Patent Description:
The present invention relates to bone plates for receiving bone anchors to affix the bone plates to bone, and particularly relates to bone plates having threaded fixation holes that are configured for multiple uses, particularly for selective threaded locking with a threaded head of a locking bone anchor or for dynamic compression via sliding engagement with a head of a compression bone anchor.

Bone plate systems for the internal fixation of bone fractures are well known. Conventional bone plate systems are particularly well-suited to promote the healing of a fracture. A bone anchor, such as a bone screw, is inserted through a fixation aperture or hole in a bone plate and is threaded into bone to compress, neutralize, buttress, tension, band, and/or bridge the fracture ends together. Bone screws that are capable of locking with the bone plate can be employed to transfer loads from one fractured bone part, over a plate, and onto another fractured bone part without drawing the bone against the plate, and to avoid loosening or backing out the bone screws with respect to the plate (which can lead to poor alignment and poor clinical results). One known embodiment of such a screw employs a screw head with external threads for engaging with a corresponding thread on the inner surface of a fixation hole, which are hereinafter referred to as "locking holes", to lock the screw to the plate. These screws, which are hereinafter referred to as "locking screws", can include standard-type locking screws that are configured to lock within a fixation hole substantially only at a "nominal" orientation whereby the central screw axis is substantially aligned with the central hole axis, as well as "variable-angle" (VA) locking screws that are configured to lock within a fixation hole at either a nominal orientation or an "angulated" orientation whereby the central screw axis is oriented at an acute angle with respect to the respective central hole axis.

Bone plate systems can also be adapted to provide anatomical reduction between fractured bone parts. The bone plates of such systems include one or more holes having ramp geometries that engage a smooth exterior surface of a screw head of a "compression screw" in a manner causing dynamic compression, meaning that the bone plate translates with respect to the compression screw and underlying bone along a direction generally perpendicular to the screw axis of the compression screw. Such holes are hereinafter referred to as "compression holes". Bone plates can include both locking holes and compression holes. For example, one or more of the locking holes can be employed to receive a locking screw that affixes the bone plate to a first underlying bone segment. One or more of the compression holes can then be employed to receive a compression screw that drives into a second underlying bone segment and effectively pushes, via engagement between the head of the compression screw and the ramp geometry within the hole, the bone plate in a translation direction that reduces a gap between the first and second underlying bone segments. <CIT> discloses variable angle holes in bone plates that are structured to facilitate the formation of axial compression or tension of a bone, or which can assist in bone distraction. The variable angle hole can extend about a central axis and includes an inwardly extending wedge wall. The variable angle hole can be sized to receive insertion of a fixation element at a location at which a central longitudinal axis of the fixation element is axially offset from the central axis of the variable angle hole by an offset distance at least when the fixation element is initially driven into bone at least in a transverse direction. The wedge wall can be configured to be engaged by a portion of the fixation element in a manner that axially displaces at least one of the bone plate, the fixation element, and/or bone(s) in a direction that can generally reduce or increase the offset distance.

The present invention relates to a bone plate as claimed hereafter. Preferred embodiments of the invention are set forth in the dependent claims. Associated methods are also described herein to aid understanding of the invention, but these do not form part of the claimed invention. References to "embodiments" throughout the description which are not under the scope of the appended claims merely represent possible exemplary executions and are therefore not part of the present invention.

According to an embodiment of the present disclosure, a bone plate has an outer surface, a bone-facing surface opposite the outer surface, and an interior surface that defines a hole extending from the outer surface to the bone-facing surface along a central hole axis. The interior surface further defines a ramp that extends from the outer surface toward the bone-facing surface and plate threads that extend from the ramp toward the bone-facing surface and are configured for optional locking engagement with external threads on a first head of a locking bone fixation member. The interior surface further defines a contact profile in a reference plane that extends along the central hole axis. The contact profile is defined at least by the ramp and is spaced from the central hole axis in an offset direction perpendicular to the central hole axis. The contact profile is configured to translate the bone plate in the offset direction responsive to contact with an exterior surface of a second head of a compression bone fixation member as the second head advances within the hole along an insertion axis that is offset from the central hole axis in the offset direction. direction, wherein the hole has a polygonal hole profile in a second reference plane that is orthogonal to the central hole axis and the polygonal hole profile is a trigonal hole profile.

A not claimed method of seating a bone screw in a hole defined by an interior surface of a bone plate includes inserting a shaft of the bone screw through the hole at an offset distance, measured between a central axis of the bone screw and a central axis of the hole along a first direction that is perpendicular to the central axis of the hole, and into underlying bone. The method includes contacting an outer surface of the head of the bone screw against at least one ramp surface defined by the interior surface within the hole. The interior surface includes internal threads that extend between the at least one ramp surface and the underlying bone. The method further includes driving the bone screw, during the contacting step, toward the underlying bone along the central axis of the screw, thereby translating the bone plate in the first direction relative to the bone screw.

The foregoing summary, as well as the following detailed description of illustrative embodiments of the present application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the locking structures of the present application, there is shown in the drawings illustrative embodiments. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown. In the drawings:.

The present disclosure can be understood more readily by reference to the following detailed description taken in connection with the accompanying figures and examples, which form a part of this disclosure. It is to be understood that this disclosure is not limited to the specific devices, methods, applications, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the scope of the present disclosure. Also, as used in the specification including the appended claims, the singular forms "a," "an," and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

The term "plurality", as used herein, means more than one. When a range of values is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.

The terms "approximately" and "substantially", as used herein with respect to dimensions, angles, and other geometries, takes into account manufacturing tolerances. Further, the terms "approximately" and "substantially" can include <NUM>% greater than or less than the stated dimension or angle. Further, the terms "approximately" and "substantially" can equally apply to the specific value stated.

