Osteotomy plate for long bones

A bone plate has a curved elongated body including a first end portion and a second end portion. The first end portion is laterally offset relative to the second end portion, and includes a plurality of screw holes. A first screw hole is defined by the second end portion. Each of the screw holes of the first end portion are laterally offset from a straight line extending in a direction along a length dimension of the bone plate and bisecting the first screw hole of the second end portion, and each of the screw holes of the first end portion are on the same side of the straight line as one another.

FIELD

This disclosure pertains to bone plates and associated methods of use.

BACKGROUND

In osteotomy procedures, it is often advantageous for a bone plate to provide stabilization of the osteotomy site and compression of the osteotomy. When adequate stability is not achieved, the bone segment(s) may move, resulting in inferior biomechanics due to deviation from the planned alignment. Lack of compression at the osteotomy interface can also result in delayed or non-union outcomes. Many conventional bone plates also necessitate a multitude of plate designs in multiple sizes and orientations to address various clinical indications in bones, complicating bone plate selection and use. Accordingly, improvements to bone plates are desirable.

SUMMARY

Certain embodiments of the disclosure concern bone plates for use with long bones. In an exemplary embodiment, a bone plate comprises a curved elongated body including a first end portion and a second end portion. The first end portion is laterally offset relative to the second end portion. The bone plate further includes a plurality of screw holes defined by the first end portion, and a first screw hole defined by the second end portion. Each of the screw holes of the first end portion are laterally offset from a straight line extending in a direction along a length dimension of the bone plate and bisecting the first screw hole of the second end portion, and each of the screw holes of the first end portion are on the same side of the straight line as one another.

In another representative embodiment, a bone plate comprises an elongated body including a first end portion and a second end portion. The elongated body defines an upper surface and a lower surface, and has a V-shaped cross section. The elongated body is curved such that the first end portion is laterally offset relative to the second end portion. The bone plate further includes a plurality of screw holes defined by the first end portion and a plurality of screw holes defined by the second end portion, at least one of the screw holes of the second end portion being a first compression screw hole oriented such that a straight line extending along a longitudinal axis of the first compression screw hole passes through a proximal screw hole of the first end portion.

In another representative embodiment, a method comprises placing a bone plate on an end portion of a long bone. The bone plate includes a curved elongated body having a first end portion and a second end portion. The first end portion is laterally offset relative to the second end portion, and the first end portion defines a plurality of screw holes. The second end portion defines at least one screw hole, and each of the screw holes of the first end portion are laterally offset from a straight line extending in a direction along a length dimension of the bone plate and bisecting the at least one screw hole of the second end portion. Each of the screw holes of the first end portion are on the same side of the straight line as one another. The method further comprises securing the bone plate to the long bone.

DETAILED DESCRIPTION

In human and animal orthopedics, various saw blades are available to make osteotomies in bone. Straight osteotomies, radial osteotomies, and spherical osteotomies can be created at specific locations in long bones to achieve realignment of a bone segment to the overall limb axis for improved biomechanics. Representative examples of a flat saw blade, a radial saw blade, and a spherical or dome saw blade are shown inFIGS. 1-3, respectively.

There are multiple physiological problems associated with long bones that can affect limb biomechanics, which can occur as a result of trauma (e.g., bone fractures that heal in a misaligned position), or birth defects. Surgical methods of re-establishing appropriate biomechanics of a limb can include repositioning proximal and distal bone segments to correct alignment issues. There are clinical examples for many long bones (e.g., femur, tibia, humerus, radius, ulna, etc.), which can be managed through corrective osteotomies to restore improved limb function. With reference to the femur, there are proximal and distal corrective osteotomies that can address different biomechanical alignment issues.

For example, a representative femoral neck angle correction is shown inFIGS. 4A-4C.FIG. 4Aillustrates a normal angle θ between a longitudinal axis12of a femur10and a longitudinal axis14of the femoral neck16.FIG. 4Billustrates a case in which the angle β between the longitudinal axis12of the femur and the longitudinal axis14of the femoral neck is greater than normal. The angle of the femoral neck can be corrected by performing an osteotomy (e.g., with flat saw blade) to remove a wedge-shaped portion18of the femur (FIG. 4B) to locate the femoral neck at the desired angle θ (FIG. 4C).

