Title of Invention	BONE PLATE
Abstract	A bone plate (10) has an upper surface (20), a lower surface (22), and at least one first hole (90) extending through the upper and lower surfaces. The first hole (90) has two or three vertically separate regions, each region communicating with or abutting the adjacent region. The first hole (90) has a first upper region (92), which is unthreaded and which, from the plate's upper surface (20) to the plate's lower surface (22), has a curved inward taper. The first hole (90) has a second middle region (94), which is threaded and which, from the plate's upper surface (20) to the plate's lower surface (22), has a conical inward taper. The first hole (90) has a third lower region, (96), which is unthreaded and which, from the plate's upper surface (20) to the plate's lower surface (22), has a conical outward taper. The bone plate (10) is straight, curved, or both straight and curved. The bone plate (10) may have at least one second hole, different from the first hole. The second hole is an elongated hole, which has a compression ramp or which has a threaded portion through part of its perimeter and a non-threaded portion through the other part of its perimeter.

Title of Invention

BONE PLATE

Abstract

A bone plate (10) has an upper surface (20), a lower surface (22), and at least one first hole (90) extending through the upper and lower surfaces. The first hole (90) has two or three vertically separate regions, each region communicating with or abutting the adjacent region. The first hole (90) has a first upper region (92), which is unthreaded and which, from the plate's upper surface (20) to the plate's lower surface (22), has a curved inward taper. The first hole (90) has a second middle region (94), which is threaded and which, from the plate's upper surface (20) to the plate's lower surface (22), has a conical inward taper. The first hole (90) has a third lower region, (96), which is unthreaded and which, from the plate's upper surface (20) to the plate's lower surface (22), has a conical outward taper. The bone plate (10) is straight, curved, or both straight and curved. The bone plate (10) may have at least one second hole, different from the first hole. The second hole is an elongated hole, which has a compression ramp or which has a threaded portion through part of its perimeter and a non-threaded portion through the other part of its perimeter.