The embodiments disclosed herein pertain to multi-use holes in a bone plate. In some of the embodiments disclosed herein, a multi-use hole includes (<NUM>) threaded locking structures for optional locking engagement with a threaded head of a locking bone anchor (e.g., a "locking bone screw") and (<NUM>) structure(s) for optional dynamic compression responsive to eccentric (axially offset) insertion of a head of a non-locking bone anchor (e.g., a "cortex screw" or "compression screw") within the hole. As used herein, the term "dynamic compression" refers to an act of engaging a bone anchor against a bone plate in a manner causing the bone plate to translate relative to the bone anchor and underlying patient anatomy along a direction that is generally perpendicular to an axis along which the bone anchor is inserted into underlying bone. Dynamic compression is particularly useful for moving fractured portions of bone relative to one another, such as for anatomical rejection to treat bone fractures. Such multi-use holes provide a physician with an option of using the hole for locking engagement with a locking bone anchor or for dynamic compression with a compression bone anchor.

The inventors have discovered, surprisingly and unexpectedly, that threaded locking holes having certain hole geometries can be alternatively used with compression bone anchors to achieve dynamic compression, even when contact between the anchor head and the interior plate surface within the hole occurs over or along the internal threads in the hole. Thus, threaded locking holes of the present disclosure, including portions of the holes having internal threads, can provide dynamic compression when the holes are used with compression anchors. In this manner, the multi-use holes of the present disclosure can provide selective locking engagement or dynamic compression without the need for a dedicated compression portion of the hole. Thus, the multi-use holes of the present disclosure provide significant advantages over combination holes (also referred to as "combi-holes") known in the art. One such advantage is that the multi-use holes of the present disclosure occupy less space of the plate by virtue of obviating the need for a dedicated compression portion of the hole. Thus, the bone plates described herein can include a higher hole quantity/density than prior art bone plates without sacrificing selective locking and compression functionality. Additionally, such higher hole density, combined with the option to use each hole for locking or for dynamic compression, provides enhanced patient-specific fracture fixation treatment, which provides further advantages in that such treatments can be less invasive and require a shorter healing and recovery period.

Referring to <FIG>, a bone plate <NUM> has a plate body <NUM> that defines therein one or more multi-use holes <NUM>. As used herein, the term "multi-use hole" refers to a plate hole that is configured for selective use with either a compression bone anchor, such as a compression screw <NUM> (see <FIG>), or a locking bone anchor, such as a locking screw. The plate body <NUM> defines interior surfaces <NUM> that respectively define the holes <NUM>. Within each multi-use hole <NUM>, the interior surface <NUM> further defines one or more compression structures, such as ramp surfaces or "ramps" <NUM>, and one or more locking structures, such as internal threads <NUM>, within the hole <NUM>. The internal threads <NUM> can also be referred to as "plate threads" or "hole threads. " The compression structure(s) are configured to engage a head of a compression bone anchor <NUM>, and the locking structures are configured to engage a head of a locking bone anchor. In the present embodiment, the multi-use holes <NUM> are particularly configured to translate the plate <NUM> substantially along a longitudinal direction X oriented along a longitudinal axis <NUM> of the plate <NUM>. In other embodiments, one or more of the holes <NUM> can be configured to translate the plate <NUM> along a direction angularly offset from the longitudinal direction X.

The bone plate <NUM> can be a bridge plate, as shown, although other bone plate types and configurations are within the scope of the present disclosure. The plate body <NUM> is elongate along the longitudinal axis <NUM> and can define a first end <NUM> and a second end <NUM> spaced from each other along the longitudinal direction X. The plate body <NUM> can also define a first lateral side <NUM> and a second lateral side <NUM> spaced from each other along a lateral direction Y that is substantially perpendicular to the longitudinal direction X. The bone plate <NUM> can also define an upper plate surface <NUM> (also referred to herein as an "outer surface" <NUM>) configured to face away from the bone and an opposed lower plate surface <NUM> (also referred to herein as a "bone-facing surface") configured to face the bone. The upper and lower plate surfaces <NUM>, <NUM> are spaced from each other along a vertical direction Z substantially perpendicular to each of the longitudinal direction X and the lateral direction Y. It is to be appreciated that, as used herein, the terms "longitudinal", "longitudinally", and derivatives thereof refer to the longitudinal direction X; the terms "lateral", "laterally", and derivatives thereof refer to the lateral direction Y; and the terms "vertical", "vertically", and derivatives thereof refer to the vertical direction Z. It should also be appreciated that a plane that contains the longitudinal and laterals directions X, Y can be referred to herein as a "horizontal" plane X-Y.

The multi-use holes <NUM> extend from the upper plate surface <NUM> to the lower plate surface <NUM> along a central hole axis <NUM>. The central hole axis <NUM> is oriented along an axial hole direction. As used herein, the term "axial direction" (e.g., "axial hole direction" and "axial screw direction") is defined as the direction along which the respective axis extends. Furthermore, the directional terms "axial", "axially", and derivatives thereof refer to the respective axial direction. Thus, as used herein, the directional term "axially upward" and derivatives thereof refers to the axial hole direction from the lower plate surface <NUM> toward the upper plate surface <NUM>. Conversely, the term "axially downward" and derivatives thereof refers to the axial hole direction from the upper plate surface <NUM> toward the lower plate surface <NUM>. Thus, "axially upward" and "axially downward" are each mono-directional components of the "axial direction", which is bi-directional. In the embodiments depicted in the Figures, the axial hole direction (and thus also the central hole axis <NUM>) is oriented along the vertical direction Z. Accordingly, the axial hole direction is also denoted by "Z" throughout this disclosure. It should be appreciated, however, that the scope of the present disclosure covers embodiments in which the axial hole direction (and thus also the central hole axis <NUM>) is offset from the vertical direction Z at an oblique angle. It should also be appreciated that when the terms "axially upper", "axially lower," and the like are used with reference to a compression screw <NUM> or locking screw, such terms refer to a central axis <NUM> of the screw, particularly as the screw would be oriented within the hole <NUM> (see <FIG>).