A representative femoral version correction is shown inFIGS. 5A-5C, wherein the femoral anteversion angle θ between the longitudinal axis14of the femoral neck16is corrected relative to a horizontal plane20.FIG. 5Aillustrates a normal femoral anteversion angle θ, whileFIG. 5Billustrates a femoral anteversion angle β that is less than normal. By performing an osteotomy (e.g., with a flat saw blade) to rotate the femoral neck16, the anteversion angle can be corrected, as shown inFIG. 5C.

A representative distal femoral loading angle correction is shown inFIGS. 6A-6C.FIG. 6Aillustrates a normal femoral loading angle θ between a loading axis22and an anatomical axis24, whileFIG. 6Billustrates an abnormal loading angle β. By performing an osteotomy (e.g., with a radial saw blade) to rotate a distal end portion26of the femur10, the loading angle can be corrected, as shown inFIG. 6C.

There can be similar clinical issues with the humerus, as illustrated inFIGS. 7A-7C and 8A-8C. For example,FIGS. 7A-7Cillustrate a representative humeral neck angle correction, with a normal humeral neck angle θ between a longitudinal axis28of the humerus30and a longitudinal axis32of the humeral neck34shown inFIG. 7A, and an abnormal humeral neck angle β illustrated inFIG. 7B. By performing an osteotomy to rotate a proximal portion36of the humerus30, the neck angle can be corrected, as illustrated inFIG. 7C.

FIGS. 8A-8Cillustrate a representative proximal humeral version correction, with a head-neck angle θ between a longitudinal axis38of the humerus30and an axis40of the proximal humerus36shown inFIG. 8A, and an abnormal humeral version angle β shown inFIG. 8B. By performing an osteotomy to rotate the proximal portion36of the humerus30in the manner indicated, the humeral version angle can be corrected, as shown inFIG. 8C.

Osteotomies of the tibia can involve plateau positional changes to correct over-loading of areas of the articular surface (e.g., surfaces with cartilage). In humans, a high tibial osteotomy (HTO) can be performed to balance the loading in both compartments of the knee, as shown inFIGS. 9A-9C.FIG. 9Aillustrates a normal femuro-tibial loading angle θ between a loading axis42of a femur44and a longitudinal axis46of a tibia48wherein about 60% of the load applied by the femur is borne by the medial aspect of proximal tibia and about 40% of the load is borne by the lateral aspect of the proximal tibia.FIG. 9Billustrates the case of an abnormal femuro-tibial loading angle β wherein, in some examples, about 80% of the load applied by the femur can be borne by the medial aspect of the tibia and only about 20% of the load can be borne by the lateral aspect of the tibia. The angle β can be corrected by performing an osteotomy to remove a wedge-shaped portion50of the proximal tibia (FIG. 9B) to restore a normal femuro-tibial loading angle θ, as illustrated inFIG. 9C.

In veterinary medicine, a tibial plateau leveling osteotomy (TPLO) can be performed to re-position the tibial plateau to, for example, function as a buttress to resist certain physiological movements or address rupture of the anterior (cranial) cruciate ligament.FIGS. 10A-10Cillustrate a representative example of a TPLO procedure.FIG. 10Aillustrates a normal angle θ between a plane52defined by the tibial plateau54and a horizontal reference plane56. In certain circumstances, it can be beneficial to rotate the plane52of the tibial plateau54to reduce the angle between the tibial plateau and the reference plane56. This can be accomplished by creating a radial cut in a proximal portion58of the tibia60and rotating the excised portion62such that the angle between the tibial plateau54and the horizontal reference plane56is lowered (e.g., to about 6 degrees in some embodiments), as shown inFIGS. 10B and 10C.

Patellar luxation is another example of a pathology that may be addressed by osteotomy procedures. With reference toFIGS. 11A-11C, patellar luxation can occur when there is a misalignment between the quadriceps mechanism generally indicated at64and the trochlear groove66of the distal femur68, and/or when there is a disparity between the loading axis70of the leg and the anatomical axis72, as illustrated inFIG. 11A. In such circumstances, when the knee is flexed, the patella74can travel out of the trochlear groove66, or luxate, resulting in pain and limited motion and function. Lateral luxation of the patella74is illustrated inFIG. 11B, while medial luxation is illustrated inFIG. 11C. By performing a distal femoral correction osteotomy in the manner ofFIGS. 6A-6C, the distal aspect of the femur68can be realigned with the pull of the quadriceps64to re-establish alignment, stability, and function.

