Patent Publication Number: US-2022233220-A1

Title: Bone Plates Having Multi-Use Combination Holes For Locking And Dynamic Compression, And Related Systems And Methods

Description:
TECHNICAL FIELD 
     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 combination holes defined by a locking hole intersected by a compression hole, more particularly such that the intersecting geometries thereof are configured to translate the bone plate in a direction from the compression hole toward the locking hole when a head of a compression bone anchor is driven eccentrically within the locking hole. 
     BACKGROUND 
     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. Additionally or alternatively, bone plates can include combination holes or “combi-holes” that include a locking hole and a compression hole that intersect one another, such that the locking hole and the compression hole overlap one another and are open to each other. Combi-holes are commonly used selectively for either locking the plate to underlying bone (by inserting a locking screw within the locking hole of the combi-hole) or translating the plate relative to the underlying bone (by inserting a compression screw within the compression hole of the combi-hole). 
     SUMMARY 
     According to an embodiment of the present disclosure, a bone plate includes a plate body that defines an interior surface that defines a combination hole that includes a locking hole and a compression hole that intersect one another. The locking hole and the combination hole each extends from an outer surface of the plate body to a bone-facing surface of the plate body. The locking hole defines a central locking hole axis and the compression hole defines a central compression hole axis that is spaced from the central locking hole axis in an offset direction. The plate body further defines a locking surface that defines the locking hole and at least one locking structure therein. The plate further defines a compression surface that defines the compression hole. An intersection boundary between the locking surface and the compression surface is configured to cause translation of the bone plate in the offset direction responsive to contact between the intersection boundary and an exterior surface of a head of a compression screw as the head advances within the combination hole along an insertion axis that is offset from the central locking hole axis at an offset distance measured in a direction having a directional component in the offset direction. 
     According to another embodiment of the present disclosure, a method of seating a bone screw in a combination hole defined by an interior surface of a bone plate includes inserting a shaft of the compression screw through a locking hole of the combination hole and into underlying bone. The locking hole is intersected by a compression hole. The shaft is inserted through the locking hole at an offset distance measured from a central locking hole axis of the locking hole toward a central screw axis of the compression screw in an offset direction. The offset direction extends from the central locking hole axis toward a central compression hole axis of the compression hole. The method includes contacting an outer surface of the head of the compression screw against opposite sides of the combination hole spaced from each other along a lateral direction that is substantially perpendicular to the offset direction. The method includes driving the bone screw, during the contacting step, toward the underlying bone along the central screw axis, responsively sliding the head along respective contact paths along the opposite sides, wherein the respective contact paths each have a directional component in the offset direction, thereby translating the bone plate in the offset direction relative to the bone screw. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1A  is a perspective view of a bone plate that defines a combi-hole, according to an embodiment of the present disclosure; 
         FIG. 1B  is a top plan view of the bone plate illustrated in  FIG. 1A ; 
         FIG. 1C  is another top plan view of the bone plate illustrated in  FIG. 1A ; 
         FIG. 1D  is a sectional side view of the bone plate taken along section line  1 D- 1 D in  FIG. 1B ; 
         FIG. 2  is a top view of a bone plate having multiple combi-holes configured according to the combi-hole illustrated in  FIGS. 1A-1D ; 
         FIG. 3A  is the sectional side view of the combi-hole of  FIG. 1D  showing a compression screw inserted eccentrically therein at a first contact position, according to an embodiment of the present disclosure; and 
         FIG. 3B  is the sectional side view of the combi-hole of  FIG. 1D  showing the compression screw inserted eccentrically therein at a fully seated position. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     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”, “about”, and “substantially”, as used herein with respect to dimensions, angles, ratios, and other geometries, takes into account manufacturing tolerances. Further, the terms “approximately”, “about”, and “substantially” can include 10% greater than or less than the stated dimension, ratio, or angle. Further, the terms “approximately”, “about”, and “substantially” can equally apply to the specific value stated. 
     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 (e.g., underlying bone) along a direction that is generally perpendicular to an axis along which the bone anchor is inserted into underlying bone. 
     The embodiments disclosed herein pertain to combi-holes in a bone plate. The combi-holes include a locking hole intersected by a compression hole. The locking hole and compression hole have respective geometries such that a non-locking bone anchor (e.g., a “cortex screw” or “compression screw”) inserted along an “eccentric” insertion axis (i.e., an insertion axis offset from a central axis of the locking hole) that is offset in an offset direction toward a central axis of the compression hole will cause the head of the compression screw to engage an intersection boundary between the locking and compression holes. Such contact between the head and the intersection boundary, as the head is driven toward the underlying bone, causes dynamic compression (i.e., translates the bone plate relative to the underlying bone) in a direction having a directional component in the offset direction. Dynamic compression is particularly useful for moving fractured portions of bone relative to one another, such as for anatomical reduction to treat bone fractures. The combi-holes of the present disclosure provide a physician with additional options for achieving dynamic compression, particularly by inserting the compression screw within the compression hole to translate the plate in a first direction and inserting the compression screw within the locking hole to translate the plate in a second direction, such as opposite the first direction. 