Referring now to <FIG>, the multi-use holes <NUM> can be arranged in the plate <NUM> in a manner providing the plate <NUM> with multi-directional compression. For example, the holes <NUM> can be arranged in a first group of holes <NUM> along a first longitudinal region 4a of the plate <NUM> and a second group of holes <NUM> along a second longitudinal region 4b of the plate <NUM>. In this example, the first and second longitudinal regions 4a, 4b extend to a common boundary at a longitudinal midpoint XM of the plate <NUM>, and each hole <NUM> of the first group is configured to provide dynamic compression (i.e., to translate the plate <NUM>) in a first translation direction T1, such as a first longitudinal direction X1 along the longitudinal axis <NUM> toward the first end <NUM> of the plate <NUM>, and each hole <NUM> of the second group is configured to provide dynamic compression in a second translation direction T2, such as a second longitudinal direction X2 opposite the first longitudinal direction X1. It should be appreciated that the arrangement of the multi-use holes <NUM> can be adapted as needed to provide the plate <NUM> with dynamic compression capabilities in various directions according to the needs of a particular surgical treatment.

Referring now to <FIG> and <FIG>, within the multi-use hole <NUM>, the interior surface <NUM> extends axially downward from an upper perimeter <NUM> of the hole <NUM> located at an interface with the upper plate surface <NUM> (<FIG>). The interior surface <NUM> can also define an undercut surface <NUM> (also referred to herein as a "relief surface") that extends axially upward from a lower perimeter <NUM> of the hole <NUM> which is located at an interface with the lower plate surface <NUM> (<FIG>). The locking structures of the hole <NUM> can be configured to provide variable-angle insertion of the locking bone anchor therein. For example, the locking structures can include columns <NUM> defined by the interior surface <NUM> within the hole <NUM>. The columns <NUM> are sequentially located about a circumference of the interior surface <NUM>. The interior surface <NUM> also defines a plurality of recesses <NUM> sequentially located circumferentially between the columns <NUM>. Stated differently, the columns <NUM> and recesses <NUM> are alternately disposed along a circumference of the interior surface <NUM>. The columns <NUM> and recesses <NUM> extend axially between the upper and lower plate surfaces <NUM>, <NUM>. The columns <NUM> and recesses <NUM> can be evenly spaced along the circumference of the hole <NUM>. However, in other embodiments, the columns <NUM> and/or recesses <NUM> can be un-evenly spaced about the circumference of the hole <NUM>. Each of the recesses <NUM> can define a central recess axis <NUM>, each of which can be parallel with the central hole axis <NUM>, although other orientations are possible for the central recess axes <NUM>. Each central recess axis <NUM> can also be radially spaced from the central hole axis <NUM> by a distance R1. The plate threads <NUM> extend through the columns <NUM> and at least portions of the recesses <NUM> along one or more thread paths between the upper and lower plate surfaces <NUM>, <NUM>. Portions of the plate threads <NUM> that traverse a column <NUM> can be referred to herein as "column threads" <NUM>.

As shown in <FIG>, each column <NUM> can define a first surface <NUM> substantially facing the central hole axis <NUM>. The first surface <NUM> can also be referred to as an "innermost surface" of the column <NUM>. Thus, the first surface <NUM> defines crests <NUM> of the column threads <NUM>. The first surface <NUM> of each column <NUM> extends between a first side <NUM> and a circumferentially opposed second side <NUM> of the column <NUM>. The first and second sides <NUM>, <NUM> of each column <NUM> can define interfaces between the column <NUM> and the circumferentially adjacent recesses <NUM>. The first surfaces <NUM> of the columns <NUM> can collectively define segments of a downward-tapering, generally frusto-conical shape, particularly one that defines a central cone axis coincident with the central hole axis <NUM>.

The one or more thread paths can include a pair of non-intersecting thread paths (i.e., double-lead); however in other embodiments the one or more thread paths can include a single thread path (i.e., single-lead), or three or more thread paths (e.g., triple-lead, etc.). The thread paths are preferably helical, although other thread path types are within the scope of the present disclosure. As shown, the plate threads <NUM> can circumferentially traverse each of the columns <NUM> and recesses <NUM> in an uninterrupted fashion. In other embodiments, however, portions of the recesses <NUM> can circumferentially interrupt the plate threads <NUM> or, stated differently, the plate threads <NUM> can "bottom-out" along one or more and up all of the recesses <NUM>.

The columns <NUM> are configured such that, during insertion of a locking screw within the hole <NUM>, a screw shaft of the locking screw or compression screw bypasses the columns <NUM>, such that the interior surface <NUM> within the hole <NUM> engages a head of the compression screw or locking screw. In the latter case, after the screw shaft bypasses the columns <NUM>, the plate threads <NUM> in turn engage external threads on the head of the locking screw in a manner providing locking engagement between the locking screw and the bone plate <NUM>. The structure and operation of the columns <NUM> is more fully described in <CIT> ("the '<NUM> Reference"); <CIT> ("the '<NUM> Reference"); <CIT> ("the '<NUM> Reference"); and <CIT> ("the '<NUM> Reference").

Referring again to <FIG>, the multi-use hole <NUM> defines a hole shape or "profile" in a horizontal reference plane X-Y. The hole <NUM> shape can thus be referred to as a "horizontal hole profile". In the present embodiment, at least an axial portion of the hole <NUM> has a generally polygonal horizontal hole profile. In particular, the hole <NUM> of the present embodiment has a trigon (i.e., generally triangular) horizontal profile, although in other embodiments the hole <NUM> can have other types of polygonal horizontal profiles (e.g., rectangle, pentagon, hexagon, etc.), or can have a circular horizontal profile, as discussed in more detail below. The hole <NUM> can have a first column 26a, a second column 26b, and a third column 26c located in a clockwise sequence along the circumference of the interior surface <NUM>. The first column 26a of the present embodiment is aligned with the longitudinal axis <NUM>. The hole <NUM> also has a first recess 28a opposite the first column 26a, a second recess 28b opposite the second column 26b, and a third recess 28c opposite the third column 26c. The plate threads <NUM> can extend along a thread path that corresponds to the horizontal profile of the hole <NUM>. Moreover, other features defined by the interior surface <NUM> can have a corresponding polygonal (e.g., trigon) horizontal profile, including the upper perimeter <NUM> and the neutral lead in surface(s) <NUM> (at least those portions thereof separate from the compression ramp <NUM>), the one or more undercut surfaces <NUM>, and the lower perimeter <NUM>.