Full Text	BONE PLATE CROSS-REFERENCE TO RELATED APPLICATIONS [001] The present application is a continuation-in-part of United States Patent Application Serial No. 10/843,113, filed on May 11, 2004, the entire contents of which is expressly incorporated herein by reference thereto. FIELD OF THE INVENTION [002] The present invention relates generally to devices for bone fracture fixation and more specifically, to bone plates and systems for stabilization and/or compression of bone fractures. BACKGROUND OF THE INVENTION [003] The use of bone plate and screw systems for treatment of bone fractures is widespread. Conventional bone plate and screw systems promote healing of a fracture by compressing the fracture ends together and drawing the bone fragments into close apposition with each other. If the plate is not provided with the appropriate hole types adapted to receive the proper screw types, then the angular relationships between the plate and screws may change postoperatively. This can lead to management and poor clinical results. [004] Among the various different types of bone plate holes that are known in the art are the two different types of holes described below, each hole primarily intended for use with a different type of bone screw. [005] The first type of hole is a non-threaded relatively smooth hole, through which a screw with a smooth (non-threaded) head is inserted. These screws do not lock with the bone plate and are thus referred to as "non-locking" screws. Because non-locking screws do not lock with the plate hole, non-locking screws are not limited to a fixed angle with respect to the plate, but rather can be inserted at numerous angles. Inserting non-locking screws through the non-threaded plate holes and threading them into the bone effectively provides the desired compression of fracture ends. [006] The second type of hole is an internally threaded hole, which is adapted to mate with a screw having an externally threaded head. The threaded-head or "locking" screw is inserted at a fixed, predetermined angular relationship (determined by the central axis of the threaded hole) with respect to the bone plate. Locking screws, when mated with threaded bone-plate holes, possess high resistance to shear and tensional forces. Locking screws therefore resist loosening and thereby ensure stability between the screw and the bone plate. [007] Bone plates having both of the aforementioned types of holes are therefore desirable and are well known. Surgeons are limited, however, by the manufacturers' placement of the varying holes on a given bone plate. A surgeon can achieve optimal compression when using a screw (e.g., a non-locking screw) without locking it to the plate. A surgeon can achieve desired stability between the screw, plate, and bone when using a locking screw with an internally-threaded hole. [008] It would thus be advantageous for a hole in a bone plate to be adapted to receive, at the surgeon's election, either non-locking screws for obtaining optimal compression or locking-screws for obtaining optimal stability, while minimizing any compromise in the strength of the bone plate. SUMMARY OF THE INVENTION 1009] The bone plate of present invention is a bone plate used for bone fracture fixation. Various embodiments of a bone plate having coaxial combination holes are described. [0010] Among the various different types of bone plate holes that are known in the art are threaded holes and non-threaded holes. "Locking" screws (screws with threaded heads) are typically used with threaded holes. Locking screws, when mated with threaded holes, possess high resistance to shear and torsional forces and therefore ensure stability between the screw and bone plate. "Non-locking" screws are typically used with unthreaded holes and, unlike locking screws that mate with threaded holes, may be inserted at any one of a number of angles. Non-locking screws provide optimal compression of fractured ends. [0011] A coaxial combination hole is, at once, adapted to receive (and utilize the benefits of) either a locking screw or non-locking screw. A coaxial combination hole is a hole which is threaded only partially through its length. In one preferred embodiment, the hole has a generally circular cross section with varying hole diameter. In a preferred embodiment, the hole has three regions: an upper region, a middle region, and a lower region. The upper region may be unthreaded and may have, in a direction from the plate's upper surface to its lower surface, a curved inward taper. The middle region may be threaded and may have, in a direction from the plate's upper surface to its lower surface, a conical inward taper. The lower region may be unthreaded and may have, in a direction from the plate's upper surface to its lower surface, an outward taper. [0012] It will be appreciated that either type of the aforementioned screws may be used (and produce its intended results) with a coaxial combination hole. The threaded head of a threaded-head screw may mate with threaded middle region of the hole. Alternatively, a screw with an unthreaded head (or even a screw with a threaded head) may be inserted through a coaxial combination hole, without any mating of any threads, at any one of a number of angles. The outward taper of the coaxial combination hole's lower region provides room for the screw's shaft to be inserted an angle (with respect to the center of the hole). Likewise the curved inward taper of the upper region of the hole provides a seat for the screw head to rest in, even when the screw is inserted ant an angle. It will be appreciated, then, that at any given coaxial combination hole, a surgeon may elect to use either a screw for screw-plate stability or a screw for compression of fracture ends. [0013] Coaxial combination holes may be placed in any type of bone plate. Coaxial combination holes provide multiple options for the surgeon. And because the holes do not require a larger cavity in the bone plate than would otherwise be necessary for an ordinary hole, the strength, size, and integrity of the bone plate are not compromised. Coaxial combination holes are therefore particularly useful in relatively small bone plates (e.g., pubic symphysis plates). [0014] A coaxial combination hole has a central axis and a vertical axis. The hole's vertical axis is perpendicular to the plane formed by the plate's upper surface (if the plate has a straight upper surface), or to the plane that is tangential to the pinnacle of the plate's upper surface (if the plate is convex). A hole may have a central axis that is parallel to its vertical axis, or that is not parallel to its vertical axis (thereby biasing the shaft of the screw in one direction or another). A plate may have holes with any combination of foregoing hole orientations. [0015] In preferred embodiments, bone plates have between 4 and 8 holes. In some embodiments, all plate holes are coaxial combination holes. In other embodiments, the bone plates may have some coaxial combination holes and at least one of another of a number of types of holes. One example of another type of hole is a dynamic compression ("DC") hole. A dynamic compression hole may be an elongated hole having an oblique portion or ramp having an inclination such that when the ramp is engaged by the underside of the head of a screw, the bone plate is displaced in a direction to move the ramp away from the non-locking screw, causing the plate to apply a pressure to hold me fracture etnas in contact or in engagement. Another example of another type of hole is a non-coaxial combination hole. A non-coaxial combination hole may be an elongated hole having a portion of its perimeter threaded and another portion of its perimeter unthreaded. In addition to, or in lieu of, the foregoing two examples, other types of holes may be formed in a bone plate having coaxial combination holes. [0016] In one embodiment of the bone plate, the plate has a longitudinal axis, and has a straight center portion and curved ends. In one embodiment, the plate has two holes in the straight portion and two holes in each of the curved end portions. In one embodiment of this plate, all six holes may be coaxial combination holes. In another embodiment of this plate, the two holes on the straight portion may be either DC holes or non-coaxial combination holes, and the four holes on the curved end portions may be coaxial combination holes. In one embodiment of this plate, the width of the bone plate is narrower where there are no holes than where there are holes. [0017] In another embodiment of the bone plate, the plate has a longitudinal axis and is straight. In one embodiment, the plate may have only coaxial combination holes, all of which may lie along the plate's longitudinal axis. [0018] In another embodiment of the bone plate, the entire plate may be curved. In one embodiment, the plate may have only coaxial combination holes, all of which may lie along the plate's longitudinal axis (which runs along the center of the plate's width). [0019] In the various embodiments, the plate's upper and lower surfaces may be straight or curved. In a preferred embodiment, the plate's upper surface may be convex, while the plate's lower surface may be concave. BRIEF DESCRIPTION OF THE DRAWINGS [0020] These figures represent preferred embodiments of the present invention. Those skilled in the art will recognize that numerous variations and modifications may be made without departing from the scope of the present invention. Accordingly, it should be understood that these figures are not intended as limitations on the scope of the invention, which is defined only by the claims. [0021] FIG. 1A is a side cross-sectional view of a first embodiment of a bone plate having coaxial combination holes. [0022] FIG. IB is a plan view of the bone plate of FIG. 1 A. [0023] FIG. 1C is a cross-sectional view of the bone plate of FIG. 1A taken along the cross section B-B. [0024] FIG. 2A is a side cross-sectional view of a second embodiment of a bone plate having coaxial combination holes and having dynamic compression holes. [0025] FIG. 2B is a plan view of the bone plate of FIG. 2A. [0026] FIG. 2C is a cross-sectional view of the bone plate of FIG. 2A taken along the cross section B-B. [0027] FIG. 3 A is a third embodiment of a bone plate having coaxial combination holes. [0028] FIG. 3B is a plan view of the bone plate of FIG. 3A. [0029] FIG. 4A is a cross-sectional view of one embodiment of a coaxial combination hole. [0030] FIG. 4B is a magnified view of a portion of the thread of the coaxial combination hole of FIG. 4A. [0031] FIG. 5 is a cross-sectional view of a screw, having a threaded head, inserted through a coaxial combination hole. [0032] FIG. 6A is a cross-sectional view of a screw, having a non-threaded head, inserted through a coaxial combination hole at one angle. [0033] FIG. 6B is a cross-sectional view of a unthreaded-head screw inserted through a coaxial combination hole at an angle different from that of the screw of FIG. 6A. [0034] FIG. 7 is a plan view of a segment of a bone plate having non-coaxial combination holes. [0035] FIG. 8 is a plan view of the bone plate of FIGS. 3A and 3B, in a curved condition. [0036] FIG. 9 is a side view of one embodiment of a screw that has a conically- tapered threaded head. [0037] FIG. 10 is a side view of one embodiment of a screw having an unthreaded head. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0038] The present invention is described below with reference to the preferred embodiments. Those skilled in the art will recognize that numerous variations and modifications may be made witliout departing from the scope of the present invention. Accordingly, it should be understood that the embodiments of the invention described below are not intended as limitations on the scope of the invention, which is defined only by the claims. [0039] Reference is now made to FIGS. 1A, 2A, and 3A, which illustrate side, cross- sectional views of various embodiments of a bone plate. The bone plates may have at least one coaxial combination hole 90, which has a length L that extends from the upper surface of the bone plate to the lower surface of the bone plate. The coaxial combination hole 90 is threaded only partially through the hole's length L. As such, with a given coaxial combination hole, a surgeon may elect to: (1) thread a screw having a thread on at least a portion of its head into and through the hole; or (2) insert a screw having an unthreaded head through the hole and into the bone. In a preferred embodiment, the hole 90 has length L of approximately 3.4mm to 4.0mm, which preferably corresponds to the thickness T of the bone plate. [0040] Reference is now made to FIGS. IB, 2B, and 3B, which illustrate plan views of various embodiments of the bone plate having at least one coaxial combination hole 90. Each bone plate may have at least a central region with a longitudinal axis L-L. Each bone plate hole 90 may have a vertical axis V-V, which is perpendicular to the plane on which the plate's upper surface lies (if the plate has a straight upper surface), or to the plane that is tangential to the pinnacle of the plate's upper surface (if the plate is convex). (See FIGS. 1A, 2A, and 3A.) [0041] Reference is now made to FIGS. 1C and 2C, which illustrate cross-sectional views of the bone plates along the respective cross sections B-B. In a preferred embodiment, the upper surface of the plate may be convex and the lower surface of the plate may be concave, as shown in FIGS 1C and 2C. In a preferred embodiment the radius of curvature for both surfaces may be from about 15mm to about 35mm, and preferably about 25mm. In another embodiment, one or both of the plate surfaces may be flat. [0042] As shown in FIG. 1 A, hole 90 may extend from the upper surface 20 to the lower surface 22 of the bone plate 10. In one embodiment, the diameters of the hole 90 at its uppermost surface and its lower most surface may be equal or close to equal. The hole 90 may be widest at the uppermost surface 20 and lowermost surface 22 of die plate 10. Each hole 90 may have a central axis C-C. (See FIGS. 1A and 2A.) In some embodiments of the hole 90, the central axis C-C of hole 90 may be parallel to the vertical axis V-V, as shown in FIG. 3A (central axis C-C not shown). In other embodiments, the central axis C-C of hole 90 will intersect with the vertical axis V-V at an angle 0, as shown in FIGS. 1A and 2A. In preferred embodiments, the angle 0 may vary from about 3° to about 17°, although other angles are contemplated. [0043] As shown in FIG. 4A, the hole 90 may have three regions: an upper region 92, a middle region 94, and a lower region 96. The upper region 92 of the hole 90 may have an unthreaded inner surface 93 which, is preferably smooth, although texturing may be provided. In a preferred embodiment, the upper region 92 may have a curved inward taper, preferably concave, more preferably spherical, from the top surface of the plate to where the upper region 92 of the hole 90 meets the middle region 94. The upper region 92 of the hole 90 is preferably narrowest where it meets the middle region 94. Preferably, the upper region is approximately 1.0mm to approximately L2mm in length (along the axis C-C). In a preferred embodiment, the upper region may comprise about 25% to about 35% of the thickness T of the plate. In one embodiment, the diameter of the upper region 92, at the region's broadest point, may be about 6mm and, at the region's narrowest point, may be about 4mm. In another embodiment the diameter of the upper region 92, at the region's broadest point, may be about 8mm and, at the region's narrowest point, may be about 6mm. [0044] The middle region 94 of the hole 90 may have a threaded inner surface 95. In one embodiment, the threads have a pitch P (as shown in FIG. 4B, which is a magnified partial view of the threaded surface 95) of approximately 0.3mm to 0.5mm. In a preferred embodiment, the thread angle γ may be approximately 50° to 70°, and preferably about 60°. In a preferred embodiment, the threaded region has at least one thread revolution, and preferably about three thread revolutions. Referring again to FIG. 4A, the threaded inner surface 95 may, in a direction from the upper surface to the lower surface, have a conical inward taper. In a preferred embodiment, the threaded inner surface 95 may taper at an angle a of approximately 5° to 15°, and preferably approximately 10°. The middle region 94 may be the narrowest region (i.e., smallest-diameter region) of the hole 90. In a preferred embodiment, the middle region 94 may be approximately 1.5mm to approximately 1.9mm in length (along the axis C-C). In a preferred embodiment, the middle region 94 may comprise about 40% to 50% of the thickness T of the plate. In one embodiment, the diameter of the middle region 94 may vary only slightly (due to the relatively shallow conical taper) and may be about 4mm or, in another embodiment, about 6mm. The diameter or taper of the middle region 94 may of course vary depending upon the size and/or taper of the screw. [0045] The lower region 96 of the hole 90 may have an unthreaded inner surface 97 which is preferably smooth, although texturing may be provided. In a preferred embodiment, the lower region 96 may, from where it meets the middle region 94 to the lower surface of the plate, have a conical outward taper. In a preferred embodiment, the lower region 96 may taper outwardly at an angle β of approximately 35° to 55°, and preferably approximately 45°. In a preferred embodiment, the lower region 96 may be approximately 0.8mm to approximately 1.2mm in length (along the axis C-C). In a preferred embodiment, the lower region 96 may comprise about 20% to 35% of the thickness T of the plate. In one embodiment, the diameter of the lower region 96, at the region's narrowest point, may be about 4mm and, at the region's broadest point, may be about 6mm. In another embodiment, the diameter of the lower region 96, at the region's narrowest point, may be about 6mm and, at the region's broadest point, may be about 8mm. [0046] Different types of screws may be used with the hole 90. One type of screw is a screw that has a conically-tapered threaded head (shown in FIG. 9). As shown in FIG. 5, the external threads of the screw's head may mate with the internal threads 95 of the middle region 94 of the hole 90. This threaded-head screw 15 may be inserted at only one angle (widi respect to the plate), which may be fixed by the threads 95 in the plate 10. [0047] A second type of screw that may be used with the hole 90 is a screw with a threaded shaft, but with an unthreaded head (shown in FIG. 10). An unthreaded-head screw may be inserted into hole 90 at any one of a number of angles. FIG. 6A illustrates an unthreaded-head screw 17 inserted at an angle substantially perpendicular to the longitudinal axis of the plate 10. FIG. 6B illustrates an unthreaded-head screw 17 inserted at a non-perpendicular angle with respect to the plate 10. The conical outward taper (shown at surface 97) of the lower region 96 of the hole 90 provides room for screw shaft 18 to be inserted at an angle with respect to the center of the hole 90. Likewise, the curved inward taper of the upper region 92 of the hole 90 provides a seat (at surface 93) for the screw head to rest in when an unthreaded-head screw 17 is inserted at an angle. A threaded-head screw may be used with a coaxial combination hole 90 in the same manner as the aforementioned unthreaded-head screw 17. [0048] Although virtually any type of bone plate may benefit from coaxial combination holes 90, coaxial combination holes are particularly useful for pubic symphysis plates and other relatively small bone plates. (The pubic syphilis is the connection between the two halves of the pubis and may be damaged as a result of an accident.) Because a surgeon may elect to use either a locking screw or a non-locking compression screw with a coaxial combination hole, a bone plate having a coaxial combination hole may be more versatile than plates having other types of holes. The