     The inventors have discovered, surprisingly and unexpectedly, that the threaded locking holes of combi-holes having certain geometries can be alternatively used with compression bone anchors to achieve dynamic compression, even when the head of the compression bone anchor contacts the interior plate surface within the locking hole, even when the contact occurs over and/or along the internal threads in the locking hole. Thus, the combi-holes of the present disclosure include intersecting locking holes and compression holes having respective geometries such that an intersection boundary therebetween can provide dynamic compression when a compression bone anchor, such as a compression screw, is inserted within the locking hole eccentrically toward the compression hole. In these combi-holes, the primary direction of dynamic compression (i.e., plate translation) is generally from the compression hole toward the locking hole, which is the opposite of most prior art combi-holes. For this reason, the combi-holes of the present disclosure can be characterized as “reverse combi-holes.” Furthermore, the combi-holes of the present disclosure can increase the overlap between the locking and compression holes thereof, thereby reducing a longitudinal length of the combi-hole, which can allow a higher combi-hole density within a bone plate (i.e., more combi-holes to be employed within the same plate area relative to prior art combi-holes). Additionally, such higher hole density, in combination with the enhanced dynamic compression options for each combi-hole, provides enhanced options for 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  FIGS. 1A and 1B , a bone plate  4  has a plate body  5  that defines therein at least one combination hole or “combi-hole”  90  that extends from an upper surface  18  of the plate body  5  to a bone-facing surface  20  of the plate body  5 . The plate body  5  defines an interior surfaces  24  that defines the combi-hole  90 . In particular, the interior surface  24  defines a locking hole  6  and a compression hole  92  that intersect and overlap one another so as to provide the combi-hole  90 . The locking hole  6  extends from the upper surface  18  to the bone facing surface  20  of the plate body  5  along a central locking hole axis  22 . The compression hole  92  extends from the upper surface  18  to the bone facing surface  20  along a central compression hole axis  94 . The central locking hole axis  22  and the central compression hole axis  94  axis are preferably parallel, although in other embodiments these axes  22 ,  94  can be angularly offset from each other at an acute angle. 
     The combi-hole  90  defines a first end  91  and a second end  93  spaced from each other at a hole length L along a first direction, which is also referred to herein as a longitudinal direction X. In particular, the first end  91  is spaced from the second end  93  in a first longitudinal direction X 1 , while the second end  93  is spaced from the first end  91  in a second longitudinal direction X 2  opposite the first longitudinal direction X 2 . It should be appreciated that the first and second longitudinal directions X 1 , X 2  each refer to mono-directional components of the longitudinal direction X, which is bi-directional. The locking hole  6  and the compression hole  92  can be characterized as extending toward and away from each other along the longitudinal direction X. The combi-hole  90  defines an intersection axis  97  that intersects both axis  22  and axis  94 . Axis  22  and axis  94  are spaced from each other at an axis separation distance LA 1 , preferably measured along the longitudinal direction X. In such embodiments, the intersection axis  97  is oriented along the longitudinal direction X and can thus also define a longitudinal axis of the combi-hole  90 . The combi-hole  90  also defines a first side  31  and a second side  33  spaced from each other along a second direction, also referred to herein as a lateral direction Y, which is substantially perpendicular to the longitudinal direction X. The combi-hole  90  defines a total depth D 1  ( FIG. 1C ) measured from the upper surface  18  to the bone-facing surface  20  along a third direction, also referred to herein as a transverse direction Z, which is substantially perpendicular to the longitudinal and lateral, directions X, Y. As used herein, the term “depth” refers to a distance within the combi-hole  90  as measured from the upper surface  18  of the plate  4  toward the lower surface  20  thereof along the transverse direction Z. 
     It should be appreciated that the longitudinal, lateral, and transverse directions X, Y, Z used herein refer to spatial aspects of the structure(s) in three-dimensional space, and are not affected by the orientation of the bone plate  4  relative to other physical structure. For example, the upper and bone-facing surfaces  18 ,  20  of the plate body  5  remain spaced from each other along the transverse direction Z regardless of the orientation of the plate body  4  relative to a patient. It should also 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 “transverse”, “transversely”, and derivatives thereof refer to the transverse direction Z. Moreover, a plane extending along the longitudinal and laterals directions X, Y can be referred to herein as a longitudinal-lateral plane X-Y or “horizontal” plane X-Y. Similarly, a plane extending along the longitudinal and transverse directions X, Z can be referred to herein as a longitudinal-transverse plane X-Z; and a plane extending along the lateral and transverse directions Y, Z can be referred to herein as a lateral-transverse plane Y-Z. 
