). It is understood that the multi-axial aperture configuration greatly enhances a clinician's ability to place a fastener into bone in a desired orientation. More specifically, the multi-axial configuration allows a fastener (e.g., a threaded screw) engaged within the aperture to be aligned with the central axis 158A, 158B of the apertures 58A, 58B (i.e., the central axis of the fastener coincides with the central axis of the tail aperture) or disposed at an oblique angle (A1; see, e.g., FIG. 3B) from the central axis 158A, 158B of the tail apertures 58A, 58B. In some embodiments, a multi-axial configuration as used in the present disclosure may allow a fastener to be engaged with tail apertures 58A, 58B such that the central axis of the fastener is inclined at an angle (A1) of up to approximately fifteen degrees (15°) from the central axes 158A, 158B of apertures 58A, 58B. Thus, the multi-axial configuration allows a user to orient the fastener in a range of orientations (at any aperture circumferential position) and select a preferred orientation for the application at hand.

[0038] Each threaded aperture having a multi-axial configuration may include multiple threaded sections 62, with adjacent threaded sections 62 separated from one another by relief pockets 64. In the example fixation plate 20 shown in the drawings, the first and second tail apertures 58A, 58B are shown to have a multi-axial configuration having four (4) threaded sections 62 and four (4) relief pockets 64 (see, e.g., FIG. 3 ). Each relief pocket 64 is disposed opposite the other relief pocket 64 (i.e., diagonally across the center of the aperture), e.g., the relief pockets 64 are disposed at ninety degree (90°) intervals around the circumference of the apertures 58A, 58B. The present disclosure is not limited to a multi-axial configuration having four (4) threaded sections 62 and four (4) relief pockets 64, and may alternatively include a greater or fewer number of threaded sections 62 and relief pockets 64.

[0039] Each threaded tail aperture 58A, 58B has a first end 66 proximate the top surface 30 of the tail section 38 and a second end 68 proximate the bottom surface 32 of the tail section 38 (see, e.g., FIG. 3B). In the embodiment shown in FIGS. 1-3C, the threaded sections 62 collectively form a conical configuration such that the threaded apertures 58A, 58B have a diameter at the first end 66 (proximate the top surface 30) that is larger than the diameter at the second end 68 (proximate the bottom surface 32). It is understood that the conical configuration of the threaded section / aperture facilitates intentional misalignment while still providing threaded engagement between the threaded section 62 and a fastener when fastener / aperture misalignment is desired. The present disclosure does not require the threaded apertures 58A, 58B to have a collective conical configuration.

[0040] In some embodiments, first and / or second tail apertures 58A, 58B can be configured to receive at least a portion of the head of a fastener. In the embodiment shown in Figures 1-3C, for example, first and second tail apertures include countersunk portions 70 disposed at first ends 66. The present disclosure does not require first and / or second tail apertures 58A, 58B to include countersunk portions 70, and if included, countersunk portions 70 are not limited to any particular configuration.

[0041] The fixation plate 20 of the present disclosure is not limited to the use of any particular type of fastener having first and second tail apertures 58A, 58B. Fasteners including a self-tapping tip and a threaded shank (including threads below the fastener head) are one example of a fastener that may be used. Specific types of fasteners that may be used include cortical screws and locking screws. A portion of the fastener threaded shank disposed adjacent the fastener head may include a thread profile configured to threadably engage with the threaded section of the respective first or second tail aperture 58A, 58B, e.g., mating threads that prevent cross-threading. The entire fastener shank (e.g., other than the self-tapping tip) may have the same thread configuration, or different portions of the fastener shank may have different thread configurations. The threaded engagement between the fastener and the threaded apertures 58A, 58B and the fastener and bone allows for positive positioning between the fixation plate 20 and the bone.