benefits may include: (1) a reduced need to manufacture many different plates having varying hole arrangement patterns; and (2) enhancement of clinical results. Because a coaxial combination hole does not require a substantially larger cavity in the bone plate than would otherwise be necessary for a simple hole, a coaxial combination hole provides desired flexibility for the surgeon without unduly compromising the strength, size, or integrity of the bone plate. Plates having coaxial combination holes may thus find particular utilization in pubic symphysis plates and other relatively small bone plates. [0049] In one embodiment, the bone plate of the present invention may be a pubic symphysis plate as shown in FIG. IB, and may have a plurality of holes, all of which may be coaxial combination holes 90. In one embodiment, the plate may have a length PL of approximately 70mm to 90mm. In one embodiment, the plate may have curved ends, as shown in FIG. IB, with a radius of curvature R. In a preferred embodiment, two coaxial combination holes 90 are located on the straight center portion of the plate. In a preferred embodiment, the plate ends may curve approximately at a 45mm-55mm radius R, spamiing a 25°-35° angle 5. Preferably two coaxial combination holes 90 are placed along an arcs (on both sides of the plate's straight center portion) having a radius of curvature of about 50mm. In a preferred embodiment, the hole 90 on the curved portion adjacent to the hole 90 on the straight portion is located approximately 12°-18° on the arc away from the hole 90 on the straight portion. Likewise, the two holes 90 on either curved portion may be placed along an arc approximately 12°-18° apart from each other. In a preferred embodiment, the plate may be symmetrical from one side to the other (i.e., a mirror hole arrangement on the other side of the plate is contemplated). In a preferred embodiment, the two holes near the center of the plate may lie along the longitudinal axis L-L of the center region of the plate 10. The remaining holes may be offset from the longitudinal axis L-L, as shown in FIG. IB. [0050] In a preferred embodiment, the central axes C-C of the holes 90 are not parallel to the respective vertical axes V-V of the holes 90. In a preferred embodiment, as shown in FIG. 1A, the two holes near the center of the plate have central axes C-C oriented to bias the tips of the screws in a direction away from the center of plate. In a preferred embodiment, the angle 0 between each of these two central axes C-C and the vertical axes V-V is approximately 8° to 15°. in a preferred embodiment, as shown in FIG. 1A, each of the holes 90, that are located near the ends of the plate, has a central axis C-C oriented to bias the tips of the screws in a direction towards the center of plate. In a preferred embodiment the angle 9 between each of these central axes C-C and the vertical axes V-V is approximately 4° to 10°. [0051] In a preferred embodiment, the linear plate-surface distance dl between the edges of holes 90 may vary from hole to hole and may be approximately 10mm to 12mm. In a preferred embodiment, as shown in FIG. IB, there may be necking of the plate surface in between hole locations (i.e., the webs between the holes may be narrowed). This necking serves to achieve a desired balance between plate strength and plate size: plate strength is maximized, while plate size is minimized. In another embodiment the width of the plate between holes may be the same as the width of the plate where the holes are located. [0052] In a preferred embodiment, the plate may have at least one hole 99, preferably near the center of the plate. Holes 99 may aid in the placement of the plate onto the bone (e.g., for use with a guide wire) or may be provided as a suture hole. [0053] Generally, for all embodiments, a shorter bone plate having only a few (e.g., 4) holes may be used when the fracture is relatively small or when the patient's bone or joint (e.g., pubic symphysis) being operated on is relatively small. [0054] A plan view of a second embodiment of a pubic symphysis plate is shown in FIG. 2B. The primary difference between this embodiment and the foregoing embodiment (which is illustrated in FIGS. 1A and IB) is that the two holes near the center of the plate 30 of this embodiment are dynamic compression ("DC") holes 70 instead of coaxial combination holes 90. This embodiment of a bone plate is particularly useful when, to bring parts closer together, "extra" compression is desired. The DC holes are substantially similar to those disclosed in the specifications of United States publication No. 2002/0045901, in U.S. patent No. 6,669,701, and in reissued U.S. Patent No. RE. 31,628, the contents of which are incorporated herein by reference. As shown in FIG. 2B, DC hole 70 is elongated in a direction substantially aligned with the longitudinal axis L-L of the plate 30. As shown in FIG. 2B, DC hole 70 has an oblique portion or ramp 35 having an inclination such that when ramp 35 is engaged by the underside 13 of the head of a screw, preferably a screw having a head that is not threaded, and is preferably smooth and curved on the underside 13 which contacts the bone plate, the bone plate 30 is displaced in a direction to move ramp 35 away from the non-locking screw, causing the plate 30 to apply a pressure to hold the fracture ends in contact, preferably in engagement, along at least a portion of the fracture length. In a preferred embodiment, each of the holes 30 has a length X (illustrated in FIG. 2A) of approximately 6mm to 7mm. [0055] Alternatively, the two holes near the center of the plate 30 may be non-coaxial combination holes 40 (instead of coaxial combination holes 90 or DC holes 70). The non-coaxial combination holes are substantially similar to those disclosed in the specifications of U.S. patent No. 6,669,701 and of United States publication No. 2002/0045901, the contents of which are hereby incorporated by reference. Reference is now made to FIG. 7. FIG. 7 illustrates a bone plate having a plurality of combination holes 40, which extend from the plate's upper surface to its lower surface. The holes 40 may be elongated (e.g., in a direction substantially aligned with a longitudinal axis of the plate) and may include a threaded portion 5 and a non-threaded portion 6. The threaded portion 5 may extend over a range of greater than about 180° with respect to a center point CI. The threaded portion 5 of the hole 40 may be dimensioned and configured to engage a threaded head portion of a threaded-head bone screw, and fix the bone screw at a predetermined angle with respect to the bone plate. Preferably, the dreaded portion 5 of the hole 40 extends through the full thickness of the bone plate (i.e., from the plate's upper surface to its lower surface) thus maximizing the stability of the bone screw to bone plate interface. A threaded-head screw or a non-direaded head screw may (e.g., for compression) pass through the non-threaded portion 6 of a combination hole 40. [0056] Another embodiment of a plate having coaxial combination holes is illustrated in FIGS. 3A and 3B. In one embodiment, the plate 50 may have a plurality of holes, all of which may be coaxial combination holes 90. Each of the holes 90 may lie along the longitudinal axis L-L of the plate 50. In one embodiment, the central axis C-C of each of the holes 90 may be parallel to the corresponding vertical axis V-V of each of the holes 90, as shown in FIG. 3A (central axis C-C not shown). In a preferred embodiment, the linear plate- surface distance d2 between the edges of holes 90 may be approximately 6mm to 9mm. [0057] A variation on the aforementioned embodiment (illustrated in FIGS. 3A and 3B) is illustrated in FIG. 8. FIG. 8. is die bone plate of FIGS. 3A and 3B, in a "curved condition." Though the bone plate of FIGS. 3A and 3B may be formed of such material to allow a surgeon to preoperatively bend the plate into a desired shape, a bone plate manufactured to a bend condition may be desirable. In the human body, a ball-and-socket joint is formed by the two acetabula of the pelvis and the head of each femur. The bone plate of FIG. 9 may be especially useful for use on the posterior outer surface of a fractured acetabulum. The plate may have a radius of curvature R, which in a preferred embodiment, is about 100-115mm. [0058] While the present invention has been described with reference to the preferred embodiments, those skilled in the art will recognize that numerous variations and modifications may be made without departing from the scope of the present invention. Accordingly, it should be understood that the embodiments of the invention described above are not intended as limitations on the scope of the invention, which is defined only by the following claims. WHAT IS CLAIMED IS: 1. A bone plate comprising: an upper surface; a lower surface; and at least one first hole, the hole extending through the upper and lower surfaces, the hole having a central axis and a vertical axis, the hole having at least two vertically separate regions, wherein a first upper region of the hole is non-threaded and a second region of the hole is threaded. 2. The bone plate of claim 1, wherein the upper region and the second region are in communication with one another. 3. The bone plate of claim 2, wherein the lowest point of the upper region abuts the highest point of the second region. 4. The bone plate of claim 1, wherein the upper region is substantially smooth. 5. The bone plate of claim 1, wherein the upper region has, in a direction from the upper surface to the lower surface, an inward taper. 6. The bone plate of claim 5, wherein the inward taper is curved. 7. The bone plate of claim 6, wherein the curved inward taper is spherical. 8. The bone plate of claim 1, wherein the first hole has a substantially circular cross section. 9. The bone plate of claim 8, wherein the diameter of the circular cross section varies along the vertical axis. 10. The bone plate of claim 1, wherein the second region is, in a direction from the upper surface to the lower surface, conically tapered inward. 11. The bone plate of claim 10, wherein the second region conically tapers at a cone angle of between about 5° and 15°. 12. The bone plate of claim 1, wherein the largest diameter of the upper region is greater than the largest diameter of the second region. 13. The bone plate of claim 1, wherein the smallest diameter of the upper region is substantially equal to the largest diameter of the second region. 14. The bone plate of claim 1, wherein the hole has a third vertically separate lower region. 15. The bone plate of claim 14, wherein the lower region communicates with the second region. 16. The bone plate of claim 15, wherein the lowest point of the second region abuts the highest point of the lower region. 17. The bone plate of claim 16, wherein the lower region is non-threaded. 18. The bone plate of claim 17, wherein the lower region is substantially smooth. 19. The bone plate of claim 17, wherein the lower region is, in a direction from the upper surface to the lower surface, tapered outward. 20. The bone plate of claim 19, wherein the outward taper of the lower region is conical. 21. The bone plate of claim 19, wherein the lower region conically tapers at a cone angle of between about 40° and 50°. 22. The bone plate of claim 19, wherein the largest diameter of the lower region is greater than the largest diameter of the second region. 23. The bone plate of claim 19, wherein the smallest diameter of the lower region is substantially equal to the smallest diameter of the second region. 24. The bone plate of claim 19, wherein the largest diameter of the lower region is substantially equal to the largest diameter of the upper region. 25. The bone plate of claim 1, further comprising at least one second hole, different from the first hole. 26. The bone plate of claim 25, wherein the second hole is elongated and extends through the upper and lower surfaces. 27. The bone plate of claim 26, wherein the second hole is non-threaded and has an outer perimeter, at least a portion of the outer perimeter tapering inward from the upper surface to the lower surface of the plate to form at least one ramp surface for engagement with a screw head. 28. The bone plate of claim 26, the second hole having a center point and wherein the second hole includes a threaded portion and a non-threaded portion, and the threaded portion extends through an angle of between about 190° and about 280° with respect to the center point. 29. The bone plate of claim 26, wherein the second hole is elongated in a direction that is substantially aligned with the longitudinal axis of the plate. 30. The bone plate of claim 29, wherein the plate comprises at least two first holes and at least two second holes. 31. The bone plate of claim 30, wherein the bone plate is elongated, substantially straight, and has a longitudinal axis. 32. The bone plate of claim 30, wherein the bone plate has a straight portion and a curved portion. 33. The bone plate of claim 32, wherein die plate is straight near its center along the plate's longitudinal axis and curved at its ends. 34. The bone plate of claim 33, wherein the curved portion has a radius of curvature between about 40mm and about 60mm. 35. The bone plate of claim 33, wherein two second holes are located adjacent to one another in the straight portion. 36. The bone plate of claim 35, wherein at least one first hole is located on the curved portion on a first side of a plate, and at least another first hole located on the curved portion on die opposite second side of the plate. 37. The bone plate of claim 36, wherein at least one first hole is located adjacent to a second hole. 38. The bone plate of claim 37, wherein the at least one first hole located adjacent to the second hole is separated from the second hole at a distance equaling about 12° to about 18° on the curved portion. 39. The bone plate of claim 37, wherein a first hole is located adjacent to another first hole. 40. The bone plate of claim 39, wherein the two first holes are separated from each other at a distance equaling about 12° to about 18° on the curved portion. 41. The bone plate of claim 40, wherein the central axis of at least one first hole is not parallel to the vertical axis of the at least one first hole. 42. The bone plate of claim 41, wherein die angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 4° and 10°. 43. The bone plate of claim 41, wherein the angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 13° and 17°. 44. The bone plate of claim 1, wherein the central axis of the at least one first hole is not parallel to the vertical axis of that hole, forming a first angle, and the central axis of at least one other first hole is not parallel to the vertical axis of that hole, creating a second angle different from the first angle. 45. The bone plate of claim 44, wherein the first angle is between about 4° and 10° and the second angle is between about 13° and 17°. 46. The bone plate of claim 1, wherein a plurality of first holes are located along the longitudinal axis of the plate. 47. The bone plate of claim 46, wherein the plate is substantially straight. 48. The bone plate of claim 46, wherein the plate is curved, having a radius of curvature between about 80mm to about 140mm. 49. A bone plate system comprising: a bone plate having: an upper surface; a lower surface; and at least one first hole, the hole extending through the upper and lower surfaces, the hole having a central axis and a vertical axis, the hole having at least two vertically separate regions, wherein a first upper region of the hole is non-threaded and a second region of the hole is threaded; and at least one fastener to fasten the bone plate to the bone. 50. The bone plate system of claim 49, wherein the upper region has, in a direction from the upper surface to the lower surface, a curved inward taper. 51. The bone plate of claim 1, wherein the first hole has a substantially circular cross section. 52. The bone plate of claim 51, wherein the diameter of the circular cross section varies along the vertical axis. 53. The bone plate of claim 49, wherein the second region is, in a direction from the upper surface to the lower surface, conically tapered inward. 54. The bone plate of claim 53, wherein the second region conically tapers at a cone angle of between about 5° and 15°. 55. The bone plate of claim 1, wherein the hole has a third vertically separate lower region. 56. The bone plate of claim 55, wherein the lowest point of the second region abuts the highest point of the lower region. 57. The bone plate of claim 55, wherein the lower region is non-threaded. 58. The bone plate of claim 55, wherein the lower region is substantially smooth. 59. The bone plate of claim 57, wherein the lower region is, in a direction from the upper surface to the lower surface, conically tapered outward. 60. The bone plate of claim 59, wherein the lower region conically tapers at a cone angle of between about 40° and 50°. 61. The bone plate of claim 49, further comprising at least one second hole, different from the first hole. 62. The bone plate of claim 61, wherein the second hole is elongated and extends through the upper and lower surfaces. 63. The bone plate of claim 62, wherein the second hole is non-threaded and has an outer perimeter, at least a portion of the outer perimeter tapering inward from the upper surface to the lower surface of the plate to form at least one ramp surface for engagement with a screw head. 64. The bone plate of claim 62, the second hole having a center point and wherein the second hole includes a threaded portion and a non-threaded portion, and the threaded portion extends through an angle of between about 190° and about 280° with respect to the center point. 65. The bone plate of claim 62, wherein the second hole is elongated in a direction that is substantially aligned with the longitudinal axis of the plate. 66. The bone plate of claim 65, wherein the plate comprises at least two first holes and at least two second holes. 67. The bone plate of claim 66, wherein the bone plate is elongated, substantially straight, and has a longitudinal axis. 68. The bone plate of claim 66, wherein the bone plate has a straight portion and a curved portion. 69. The bone plate of claim 68, wherein the plate is straight near its center along the longitudinal axis and curved at its ends. 70. The bone plate of claim 69, wherein the curved portion has a radius of curvature of about 50mm. 71. The bone plate of claim 70, wherein two second holes are located adjacent to one another in the straight portion. i. 72. The bone plate of claim 68, wherein at least one first hole is located on the curved portion on a first side of a plate, and at least another first hole located on the curved portion on the opposite second side of the plate.. 73. The bone plate of claim 49, wherein the central axis of at least one first hole is not parallel to the vertical axis of the at least one first hole. 74. The bone plate of claim 73, wherein the angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 4° and 10°. 75. The bone plate of claim 73, wherein the angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 13° and 17°. 76. The bone plate of claim 49, wherein the central axis of the at least one first hole is not parallel to the vertical axis of that hole, forming a first angle, and the central axis of at least one other first hole is not parallel to the vertical axis of the hole, creating a second angle different from the first angle. 77. The bone plate of claim 76, wherein the first angle is between about 4° and 10° and the second angle is between about 13° and 17°. 78. The bone plate of claim 49, wherein a plurality of first holes are located along the longitudinal axis of the plate. 79. The bone plate of claim 78, wherein the plate is substantially straight. 80. The bone plate of claim 79, wherein the plate is curved. 81. The bone plate of claim 80, where in the plate is curved at a radius between about 80mm to about 140mm.