     The central locking hole axis  22  is oriented along an axial locking hole direction. The central compression hole axis  94  is oriented along an axial compression hole direction. As used herein, the terms “axial” in conjunction with “direction” (e.g., “axial hole direction”, “axial locking hole direction”, “axial compression hole direction”, and “axial screw direction”) refers to 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 terms “axially upward”, “upward”, and derivatives thereof refer to the respective axial hole direction from the lower plate surface  20  toward the upper plate surface  18 . Conversely, the terms “axially downward”, “downward”, and derivatives thereof refer to the respective axial hole direction from the upper plate surface  18  toward the lower plate surface  20 . Thus, “axially upward” and “axially downward” (and their respective derivatives) each refer to mono-directional components of the respective “axial hole direction” or “axial screw direction”, which are bi-directional. In the embodiments depicted in the Figures, the axial hole directions are oriented along the transverse direction Z. Accordingly, the axial hole directions can be denoted by “Z” throughout this disclosure. It should be appreciated, however, that the scope of the present disclosure covers embodiments in which one or more of the axial hole directions (and thus also the respective hole axis  22 ,  94 ) is offset from the transverse direction Z at an acute angle. It should also be appreciated that when the terms “axially upper”, “axially lower,” and the like are used with reference to a bone anchor, such as a compression screw  7 , such terms refer to a central axis  52  of the screw, particularly as the screw would be oriented within the combi-hole  90 . 
     A portion of the interior surface  24  that defines the locking hole  6  is referred to herein as a “locking surface”  24   a,  while a portion of the interior surface  24  that defines the compression hole  92  is referred to herein as a “compression surface”  24   b.  The locking surface  24   a  and the compression surface  24   b  each extend from the upper surface  28  to the bone-facing surface  20  of the plate body  5 . The locking and compression surfaces  24   a,    24   b  can define respective upper perimeters  30   a,    30   b  at an interface with the upper plate surface  18  and can further define respective lower perimeters  32   a,    32   b  at an interface with the lower plate surface  20 . The locking and compression surfaces  24   a,    24   b  intersect each other along an intersection boundary  119  along the first and second sides  31 ,  33  of the combi-hole  90 . The interior surface  24  also defines a hole intersection zone  120  in which the intersection boundary  119  is located. 
     The locking and compression surfaces  24   a,    24   b  each revolve about their respective axis  22 ,  94  along respective circumferential directions C 1 , C 2  from the intersection boundary  119  on the first side  31  to the intersection boundary  119  on the second side  33 . As used herein with reference to the locking surface  24   a  and the compression surface  24   b,  the term “circumference” refers to a path that extends along the respective surface  24   a,    24   b  in revolving fashion between the intersection boundary  119  on the first side  31  and the intersection boundary  119  on the second side  33  (irrespective of the fact that the locking and compression surfaces  24   a ,  24   b  do not complete a full revolution about their respective axis  22 ,  94 ). It should be appreciated that, as used herein, the terms “circumferential”, “circumferentially”, and derivatives thereof refer to the respective circumferential direction C 1 , C 2 . 
     The first and second sides  31 ,  33  extend laterally toward each other along the intersection boundary  119 , such that the interior surface  24  defines a neck  35  at the intersection boundary  119 . A gap  124  extends laterally between the first and second sides  31 ,  33  at the neck  35 . The locking hole  6  and the compression hole  92  are open to each other through the gap  124 . The combi-hole  90  further defines an intermediate zone  115  between the central locking hole axis  22  and the central compression hole axis  94 . In particular, the intermediate zone  115  extends longitudinally from axis  22  to axis  94 . In three-dimensional space, the intermediate zone  115  also extends laterally from the first side  31  to the second side  33  of the combi-hole  90  and transversely from the upper surface  18  to the bone-facing surface  20 . The intermediate zone  115  thus defines the space between axes  22  and  94  with respect to the longitudinal direction X. The combi-hole  90  of the present embodiment is configured such that, within the intermediate zone  115 , a minimum lateral dimension G between the first and second sides  31 ,  33  occurs at the gap  124  of the neck  35 . In such embodiments, the minimum lateral dimension can be referred to as the “gap width” G. 
     The locking surface  24   a  defines at least one locking structure within the locking hole  6 . The at least one locking structure can include internal threads  9  that are configured to threadedly engage (i.e., intermesh with) external threads on a head of a locking bone screw in a manner allowing the intermeshed threads to lock to each other, thus locking the locking bone screw at a specific orientation relative to the bone plate  4 . The at least one locking structure (e.g, internal threads  9 ) can be configured to lock with the external threads of standard-type locking screws and/or variable-angle” (VA) locking screws. Standard-type locking screws are configured to lock within the locking hole  6  substantially only at a “nominal” orientation whereby the central axis of the locking screw (also referred to herein as the “central screw axis”) is substantially aligned with the central locking hole axis  22 . VA locking screws are configured to lock within the locking hole  6  selectively at either a nominal orientation or an “angulated” orientation, whereby the central screw axis is oriented at an acute angle with respect to the central locking hole axis  22 . Such angulated orientations are also referred to herein as “angulation.” Although the at least one locking structure of the illustrated embodiments are threads  9 , it should be appreciated that the locking surface  24   a  can employ other locking structure types can be employed, such as ribs, projections, recesses, and the like, which can optionally be configured to deform responsive to engagement with the head of a locking screw in a manner locking the head to the plate body  5  within the locking hole  6 . 