As another example, a TPLO may be performed to compensate for ruptures of the cranial cruciate ligament (for example, in dogs). A representative example of a TPLO to repair a ruptured cranial cruciate ligament is illustrated inFIGS. 12A-12C. As illustrated inFIG. 12A, the cranial cruciate ligament76can extend between the femur78and the tibia80, and can resist advancement of the tibia in the direction indicated by arrow82due to force applied to the tibia by the femur.FIG. 12Billustrates forward advancement of the tibia80in the direction of arrow82due to rupture of the cranial cruciate ligament76. In a typical example, an osteotomy using any of the saw blades disclosed herein can be made in the lateral plane on the medial side of the tibia80to reduce the angle θ of the tibial plateau84with respect to a horizontal reference plane86, as illustrated inFIG. 12C. This can create a mechanical abutment in the caudal aspect of the knee, assisting the soft tissues in preventing the femur from sliding off the back of the tibia, mitigating the effects of a non-functional cranial cruciate ligament.

Bone plates used in association with osteotomy procedures such as the procedures described herein can provide two primary functions, namely stabilization of the osteotomy and compression of the osteotomy. In some embodiments, the bone plates described herein can incorporate one or more compression slots or compression screw holes that utilize an internal ramp within the side walls of the screw hole to apply compression to the underlying osteotomy.FIG. 13Aillustrates a plan view of a representative bone plate88including a compression screw hole90, andFIGS. 13B and 13Cillustrate sectional views taken through the bone plate88along line X-X ofFIG. 13A. A screw92can be inserted through the opening of the compression slot90, and the head94of the screw can contact a ramp96. As the screw92is tightened and advanced into the bone, the head of the screw applies pressure to the sloped surface of the ramp causing the bone plate to move in the direction indicated by arrow98shown inFIG. 13C. This can cause bone sections on opposite sides of the osteotomy to be drawn together and compressed, reducing the space between the bone sections at the osteotomy site. In some embodiments, such ramp and screw configurations can close a gap of, for example, about one (1) mm, and can provide compression (e.g., of about 10 pounds) of the bone sections against one another at the osteotomy interface. The ramp can have different configurations as, for example, an inclined plane or an inclined curvilinear surface, as shown.

FIG. 14illustrates a bone plate100having an elongated body101including a first end portion102(also referred to as a proximal end portion) and a second end portion104(also referred to as a distal end portion). With reference to the coordinate axes ofFIG. 14, the bone plate can be curved in the X-Y plane such that the first end portion102is offset from the second end portion104in a direction along the X-axis. The first end portion102can have a generally curved shape, and can include a proximal lobe128and a distal lobe130separated from one another by a recessed portion132. The first end portion can also define one or more screw holes. For example, in the illustrated embodiment the first end portion includes three screw holes116,118,120for receiving any of a variety of bone fixation screws. The screw holes116,118,120can be arranged in a generally triangular arrangement, with screw hole116being located on the proximal lobe128and the screw hole120being located on the distal lobe130. In the illustrated embodiment, the screw hole118can be intermediate screw holes116,118, and offset from screw holes116,118along the X-axis. In some embodiments, the location of the screw holes can be associated with optimal bone cross sections (for example, areas in which the cortical bone is thicker to aid in fixation), although it should be appreciated that the first end portion can include any suitable number of screw holes located at any suitable location.

Referring still toFIG. 14, the second end portion104can have a generally curved shape, and can have a width dimension that is less than a width dimension of the first end portion102. For example, in the illustrated embodiment, the first and second end portions can be joined by a transition region generally indicated at134, in which the width of the bone plate tapers from the relatively wider first end portion to the relatively narrower second end portion.