In the illustrated embodiment, the first surfaces <NUM> of the columns <NUM> have linear horizontal profiles. In other embodiments, one or more of the first surfaces <NUM> can have arcuate profiles having a relatively large radii (as measured from the central hole axis <NUM>). Each column <NUM> can define a column centerline <NUM> that is spaced equidistantly between the first and second sides <NUM>, <NUM> of the column <NUM>. In a horizontal reference plane X-Y, the hole <NUM> can define a main radius R2 measured from the central hole axis <NUM> to the first surface <NUM> of the column <NUM> at the column centerline <NUM>.

In the present embodiment, the recesses <NUM> extend tangentially from the first and second sides <NUM>, <NUM> of the associated columns <NUM>. In this manner, the first surfaces <NUM> of the columns <NUM> effectively define the sides of the trigon, while the recesses <NUM> effectively define the corners of the trigon, each as viewed in the horizontal reference plane. Accordingly, the columns <NUM> and recesses <NUM> of the present embodiment can also be referred to respectively as "sides" and "corners" <NUM> of the trigon-shaped hole <NUM>. Each of the corners <NUM> can define a corner radius R3, measured from the corner axis <NUM>. The plate threads <NUM> extend along respective splines that revolve about the central hole axis <NUM> helically along the trigon profile of the interior surface <NUM> between the upper plate surface <NUM> and the lower plate surface <NUM>. Additionally, the interior surface <NUM>, including the columns <NUM> as well as the corners <NUM>, tapers inwardly toward the central hole axis <NUM> from the upper plate surface <NUM> toward the lower plate surface <NUM>. Moreover, as shown, the plate threads <NUM> can circumferentially traverse the columns <NUM> and the corners <NUM> in an uninterrupted fashion (i.e., the plate threads <NUM> need not bottom-out in the corners <NUM>). Accordingly, the plate threads <NUM> can transition smoothly and continuously between the columns <NUM> and the corners <NUM>.

The first surfaces <NUM> of each column <NUM> define a column length LC measured between the sides <NUM>, <NUM> of the column <NUM>. In the present embodiment, the column length LC can be substantially consistent within each column <NUM> as the thread path advances between the upper and lower surfaces <NUM>, <NUM> of the plate <NUM>. In such embodiments, the column length LC can also be referred to as a "side length" LC of the trigon-shaped hole <NUM>. The columns <NUM> of the present embodiment can have substantially equivalent column lengths LC, thus providing the hole <NUM> with a substantially equilateral triangular shape, as shown. Alternatively, the column lengths LC of two or all of the columns can differ from one another, as described in more detail below. In further embodiments, the column length LC of one or more and up to all of the columns <NUM> can successively increase as the thread path advances from the upper surface <NUM> toward the lower surface <NUM> of the plate <NUM>, thereby causing the corner radii R3 to progressively decrease toward the lower surface <NUM> of the plate <NUM>.

Referring again to <FIG> and <FIG>, the one or more compression structures of the multi-use hole <NUM> can include at least one lead-in surface <NUM> or "compression ramp" <NUM> that tapers axially downward from the upper perimeter <NUM> toward the lower plate surface <NUM>. Each compression ramp <NUM> is configured to cause the plate <NUM> to translate in a specific translation direction T1 in the horizontal plane X-Y responsive to engagement with the head of a compression bone anchor <NUM>. In the present embodiment, the hole <NUM> includes a compression ramp <NUM> that extends less than a full revolution about the central hole axis <NUM>. For example, the ramp <NUM> can be located on a specific side of the hole <NUM> in the intended translation direction T1. Stated differently, the translation direction T1 extends substantially horizontally from the central hole axis <NUM> toward the ramp <NUM>.

As shown in <FIG>, the compression ramp <NUM> is centrally located along the longitudinal axis <NUM>, such that the ramp <NUM> is configured to direct or "funnel" or otherwise influence the translation direction T1 to be along the longitudinal direction X. For example, the compression ramp <NUM> can define a crescent shape as viewed in a horizontal reference plane X-Y, such that a maximum horizontal dimension L0 of the crescent occurs along the longitudinal axis <NUM>. The ramp <NUM> can revolve about the central hole axis <NUM> from a first terminus <NUM> to a second terminus <NUM>. In this manner, the ramp <NUM> can define an angular ramp span A1 measured between the termini <NUM> in a horizontal plane X-Y. As shown, the ramp <NUM> can revolve about the central hole axis <NUM> such that one or both of the termini <NUM> is located across the column centerline <NUM> of the adjacent column <NUM>. In other embodiments, however, the compression ramp <NUM> can have an angular span A1 such that one or both of the termini <NUM> is located respectively on a near side of the column centerline <NUM> of the adjacent column <NUM>. Stated differently, the first compression ramp <NUM> need not extend across one or both of the adjacent column centerlines <NUM>. It should be appreciated that in further embodiments, any and up to each of the corners <NUM> can include a compression ramp <NUM> for directing dynamic compression responsive to eccentric insertion of a compression screw <NUM> toward the respective corner <NUM>. Such compression ramps <NUM> can be separate from one another or can be defined by different portions of a single ramp surface.

The angular ramp span A1 can be in a range of about <NUM> degrees up to about <NUM> degrees, and more particularly from about <NUM> degrees <NUM> degrees, and more particularly from about <NUM> degrees to about <NUM> degrees. The hole <NUM> can also include a neutral lead-in surface <NUM> that extends from the upper perimeter <NUM> axially downward into the hole <NUM> and revolve about the central hole axis <NUM> and can extend to interfaces with the compression ramp <NUM>.

Referring now to <FIG>, the compression ramp <NUM> tapers axially downward from the upper perimeter <NUM> and can be intersected by the plate threads <NUM>. In the present embodiment, the compression ramp <NUM> has a linear surface profile in a reference plane that extends along the central hole axis <NUM> and the longitudinal direction X. This reference plane is also referred to herein as an "axial reference plane. " The ramp <NUM> is oriented at an acute ramp angle A2 with respect to the central hole axis <NUM>. The ramp angle A2 can be in a range of about <NUM> degrees to about <NUM> degrees, and more particularly in a range of about <NUM> degrees to about <NUM> degrees, and more particularly in a range of about <NUM> degrees to about <NUM> degrees. It should be appreciated that, in other embodiments, the compression ramp <NUM> can have a concave arcuate profile in the axial reference plane. In such embodiments, the ramp angle A2 can be measured between the central hole axis <NUM> and a tangent axis that intersects the compression ramp <NUM> at a location thereof in the axial reference plane.