     The internal threads  9  can be located at a transversely intermediate region of the locking hole  6  (i.e., a region spaced from both the upper surface  18  and the bone-facing surface  20  of the locking hole  6 ). The locking surface  24   a  can define one or more lead-in surfaces  34  that extend from the upper perimeter  30   a  and downward to the threads  9 . The locking surface  24  can also define at least one undercut surfaces  36   a  (also referred to herein as a “relief surface”) that extends axially upward from the lower perimeter  32   a  toward the threads  9 . The threads  9  can extend axially between the lead-in surface(s)  34  and the undercut surface(s)  36 . As shown, the threads  9  can traverse at least portions of the lead-in surface(s)  34  and/or undercut surface(s)  36 . 
     The internal threads  9  revolve around the central locking hole axis  22  along one or more thread paths between the upper and bone-facing surfaces  18 ,  20  of the plate  4 . The threads  9  preferably extend continuously along the circumference of the locking surface  24   a , interrupted substantially only by the gap  124 . In other embodiments, the threads  9  can extend non-continuously along the circumference of the locking surface  24   a.  It should be appreciated that the threads  9  can be configured similar to those disclosed in U.S. patent application Ser. No. 16/437,105, filed Jun. 11, 2019, in the name of Oberli et al. (“the &#39;105 Reference” [7683]), and U.S. patent application Ser. No. 17/062,708, filed Oct. 5, 2020, in the name of Oberli et al. (“the &#39;708 Reference”), the entire disclosures of each of which are hereby incorporated by reference herein. 
     The locking surface  24   a  is preferably configured for locking with both standard-type and VA locking screws. For example, the locking surface  24   a  can define at least one column  26 , and preferably also defines at least portions of additional columns  26  sequentially located about a circumference of the locking surface  24   a.  The locking surface  24   a  can also define a plurality of recesses  28  sequentially located circumferentially between the column  26  and the at least the portions of the additional columns  26 . As shown in  FIG. 1C , the locking surface  24   a  can define a first column  26   a,  at least a portion of second column  26   b,  and at least a portion of a third column  26   c.  In the present embodiment, the remainder of the second and third columns  26   b,    26   c  have effectively been removed by the intersection of the locking and compression holes  6 ,  92 . Thus, the intersection boundary  119  traverses portions of the second and third columns  26   b,    26   c.  For example, the intersection boundary  119  can traverse entireties of the second and third columns  26   b,    26   c  with respect to the circumferential direction C 1 . Moreover, at least some of the threads  9  along each of the first and second sides  31 ,  33 , such as threads  9  that traverse the second and third columns  26   b,    26   c,  preferably extend to the intersection boundary  119  such that interface edges between the locking surface  24   a  and the compression surface  24   b  include edges of fully formed thread profiles (i.e., from root to crest) of the threads  9 . 
     The first, second, and third columns  26   a - c  can each be centered along a respective column centerline  43  as viewed in a horizontal plane X-Y. The columns centerlines  43  are preferably oriented to intersect the central locking hole axis  22 . With respect to any column  26  that effectively has a portion removed by the intersection of the locking and compression holes  6 ,  92 , it should be appreciated that the column centerline  43  extends along the theoretical center of the column  26  (i.e., the center of the theoretical complete column  26 ). The column centerlines  43  are preferably evenly spaced along the circumference of the locking surface  24   a,  as shown. In the present embodiment, the column centerlines  43  of the first, second, and third columns  26   a - c  are located at about 120-degree intervals about axis  22 . In other embodiments, the columns  26  can be un-evenly spaced along the circumference of the locking surface  24   a.    
     Each column  26  can define a first surface  42  substantially facing the central locking hole axis  22 . The first surface  42  can also be referred to as an “innermost surface” of the column  26 . Thus, the first surface  42  defines crests of the threads  9 . The first surface  42  of each column  26  extends between a first side  44  and a circumferentially opposed second side  45  of the column  26 , with the column centerline  43  equidistantly spaced therebetween. The portions of the internal threads  9  that traverse the columns  26   a - c  are configured to provide the primary locking threaded engagement (intermeshing) with the exterior threads on the head of the locking screw. The first and second sides  44 ,  45  of each column  26  can define interfaces between the column  26  and the circumferentially adjacent recesses  28 . The plate threads  9  extend through the columns  26  and at least portions of the recesses  28 . For example, the threads  9  can circumferentially traverse each of the columns  26  and recesses  28  in an uninterrupted fashion along the circumference of the locking surface  24   a.  The internal threads  9 , columns  26 , and recesses  28  can be configured as more fully described in the &#39;708 Reference. 