The second end portion can also define one or more screw holes. For example, in the illustrated embodiment the second end portion can define three screw holes122,124,126, with screw holes122and126being configured as compression screw holes, although the second end portion can include any suitable number of screw holes in any suitable configuration. In the illustrated embodiment, the compression screw hole122can be oriented generally in the direction of the lobes128,130of the first end portion102such that a straight line136extending along a longitudinal axis of the compression screw hole122passes through the screw hole116of the first end portion. In some embodiments, the straight line136can bisect the screw hole116. Aligning the screw hole116with the longitudinal axis of the compression screw hole122, which can be generally representative of the direction of movement of the bone plate when a screw is inserted through the compression screw hole122, can provide increased compression between bone segments at the osteotomy site while reducing movement of the bone segments relative to one another. In some embodiments, the straight line136along the longitudinal axis of the screw hole122can define an angle θ of from about 10 degrees to about 45 degrees with a vertical reference, such as vertical line138bisecting the screw hole124. In some embodiments, the angle θ can be about 25 degrees.

Referring again to the straight line138, line138can extend in the direction of a length dimension L of the bone plate and can bisect the screw hole124of the second end portion. As illustrated inFIG. 14, each of the screw holes116,118,120of the first end portion can be offset from the straight line138along the X-axis. In the illustrated embodiment, each of the screw holes116,118,120of the first end portion are offset from the straight line138along the X-axis in the same direction (to the right inFIG. 14) such that all of the screw holes of the first end portion are on the same side of line138as one another. However, it should be understood that in left-handed configurations of the bone plate (see, e.g.,FIG. 23), the screw holes of the first end portion can be offset from a straight line bisecting the screw hole124along the X-axis in the opposite direction (e.g., to the left).

In the illustrated embodiment, a longitudinal axis146of the compression screw hole126can be oriented in a direction away from the first end portion102, as shown inFIG. 14. This can provide additional compression of the osteotomy site and rotation of the bone plate and/or of the bone segments in a counterclockwise direction upon fixation of the bone plate to the bone to improve the stability of the joint. In the illustrated embodiment, the longitudinal axis146of the compression screw hole126can define an angle α of from about 20 degrees to about 60 degrees as measured with respect to a vertical reference, such as line138. In some embodiments, the angle α can be from about 30 degrees to about 50 degrees. In some embodiments, the angle α can be about 40 degrees.

In some embodiments, the bone plate100can have an outer plate contour (e.g., medial or lateral) such that overhang of a long bone to which the bone plate is affixed is reduced or prevented. Reducing overhang can be important to avoid soft tissue impingement, which can result in reduced range of motion and pain post-operatively. For example, in some embodiments, the ratio of the radius R1of an outer edge135of the bone plate and the radius R2of an inner edge137(seeFIG. 16) can be from about 1.01 to about 4 along the length of the bone plate. The bone plate can also be made in left or right configurations to accommodate long bones on different sides of the body. For example, the bone plate illustrated inFIG. 14is a right-handed configuration. A bone plate in a left-handed configuration is illustrated inFIG. 23.

With reference toFIG. 15, the bone plate100can have an upper surface106and a lower surface108, with the lower surface108being adjacent the surface of a bone on which the bone plate is placed. Many conventional bone plates are contoured for a fit in which a large proportion of the surface area of the bone plate is in contact with the surface of the bone to which it is affixed. In contrast, the bone plate embodiments disclosed herein can be contoured such that only a small proportion of the surface area of the bone plate is in contact with the underlying bone, while maintaining a low profile to aid with skin closure over the bone plate. For example, in the embodiment shown, the lower surface108is V-shaped in cross-section, in which respective angled portions of the lower surface define an angle β of from about 90 degrees to about 170 degrees and converge at an apex142. In some embodiments, the angle β can be from about 120 degrees to about 170 degrees. In some embodiments, the angle β can be about 155 degrees. By angling the lower surface108in the shape of a V, contact with the surface of the bone can be minimized to reduce damage to the periosteum and allow blood flow to the bone, while reducing issues with tissue closure over the bone plate. This can promote improved healing of the bone since the periosteum contains fibroblasts and progenitor cells that develop osteoblasts for maintaining and healing bone.

In some embodiments, both the upper surface106and the lower surface108can have V-shaped cross-sections. In other embodiments, the upper surface106can be relatively level, or rounded, while only the lower surface108has an angled cross-section. In some embodiments, the apex142can be located at or near the center of the recessed portion132, and can be continuous along the length of the bone plate such that the entirety of the bone plate and/or the lower surface has a V-shaped cross-section. In other embodiments, the apex142can be proximally or distally offset from the center of the recessed portion132, or can be continuous along only a portion of the length of the bone plate. The bone plate can also be relatively thin, such that the overlying tissue can be closed over the bone plate without undue tension.