In the illustrated embodiment, the compression ramp <NUM> extends from the upper perimeter <NUM> to, and is intersected by, the threads <NUM>. In other embodiments, a portion of the neutral lead-in surface <NUM> can extend axially downward from the compression ramp <NUM>, such as at the first recess 28a. In this manner, the compression ramp <NUM> can define a first compression ramp <NUM>, and such portion of the neutral lead-in surface <NUM> can define a second, axially lower compression ramp, such as along the first corner 28a. In such an embodiment, the second compression ramp <NUM> can extend axially downward from the first compression ramp <NUM> to the plate threads <NUM>. The first ramp <NUM> defines a first ramp angle A2, and the second compression ramp <NUM> can define a second ramp angle, which can be less than (i.e., steeper than) or greater than (i.e., shallower than) the first ramp angle A2 with respect to the central hole axis <NUM> in an axial reference plane along the longitudinal axis <NUM>.

Referring again to <FIG>, the plate threads <NUM> have a cross-sectional profile in the axial reference plane. Such as cross-sectional profile is also referred to as a "thread-form," and includes crests <NUM>, roots <NUM>, and upper and lower flanks <NUM>, <NUM> that extend between the crests <NUM> and roots <NUM>. As used herein with reference to the plate threads <NUM>, the term "crest" refers to the apex of a fully-developed thread-form. The thread-forms of the plate threads <NUM> are configured for complimentary engagement (i.e., intermeshing) with exterior threads on the head of a locking screw, particularly for providing favorable mating engagement therebetween. The thread-forms of the plate threads <NUM> are also configured to engage an outer surface on the head of a compression screw inserted eccentrically within the hole <NUM>. In this manner, the plate threads <NUM> can be characterized as defining a compression ramp for providing dynamic compression. It should be appreciated that, in this manner, the compression ramp <NUM> and the plate threads <NUM> together can provide complimentary dynamic compression.

The crests <NUM> of the plate threads <NUM> can be sharp, although one or more and up to all of the crests <NUM> can be rounded for reducing stress concentrations and also for reducing undesirable mechanical interference with the exterior threads on the head of the locking screw. In other embodiments, one or more of the crests <NUM> can be truncated and can have a linear crest profile, as described in more detail below.

In the reference plane, the crests <NUM> of the plate threads <NUM> extend along a crest trajectory axis <NUM>. In the present embodiment, the crest trajectory axis <NUM> is linear, and can be oriented at an acute crest trajectory angle A3 relative to the central hole axis <NUM>. The crest trajectory angle A3 can be in a range of about <NUM> degrees to about <NUM> degrees, and more particularly in a range of about <NUM> degrees to about <NUM> degrees, and preferably in a range of about <NUM> degrees to about <NUM> degrees. As shown, the crest trajectory angle A3 can be less (i.e., steeper) than the ramp angle A2, although in other embodiments the crest trajectory angle A3 can be equivalent to or greater (i.e., shallower) than the ramp angle A2. In yet other embodiments, one or both of the compression ramp <NUM> and the crest trajectory axis <NUM> can be curvilinear, such that various portions of the crest trajectory axis <NUM> can be shallower, equivalent to, and/or steeper than various portions of the compression ramp <NUM>, and vice versa. The crest trajectory angle A3 is configured, among other things, to prevent the head of a locking screw or compression screw from passing completely through the multi-use hole <NUM>.

The threads <NUM> can also define a thread pitch P that extends between axially adjacent crests <NUM> along the axial direction, and is in a range of about <NUM> to about <NUM>. The plate threads <NUM> also define a thread lead L, which can also be defined at the crests <NUM>, and can be in a range of <NUM> to about <NUM>. The thread pitch P and thread lead L can be as more fully described in the '<NUM> and '<NUM> References. The hole <NUM> can define a minimum minor diameter D1, which can be measured at the axially lowermost crest <NUM> along the crest trajectory axis <NUM>. The undercut surface <NUM> can truncate at least a portion of one or more of the plate threads <NUM>. The undercut surface <NUM> can extend circumferentially continuously and uninterrupted along a full revolution about the central hole axis <NUM>. Alternatively, the undercut surface <NUM> can be circumferentially interrupted by one or more of the corners <NUM>.

It should be appreciated that the plate threads <NUM> described herein are configured to enhance the mechanical strength of a locked thread interface between the plate threads <NUM> and the exterior threads on the head of a locking screw, and also to be sufficiently robust to provide dynamic compression responsive to engagement with the head <NUM> of a compression screw <NUM>.

With continued reference to <FIG>, the interior surface <NUM> defines at least one contact profile <NUM> in the axial reference plane that extends along the translation direction T1. Each contact profile <NUM> can be characterized as a path along which the head <NUM> of the compression anchor <NUM> (<FIG>) contacts the interior surface <NUM> within the hole <NUM> as the head <NUM> advances axially downward within the hole <NUM> along the central axis <NUM> of the compression anchor <NUM> that is eccentric with respect to the central hole axis <NUM>, meaning that the central screw axis <NUM> is offset from the central hole axis <NUM> in an offset direction during insertion. It should be appreciated that the central screw axis <NUM> can also be referred to as the "insertion axis" <NUM> along which the screw is inserted through the hole <NUM>. The geometry of each contact profile <NUM> can be tailored to enhance the translation of the bone plate <NUM> in the respective translation direction during eccentric head <NUM> insertion within the hole <NUM>. In the present embodiment, the compression ramp <NUM> is intersected by the threads <NUM>, which are therefore part of the compression structures within the hole <NUM>. Accordingly, the interior surface <NUM> of the present embodiment can define a first contact profile <NUM> that is defined at least by the compression ramp <NUM> and is also partially defined by the plate threads <NUM>. In this manner, portions of the threads <NUM>, such as the crests <NUM>, can also define a compression ramp within the hole <NUM>. In the present embodiment, the compression structures are configured such that a first offset direction B1 is in the same axial reference plane as the first contact profile <NUM>.