[0042] 1-4, the slotted tail aperture 60 is generally oval-shaped with a length 61 greater than a width 63 and configured to receive a fastener. The length 61 of the slotted tail aperture 60 extends along a longitudinal axis 72. The width 63 of the slotted tail aperture 60 extends along a widthwise axis 74 perpendicular to the longitudinal axis 72. The slotted tail aperture 60 is angled to allow compression to be applied to the center of the osteotomy such that all or substantially all of the cut line is compressed. For example, the longitudinal axis 72 is angled relative to the Y axis (A2—see FIG. 4) (e.g., A2≈A3), which may be substantially equal to the angle at which the head section axis is angled relative to the Y axis (A3—see FIG. 2), as described below. In other words, the longitudinal axis 72 of the slotted tail aperture 60 may be generally parallel to the head section axis. The length 61 of the slotted tail aperture 60 allows the user to vary the placement of the fastener, for example, allowing the user to position the fastener in a desired location, for example, oriented generally toward the cranial side 28 (or conversely, the caudal side 26; see e.g., FIG. 3) of the tail section 38, and generally toward the proximal end 22 (or conversely, the distal end 24; see e.g., FIG. 3) of the fixation plate 20, and thus oriented relative to the curved cut line.

[0043] As described above, in the TPLO procedure, a curvilinear cut is made in the canine proximal tibia to separate the metaphysis from the proximal tibia, thereby creating an arcuate interface therebetween. The bevel angle A2 of the longitudinal axis 72 of the slotted tail aperture 60 is such that the longitudinal position of the fastener within the slotted tail aperture 60 does not significantly change the orientation of the fastener toward or away from the lateral ends of the arcuate interface. Rather, the longitudinal position of the fastener within the slotted tail aperture 60 primarily changes the position of the fastener relative to the central portion of the arcuate interface. As a result, it is understood that fasteners disposed within the slotted tail aperture 60 more desirably create compression at the central portion of the arcuate interface rather than at the lateral end portions of the interface.

[0044] Embodiments of the present disclosure may include a slotted tail aperture 60 configured to receive a fastener without threaded engagement; i.e., in these embodiments, the slotted tail aperture 60 is unthreaded. The slotted tail aperture 60 may be configured to receive at least a portion of the head of a fastener. In the embodiment shown in FIGS. 1-3C, for example, the slotted tail aperture 60 includes a countersink portion 76 (see FIG. 3B) disposed at the end of the top surface 30 of the slotted tail aperture 60. More specifically, the slotted tail aperture 60 shown in FIGS. 1-4 includes a relatively deep depth (Z-axis) countersink 76 that allows a fastener disposed within the slotted tail aperture 60 to be tilted relative to the longitudinal axis 72 and / or width axis 74 of the slotted tail aperture 60 in a variety of different angular orientations. Slotted tail aperture 60, including countersunk portion 76, may be configured to allow a variety of different fastener types (e.g., having different head configurations) to be used and / or to allow more than one fastener to be disposed at a time within slotted tail aperture 60. However, the present disclosure does not require slotted tail aperture 60 to include countersunk portion 76.

[0045] In some embodiments, the bottom surface 32 of the tail section 38 may be arcuately shaped. For example, in the embodiments shown in Figures 3A, 5, and 6, the bottom surface 32 of the tail section 38 is curved in the width direction, e.g., along the X-axis. In some embodiments, both the bottom surface 32 and the top surface 30 of the tail section 38 may both be curved in the width direction. The arcuate shape of the bottom surface 32 may be selected to complement the general shape of the tibia.

[0046] In some embodiments, the caudal section 38 can include a plurality of recessed channels 78 that intersect the bottom surface 32 and the caudal edge surface 44, and a plurality of recessed channels 78 that intersect the bottom surface 32 and the cranial edge surface 46. See, for example, Figures 5 and 6. The recessed channels 78 reduce the surface area of ​​the bottom surface 32, thereby reducing the potential contact area between the bottom surface 32 of the fixation plate 20 and the tibia when the fixation plate 20 is secured in place.