Full Text

BONE PLATE
CROSS-REFERENCE TO RELATED APPLICATIONS
[001] The present application is a continuation-in-part of United States Patent
Application Serial No. 10/843,113, filed on May 11, 2004, the entire contents of which is expressly incorporated herein by reference thereto.
FIELD OF THE INVENTION
[002] The present invention relates generally to devices for bone fracture fixation
and more specifically, to bone plates and systems for stabilization and/or compression of bone fractures.
BACKGROUND OF THE INVENTION
[003] The use of bone plate and screw systems for treatment of bone fractures is
widespread. Conventional bone plate and screw systems promote healing of a fracture by
compressing the fracture ends together and drawing the bone fragments into close apposition
with each other. If the plate is not provided with the appropriate hole types adapted to
receive the proper screw types, then the angular relationships between the plate and screws
may change postoperatively. This can lead to management and poor clinical results.
[004] Among the various different types of bone plate holes that are known in the art
are the two different types of holes described below, each hole primarily intended for use with a different type of bone screw.
[005] The first type of hole is a non-threaded relatively smooth hole, through which
a screw with a smooth (non-threaded) head is inserted. These screws do not lock with the bone plate and are thus referred to as "non-locking" screws. Because non-locking screws do not lock with the plate hole, non-locking screws are not limited to a fixed angle with respect to the plate, but rather can be inserted at numerous angles. Inserting non-locking screws through the non-threaded plate holes and threading them into the bone effectively provides the desired compression of fracture ends.
[006] The second type of hole is an internally threaded hole, which is adapted to
mate with a screw having an externally threaded head. The threaded-head or "locking" screw is inserted at a fixed, predetermined angular relationship (determined by the central axis of