Referring now to <FIG>, methods of using the multi-use hole <NUM> of the present embodiment in a bone plating operation for selective dynamic compression will now be described, according to an example technique of eccentrically inserting a compression screw <NUM> toward the associated corner <NUM> and compression ramp <NUM> aligned with the first translation direction T1. During the bone plating operation, a physician can insert a shaft <NUM> of a compression screw <NUM> through the hole <NUM> along an insertion axis <NUM> and drive the shaft <NUM> into underlying bone, such as a bone segment <NUM>. In this example, the physician can cause the insertion axis <NUM> to be offset from the central hole axis <NUM> by a first offset distance O1 measured in the first offset direction B1 toward the corner <NUM> and the compression ramp <NUM>. In this example, the first offset direction B1 is in the first translation direction T1. As shown in <FIG>, the physician can further drive the shaft <NUM> through the hole <NUM> along the insertion axis <NUM> at the first offset distance O1 in a manner causing an outer surface <NUM> of the head <NUM> of the compression screw <NUM> to engage the interior surface <NUM> of the hole <NUM> at a first position of the screw head <NUM> with respect to the interior surface <NUM>. At the first position, the outer surface <NUM> of the screw head <NUM> contacts the interior surface <NUM> at a first initial contact location <NUM>, such as along the contact profile <NUM>, such as on the compression ramp <NUM>. It should be appreciated that a maximum of the first offset distance O1 can be determined by a variety of factors, such as the corner radius R3, the minimum minor diameter D1 of the plate threads <NUM>, and the major diameter of a threaded shaft <NUM> of the compression screw <NUM>, such that the threads of the threaded shaft <NUM> can bypass the plate threads <NUM> during insertion along the insertion axis <NUM> toward the corner <NUM>.

As shown in <FIG>, after the outer surface <NUM> of the head <NUM> contacts the interior surface <NUM> at the first initial contact location <NUM> (<FIG>), the physician can further drive the compression screw <NUM> axially downward along the insertion axis <NUM>, causing the outer surface <NUM> of the head <NUM> to travel or ride along the interior surface <NUM>, such as along the first contact profile <NUM> (<FIG>), to a second position of the screw head <NUM> relative to the interior surface <NUM>, which can be a fully seated position of the screw head <NUM> within the hole <NUM>. The interfacing geometries of the interior surface <NUM> of the hole <NUM>, such as along the contact profile <NUM>, and the outer surface <NUM> of the head <NUM>, causes the plate <NUM> and the underlying bone segment <NUM> to translate in the first translation direction T1 as the outer surface <NUM> rides along the interior surface <NUM>, as the screw head <NUM> advances axially downward along the insertion axis <NUM>. In this manner, the bone segment <NUM> can translate in the translation direction T1 in a manner reducing a gap G (<FIG>) between the bone segment <NUM> and an adjacent bone segment <NUM>.

In the present embodiment, the size and shape of the screw head <NUM> is configured such that the screw axis <NUM> will be substantially co-extensive with the central hole axis <NUM> when the screw head <NUM> is fully seated within the hole <NUM>, as shown. In such embodiments, the first offset distance O1 effectively defines a first translation distance L1 of the plate <NUM> (along the first translation direction T1) provided by the eccentric screw insertion. The trigon shape of the hole <NUM> in the present embodiment can cause the outer surface <NUM> of the screw head <NUM> to contact the columns <NUM> and be remote from the corners <NUM>, including the contact profile <NUM>, when fully seated in the hole <NUM>.

The multi-use holes <NUM> of the present disclosure are versatile in that the side of the hole <NUM> opposite the compression ramp <NUM> can also be used to achieve dynamic compression, which occurs in a second translation direction T2 opposite first translation direction T1. Referring now to <FIG>, methods of using the multi-use hole <NUM> of the present embodiment for selective dynamic compression in the second translation direction T2 will now be described, according to an example technique of eccentrically inserting the compression screw <NUM> toward the associated column <NUM> opposite the compression ramp <NUM> along the second translation direction T2. In this example, the physician can insert the shaft <NUM> of the compression screw <NUM> through the hole <NUM> an into an underlying bone segment <NUM> along an insertion axis <NUM> that is offset from the central hole axis <NUM> by a second offset distance O2 measured in a second offset direction B2 toward the column <NUM>. In this example, the second offset direction B2 is in the second translation direction T2. As shown in <FIG>, the physician inserts the shaft <NUM> through the hole <NUM> along the insertion axis <NUM> at the second offset distance O2 in a manner causing the outer surface <NUM> of the head <NUM> to engage the interior surface <NUM> of the hole <NUM> at a third position of the screw head <NUM> relative to the interior surface <NUM>. At the third position, the outer surface <NUM> of the screw head <NUM> contacts the interior surface <NUM> at a second initial contact location <NUM>, which can occur at an interface between the upper perimeter <NUM> and the neutral lead-in surface <NUM>. As with eccentric insertion of the screw <NUM> toward the compression ramp <NUM> (<FIG>), the maximum second offset distance O2 can be determined by minimum minor diameter D1 of the plate threads <NUM> and the major diameter of a threaded shaft <NUM> of the compression screw <NUM>, such that the threads of the threaded shaft <NUM> can bypass the plate threads <NUM> during insertion along the insertion axis <NUM>. However, because geometry of the corners <NUM> provides that first surfaces <NUM> of the columns <NUM> are closer to the central hole axis <NUM> that the interior surface <NUM> along the corners <NUM>, the maximum second offset distance O2 is shorter than offset distance O1 in the present embodiment of the hole <NUM>.