[0047] 1-3 , the head section 34 is disposed at the proximal end 22 of the fixation plate 20. The head section 34 is substantially diamond-shaped and is defined at least in part by a first proximal edge surface 80 and a second proximal edge surface 82 that are oriented to intersect one another. The head section 34 may be generally symmetrical about a head section centerline 84 (HS centerline 84—see FIG. 2 ). As described herein, embodiments of the head section 34 may have complex and / or asymmetric configurations. Thus, the statement that the head section 34 may be “generally symmetrical” about the HS centerline 84 should not be interpreted as requiring the head section 34 to have perfectly symmetrical halves on either side of the HS centerline 84. The head section 34 (and thus the HS centerline 84) is disposed at an angle toward the caudal side 26 of the fixation plate 20. The HS centerline 84 is disposed at an angle A3 relative to a vertical line 52 (parallel to the Y-axis), which bisects the head section 34 and is shown intersecting the center point of the first tail aperture 58. The angle A3 at which the head section 34 is angled can range from approximately fifteen degrees (15°) to approximately thirty-five degrees (35°). As can be seen in FIGS. 3B and 7, the head section 34 deviates from the XY plane in the Z-axis direction. FIG. 7 shows the head section 34 deviating by an angle A4. Angle A4 is shown in FIGS. 3B and 7 to illustrate a typical angular deviation of the head section 34. The angle A4 at which the head section 34 is angled can range from approximately twenty degrees (20°) to approximately forty-five degrees (45°). As described herein, the head section 34 has a complex curved shape, and the degree of angular deviation (in the Z-axis direction) from the XY plane may vary across the head section 34, i.e., angle A4 may vary across the head section 34.

[0048] The head section 34 is anatomically contoured to reflect the contour of the tibia and facilitate attachment of the fixation plate 20 to a portion of the tibia after rotation. The contouring includes angular disposition of the head section 34 along angles A3 and A4 and may also include a contoured bottom surface 32 to reflect the surface geometry of the tibia. The contouring of the head section 34 may be asymmetric. The contouring of the head section 34 also allows the fixation plate 20 to be positioned in multiple positions on the tibia to achieve the desired fixation after rotation. The shape of the head section 34 also allows for significant causal lift in the osteotomy. In a preferred embodiment, the head section 34 is contoured to reflect the average contour of the tibia after TPLO curve cutting and rotation has occurred, based on a database containing a clinically sufficient amount of empirical data.

[0049] In the embodiment shown in FIGS. 1-3 , the first and second proximal edge surfaces 80, 82 are connected to one another by a connecting edge surface 86. The HS centerline 84, which bisects the head section 34, may also bisect the connecting edge surface 86. The first proximal edge surface 80 transitions to the fixation plate curved section 36 via a first transition edge surface 88, and the second proximal edge surface 82 transitions to the fixation plate curved section 36 via a second transition edge surface 90. As illustrated in FIGS. 1-3 , the connecting edge surface 86, the first transition edge surface 88, and the second transition edge surface 90 may be arcuately formed. The width of the head section 34 may be described as extending along a line 92 perpendicular to the HS centerline 84. The width of the head section 34 may increase from the proximal end 22 of the fixation plate 20 (e.g., at the connecting edge surface 86) to a maximum value (e.g., near the first and third head apertures 96A, 96C) and then decrease to the curved section 36 of the fixation plate 20, thus creating a substantially diamond-shaped configuration. The head section 34 shown in Figures 1-3 is a non-limiting example of a head section 34 that may be used in the fixation plate 20 of the present disclosure.

[0050] The head section 34 includes a head positioning aperture 94, a first head aperture 96A, a second head aperture 96B, and a third head aperture 96C. The head apertures 96A-C allow the head section 34 to be fixed to a tibial segment (e.g., the medial segment). The head positioning aperture 94 is configured to receive a fixation member (not shown; e.g., a pin, screw, or other mechanical structure) for temporarily positioning the fixation plate 20 on the subject's tibia and / or to facilitate a user's visualization of the desired trajectory of a screw inserted through the head aperture. The first head aperture 96A is disposed caudal 26 of the HS centerline 84, adjacent to a first lateral "point" of the diamond shape. See, for example, FIG. 2 . The third head aperture 96C is disposed cranial 28 of the HS centerline 84, adjacent to a second lateral "point" of the diamond shape, opposite the first lateral point. The head positioning aperture 94 may be disposed between the first head aperture 96A and the third head aperture 96C, generally aligned with the HS centerline 84. The present disclosure is not limited to disposing the head positioning aperture 94 between the first head aperture 96A and the third head aperture 96C. The second head aperture 96B is disposed at the proximal end 22 of the fixation plate 20, generally aligned with the HS centerline 84, and centrally disposed relative to the first and third head apertures 96A, 96C, but proximal to the proximal end 22.