In some embodiments, the lower surface108can include a plurality of standoffs or protrusions to further reduce contact between the bone plate and the surface of the underlying bone. For example, with reference toFIGS. 16 and 17, the lower surface can include three protrusions110A-110C, which can provide three points of contact to establish a primary plane for reconstruction. In the representative embodiment ofFIG. 16, the protrusion110A can extend from the lower surface of the proximal lobe128, the protrusion110B can extend from the lower surface of the distal lobe130, and the protrusion110C can extend from the distal end of the second end portion104. In this manner, when the bone plate is affixed to a bone, the protrusions110A-110C can be the primary points of contact between the bone plate and the bone surface, thereby reducing damage to the periosteum. The protrusions110A-110C can have a diameter D and a height dimension H, as shown inFIG. 17. In a representative embodiment, the protrusions can have a diameter of about 2 mm and a height of about 1 mm, although it should be understood that the protrusions can have any suitable size and/or shape. Additionally, it should be understood that the bone plates disclosed herein are not limited to three protrusions, but can have any suitable number of protrusions, including no protrusions, as desired.

In some embodiments, the bone plate100can be curved in multiple planes to maintain a geometry capable of placement within the boundaries of a bone following an osteotomy. For example, in addition to the curvature of the bone plate100in the X-Y plane as shown inFIG. 14, the bone plate can also be curved along the Z-axis out of the X-Y plane, as shown inFIG. 18. More specifically, in the illustrated embodiment, the first end portion102can be angled in the Z-direction to allow the first end portion to conform to the shape of the proximal or distal portion of a bone to which the bone plate is applied. In some embodiments, a plane defined by the lower surface108of the first end portion102can define an angle ϕ with a plane defined by the lower surface of the second end portion104of from about 5 degrees to about 40 degrees. In some embodiments, the angle ϕ can be from about 15 degrees to about 40 degrees. In some embodiments, the angle ϕ can be about 25 degrees. The angle ϕ may be varied from application to application, including by being bent to a desired angle by a surgeon during an osteotomy procedure, as required.

The screw holes of the bone plate can be configured for use with locking screws, non-locking screws, or combinations thereof, which can be driven into a bone to secure the plate to the bone. In some embodiments, the bone plate100can be used in combination with one or more locking bone screws, which can provide a locking feature in the head of the screw that locks or engages the screw with the bone plate when the screw is inserted into the bone. In some embodiments, using locking screws can help prevent the bone plate from being compressed against the bone and damaging the periosteum. Certain embodiments of locking screws that may be used in combination with the bone plates described herein are disclosed in U.S. Pat. No. 8,696,715, which is incorporated herein by reference.

FIGS. 19A and 19Billustrate the use of a representative embodiment of a locking screw150in combination with the bone plate100.FIG. 19Billustrates a cross-section X-X taken through screw hole124of the bone plate100illustrated inFIG. 19A. Generally, locking screws include a head152and a threaded body154capable of fixation in cancellous or cortical bone. In some embodiments, the screw head152can have an external feature (for example, a partial spiral groove) to engage an internal wire (not shown) within the screw hole. This configuration can allow the screw150to follow multiple paths through the screw hole into the bone to address variations in the location of optimal bone between, for example, the femur, tibia, and humerus. The free movement of the wire and the diameter of the screw hole can provide for adjustment of the angle of the screw150relative to the longitudinal axis156of the hole while still providing locking between the screw and bone plate upon final tightening of the screw. This can allow a surgeon to position the screw to target desirable areas of cortical and/or cancellous bone that may not be located directly in line with the longitudinal axis of the screw hole, allowing improved fixation of the bone plate to the bone. In some embodiments, the angle of the screw can vary up to about 12 degrees from the longitudinal axis156of the screw hole.