As shown in <FIG>, after the outer surface <NUM> of the head <NUM> contacts the interior surface <NUM> at the second initial contact location <NUM>, the physician can further drive the compression screw <NUM> axially downward along the insertion axis <NUM> into the underlying bone segment <NUM>, causing the outer surface <NUM> of the head <NUM> to travel or ride along the neutral lead-in surface <NUM> and the column <NUM>, and optionally along a portion of the plate threads <NUM> of the column <NUM>, to a fourth position of the screw head <NUM> relative to the interior surface <NUM>. The fourth position can be the fully seated position of the screw head <NUM> within the hole <NUM>, and thus can be equivalent to the second position (see <FIG>). In this manner, the neutral lead-in surface <NUM>, the column, and a portion of the threads <NUM> thereof can define a second contact profile <NUM> (see <FIG>) in the axial reference plane. The interfacing geometries of the outer surface <NUM> of the screw head <NUM> and the interior surface <NUM> of the hole <NUM>, such as along the second contact profile <NUM>, causes the plate <NUM> and the bone segment <NUM> to translate in the second translation direction T2 as the outer surface <NUM> rides along the interior surface <NUM>, optionally until the screw head <NUM> is fully seated within the hole <NUM>, at which position the screw axis <NUM> is substantially co-extensive with the central hole axis <NUM>. In such embodiments, the second offset distance O2 effectively defines a second translation distance L2 of the plate <NUM> along the second translation direction T2. Because the maximum first offset distance O1 is greater than the maximum second offset distance O2 in the present embodiment, the maximum first translation distance T1 is greater than the maximum second translation distance T2.

It should be appreciated that the configuration of the hole <NUM> according to the present embodiment provides numerous additional options for dynamic compression along other translation directions. For example, the physician can elect to translate the plate <NUM> in a third translation direction T3 by inserting the compression screw <NUM> eccentrically toward the second corner 28b or in a fourth translation direction T4 by inserting the compression screw <NUM> eccentrically toward the third corner 28c.

Referring to <FIG>, in other embodiments the bone plate <NUM> can employ multi-use holes <NUM> that have multiple compression ramps, such as a first ramp 33a and a second ramp 33b opposite each other along the longitudinal axis <NUM>. As in the embodiment described above (<FIG>), first ramp 33a can be centered along the longitudinal axis <NUM> at the first corner 28a. The second ramp 33b can centered along the longitudinal axis <NUM> at the first column 26a, and can otherwise be a substantial mirror image of the first ramp 33a. Accordingly, like the first ramp 33a, the second ramp 33b can be configured to direct, funnel, or otherwise influence the second translation direction T2 to be along the longitudinal direction X. In the present embodiment, the neutral lead-in surface <NUM> can extend from the upper perimeter <NUM> axially downward into the hole <NUM> and revolve about the central hole axis <NUM> and can extend to interfaces with the first and second compression ramps 33a, 33b.

Referring to <FIG>, in additional embodiments, the shape of the hole <NUM> can be further adapted to provide an increased translation distance L1. As shown in <FIG>, the second and third columns 26b, 26c of the present embodiment can define column lengths LC-<NUM> that are greater than a length LC of the first column 26a, thereby causing the hole <NUM> to be elongated in the horizontal reference plane X-Y, particularly along the first translation direction T1. In this embodiment, the corner axis <NUM> of the first corner 28a can be spaced from the central hole axis <NUM> at a distance R1-<NUM> that is greater than distances R1 by which the corner axes <NUM> of the second and third corners 28b, 28c are spaced from the central hole axis <NUM>. The first corner 28a can have a corner radius R3-<NUM> shorter than the corner radii R3 of the second and third corners 28b, 28c. The foregoing adjustments to the hole <NUM> geometry can effectively provide additional space between the central hole axis <NUM> and the first corner 28a for eccentric insertion of the compression screw <NUM> for increased dynamic compression. Stated differently, the hole <NUM> of the present embodiment can provide a greater maximum offset distance O1 and translation distance L1 (<FIG>) compared to the embodiments described above.

As shown in <FIG> and <FIG>, the physician can insert the compression screw <NUM> eccentrically within the hole <NUM> such that the insertion axis <NUM> is offset in the first offset direction B1 toward the first corner 28a, such as along a longitudinal axis <NUM>' that intersects the column centerline <NUM> of the first column 26a. In this example, the first offset direction B1 is in the first translation direction T1. As shown in <FIG>, at such an offset the outer surface <NUM> of the head <NUM> of the compression screw <NUM> can engage the interior surface <NUM> of the hole <NUM> at a first position of the screw head <NUM> relative to the interior surface <NUM>. At the first position, the outer surface <NUM> of the screw head <NUM> contacts the interior surface <NUM> at first and second initial contact locations 75a, 75b, which can be offset from the longitudinal axis <NUM>'. As shown, the first and second initial contact locations 75a, 75b can be on the second and third columns 26b, 26c. Thus, in the present embodiment, the screw head <NUM> can travel along at least two contact profiles that 50a, 50b (<FIG>) that are opposite each other with respect to the longitudinal axis <NUM>'. Thus, the second and third columns 26b, 26c can define corresponding compression ramps.

As shown in <FIG> and <FIG>, after the outer surface <NUM> of the head <NUM> contacts the interior surface <NUM> at the first and second initial contact locations 75a, 75b, the physician can further drive the compression screw <NUM> axially downward along the insertion axis <NUM>, causing the outer surface <NUM> of the head <NUM> to travel or ride along the interior surface <NUM>, such as along the contact profiles 50a, 50b, from the first position to a second position of the screw head <NUM> relative to the interior surface <NUM>. In this embodiment, the interior surface <NUM> of the hole <NUM> can be characterized as providing a pair of compression rails, along which the outer surface <NUM> of the screw head <NUM> can travel during plate translation along the translation direction T1 to the first translation distance L1, until the screw head <NUM> reaches the second position, which can be the fully seated position of the screw head <NUM> within the hole <NUM>. As in the embodiments described above, the screw axis <NUM> can be substantially co-extensive with the central hole axis <NUM> when the screw head <NUM> is fully seated within the hole <NUM>. Also as above, the first offset distance O1 can effectively define the first translation distance L1. It should be appreciated that, in the present embodiment, dynamic compression via eccentric screw insertion toward the first column 26a can be substantially similar to that described above with reference to <FIG>.

Referring now to <FIG>, in additional embodiments of a multi-use hole <NUM>, one or more of the plate threads <NUM> adjacent the axial lower portion of the hole <NUM> can be truncated, such as by having truncated crests 56a, in a manner providing additional clearance along the radial direction R for the threads of the threaded shaft <NUM> of the compression screw <NUM> during eccentric insertion toward the compression ramp <NUM>.