[0051] The first, second, and third head apertures 96A-C may have a polyaxial configuration similar to that described above with respect to the first and second tail apertures 58A, 58B, for example, a polyaxial configuration that allows a fastener engaged within the head apertures 96A-C to be aligned with the central axis of the head apertures 96A-C or disposed at an oblique angle from the central axis of the head apertures 96A-C. The polyaxial configuration may include multiple threaded sections 62, with adjacent threaded sections 62 separated from one another by relief pockets 64, and the threaded sections 62 may collectively form a conical configuration, or the like. Each of the head apertures 96A-C may also be configured to receive at least a portion of the head of a fastener in the manner described above with respect to the tail apertures 58A, 58B.

[0052] 3B, 3C, 5, 6, and 8, in some embodiments of the present disclosure, one or more screw angle limiting protrusions 98 (“SAR protrusions 98”) may be disposed proximate any or all of the first, second, and third head apertures extending from the bottom surface 32 of the head section 34. As explained above, the multi-axial configuration of the head apertures 96A-C allows a fastener (e.g., a threaded screw) to be engaged within the head apertures 96A-C so as to be disposed at an angle A1 (see, e.g., FIG. 3B) tilted from the central axis of the head apertures 96A-C, where the angle A1 may be up to approximately fifteen degrees (15°) from the central axis of the head apertures 96A-C. The SAR protrusions 98 are configured to limit the amount of angle (A1) that the fastener central axis may be tilted from the central axis of the head apertures 96A-C within a predetermined region of each head aperture 96A-C. In other words, each SAR projection 98 is positioned to limit the fastener cant angle within a predetermined region of its respective head aperture 96A-C. In those regions of the head aperture 96A-C without a SAR projection 98, fasteners may be canted at an otherwise possible cant angle A1. The SAR projections 98 function to prevent fasteners from being inserted into areas of the tibial portion where fasteners may be problematic, for example, in a direction toward the articulation with the femur.

[0053] The SAR projections 98 include a circumferentially extending length 100, a width 102, and a height 104. See, for example, FIGS. 6 and 8 . The circumferential length 100 extends to a predetermined portion of the outer diameter of each of the head apertures 96A-C. The circumferential length 100 may be selected based on the region of the tibia, where a preference is given to avoiding angled fastener placement entirely or to avoiding fastener placements that are angled beyond a predetermined oblique angle. For example, in the region of the head aperture where the SAR projections 98 are disposed, the SAR projections 98 may be configured to prevent any fastener canting; i.e., in the region of the head apertures 96A-C where the SAR projections 98 are disposed, fasteners may only be oriented so that their central axes coincide with the central axes of the respective head apertures 96A-C. Alternatively, in the region of the head aperture 96A-C where the SAR projection 98 is disposed, the SAR projection 98 may be configured to allow limited fastener cant, i.e., in the region of the head aperture 96A-C where the SAR projection 98 is disposed, the fastener may be oriented with its central axis canted at a percentage of the maximum allowable fastener cant possible elsewhere around the head aperture 96A-C where the SAR projection 98 is not present (e.g., 50% of A1, or only about 7.5 degrees cant if the maximum allowable cant angle elsewhere is 15 degrees).

[0054] 3C, 5, 6, and 8, the SAR protrusions 98 associated with the first head aperture 96A are disposed on the caudal side 26 of the first head aperture 96A, the SAR protrusions 98 associated with the second head aperture 96B are disposed on the proximal end 22 of the second head aperture 96B (see FIG. 6), and the SAR protrusions 98 associated with the third head aperture 96C are disposed on the cranial side 28 of the third head aperture 96C. In this exemplary embodiment, each of the SAR protrusions 98 has a length 100 that is approximately one-third of the circumference of the respective head aperture at the bottom surface 32. In this exemplary embodiment, each of the SAR protrusions 98 has a height 104 sufficient to limit the fastener bevel to that desired within that region, e.g., a range of A1 less than a maximum value including A1=0.