the threaded hole) with respect to the bone plate. Locking screws, when mated with threaded
bone-plate holes, possess high resistance to shear and tensional forces. Locking screws
therefore resist loosening and thereby ensure stability between the screw and the bone plate.
[007] Bone plates having both of the aforementioned types of holes are therefore
desirable and are well known. Surgeons are limited, however, by the manufacturers' placement of the varying holes on a given bone plate. A surgeon can achieve optimal compression when using a screw (e.g., a non-locking screw) without locking it to the plate. A surgeon can achieve desired stability between the screw, plate, and bone when using a locking screw with an internally-threaded hole.
[008] It would thus be advantageous for a hole in a bone plate to be adapted to
receive, at the surgeon's election, either non-locking screws for obtaining optimal compression or locking-screws for obtaining optimal stability, while minimizing any compromise in the strength of the bone plate.
SUMMARY OF THE INVENTION
1009] The bone plate of present invention is a bone plate used for bone fracture
fixation. Various embodiments of a bone plate having coaxial combination holes are described.
[0010] Among the various different types of bone plate holes that are known in the art
are threaded holes and non-threaded holes. "Locking" screws (screws with threaded heads)
are typically used with threaded holes. Locking screws, when mated with threaded holes,
possess high resistance to shear and torsional forces and therefore ensure stability between
the screw and bone plate. "Non-locking" screws are typically used with unthreaded holes
and, unlike locking screws that mate with threaded holes, may be inserted at any one of a
number of angles. Non-locking screws provide optimal compression of fractured ends.
[0011] A coaxial combination hole is, at once, adapted to receive (and utilize the
benefits of) either a locking screw or non-locking screw. A coaxial combination hole is a hole which is threaded only partially through its length. In one preferred embodiment, the hole has a generally circular cross section with varying hole diameter. In a preferred embodiment, the hole has three regions: an upper region, a middle region, and a lower region. The upper region may be unthreaded and may have, in a direction from the plate's upper surface to its lower surface, a curved inward taper. The middle region may be threaded and may have, in a direction from the plate's upper surface to its lower surface, a conical inward

taper. The lower region may be unthreaded and may have, in a direction from the plate's upper surface to its lower surface, an outward taper.
[0012] It will be appreciated that either type of the aforementioned screws may be
used (and produce its intended results) with a coaxial combination hole. The threaded head of a threaded-head screw may mate with threaded middle region of the hole. Alternatively, a screw with an unthreaded head (or even a screw with a threaded head) may be inserted through a coaxial combination hole, without any mating of any threads, at any one of a number of angles. The outward taper of the coaxial combination hole's lower region provides room for the screw's shaft to be inserted an angle (with respect to the center of the hole). Likewise the curved inward taper of the upper region of the hole provides a seat for the screw head to rest in, even when the screw is inserted ant an angle. It will be appreciated, then, that at any given coaxial combination hole, a surgeon may elect to use either a screw for screw-plate stability or a screw for compression of fracture ends.
[0013] Coaxial combination holes may be placed in any type of bone plate. Coaxial
combination holes provide multiple options for the surgeon. And because the holes do not require a larger cavity in the bone plate than would otherwise be necessary for an ordinary hole, the strength, size, and integrity of the bone plate are not compromised. Coaxial combination holes are therefore particularly useful in relatively small bone plates (e.g., pubic symphysis plates).
[0014] A coaxial combination hole has a central axis and a vertical axis. The hole's
vertical axis is perpendicular to the plane formed by the plate's upper surface (if the plate has a straight upper surface), or to the plane that is tangential to the pinnacle of the plate's upper surface (if the plate is convex). A hole may have a central axis that is parallel to its vertical axis, or that is not parallel to its vertical axis (thereby biasing the shaft of the screw in one direction or another). A plate may have holes with any combination of foregoing hole orientations.
[0015] In preferred embodiments, bone plates have between 4 and 8 holes. In some
embodiments, all plate holes are coaxial combination holes. In other embodiments, the bone plates may have some coaxial combination holes and at least one of another of a number of types of holes. One example of another type of hole is a dynamic compression ("DC") hole. A dynamic compression hole may be an elongated hole having an oblique portion or ramp having an inclination such that when the ramp is engaged by the underside of the head of a screw, the bone plate is displaced in a direction to move the ramp away from the non-locking

screw, causing the plate to apply a pressure to hold me fracture etnas in contact or in engagement. Another example of another type of hole is a non-coaxial combination hole. A non-coaxial combination hole may be an elongated hole having a portion of its perimeter threaded and another portion of its perimeter unthreaded. In addition to, or in lieu of, the foregoing two examples, other types of holes may be formed in a bone plate having coaxial combination holes.
[0016] In one embodiment of the bone plate, the plate has a longitudinal axis, and has
a straight center portion and curved ends. In one embodiment, the plate has two holes in the straight portion and two holes in each of the curved end portions. In one embodiment of this plate, all six holes may be coaxial combination holes. In another embodiment of this plate, the two holes on the straight portion may be either DC holes or non-coaxial combination holes, and the four holes on the curved end portions may be coaxial combination holes. In one embodiment of this plate, the width of the bone plate is narrower where there are no holes than where there are holes.
[0017] In another embodiment of the bone plate, the plate has a longitudinal axis and
is straight. In one embodiment, the plate may have only coaxial combination holes, all of which may lie along the plate's longitudinal axis.
[0018] In another embodiment of the bone plate, the entire plate may be curved. In
one embodiment, the plate may have only coaxial combination holes, all of which may lie
along the plate's longitudinal axis (which runs along the center of the plate's width).
[0019] In the various embodiments, the plate's upper and lower surfaces may be
straight or curved. In a preferred embodiment, the plate's upper surface may be convex, while the plate's lower surface may be concave.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] These figures represent preferred embodiments of the present invention.
Those skilled in the art will recognize that numerous variations and modifications may be made without departing from the scope of the present invention. Accordingly, it should be understood that these figures are not intended as limitations on the scope of the invention, which is defined only by the claims.
[0021] FIG. 1A is a side cross-sectional view of a first embodiment of a bone plate
having coaxial combination holes.
[0022] FIG. IB is a plan view of the bone plate of FIG. 1 A.

[0023] FIG. 1C is a cross-sectional view of the bone plate of FIG. 1A taken along the
cross section B-B.
[0024] FIG. 2A is a side cross-sectional view of a second embodiment of a bone plate
having coaxial combination holes and having dynamic compression holes.
[0025] FIG. 2B is a plan view of the bone plate of FIG. 2A.
[0026] FIG. 2C is a cross-sectional view of the bone plate of FIG. 2A taken along the
cross section B-B.
[0027] FIG. 3 A is a third embodiment of a bone plate having coaxial combination
holes.
[0028] FIG. 3B is a plan view of the bone plate of FIG. 3A.
[0029] FIG. 4A is a cross-sectional view of one embodiment of a coaxial combination
hole.
[0030] FIG. 4B is a magnified view of a portion of the thread of the coaxial
combination hole of FIG. 4A.
[0031] FIG. 5 is a cross-sectional view of a screw, having a threaded head, inserted
through a coaxial combination hole.
[0032] FIG. 6A is a cross-sectional view of a screw, having a non-threaded head,
inserted through a coaxial combination hole at one angle.
[0033] FIG. 6B is a cross-sectional view of a unthreaded-head screw inserted through
a coaxial combination hole at an angle different from that of the screw of FIG. 6A.
[0034] FIG. 7 is a plan view of a segment of a bone plate having non-coaxial
combination holes.
[0035] FIG. 8 is a plan view of the bone plate of FIGS. 3A and 3B, in a curved
condition.
[0036] FIG. 9 is a side view of one embodiment of a screw that has a conically-
tapered threaded head.
[0037] FIG. 10 is a side view of one embodiment of a screw having an unthreaded
head.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] The present invention is described below with reference to the preferred
embodiments. Those skilled in the art will recognize that numerous variations and modifications may be made witliout departing from the scope of the present invention.