This concept is applicable to all of the screw holes and compression screw holes of the bone plate, as illustrated inFIGS. 20A-20C and 21A-21B. For example,FIGS. 20A-20Cillustrate exemplary regions of a tibia160in which screws may be inserted through screw holes116,118, and120of the first end portion102of the bone plate100in a representative TPLO procedure. In a TPLO procedure, a bone segment162may be cut from the proximal portion of the tibia with a radial saw blade. A circle indicated at164outlines the path of the osteotomy. Thus, the radially-shaped cut can have a radius substantially equal to a radius of the circle164.

With reference toFIG. 20A, the first end portion102of the bone plate is located generally over the bone segment162, while the second end portion104is located generally over the portion of the tibia distal to the osteotomy.FIG. 20Billustrates a plan view of the tibial head and the tibial plateau163above a side elevation view of the bone segment162. Lines1-1,2-2, and3-3indicate cross-sections taken through the transverse plane of the tibia corresponding to the locations of the screw holes116,118,120on the bone segment162, with section1-1being the cranial-most section and section3-3being the caudal-most section. The cross-sections are illustrated inFIG. 20C, where the medial aspect of the tibia is to the right in the figure. The region bounded by lines165and166illustrates the range of angles at which a bone screw can be advanced into the bone segment162through the screw hole118. The region bounded by lines167and168indicates the range of angles at which a bone screw can be advanced into the bone segment through the screw hole116, and the region bounded by lines169and170indicates the range of angles at which a bone screw can be advanced into the bone segment through the screw hole120. In some embodiments, the screws can be advanced into the bone segment at an angle of up to about 12 degrees from the longitudinal axis of the screw hole, allowing the surgeon to target thicker and/or healthier areas of cortical bone for improved fixation, as described above.

In some embodiments, the screw hole116can be positioned at the geometric center172of the circle164circumscribing the osteotomy, as illustrated inFIG. 20A. Thus, the straight line136(seeFIG. 14) bisecting the compression screw hole122of the second end portion104can also pass near or through the geometric center172of the osteotomy, which can improve compression applied to the osteotomy by the bone plate and reduce movement of the bone segment162after fixation of the bone plate100. For example,FIG. 21illustrates a prior art bone plate positioned over a tibia in which the geometric center of the osteotomy does not coincide with the location of a screw hole.

FIGS. 22A and 22Billustrate exemplary regions of the tibia160in which screws may be inserted through screw holes122,124, and126of the second end portion104of the bone plate. Lines4-4,5-5, and6-6represent cross-sections taken in respective transverse planes of the tibia160through the screw holes122,124, and126, respectively. The cross-sections are illustrated inFIG. 22B. The region bounded by lines174and175illustrates the range of angles at which a bone screw can be advanced into the tibia through the compression screw hole122. The region bounded by lines176and177indicate the range of angles at which a bone screw can be advanced into the tibia through the screw hole124, and the region bounded by lines178and179indicate the range of angles at which a bone screw can be advanced into the tibia through the compression screw hole126. The screws can be advanced into the bone segment at an angle of up to about 12 degrees from the longitudinal axis of the screw hole, as described above.

FIG. 23illustrates a representative embodiment of the bone plate100in a left-handed configuration. In the bone plate ofFIG. 23, the screw holes116-126are also numbered in accordance with an exemplary order in which bones screws can be inserted into the bone. The sequence of use of these holes can be specific to surgical techniques for particular long bone osteotomies. In some embodiments, the objective can be to establish initial fixation between the plate and the bone, then to provide compression to the osteotomy site, and then secure the bone plate and bone together. Each screw hole and compression screw hole can be marked with a number indicating its position in the sequence of screw insertion for a particular operation.

For example, in the illustrated embodiment, a screw can be inserted through compression screw hole122first to provide fixation of the bone plate to the proximal portion of the bone distal to the osteotomy. As shown inFIG. 23, screw hole122can be marked with a “1”. Next, a screw can be inserted through the screw hole120, which can be marked with a “2”. A screw can then be inserted through screw hole116, marked with a “3”, to close the osteotomy gap and compress the bone segment against the remainder of the bone. A screw can then be inserted through compression screw hole126, marked with a “4”, to further compress the osteotomy and provide additional resistance to rotation of the bone segment. Next, a screw can be inserted through screw hole124, marked with a “5”, to provide further fixation of the second end portion104to the bone. A screw can then be inserted through screw hole118marked with a “6” to complete fixation of the bone plate to the bone segment, although it should be understood that insertion of bone screws into the screw holes can be performed in any suitable order depending upon the nature of procedure, etc.