[0055] The configurations of the SAR protrusions 98 (e.g., circumferentially extending length, width, and height) shown in Figures 3C, 5, 6, and 8 are examples of SAR protrusion 98 configurations, and the present disclosure is not limited thereto. The positioning of the SAR protrusions 98 shown in Figures 3C, 5, 6, and 8 are examples of SAR protrusion 98 positioning, and the present disclosure is not limited thereto. The example of the SAR protrusions 98 shown in Figures 3C, 5, 6, and 8 includes a single SAR protrusion 98 for each head aperture 96A-C. In alternative embodiments, the present disclosure may include two or more SAR protrusions 98 for each head aperture 96A-C. Example SAR protrusions 98 are described above as being associated with the head apertures 96A-C. In some embodiments, the present disclosure may include one or more SAR protrusions 98 associated with the tail apertures 58A, 58B.

[0056] As described above, the curved section 36 of the fixation plate 20 is disposed between and continuous with both the head section 34 and the tail section 38. The tail section-curved section boundary 40 and head section-curved section boundary 42 shown in FIG. 2 are included to illustrate the approximate boundaries between the respective fixation plate sections 34, 36, 38. The curved section 36 curves caudally away from the tail section 38. The curvature of the curved section 36 in the XY plane is typically selected to match the desired orientation of the head section 34 described above (e.g., HS centerline angle A3—see FIG. 2). The curved section 36 may also deviate from the XY plane of the tail section 38 in the Z-axis direction, again to match the desired orientation of the head section 34 described above (e.g., HS centerline angle A4—see FIG. 3B).

[0057] The fixation plate 20 can comprise a variety of different materials. For example, in some embodiments, the fixation plate 20 can comprise surgical implant grade 316L stainless steel, or titanium, or a polymeric material (e.g., a bioabsorbable polymer), or the like, or any combination thereof. In some embodiments, the fixation plate 20 can include one or more materials that support and stimulate bone growth, or pharmaceutical or other healing compounds, or the like, and any combination thereof. In some embodiments, the fixation plate 20 can comprise a radiolucent material that allows only the bone growth to be seen when x-rayed, and not the fixation plate 20 itself.

[0058] While the principles of the present disclosure have been described above in connection with specific devices and methods, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of the disclosure.

[0059] The singular forms "a," "an," and "the" refer to one or more than one unless the context clearly dictates otherwise. For example, the term "comprising a specimen" includes one or more specimens and is considered equivalent to the phrase "comprising at least one specimen." The term "or" refers to a single element of the described alternative elements or a combination of two or more elements unless the context clearly dictates otherwise. As used herein, "comprises" means "includes." Thus, "comprising A or B" means "including A, B, or A and B," without excluding additional elements. Furthermore, the term "coupled" does not exclude the presence of intermediate elements between coupled items. References to affixing, fastening, connecting, or the like may include permanent, removably, temporarily, partially, completely, and / or other possible attachment options.

[0060] It is noted that various connections between elements are shown in this description and in the drawings, the contents of which are incorporated by reference into this disclosure. These connections are general and, unless otherwise specified, may be direct or indirect, and this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities or spaces / gaps between the entities that are coupled to each other.

[0061] Furthermore, no element, component, or method step in this disclosure is intended to be dedicated to the public, regardless of whether the element, component, or method step is expressly recited in a claim. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless expressly recited using the phrase "means for."

[0062] While various inventive aspects, concepts, and features of the present disclosure may be described and illustrated as being embodied in combination in exemplary embodiments, these various aspects, concepts, and features may be used individually or in various combinations and subcombinations in many alternative embodiments. Unless expressly excluded herein, all such combinations and subcombinations are intended to be within the scope of the present application. Furthermore, while various alternative embodiments of various aspects, concepts, and features of the present disclosure (such as alternative materials, structures, configurations, methods, devices, and components, and substitutions (in terms of form, fit, and function)) may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether currently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features for additional embodiments and uses within the scope of the present application, even in embodiments not explicitly disclosed herein. For example, in the exemplary embodiments described above in the "Detailed Description" section of this specification, elements are described as individual units and shown separately from one another for ease of description. In an alternative embodiment, such elements may be configured as coupling elements.