Accordingly, it should be understood that the embodiments of the invention described below are not intended as limitations on the scope of the invention, which is defined only by the claims.
[0039] Reference is now made to FIGS. 1A, 2A, and 3A, which illustrate side, cross-
sectional views of various embodiments of a bone plate. The bone plates may have at least one coaxial combination hole 90, which has a length L that extends from the upper surface of the bone plate to the lower surface of the bone plate. The coaxial combination hole 90 is threaded only partially through the hole's length L. As such, with a given coaxial combination hole, a surgeon may elect to: (1) thread a screw having a thread on at least a portion of its head into and through the hole; or (2) insert a screw having an unthreaded head through the hole and into the bone. In a preferred embodiment, the hole 90 has length L of approximately 3.4mm to 4.0mm, which preferably corresponds to the thickness T of the bone plate.
[0040] Reference is now made to FIGS. IB, 2B, and 3B, which illustrate plan views
of various embodiments of the bone plate having at least one coaxial combination hole 90. Each bone plate may have at least a central region with a longitudinal axis L-L. Each bone plate hole 90 may have a vertical axis V-V, which is perpendicular to the plane on which the plate's upper surface lies (if the plate has a straight upper surface), or to the plane that is tangential to the pinnacle of the plate's upper surface (if the plate is convex). (See FIGS. 1A, 2A, and 3A.)
[0041] Reference is now made to FIGS. 1C and 2C, which illustrate cross-sectional
views of the bone plates along the respective cross sections B-B. In a preferred embodiment, the upper surface of the plate may be convex and the lower surface of the plate may be concave, as shown in FIGS 1C and 2C. In a preferred embodiment the radius of curvature for both surfaces may be from about 15mm to about 35mm, and preferably about 25mm. In another embodiment, one or both of the plate surfaces may be flat.
[0042] As shown in FIG. 1 A, hole 90 may extend from the upper surface 20 to the
lower surface 22 of the bone plate 10. In one embodiment, the diameters of the hole 90 at its uppermost surface and its lower most surface may be equal or close to equal. The hole 90 may be widest at the uppermost surface 20 and lowermost surface 22 of die plate 10. Each hole 90 may have a central axis C-C. (See FIGS. 1A and 2A.) In some embodiments of the hole 90, the central axis C-C of hole 90 may be parallel to the vertical axis V-V, as shown in FIG. 3A (central axis C-C not shown). In other embodiments, the central axis C-C of hole 90

will intersect with the vertical axis V-V at an angle 0, as shown in FIGS. 1A and 2A. In preferred embodiments, the angle 0 may vary from about 3° to about 17°, although other angles are contemplated.
[0043] As shown in FIG. 4A, the hole 90 may have three regions: an upper region 92,
a middle region 94, and a lower region 96. The upper region 92 of the hole 90 may have an
unthreaded inner surface 93 which, is preferably smooth, although texturing may be
provided. In a preferred embodiment, the upper region 92 may have a curved inward taper,
preferably concave, more preferably spherical, from the top surface of the plate to where the
upper region 92 of the hole 90 meets the middle region 94. The upper region 92 of the hole
90 is preferably narrowest where it meets the middle region 94. Preferably, the upper region
is approximately 1.0mm to approximately L2mm in length (along the axis C-C). In a
preferred embodiment, the upper region may comprise about 25% to about 35% of the
thickness T of the plate. In one embodiment, the diameter of the upper region 92, at the
region's broadest point, may be about 6mm and, at the region's narrowest point, may be
about 4mm. In another embodiment the diameter of the upper region 92, at the region's
broadest point, may be about 8mm and, at the region's narrowest point, may be about 6mm.
[0044] The middle region 94 of the hole 90 may have a threaded inner surface 95. In
one embodiment, the threads have a pitch P (as shown in FIG. 4B, which is a magnified partial view of the threaded surface 95) of approximately 0.3mm to 0.5mm. In a preferred embodiment, the thread angle γ may be approximately 50° to 70°, and preferably about 60°. In a preferred embodiment, the threaded region has at least one thread revolution, and preferably about three thread revolutions. Referring again to FIG. 4A, the threaded inner surface 95 may, in a direction from the upper surface to the lower surface, have a conical inward taper. In a preferred embodiment, the threaded inner surface 95 may taper at an angle a of approximately 5° to 15°, and preferably approximately 10°. The middle region 94 may be the narrowest region (i.e., smallest-diameter region) of the hole 90. In a preferred embodiment, the middle region 94 may be approximately 1.5mm to approximately 1.9mm in length (along the axis C-C). In a preferred embodiment, the middle region 94 may comprise about 40% to 50% of the thickness T of the plate. In one embodiment, the diameter of the middle region 94 may vary only slightly (due to the relatively shallow conical taper) and may be about 4mm or, in another embodiment, about 6mm. The diameter or taper of the middle region 94 may of course vary depending upon the size and/or taper of the screw.

[0045] The lower region 96 of the hole 90 may have an unthreaded inner surface 97
which is preferably smooth, although texturing may be provided. In a preferred embodiment, the lower region 96 may, from where it meets the middle region 94 to the lower surface of the plate, have a conical outward taper. In a preferred embodiment, the lower region 96 may taper outwardly at an angle β of approximately 35° to 55°, and preferably approximately 45°. In a preferred embodiment, the lower region 96 may be approximately 0.8mm to approximately 1.2mm in length (along the axis C-C). In a preferred embodiment, the lower region 96 may comprise about 20% to 35% of the thickness T of the plate. In one embodiment, the diameter of the lower region 96, at the region's narrowest point, may be about 4mm and, at the region's broadest point, may be about 6mm. In another embodiment, the diameter of the lower region 96, at the region's narrowest point, may be about 6mm and, at the region's broadest point, may be about 8mm.
[0046] Different types of screws may be used with the hole 90. One type of screw is
a screw that has a conically-tapered threaded head (shown in FIG. 9). As shown in FIG. 5,
the external threads of the screw's head may mate with the internal threads 95 of the middle
region 94 of the hole 90. This threaded-head screw 15 may be inserted at only one angle
(widi respect to the plate), which may be fixed by the threads 95 in the plate 10.
[0047] A second type of screw that may be used with the hole 90 is a screw with a
threaded shaft, but with an unthreaded head (shown in FIG. 10). An unthreaded-head screw may be inserted into hole 90 at any one of a number of angles. FIG. 6A illustrates an unthreaded-head screw 17 inserted at an angle substantially perpendicular to the longitudinal axis of the plate 10. FIG. 6B illustrates an unthreaded-head screw 17 inserted at a non-perpendicular angle with respect to the plate 10. The conical outward taper (shown at surface 97) of the lower region 96 of the hole 90 provides room for screw shaft 18 to be inserted at an angle with respect to the center of the hole 90. Likewise, the curved inward taper of the upper region 92 of the hole 90 provides a seat (at surface 93) for the screw head to rest in when an unthreaded-head screw 17 is inserted at an angle. A threaded-head screw may be used with a coaxial combination hole 90 in the same manner as the aforementioned unthreaded-head screw 17.
[0048] Although virtually any type of bone plate may benefit from coaxial
combination holes 90, coaxial combination holes are particularly useful for pubic symphysis plates and other relatively small bone plates. (The pubic syphilis is the connection between the two halves of the pubis and may be damaged as a result of an accident.) Because

a surgeon may elect to use either a locking screw or a non-locking compression screw with a coaxial combination hole, a bone plate having a coaxial combination hole may be more versatile than plates having other types of holes. The benefits may include: (1) a reduced need to manufacture many different plates having varying hole arrangement patterns; and (2) enhancement of clinical results. Because a coaxial combination hole does not require a substantially larger cavity in the bone plate than would otherwise be necessary for a simple hole, a coaxial combination hole provides desired flexibility for the surgeon without unduly compromising the strength, size, or integrity of the bone plate. Plates having coaxial combination holes may thus find particular utilization in pubic symphysis plates and other relatively small bone plates.
[0049] In one embodiment, the bone plate of the present invention may be a pubic
symphysis plate as shown in FIG. IB, and may have a plurality of holes, all of which may be
coaxial combination holes 90. In one embodiment, the plate may have a length PL of
approximately 70mm to 90mm. In one embodiment, the plate may have curved ends, as
shown in FIG. IB, with a radius of curvature R. In a preferred embodiment, two coaxial
combination holes 90 are located on the straight center portion of the plate. In a preferred
embodiment, the plate ends may curve approximately at a 45mm-55mm radius R, spamiing a
25°-35° angle 5. Preferably two coaxial combination holes 90 are placed along an arcs (on
both sides of the plate's straight center portion) having a radius of curvature of about 50mm.
In a preferred embodiment, the hole 90 on the curved portion adjacent to the hole 90 on the
straight portion is located approximately 12°-18° on the arc away from the hole 90 on the
straight portion. Likewise, the two holes 90 on either curved portion may be placed along an
arc approximately 12°-18° apart from each other. In a preferred embodiment, the plate may
be symmetrical from one side to the other (i.e., a mirror hole arrangement on the other side
of the plate is contemplated). In a preferred embodiment, the two holes near the center of the
plate may lie along the longitudinal axis L-L of the center region of the plate 10. The
remaining holes may be offset from the longitudinal axis L-L, as shown in FIG. IB.
[0050] In a preferred embodiment, the central axes C-C of the holes 90 are not
parallel to the respective vertical axes V-V of the holes 90. In a preferred embodiment, as shown in FIG. 1A, the two holes near the center of the plate have central axes C-C oriented to bias the tips of the screws in a direction away from the center of plate. In a preferred embodiment, the angle 0 between each of these two central axes C-C and the vertical axes V-V is approximately 8° to 15°. in a preferred embodiment, as shown in FIG. 1A, each of the