It should be understood that the bone plates and methods described herein are applicable to any long bones in canids, as well as in other mammals including felines and humans. More specifically, the ability to adjust the angle of the screws in combination with the V-shaped cross-section can allow the bone plate100to be used with a variety of long bones and a variety of osteotomy procedures and/or fractures of those bones. The bone plates described herein can also be used on multiple sides of the body, and at the proximal or distal ends of bones without significant modification, contrary to known bone plates. For example,FIGS. 24, 25, and 26illustrate use of the bone plate100in combination with various long bones, including the proximal lateral, distal medial, and distal lateral aspects of the femur (FIG. 24), the proximal lateral and proximal medial aspects of the humerus (FIG. 25), and the proximal medial aspect of the tibia (FIG. 26).

The bone plate embodiments described herein can provide improved initial stability and improved compression at the osteotomy interface, which can yield faster healing in the desired realigned position. In some embodiments, this can be accomplished with a single bone plate family (including multiple sizes) in left and right orientations, as opposed to multiple families of plates with multiple iterations in each family.

In some embodiments, the bone plate100can be made of any biocompatible metal such as, for example, stainless steel, titanium, etc. In some embodiments, the bone plate100can comprise any of various biocompatible polymers or plastics, including polylactic acid, or other aliphatic polymers. When fabricated from polylactic acid, for example, the bone plate can be configured to be naturally resorbed or dissolved by the body after a period of time has elapsed sufficient to allow the osteotomy to heal. For example, in some embodiments the bone plate can be configured to dissolve over a period of from about 8 weeks to about 12 weeks.

FIGS. 27-31illustrate another embodiment of a multi-directional locking screw and associated screw hole that may be used in combination with the bone plates described herein.FIGS. 27 and 28illustrate a portion of a bone plate200including a screw hole202having threads204adapted to engage the head of a locking screw. The threads204can be, for example, female threads, and can be relatively coarse, and can be separated by groove portions206such that the threads are discontinuous around the inner circumference of the screw hole. The screw hole202can also be tapered such that the circumference of the screw hole decreases in a direction from the top surface208to the bottom surface210of the bone plate.

FIGS. 29 and 30illustrate a representative embodiment of a locking bone screw212configured to be received in the screw hole202. The screw212can include a head214and a threaded body216. In some embodiments, the head214can be relatively spherical, and can include relatively coarse threads218(e.g., male threads) to engage the threads204of the screw hole202in the bone plate. In some embodiments, the threads of the body216can be have a relatively larger diameter to increase the strength of fixation to the bone.

With reference toFIGS. 30 and 31A-31C, the screw212can be movable within the screw hole202such that an angle θ defined by a longitudinal axis of the screw with reference to a longitudinal axis of the screw hole202can vary. For example, in some embodiments, the angle θ can be up to about 12 degrees with respect to the longitudinal axis of the screw hole.FIG. 31Aillustrates the screw212angulated to the left with respect to the longitudinal axis of the screw hole,FIG. 31Billustrates the screw aligned with the longitudinal axis of the screw hole, andFIG. 31Cillustrates the screw angulated to the right with respect to the longitudinal axis of the screw hole.

As used herein, the term “long bone” refers to a bone that has a length dimension greater than its diameter or width, and including, for example, the tibia, the femur, and the humerus.

As used herein, the term “proximal” refers to a direction toward the point of origin or attachment, frequently toward the center of the body.

As used herein, the term “distal” refers to a direction away from the point of origin or attachment, frequently away from the center of the body.

General Considerations

Some of the Figures provided herein include an orientation system that designates the X-axis, the Y-axis, and the Z-axis that are orthogonal to each other. In a majority of these Figures, the Z-axis is oriented out of the page. It should be understood that the orientation system is merely for reference and can be varied. For example, the X-axis can be switched with the Y-axis and/or the stage assembly10can be rotated. Moreover, these axes can alternatively be referred to as first, second, or third axes. For example, the X-axis can be referred to as the first axis, the Y-axis can be referred to as the second axis, and the Z-axis can be referred to as the third axis.