[0063] Furthermore, even if some features, concepts, or aspects of the present disclosure are described herein as being preferred arrangements or methods, such description does not imply that such features are necessary or essential unless expressly stated. Furthermore, to aid in understanding the present application, example or representative values ​​and ranges may be included, but such values ​​and ranges should not be construed in a limiting sense, and only when explicitly stated are significant values ​​or ranges intended.

[0064] Descriptions of exemplary methods or processes are not limited to including every step required in all cases, nor is the order in which steps are presented limited as to whether a step is necessary or required unless expressly stated. The words used in the claims have their full ordinary meaning and are not limited in any way by the description of the embodiments herein.

Claims

1. 1. A bone fixation plate comprising: a head section disposed at a proximal end of the fixation plate, the head section having a first upper surface, a first bottom surface opposite the first upper surface, at least one edge surface extending between the first upper surface and the first bottom surface, and at least one head aperture extending between the first upper surface and the first bottom surface, the head section having a head section centerline bisecting the head section; a tail section disposed at a proximal end of the fixation plate, a second upper surface; a second bottom surface opposite the second top surface; a caudal surface extending between the second top surface and the second bottom surface; a head side extending between the second top surface and the second bottom surface; at least one tail aperture extending between the second top surface and the second bottom surface; and a slotted tail aperture extending between the second top surface and the second bottom surface, thereby forming a fastener passageway through the head section, the slotted tail aperture including a longitudinal axis and a widthwise axis, the longitudinal axis being greater than the widthwise axis, and the longitudinal axis being substantially parallel to the head section centerline; a tail section having a curved section disposed between the tail section and the head section and continuous with the tail section and the head section; A bone fixation plate, wherein the head section is oriented toward a caudal side of the fixation plate, the head section centerline is disposed at a head section angle, the head section angle being greater than zero.

2. 2. The bone fixation plate of claim 1, wherein the at least one head aperture and the at least one tail aperture each have a polyaxial configuration including a plurality of threaded sections, each having an aperture central axis and having adjacent threaded sections separated from one another by relief pockets.

3. 3. The bone fixation plate of claim 2, wherein the polyaxial configuration of the at least one head aperture is configured to allow a threaded fastener having a fastener center axis to be disposed within the at least one head aperture at an oblique angle with threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, the oblique angle being up to and including 15 degrees.

4. 4. The bone fixation plate of claim 3, wherein the at least one head aperture has a first diameter adjacent the first top surface and a second diameter adjacent the first bottom surface, the second diameter being smaller than the first diameter.

5. 3. The bone fixation plate of claim 2, wherein the polyaxial configuration of the at least one tail aperture is configured to allow a threaded fastener having a fastener center axis to be disposed within the at least one head aperture at an oblique angle with threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, the oblique angle being up to and including 15 degrees.

6. 6. The bone fixation plate of claim 5, wherein the at least one tail aperture has a first diameter adjacent the first top surface and a second diameter adjacent the first bottom surface, the second diameter being smaller than the first diameter.

7. The bone fixation plate of claim 1 , wherein the tail section has a tail section centerline that extends along an arcuate path.

8. The bone fixation plate of claim 7 , wherein the caudal surface is disposed medially of the arcuate pathway and the cranial surface is disposed laterally of the arcuate pathway.

9. the at least one tail aperture includes a first tail aperture and a second tail aperture; both the first and second tail apertures have an aperture central axis and a multi-axial configuration including a plurality of threaded sections with adjacent threaded sections separated from each other by relief pockets; 9. The bone fixation plate of claim 8, wherein the first tail aperture is disposed proximate the distal end of the fixation plate and the second tail aperture is disposed between the first tail aperture and the slotted tail aperture.

10. 10. The bone fixation plate of claim 9, wherein both the first and second tail apertures have a first diameter adjacent the second top surface and a second diameter adjacent the second bottom surface, the second diameter being smaller than the first diameter.