     The locking hole  6  defines a hole shape (also referred to as a “horizontal hole profile” or “hole profile”) in a horizontal reference plane X-Y. It should be appreciated that the horizontal hole profiles referred to herein specifically refer to a theoretical shape of a “base version” of the locking hole  6 , meaning a theoretical version of the locking hole  6  that is not intersected by a compression hole  92 . In the present embodiment, at least an axial portion of the locking hole  6  has a generally polygonal horizontal hole profile. In particular, the locking hole  6  of the present embodiment has a trigon (i.e., generally triangular) horizontal profile, although in other embodiments the locking hole  6  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 first column  26   a  of the present embodiment is aligned with the longitudinal axis  97 . The threads  9  also preferably extend along respective thread path(s) that corresponds to the horizontal profile of the locking hole  6 . In the illustrated embodiment, the first surfaces  42  of the columns  26  have linear horizontal profiles corresponding to “sides” of the trigon, while the recesses  28  effectively define the “corners” of the trigon, each as viewed in the horizontal reference plane X-Y. Accordingly, the columns  26  and recesses  28  of the present embodiment can also be referred to respectively as “sides” and “corners”  28  of the trigon-shaped locking hole  6 . 
     The locking hole  6  defines a locking hole radius R 1  measured orthogonally from the central locking hole axis  22  to the first surfaces  42  of the respective columns  26  (or to the theoretical first surface  42  of any column  26  interrupted by the intersection boundary  119 , such as the second and third columns  26   b,    26   c  in the illustrated embodiment). The locking hole  6  also defines a lateral dimension Y 1  measured along a lateral locking hole axis  23  that is oriented along the lateral direction Y and intersects the central locking hole axis  22 . 
     Referring now to  FIG. 1D , in a cross-sectional reference plane that extends along axes  22  and  97  (and thus along the longitudinal and transverse directions X, Z), crests of the threads  9  extend along a crest trajectory axis  46 . In the present embodiment, the crest trajectory axis  46  is linear, and can be oriented at an acute crest trajectory angle A 1  relative to the central hole axis  22 . The crest trajectory angle A 1  can be in a range of about 5 degrees to about 30 degrees, and more particularly in a range of about 10 degrees to about 20 degrees, and preferably in a range of about 13 degrees to about 17 degrees. 
     The combi-hole  90  defines a reference midplane P 1  that is orthogonal to the central locking hole axis  22  and intersects axis  22  at a location thereof that is equidistantly spaced between the upper and bone-facing surfaces  18 ,  20  with respect to the transverse direction Z. Because the respective geometries of the locking hole  6  and the compression hole  92  change along the hole depth, the reference midplane P 1  is a particularly useful reference feature for discussing dimensional features of the locking and compression holes  6 ,  92 . For example, although the locking hole radius R 1  and the lateral dimension Y 1  can be measured at any hole depth, the following discussion of these dimensions refers to their respective measurements in the reference midplane P 1 . 
     With continued reference to  FIG. 1D , the compression hole  92  include a primary surface portion  96  of the compression surface  24   b.  The primary surface portion  96  is also referred to herein as a “countersink”  96 . The countersink  96  extends axially downward into the compression hole  92  from the upper perimeter  30   b  toward one or more secondary surface portions  98  of the compression surface  24   b,  which in turn extend axially downward to the lower perimeter  32   b.  An intermediate perimeter  30   c  of the compression surface  24   b  can define an interface between the countersink  96  and the one or more secondary surface portions  98 . Accordingly, the intermediate perimeter  30   c  of the compression surface  24   b  can also define a lower perimeter of the countersink  96 , and can thus also be referred to herein as the “lower countersink perimeter”  30   c.  As shown in  FIGS. 1B-1C , the countersink  96  extends along the circumferential direction C 2  from the intersection boundary  119  on the first side  31  of the combi-hole  90  to the intersection boundary  119  on the second side  33  of the combi-hole  90 . Preferably, at least an entirety of the countersink  96  outside the hole intersection zone  120  is smooth and unthreaded. 
     As shown in  FIG. 1D , the countersink  96  preferably has a concave surface profile in a refence plane that extends along the central compression hole axis  94 . For example, in a longitudinal reference plane  99  ( FIG. 1B ) that extends along the intersection axis  97  and axis  94  (and thus along the longitudinal and transverse directions X, Z), the surface profile of the countersink can be defined by a segment of a circle having radius R 2 , which can also be referred to herein as the “countersink profile radius” R 2 . The countersink profile radius R 2  can be substantially constant along at least a circumferential portion of the countersink  96 . For example, in the illustrated embodiment, the countersink profile radius R 2  can be substantially constant along a circumferential portion  96   a  of the countersink  96  that extends between the second end  93  and a first lateral reference plane  94   a  extending along axis  94  (and thus along the transverse direction Z) and also along the lateral direction Y. The surface profile of the countersink  96  along circumferential portion  96   a  preferably corresponds to the exterior surface of the head of the compression screw, as described in more detail below. Additionally, the surface profile of the countersink  96  can vary along one or more circumferential portions thereof, as described in more detail below. 