holes 90, that are located near the ends of the plate, has a central axis C-C oriented to bias the tips of the screws in a direction towards the center of plate. In a preferred embodiment the angle 9 between each of these central axes C-C and the vertical axes V-V is approximately 4° to 10°.
[0051] In a preferred embodiment, the linear plate-surface distance dl between the
edges of holes 90 may vary from hole to hole and may be approximately 10mm to 12mm. In
a preferred embodiment, as shown in FIG. IB, there may be necking of the plate surface in
between hole locations (i.e., the webs between the holes may be narrowed). This necking
serves to achieve a desired balance between plate strength and plate size: plate strength is
maximized, while plate size is minimized. In another embodiment the width of the plate
between holes may be the same as the width of the plate where the holes are located.
[0052] In a preferred embodiment, the plate may have at least one hole 99, preferably
near the center of the plate. Holes 99 may aid in the placement of the plate onto the bone
(e.g., for use with a guide wire) or may be provided as a suture hole.
[0053] Generally, for all embodiments, a shorter bone plate having only a few (e.g.,
4) holes may be used when the fracture is relatively small or when the patient's bone or joint (e.g., pubic symphysis) being operated on is relatively small.
[0054] A plan view of a second embodiment of a pubic symphysis plate is shown in
FIG. 2B. The primary difference between this embodiment and the foregoing embodiment (which is illustrated in FIGS. 1A and IB) is that the two holes near the center of the plate 30 of this embodiment are dynamic compression ("DC") holes 70 instead of coaxial combination holes 90. This embodiment of a bone plate is particularly useful when, to bring parts closer together, "extra" compression is desired. The DC holes are substantially similar to those disclosed in the specifications of United States publication No. 2002/0045901, in U.S. patent No. 6,669,701, and in reissued U.S. Patent No. RE. 31,628, the contents of which are incorporated herein by reference. As shown in FIG. 2B, DC hole 70 is elongated in a direction substantially aligned with the longitudinal axis L-L of the plate 30. As shown in FIG. 2B, DC hole 70 has an oblique portion or ramp 35 having an inclination such that when ramp 35 is engaged by the underside 13 of the head of a screw, preferably a screw having a head that is not threaded, and is preferably smooth and curved on the underside 13 which contacts the bone plate, the bone plate 30 is displaced in a direction to move ramp 35 away from the non-locking screw, causing the plate 30 to apply a pressure to hold the fracture ends in contact, preferably in engagement, along at least a portion of the fracture length. In a

preferred embodiment, each of the holes 30 has a length X (illustrated in FIG. 2A) of approximately 6mm to 7mm.
[0055] Alternatively, the two holes near the center of the plate 30 may be non-coaxial
combination holes 40 (instead of coaxial combination holes 90 or DC holes 70). The non-coaxial combination holes are substantially similar to those disclosed in the specifications of U.S. patent No. 6,669,701 and of United States publication No. 2002/0045901, the contents of which are hereby incorporated by reference. Reference is now made to FIG. 7. FIG. 7 illustrates a bone plate having a plurality of combination holes 40, which extend from the plate's upper surface to its lower surface. The holes 40 may be elongated (e.g., in a direction substantially aligned with a longitudinal axis of the plate) and may include a threaded portion 5 and a non-threaded portion 6. The threaded portion 5 may extend over a range of greater than about 180° with respect to a center point CI. The threaded portion 5 of the hole 40 may be dimensioned and configured to engage a threaded head portion of a threaded-head bone screw, and fix the bone screw at a predetermined angle with respect to the bone plate. Preferably, the dreaded portion 5 of the hole 40 extends through the full thickness of the bone plate (i.e., from the plate's upper surface to its lower surface) thus maximizing the stability of the bone screw to bone plate interface. A threaded-head screw or a non-direaded head screw may (e.g., for compression) pass through the non-threaded portion 6 of a combination hole 40.
[0056] Another embodiment of a plate having coaxial combination holes is illustrated
in FIGS. 3A and 3B. In one embodiment, the plate 50 may have a plurality of holes, all of
which may be coaxial combination holes 90. Each of the holes 90 may lie along the
longitudinal axis L-L of the plate 50. In one embodiment, the central axis C-C of each of the
holes 90 may be parallel to the corresponding vertical axis V-V of each of the holes 90, as
shown in FIG. 3A (central axis C-C not shown). In a preferred embodiment, the linear plate-
surface distance d2 between the edges of holes 90 may be approximately 6mm to 9mm.
[0057] A variation on the aforementioned embodiment (illustrated in FIGS. 3A and
3B) is illustrated in FIG. 8. FIG. 8. is die bone plate of FIGS. 3A and 3B, in a "curved condition." Though the bone plate of FIGS. 3A and 3B may be formed of such material to allow a surgeon to preoperatively bend the plate into a desired shape, a bone plate manufactured to a bend condition may be desirable. In the human body, a ball-and-socket joint is formed by the two acetabula of the pelvis and the head of each femur. The bone plate of FIG. 9 may be especially useful for use on the posterior outer surface of a fractured

acetabulum. The plate may have a radius of curvature R, which in a preferred embodiment, is about 100-115mm.
[0058] While the present invention has been described with reference to the preferred
embodiments, those skilled in the art will recognize that numerous variations and modifications may be made without departing from the scope of the present invention. Accordingly, it should be understood that the embodiments of the invention described above are not intended as limitations on the scope of the invention, which is defined only by the following claims.

WHAT IS CLAIMED IS:
1. A bone plate comprising:
an upper surface;
a lower surface; and
at least one first hole, the hole extending through the upper and lower surfaces, the hole having a central axis and a vertical axis, the hole having at least two vertically separate regions, wherein a first upper region of the hole is non-threaded and a second region of the hole is threaded.
2. The bone plate of claim 1, wherein the upper region and the second region are in communication with one another.
3. The bone plate of claim 2, wherein the lowest point of the upper region abuts the highest point of the second region.
4. The bone plate of claim 1, wherein the upper region is substantially smooth.
5. The bone plate of claim 1, wherein the upper region has, in a direction from the upper surface to the lower surface, an inward taper.
6. The bone plate of claim 5, wherein the inward taper is curved.
7. The bone plate of claim 6, wherein the curved inward taper is spherical.
8. The bone plate of claim 1, wherein the first hole has a substantially circular
cross section.
9. The bone plate of claim 8, wherein the diameter of the circular cross section varies along the vertical axis.
10. The bone plate of claim 1, wherein the second region is, in a direction from the upper surface to the lower surface, conically tapered inward.
11. The bone plate of claim 10, wherein the second region conically tapers at a cone angle of between about 5° and 15°.
12. The bone plate of claim 1, wherein the largest diameter of the upper region is greater than the largest diameter of the second region.
13. The bone plate of claim 1, wherein the smallest diameter of the upper region is substantially equal to the largest diameter of the second region.
14. The bone plate of claim 1, wherein the hole has a third vertically separate lower region.

15. The bone plate of claim 14, wherein the lower region communicates with the second region.
16. The bone plate of claim 15, wherein the lowest point of the second region abuts the highest point of the lower region.
17. The bone plate of claim 16, wherein the lower region is non-threaded.
18. The bone plate of claim 17, wherein the lower region is substantially smooth.
19. The bone plate of claim 17, wherein the lower region is, in a direction from the upper surface to the lower surface, tapered outward.
20. The bone plate of claim 19, wherein the outward taper of the lower region is conical.
21. The bone plate of claim 19, wherein the lower region conically tapers at a cone angle of between about 40° and 50°.
22. The bone plate of claim 19, wherein the largest diameter of the lower region is greater than the largest diameter of the second region.
23. The bone plate of claim 19, wherein the smallest diameter of the lower region is substantially equal to the smallest diameter of the second region.
24. The bone plate of claim 19, wherein the largest diameter of the lower region is substantially equal to the largest diameter of the upper region.
25. The bone plate of claim 1, further comprising at least one second hole, different from the first hole.
26. The bone plate of claim 25, wherein the second hole is elongated and extends through the upper and lower surfaces.
27. The bone plate of claim 26, wherein the second hole is non-threaded and has an outer perimeter, at least a portion of the outer perimeter tapering inward from the upper surface to the lower surface of the plate to form at least one ramp surface for engagement with a screw head.
28. The bone plate of claim 26, the second hole having a center point and wherein the second hole includes a threaded portion and a non-threaded portion, and the threaded portion extends through an angle of between about 190° and about 280° with respect to the center point.
29. The bone plate of claim 26, wherein the second hole is elongated in a direction that is substantially aligned with the longitudinal axis of the plate.
30. The bone plate of claim 29, wherein the plate comprises at least two first holes and at least two second holes.