11. 10. The bone fixation plate of claim 9, wherein the polyaxial configuration of the first and second tail apertures is configured to allow a respective threaded fastener having a fastener center axis to be disposed within the respective first or second tail aperture at an oblique angle with threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, the oblique angle being up to and including 15 degrees.

12. The bone fixation plate of claim 1 , wherein the curved section curves caudally away from the tail section causing the head section to project caudally from the tail section.

13. 2. The bone fixation plate of claim 1, further comprising at least one thread angle limiting projection (SAR projection) extending outward from the first bottom surface of the head section, the at least one SAR projection disposed proximate to the at least one head aperture, the SAR projection configured to limit an amount of fastener skew relative to a circumferential portion of each of the at least one head aperture.

14. the at least one head aperture includes a first head aperture having a first head aperture central axis, the first head aperture having a multi-axial configuration including a plurality of threaded sections having adjacent threaded sections separated from one another by relief pockets, the multi-axial configuration allowing a threaded fastener having the fastener central axis to be disposed within the first head aperture at an angle such that the fastener central axis is oblique with respect to the first head aperture central axis; The bone fixation plate of claim 1 , comprising a threaded engagement between the threaded fastener and at least one of the plurality of threaded sections, and wherein the bevel angle is up to and including 15 degrees.

15. the at least one head aperture includes a first head aperture having a first head aperture central axis; the first head aperture is configured to allow a threaded fastener having a fastener central axis to be disposed within the first head aperture at an angle such that the fastener central axis is inclined relative to the first head aperture central axis, and the fixation plate is 2. The bone fixation plate of claim 1, further comprising at least one first thread angle limiting protrusion (SAR protrusion) extending outward from the first bottom surface of the head section, the at least one first SAR protrusion disposed proximate the first head aperture and configured to limit an amount that the fastener central axis of the threaded fastener can be tilted relative to the first head aperture central axis for at least a circumferential portion of the first head aperture.

16. The bone fixation plate of claim 15, wherein the first head aperture has a polyaxial configuration including a plurality of threaded sections having adjacent threaded sections separated from one another by relief pockets.

17. 17. The bone fixation plate of claim 16, wherein the multi-axial configuration of the first head aperture is configured to allow the fastener central axis of the threaded fastener to be tilted at an angle up to and including 15 degrees relative to the first head aperture central axis, except for a portion of the first head aperture coincident with the at least one first SAR protrusion.

18. 17. The bone fixation plate of claim 16, wherein the at least one first SAR projection is a single SAR projection that extends circumferentially around a portion of the first head aperture and extends outwardly from the first bottom surface of the head section a height amount.

19. 20. The bone fixation plate of claim 18, wherein the caudal section has a caudal section centerline extending along an arcuate path, the caudal side surface being disposed medially of the arcuate path and the cranial side surface being disposed lateral to the arcuate path.

20. 1. A bone fixation plate comprising: a head section disposed at a proximal end of the fixation plate, the head section having a first upper surface, a first bottom surface opposite the first upper surface, at least one edge surface extending between the first upper surface and the first bottom surface, at least one head aperture extending between the first upper surface and the first bottom surface, and at least one thread angle limiting projection (SAR projection) extending outward from the first bottom surface of the head section, the at least one SAR projection disposed proximate to the at least one head aperture, the SAR projection configured to limit fastener skew about a circumferential portion of each of the at least one head aperture, the head section having a head section centerline bisecting the head section; a tail section disposed at a proximal end of the fixation plate, a second upper surface; a second bottom surface opposite the second top surface; a caudal surface extending between the second top surface and the second bottom surface; a head side extending between the second top surface and the second bottom surface; at least one tail aperture extending between the second top surface and the second bottom surface; and a slotted tail aperture extending between the second top surface and the second bottom surface; a tail section having a curved section disposed between the tail section and the head section and continuous with the tail section and the head section; A bone fixation plate, wherein the head section is oriented toward a caudal side of the fixation plate, the head section centerline is disposed at a head section angle, the head section angle being greater than zero.

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