     As shown in  FIGS. 1B and 1C , the compression hole  92  defines a hole shape (or “horizontal hole profile” or “hole profile”) in a horizontal reference plane X-Y. Similar to the locking hole  6  described above, the “horizontal hole profile” of the compression hole  92  refers specifically to a theoretical shape of a “base version” of the compression hole  92 , meaning a theoretical version of the compression hole  92  that is not intersected by a locking hole  6 . For example, the compression hole  92  can have a hole profile that is generally circular, round, oval, elliptical, obround (i.e., a rectangle with semicircles at opposite ends, also referred to as a “stadium” or “discorectangle”), or a shape having various features of the foregoing. 
     With specific reference to the illustrated embodiment, the compression hole  92  has an obround-like hole profile. It should be appreciated that this embodiment is provided as a non-limiting example of intersecting locking hole  6  and compression hole  92  geometries to provide dynamic compression in a direction from the compression hole  92  toward the locking hole  6 . In this embodiment, the compression hole  92  defines a second axis  95  that is parallel with the central compression hole axis  94 . The second axis  95  intersects the intersection axis  97  as a location thereof between axis  22  and  94  (and thus within the intermediate zone  115 ). The second axis  95  is spaced from axis  94  at a distance LA 2  along the intersection axis  97 . A second lateral reference plane  95   a  extends along axis  95  (and thus along the transverse direction Z) and along the lateral direction Y. Along circumferential portion  96   a,  the countersink  96  has a semi-circular hole profile, which preferably is complimentary with the exterior surface of the head of the compression screw. In this manner, the head can engage circumferential portion  96   a  of the countersink  96  in complimentary fashion when fully seated within the compression hole  92 . In this longitudinal region (along circumferential portion  96   a ), the upper and lower perimeters  30   b ,  30   c  extend circumferentially along parallel curves. In a longitudinal region  96   b  between reference planes  94   a  and  95   a,  the upper perimeter  30   b  can transition to a horizontal profile that deviates from that of the lower countersink perimeters  30   c.  In particular, in region  96   b,  the lower countersink perimeter  30   c  extends parallel with itself along the first and second sides  31 ,  33  of the combi-hole  90 . In the hole intersection zone  120 , the lower countersink perimeter  30   c  extends again along a semi-circular hole profile. Within the longitudinal region between reference planes  94   a  and  95   a,  the upper perimeter  30   b  extends from reference plane  94   a  to opposite transition locations  94   b  on the first and second sides  31 ,  33  of the combi-hole  90 . At these transition locations  94   b,  the upper perimeter  30   b  transitions to linear paths that converge toward each other at an acute angle as they extend to the intersection boundary  119 . In this manner, from the transition locations  94   b  to the intersection boundary  119 , the upper perimeter  30   b  effectively defines the non-parallel sides of an isosceles trapezoid. For example, moving from the second end  93  toward the first end  91  of the combi-hole  90 , the upper perimeter  30   b  approaches the transition locations  94   b  along a circular path and exits the transition locations  94   b  along respective tangent lines (i.e., tangent to the circular path at which the upper perimeter  30   b  intersects transition locations  94   b ). 
     The foregoing intersecting geometries of the countersink  96  and the locking surface  24   a  are favorable for causing dynamic compression when a compression screw is inserted eccentrically within the intermediate zone  115  (that is, inserted along an insertion axis  52  located between axis  22  and axis  94 ). As shown, in the hole intersection zone  120 , the countersink  96  intersects and thus truncates portions of the threads  9  on the first and second sides  31 ,  33 . It should be appreciated that the intersection boundary  119  can extend beyond the intermediate zone  115  toward the first end  91  of the combi-hole  90 . In other embodiments, the intersection boundary  119  can be entirely located within the intermediate zone  115 . 
     The intersecting geometries of the countersink  96  and the locking surface  24   a  along the intersection boundary  119  defines guide formations  55  opposite each other on the first and second sides  31 ,  33  of the combi-hole  90 . The guide formations  55  can also be referred to herein as “chamfers”, “ramps” or “rails”. The guide formations  55  are configured to provide dynamic compression (i.e., to translate the plate  4 ) in a first translation direction T 1  responsive to engagement (i.e., contact) with the head of a compression screw inserted along an eccentric screw insertion axis  52  located between axis  22  and  94  (i.e., within the intermediate zone  115 ). In particular, the guide formations  55  define contact interfaces or paths between the interior surface  24  of the combi-hole  90  and the head of the compression screw. The guide formations  55  extend along respective guide axes  56  that extend along the intersection boundary  119  on the first and second sides  31 ,  33  of the combi-hole  90 . In the illustrated embodiment, the guide axes  56  are shown intersecting the respective roots along the intersection boundary  119 . As shown in  FIG. 1C , the guide axes  56  can be linear as viewed orthogonally from a horizontal reference plane X-Y. In such embodiments, the guide axes  56  on the opposite sides  31 ,  33  of the combi-hole  90  can each define a horizontal guide angle A 2 , as measured between the respective guide axis  56  and the intersection axis  97  in the horizontal reference plane X-Y. The horizontal guide angle A 2  can be in a range from about 10 degrees to about 80 degrees, and more particularly in a range from about 25 degrees to about 65 degrees, and more particularly in a range from about 40 degrees to about 50 degrees. In other embodiments, at least a portion of, and up to an entirety of, each horizontal guide axis  56  can extend along a curved path as viewed orthogonally from a horizontal reference plane X-Y. In such embodiments, the horizontal guide angle A 2  can be measured from the intersection axis  97  to a reference tangent line that intersects the guide axis  56  at the reference midplane P 1 . 