31. The bone plate of claim 30, wherein the bone plate is elongated, substantially straight, and has a longitudinal axis.
32. The bone plate of claim 30, wherein the bone plate has a straight portion and a curved portion.
33. The bone plate of claim 32, wherein die plate is straight near its center along the plate's longitudinal axis and curved at its ends.
34. The bone plate of claim 33, wherein the curved portion has a radius of curvature between about 40mm and about 60mm.
35. The bone plate of claim 33, wherein two second holes are located adjacent to one another in the straight portion.
36. The bone plate of claim 35, wherein at least one first hole is located on the curved portion on a first side of a plate, and at least another first hole located on the curved portion on die opposite second side of the plate.
37. The bone plate of claim 36, wherein at least one first hole is located adjacent to a second hole.
38. The bone plate of claim 37, wherein the at least one first hole located adjacent to the second hole is separated from the second hole at a distance equaling about 12° to about 18° on the curved portion.
39. The bone plate of claim 37, wherein a first hole is located adjacent to another first hole.
40. The bone plate of claim 39, wherein the two first holes are separated from each other at a distance equaling about 12° to about 18° on the curved portion.
41. The bone plate of claim 40, wherein the central axis of at least one first hole is not parallel to the vertical axis of the at least one first hole.
42. The bone plate of claim 41, wherein die angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 4° and 10°.
43. The bone plate of claim 41, wherein the angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 13° and 17°.
44. The bone plate of claim 1, wherein the central axis of the at least one first hole is not parallel to the vertical axis of that hole, forming a first angle, and the central axis of at least one other first hole is not parallel to the vertical axis of that hole, creating a second angle different from the first angle.
45. The bone plate of claim 44, wherein the first angle is between about 4° and 10° and the second angle is between about 13° and 17°.
46. The bone plate of claim 1, wherein a plurality of first holes are located along the longitudinal axis of the plate.

47. The bone plate of claim 46, wherein the plate is substantially straight.
48. The bone plate of claim 46, wherein the plate is curved, having a radius of curvature between about 80mm to about 140mm.
49. A bone plate system comprising:
a bone plate having:
an upper surface;
a lower surface; and
at least one first hole, the hole extending through the upper and lower surfaces, the hole having a central axis and a vertical axis, the hole having at least two vertically separate regions, wherein a first upper region of the hole is non-threaded and a second region of the hole is threaded;
and at least one fastener to fasten the bone plate to the bone.
50. The bone plate system of claim 49, wherein the upper region has, in a direction from the upper surface to the lower surface, a curved inward taper.
51. The bone plate of claim 1, wherein the first hole has a substantially circular cross section.
52. The bone plate of claim 51, wherein the diameter of the circular cross section varies along the vertical axis.
53. The bone plate of claim 49, wherein the second region is, in a direction from the upper surface to the lower surface, conically tapered inward.
54. The bone plate of claim 53, wherein the second region conically tapers at a cone angle of between about 5° and 15°.
55. The bone plate of claim 1, wherein the hole has a third vertically separate lower region.
56. The bone plate of claim 55, wherein the lowest point of the second region abuts the highest point of the lower region.
57. The bone plate of claim 55, wherein the lower region is non-threaded.
58. The bone plate of claim 55, wherein the lower region is substantially smooth.
59. The bone plate of claim 57, wherein the lower region is, in a direction from the upper surface to the lower surface, conically tapered outward.
60. The bone plate of claim 59, wherein the lower region conically tapers at a cone angle of between about 40° and 50°.

61. The bone plate of claim 49, further comprising at least one second hole, different from the first hole.
62. The bone plate of claim 61, wherein the second hole is elongated and extends through the upper and lower surfaces.
63. The bone plate of claim 62, wherein the second hole is non-threaded and has an outer perimeter, at least a portion of the outer perimeter tapering inward from the upper surface to the lower surface of the plate to form at least one ramp surface for engagement with a screw head.
64. The bone plate of claim 62, the second hole having a center point and wherein the second hole includes a threaded portion and a non-threaded portion, and the threaded portion extends through an angle of between about 190° and about 280° with respect to the center point.
65. The bone plate of claim 62, wherein the second hole is elongated in a direction that is substantially aligned with the longitudinal axis of the plate.
66. The bone plate of claim 65, wherein the plate comprises at least two first holes and at least two second holes.
67. The bone plate of claim 66, wherein the bone plate is elongated, substantially straight, and has a longitudinal axis.
68. The bone plate of claim 66, wherein the bone plate has a straight portion and a curved portion.
69. The bone plate of claim 68, wherein the plate is straight near its center along the longitudinal axis and curved at its ends.
70. The bone plate of claim 69, wherein the curved portion has a radius of curvature of about 50mm.
71. The bone plate of claim 70, wherein two second holes are located adjacent to
one another in the straight portion.
i.
72. The bone plate of claim 68, wherein at least one first hole is located on the curved portion on a first side of a plate, and at least another first hole located on the curved portion on the opposite second side of the plate..
73. The bone plate of claim 49, wherein the central axis of at least one first hole is not parallel to the vertical axis of the at least one first hole.
74. The bone plate of claim 73, wherein the angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 4° and 10°.
75. The bone plate of claim 73, wherein the angle of intersection between the central axis of the hole and the vertical axis of the hole is between about 13° and 17°.

76. The bone plate of claim 49, wherein the central axis of the at least one first
hole is not parallel to the vertical axis of that hole, forming a first angle, and the central axis
of at least one other first hole is not parallel to the vertical axis of the hole, creating a second
angle different from the first angle.
77. The bone plate of claim 76, wherein the first angle is between about 4° and 10°
and the second angle is between about 13° and 17°.
78. The bone plate of claim 49, wherein a plurality of first holes are located along
the longitudinal axis of the plate.
79. The bone plate of claim 78, wherein the plate is substantially straight.
80. The bone plate of claim 79, wherein the plate is curved.
81. The bone plate of claim 80, where in the plate is curved at a radius between
about 80mm to about 140mm.

Documents:

4700-CHENP-2006 CORRESPONDENCE OTHERS 12-09-2012.pdf

4700-CHENP-2006 OTHER PATENT DOCUMENT 22-03-2013.pdf

4700-CHENP-2006 AMENDED CLAIMS 08-05-2013.pdf

4700-CHENP-2006 AMENDED CLAIMS 13-12-2012.pdf

4700-CHENP-2006 CORRESPONDENCE OTHERS 08-05-2013.pdf

4700-CHENP-2006 CORRESPONDENCE OTHERS 30-04-2013.pdf

4700-CHENP-2006 FORM-3 08-05-2013.pdf

4700-CHENP-2006 FORM-3 13-12-2012.pdf

4700-CHENP-2006 OTHER PATENT DOCUMENT 13-12-2012.pdf

4700-CHENP-2006 PCT NOTIFICATION 08-05-2013.pdf

4700-CHENP-2006 CORRESPONDENCE OTHERS.pdf

4700-CHENP-2006 EXAMINATION REPORT REPLY RECEIVED 13-12-2012.pdf

4700-CHENP-2006 FORM-18.pdf

4700-CHENP-2006 POWER OF ATTORNEY 13-12-2012.pdf

4700-chenp-2006-abstract.pdf

4700-chenp-2006-claims.pdf

4700-chenp-2006-correspondnece-others.pdf

4700-chenp-2006-description(complete).pdf

4700-chenp-2006-drawings.pdf

4700-chenp-2006-form 1.pdf

4700-chenp-2006-form 26.pdf

4700-chenp-2006-form 3.pdf

4700-chenp-2006-form 5.pdf

4700-chenp-2006-pct.pdf

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Patent Number

256598

Indian Patent Application Number

4700/CHENP/2006

PG Journal Number

28/2013

Publication Date

12-Jul-2013

Grant Date

05-Jul-2013

Date of Filing

21-Dec-2006

Name of Patentee

SYNTHES GMBH

Applicant Address

EIMASTRASSE 3, CH-4436 OBERDORF, SWITZERLAND

Inventors:

#	Inventor's Name	Inventor's Address
1	MAST, JEFF, W	3405 SOUTHAMPTON DRIVE, RENO, NV 89509, USA
2	BOLHOFNER, BRETT, R	4600 4TH STREET NORTH, ST. PETERSBURG, FL 33703, USA
3	GRADY, MARK, P., JR	1506 EAST WOODBANK WAY, WEST CHESTER, PA 19380, USA
4	MAYO, KEITH, A	3614 FOREST BEACH DRIVE, NW GIG HARBOR, WA 98335, USA
5	KOAY, KENNY	990 FERN HILL ROAD, UNIT 208, WEST CHESTER, PA 19380, USA

PCT International Classification Number

A61B 17/56

PCT International Application Number

PCT/US05/17987

PCT International Filing date

2005-05-19

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10/851,849	2004-05-21	U.S.A.