As described above, the multi-use hole <NUM> can have a circular hole shape in a horizontal reference plane. Examples of such circular holes <NUM> are shown in <FIG>. The plate threads <NUM> of the circular multi-use holes <NUM> can extend along respective splines that revolve about the central hole axis <NUM> helically along the circular profile of the interior surface <NUM> of the hole <NUM>.

As shown in <FIG>, a circular multi-use hole <NUM> can include a compression ramp <NUM> located on a specific side of the hole <NUM>, such as in an intended translation direction T1 from the central hole axis <NUM>. For example, the compression ramp <NUM> can be centrally located along the longitudinal axis <NUM>, similar to the manner described above with reference to <FIG>. The ramp <NUM> can be configured to direct, funnel, or otherwise influence dynamic compression along the translation direction T1.

As shown in <FIG>, a circular multi-use hole <NUM> can have multiple compression ramps, such as a first ramp 33a and a second ramp 33b opposite each other along the longitudinal axis <NUM>. The first and second ramps 33a, 33b can each be centered along the longitudinal axis <NUM> and can be substantial mirror images of each other, as in the embodiment described above with reference to <FIG>. The first and second compression ramps 33a, 34b can be configured to direct, funnel, or otherwise influence dynamic compression along respective first and second translation directions T1, T2 extending from the central hole axis <NUM>. The circular multi-use holes <NUM> can be employed for dynamic compression in various other translation directions responsive to eccentric screw insertion. For example, circular holes <NUM> can provide dynamic compression along virtually any translation direction extending radially outward from the central hole axis <NUM> to the location of eccentric screw insertion within the hole <NUM>.

It should be appreciated that although the illustrated embodiments of the present disclosure show the multi-use holes <NUM> as having a minimum minor thread diameter less than a maximum diameter of the head <NUM> of the compression screw <NUM>, the holes <NUM> and/or compression screws <NUM> of the present disclosure can be adapted such that a compression screw <NUM> can engage the interior surface <NUM> within a hole <NUM> in a manner providing dynamic compression even should the minimum minor thread diameter of the hole <NUM> be greater, even significantly greater, than the maximum diameter of the head <NUM> of the compression screw <NUM>.

The plate body <NUM>, compression screws <NUM>, and locking screws described herein can each comprise one or more biocompatible materials. By way of non-limiting examples, the plate body <NUM> can be formed of a material selected from a group comprising: metal, such as titanium, titanium alloys (e.g., titanium-aluminum-niobium (TAN) alloys, such as Ti-6Al-7Nb, and titanium-aluminum-vanadium (TAV) alloys such as Ti-6Al-4V, titanium molybdenum alloys (Ti-Mo) or any other molybdenum metal alloy, and nickel-titanium alloys, such as nitinol), stainless steel, and cobalt base alloys (e.g., cobalt-chrome alloys); composite materials; polymeric materials; ceramic materials; and/or resorbable materials, including resorbable versions of the foregoing material categories (metals, composites, polymers, ceramics). Also by way of non-limiting examples, the compression screws <NUM> and locking screws can be formed of a material selected from a group comprising: metal, such as titanium, titanium alloys (e.g., TAN alloys, TAV alloys, such as Ti-6A1-4V, titanium molybdenum alloys (Ti-Mo) or any other molybdenum metal alloy, and nickel-titanium alloys, such as nitinol), stainless steel, cobalt base alloys (e.g., cobalt-chrome alloys); composite materials; polymeric materials; ceramic materials; and/or resorbable materials, including resorbable versions of the foregoing material categories (metals, composites, polymers, ceramics). Preferably, the material of the compression screws <NUM> and locking screw ha a hardness that is greater than that of the material of the plate body <NUM>. This parameter contributes to the threaded locking characteristics and the dynamic compression characteristics described throughout the present disclosure. Preferably, the plate body <NUM> primarily or entirely comprises titanium and the compression screws <NUM> and locking screws primarily or entirely comprise TAN. It should be appreciated, however, that other material compositions of the bone plates <NUM> and/or the screws are within the scope of the present disclosure.

Moreover, surfaces of the plate body <NUM> and/or the screws can optionally be subjected to one or more processes, such as coating, treating, and/or finishing processes, which can be performed to provide such surfaces, or the underlying subject body material, with certain characteristics, such as to adjust hardness, softness, and/or friction parameters of the body material, as more fully described in the '<NUM> and '<NUM> References.

It should be appreciated that the various hole <NUM> parameters described above are provided as exemplary features for adapting the holes <NUM> to achieve selective dynamic compression or locking engagement with the heads of respective compression screws and locking screws.

Claim 1:
A bone plate (<NUM>), comprising:
an outer surface (<NUM>) and a bone-facing surface (<NUM>) opposite the outer surface (<NUM>); and
an interior surface (<NUM>) that defines a hole that extends from the outer surface (<NUM>) to the bone-facing surface (<NUM>) along a central hole axis (<NUM>), wherein the interior surface (<NUM>) further defines:
a ramp (<NUM>) extending from the outer surface toward the bone-facing surface (<NUM>);
plate threads (<NUM>) extending from the ramp (<NUM>) toward the bone-facing surface (<NUM>), wherein the plate threads (<NUM>) are configured for optional locking engagement with external threads on a first head (<NUM>) of a locking bone fixation member (<NUM>),
a contact profile (<NUM>) defined at least by the ramp (<NUM>) in a reference plane that extends along the central hole axis (<NUM>), wherein the contact profile (<NUM>) is spaced from the central hole axis (<NUM>) in an offset direction perpendicular to the central hole axis (<NUM>), and the contact profile (<NUM>) is configured to translate the bone plate (<NUM>) in the offset direction responsive to contact with an exterior surface of a second head of a compression bone fixation member as the second head advances within the hole along an insertion axis (<NUM>) that is offset from the central hole axis (<NUM>) in the offset
direction, wherein the hole (<NUM>) has a polygonal hole profile in a second reference plane that is orthogonal to the central hole axis (<NUM>)
characterized in that the polygonal hole profile is a trigonal hole profile.