     The guide formations  55  each have at least a directional component in the offset direction (i.e., the second longitudinal direction X 2 ), thus guiding the first translation direction T 1  such that it has at least a directional component in the first longitudinal direction Xl, at least when the insertion axis  52  is offset from axis  22  at least at a minimum offset distance  0  in the second longitudinal direction X 2 . Accordingly, the second longitudinal direction X 2  of the present embodiment can also be referred to as the “offset direction”. The minimum offset distance O refers to the shortest offset distance that will result in dynamic compression in the first longitudinal direction X. The minimum offset distance O can be defined as the shortest distance between the central locking hole axis  22  and the guide formations  55  along the longitudinal direction X. Stated differently, the minimum offset distance O can be the shortest longitudinal distance from the central locking hole axis  22  to the hole intersection zone  120  (i.e., to the intersection boundary  119 ). The minimum offset distance O can be reduced or increased by narrowing or widening, respectively, the horizontal guide angle A 2 . In this manner, the guide formations  55  are preferably configured to direct or “funnel” or otherwise influence the translation direction T 1  in the first longitudinal direction X 1  as the head advances axially downward within the combi-hole  90 , including when the insertion axis  52  is also laterally offset from (i.e., spaced from the intersection axis  97  along the lateral direction Y). It should be appreciated that higher axial loads on the screw head and/or higher torques on the screw head during screw insertion into underlying bone can require steeper (i.e., wider) horizontal guide angles A 2  to enhance sliding (i.e., dynamic compression) performance of the plate  4 . Additionally, the combi-hole  90 , particularly the countersink  96  and intersection boundary  119  thereof, are preferably configured such that the plate  4  translation results in the central compression hole axis  94  being substantially colinear with the central axis  52  of the compression screw when the head is fully seated in the compression hole  92 . 
     A ratio of the axis separation distance LA 1  to the hole length L can be in a range from about 0.24:1 to about 0.50:1, and more particularly in a range from about 0.30:1 to about 0.38:1, and preferably in a range from about 0.33 to about 0.35. A ratio of the radius R 1  to the axis separation distance LA 1  is in a range from about  0 .75:1 to about 1.25:1, and more particularly in a range from about 0.85:1 to about 1.15:1, and more particularly in a range from about 0.98:1 to about 1.02:1. A ratio of the minimum offset distance O to radius R 1  (as measured in the reference midplane P 1 ) is in a range from about 0.0:1 to about 0.95:1, and more particularly in a range from about 0.125:1 to about 0.225:1, and more particularly in a range from about 0.16:1 to about 0.20:1. 
     Referring now to  FIG. 2 , an example embodiment of a bone plate  4  is shown having a plurality of combi-holes  90  according to the present disclosure. The plate  4  has a first end  10  and a second end  12  spaced from each other along the longitudinal direction X. The plate  4  defines a longitudinal axis  3  oriented along the longitudinal direction X. The combi-holes  90  can be arranged in the plate  4  in a manner providing the plate  4  with multi-directional dynamic compression. For example, the combi-holes  90  can be arranged in a first group of combi-holes  90  along a first longitudinal region  4   a  of the plate  4  and a second group of combi-holes  90  along a second longitudinal region  4   b  of the plate  4 . In this example, the first and second longitudinal regions  4   a,    4   b  extend to a common boundary at a longitudinal midpoint XM of the plate  4 . Each combi-hole  90  of the first group is oriented to provide dynamic compression (i.e., to translate the plate  4 ) in a first translation direction T 1 , such as in the longitudinal direction X 1  extending from the first end  10  to the second end  12  of the plate  4 . Each combi-hole  90  of the second group is oriented to provide dynamic compression in a second translation direction T 2 , such as in the longitudinal direction X 2  extending from the second end  12  to the first end of the plate  4 . It should be appreciated that the arrangement and orientation of the combi-holes  90  can be adapted as needed to provide the plate  4  with dynamic compression capabilities in various directions according to the needs of a particular surgical treatment. 
     Referring now to  FIGS. 3A and 3B , methods of using a combi-hole  90  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  7  in the intermediate zone  115  of the combi-hole  90 . During the bone plating operation, a physician can insert a shaft  25  of a compression screw  7  through the combi-hole  90  along an insertion axis  52  and drive the shaft  25  into underlying bone, such as a bone segment  100 . In this example, the physician can cause the insertion axis  52  to be offset from the central locking hole axis  22  by a first offset distance O 1  in an offset direction B 1  (which is the second longitudinal direction X 2  in this example). As shown in  FIG. 3A , the physician can further drive the shaft  25  along the insertion axis  52  in a manner causing an outer surface  74  of the head  27  of the compression screw  7  to contact the interior surface  24  of the combi-hole  90  at a first position of the screw head  27  with respect to the interior surface  24 . At the first position ( FIG. 3A ), the outer surface  74  of the screw head  27  contacts the interior surface  24  at a first initial contact location  75 , such as at a pair of contact locations  75  along the intersection boundary  119  (see  FIG. 1C ). 
     As shown in  FIG. 3B , after the outer surface  74  of the head  27  contacts the interior surface  24  at the first initial contact location  75  ( FIG. 3A ), the physician can further drive the compression screw  7  axially downward along the insertion axis  52 , causing the outer surface  74  of the head  27  to travel or ride along the guide formations  55  to a second position of the screw head  27  relative to the interior surface  24 , which can be a fully seated position of the screw head  27  against the countersink  96 . In the fully seated position, the central axis  52  of the compression screw  7  is preferably colinear with the central compression hole axis  94 . It should be appreciated that the translation distance X 3  is substantially determined by the offset distance O 1 . For maximizing the translation distance X 3 , the physician can select an offset distance O 1  that is substantially equivalent to the minimum offset distance O. The translation distance X 3  decreases as the offset distance O 1  increases. In this manner, the physician can select the suitable offset distance O 1  to achieve the desired translation distance X 3  for the bone plate  4  relative to the underlying bone segment  100 . The interfacing geometries of the head  27  and the interior surface  24  of the combi-hole  90 , such as along the guide formations  55 , can provide a maximum translation distance X 3  that is greater than the minimum offset distance O at a ratio in a range from about 1:1 to about 5:1, and more particularly in a range from about 2.25:1 to about 4.0:1, and more particularly in a range from about 3.0:1 to about 3.4:1. In this manner, the physician can manipulate bone plate  4  in the translation direction T 1  in a manner reducing a gap G 1  ( FIG. 3A ) between the bone segment  100  and an adjacent bone segment  102 . 
     The combi-holes  90  of the present disclosure are versatile in that the first side  91  of the combi-hole  90  can be used to achieve dynamic compression in a second translation direction having at least a directional component in the second longitudinal direction X 2 . Such dynamic compression can be achieved by inserting the compression screw  7  along an insertion axis  52  at an offset distance between axis  22  and the first end  91  of the combi-hole, similar to the manner described more fully in U.S. Patent Application Ser. No. 63/107,699, filed Oct. 30, 2020, in the name of Aebi et al. (“the &#39;699 Reference”), the entire disclosure of which is hereby incorporated by reference herein. 
     It should be appreciated that the configuration of the combi-holes  90  described herein provides numerous additional options for dynamic compression, including along other translation directions. For example, dynamic compression can be achieved to translate the plate  4  in the second longitudinal direction X 2  by inserting the compression screw  7  along an insertion axis  52  offset from the central compression hole axis  94  in the second longitudinal direction X 2 . 
     The plate body  5 , compression screws  7 , and locking screws described herein can each comprise one or more biocompatible materials. By way of non-limiting examples, the plate body  5  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  7  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-6Al-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  7  and locking screw ha a hardness that is greater than that of the material of the plate body  5 . This parameter contributes to the threaded locking characteristics and the dynamic compression characteristics described throughout the present disclosure. Preferably, the plate body  5  primarily or entirely comprises titanium and the compression screws  7  and locking screws primarily or entirely comprise TAN. It should be appreciated, however, that other material compositions of the bone plates  4  and/or the screws are within the scope of the present disclosure. 
     Moreover, surfaces of the plate body  5  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 &#39;105 and &#39;708 References. 
     It should be appreciated that the various parameters of the combi-holes  90  described above are provided as exemplary features for adapting the combi-holes  90  to achieve selective dynamic compression or locking engagement with the heads of respective compression screws and locking screws. These parameters can be adjusted as needed without departing from the scope of the present disclosure. 
     It should also be appreciated that in additional embodiments, the interior surface  24  of any combi-hole  90  can be defined by an insert plate body (e.g., an “insert” or “inlay”) that is fitted within an axial aperture or receptacle of the plate body  5 . In such embodiments, the bone plate  4  can be provided in a kit that includes a plurality of interchangeable inserts having different combi-hole shapes and geometries, such that the physician can select the particular insert having the desired dynamic compression characteristics needed. 
     Although the disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present disclosure is not intended to be limited to the particular embodiments described in the specification. In particular, one or more of the features from the foregoing embodiments can be employed in other embodiments herein. As one of ordinary skill in the art will readily appreciate from that processes, machines, manufacture, composition of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure.