Patent Application
20120035666
Bone or fracture voids may occur in many different types of bones in many different ways. For example, an unstable distal radius fracture is common especially in the endemic osteoporotic populations of North America, Europe, Asia, and Australia. This type of low energy fracture may be sustained by a fall on an outstretched hand. The classic, osteopenic osteoporotic fragility fracture is extra-articular or includes a simple intra-articular component, i.e., the fracture is primarily outside of a joint or may include a simple component within the joint. The fracture may result in dorsal comminution, loss of radial height, loss of volar tilt, radial shift, and shortening. In this regard, dorsal comminution refers to pulverization of the bone in the wrist in the direction of the back of the hand, loss of radial height refers to loss of height in the wrist on the side near the thumb, loss of volar tilt refers to loss of tilt in the wrist in the direction of the palm of the hand, and radial shift refers to shift of the wrist towards the side of the thumb. In addition, poor bone mineral quality and the degree of comminution, especially with proximal extension on the radial column, may render this fracture unstable, such that closed treatment alone may be insufficient. Further, the forces experienced by the wrist during daily activities are primarily compression, e.g., digital motion, and shear/torsion, e.g., forearm rotation. Fracture, e.g., catastrophic collapse, occurs typically in tension, thereby creating a relatively transverse fracture across the metaphysis, the metaphysis being the part of a bone between the shaft of the bone, i.e. diaphysis, and the end of the bone, i.e., epiphysis. The position of the wrist, the forces applied, and the bone quality may determine other components of the fracture, such as, for example, extension into the joint, extension into the diaphysis, and more oblique components from torsional forces.
Reduction, i.e., architectural restoration, of a simple but unstable fracture may be obtained through a variety of means. Although there has been a historical preference for non-operative treatment, more invasive treatments intended to restore cortical, i.e. external or surface, integrity have historically included pins and plaster techniques, external fixation, and cross metaphyseal pinning. Later treatment techniques have included dorsal plating systems that address the radial column, and volar plate fixation. Examples of dorsal plating systems include, e.g., Forte Zimmer low profile plate or Synthes pi plate. The more rigid construct required for volar fixation, given its application on the compression side of the radius, has been purportedly outweighed by soft tissue coverage of the volar plate not afforded by dorsal plating systems.
Although plating systems may address cortical reconstitution, they do not address metaphyseal voids that are formed when osteopenic/osteoporotic bone collapses. Further, rigid volar plates may not adequately overcome the loss of cancellous bone in the metaphysis when significant comminution and severe loss of bony architecture has occurred. To fill these metaphyseal voids, patients' autograft bone, banked allograft bone, and/or synthetic fillers, e.g., calcium phosphate or calcium sulfate, may be used. Moreover, although PMMA (polymethylmethacrylate) cement has historically been used as a void filler, this material is rarely used in radius fractures since biologic and biologically active alternatives are preferred.
Plating systems and volar plate fixation may be more substantial and invasive than a patient's bone or fracture void and co-morbidities may warrant. While such fractures may frequently be reduced (architectural reconstitution) by closed manipulation and successfully casted, follow-up examination in the casting period over the next few weeks often shows that fragility fractures experience loss of reduction with resulting deformity. The typical patient with a fragility fracture is elderly and has co-morbid health conditions, which underscores the importance of minimizing risk at the same time as improving treatment methods. In these patients, it is the maintenance of the fracture reduction that is the challenge rather than obtaining a satisfactory reduction in the first place. Aggressive open fracture treatment is best avoided if it is not necessary to obtain reduction.
Reduced bone fracture fixation devices and methods for using the same are provided. Aspects of the reduced bone fracture fixation devices include a body dimensioned to be positioned in a reduced bone fracture, wherein the body includes at least one tension element configured to exert a force on bone of the reduced bone fracture sufficient to maintain reduction of the reduced bone fracture. Aspects of the invention further include kits and methods of using and manufacturing the bone fracture fixation devices. The devices, kits and methods of the invention find use in a variety of applications, such as in applications in which it is desired to repair a reduced bone fracture.
Reduced bone fracture fixation devices and methods for using the same are provided. Aspects of the reduced bone fracture fixation devices include a body dimensioned to be positioned in a reduced bone fracture, wherein the body includes at least one tension element configured to exert a force on bone of the reduced bone fracture sufficient to maintain reduction of the reduced bone fracture. Aspects of the invention further include kits and methods of using and manufacturing the bone fracture fixation devices. The devices, kits and methods of the invention find use in a variety of applications, such as in applications in which it is desired to repair a reduced bone fracture.
Before the present invention is described in greater detail, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.
Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.
Certain ranges are presented herein with numerical values being preceded by the term “about.” The term “about” is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrecited number may be a number which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, representative illustrative methods and materials are now described.
All publications and patents cited in this specification are herein incorporated by reference as if each individual publication or patent were specifically and individually indicated to be incorporated by reference and are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.
It is noted that, as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.
As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present invention. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.
In further describing various aspects of the invention in greater detail, embodiments of devices of the invention are reviewed first, followed by descriptions of embodiments of the methods and manufacture and use of the devices, as well as kits that include the devices.
Reduced bone fracture fixation devices are devices that are configured to maintain reduction of a reduced a bone fracture. In some instances, the devices can be used to reduce a bone fracture. By “reduced bone fracture” is meant a bone fracture wherein the fractured pieces of bone have been restored to their normal or nearly normal anatomic alignment. The goal of fracture treatment is to maintain the bone in a reduced position, i.e., properly aligned, while the bone heals. Accordingly, a reduced bone fracture is a fracture in which the fractured pieces of bone have been restored to the substantially normal, if not normal, anatomic alignment. As is known in the art, a fracture may be reduced by a variety of different reduction protocols. In some instances, the subject devices can be used to reduce or partially reduce a bone fracture. In some instances, the subject devices can be used to both reduce and maintain reduction of a bone fracture. Reduced bone fractures with which devices of invention find use are fractures that have been reduced using any convenient protocol.
As indicated above, the subject devices are configured to exert a force on the surfaces of a reduced bone fracture to maintain the bone in a reduced (i.e., anatomically or nearly anatomically aligned) position. The subject devices can exert forces that include but are not limited to: distraction forces (i.e., forces in which pieces of bone are forced in opposite directions), torsional forces (to prevent a piece of fractured bone from rotating), expansion forces (to resist compression), retention forces (to prevent a bone fragment from migrating), etc.
The reduced bone fracture fixation devices of the subject invention have a body dimensioned to be positioned in a reduced bone fracture. By “dimensioned to be positioned in a reduced bone fracture” is meant that the body of the device can be any size suitable for positioning in the reduced fracture site of interest, which can include, but is not limited to, the distal radius, proximal humerus, proximal tibia, calcaneus, vertebral body, hip, etc. The dimensions of the subject devices can vary according to the size of the bone at the reduced fracture site of interest, the extent or size of the fracture, the size of the subject (e.g., child or adult), etc. The subject devices can be positioned so that they are located entirely within the fracture site; i.e., no portion of the device extends outside of the bone, which minimizes irritation of the surrounding soft tissues. In certain embodiments, the devices have a longest dimension ranging from 3 mm to 6 cm, such as 4 mm to 5 cm, and including 8 mm to 4 cm. In certain embodiments, when fully deployed, the device will occupy a volume ranging from 27 mm3 to 10 cm3, such as 50 mm3 to 8 cm3 and including 1 cm3 to 6 cm3.
The subject devices include at least one tension element. By “tension element” is meant the portion or portions of the body of a reduced fracture fixation device which is configured to exert a force on bone. The force exerted by the one or more tension elements on bone of a reduced fracture is sufficient to maintain reduction of the reduced bone fracture. In some embodiments, the tension element can include the entire body of the device. The amount of force exerted by the one or more tension elements on the surfaces of the bone at a reduced bone fracture site is sufficient to maintain reduction of the reduced bone fracture. When deployed, the one or more tension elements can exert force on a single bone portion of the reduced bone fracture or two or more different bone portions, depending on a number of factors, such as the particular device configuration, the anatomical structure of the reduced fracture, etc.
The amount and direction of the force exerted by the reduced bone fracture fixation devices of the invention can be determined by a number of factors, including variations in the configuration of the device, differences in the material used to construct the subject devices, differences in the dimensions or thickness of the subject device, etc. In some instances, the force exerted can range, for example, from 2 lbf to 60 lbf, such as from 5 lbf to 40 lbf, or 10 lbs. to 20 lbs. of pound-force (lbf).
The subject devices can have different configurations, which can vary depending on the materials and methods used for constructing the device. In some configurations, the devices are configured to undergo a conformational change from a pre-deployed to a deployed state, where in the deployed state the radial width (i.e., a dimension transecting the longitudinal axis at a right angle) a one of the device is longer than the radial width at the other end of the device, e.g., by a factor of 2-fold or more, such as 5-fold or more, including 10-fold or more. The transition from the pre-deployed to a deployed state may achieved using any convenient protocol, e.g., by removal of a constraining element during implantation of the device, etc. Devices of these configurations are therefore distinguished from those devices disclosed in U.S. Published Patent Application 20090143781. In some configurations, the devices are not “caged” devices, i.e., devices that include a first component present inside of a second cage component, such as those devices described in U.S. Published Patent Application 20090182336. Configurations of the subject devices can include, but are not limited to: a conical screw configuration, configurations that can be constructed of wire or a planar element which can include a biased hinge or spring configuration, a looped or coiled configuration, a leaf spring configuration, a ratcheted configuration, etc. In some instances, the devices can be formed by a combination of any of the above configurations, such as a conical screw configuration combined with a wire element, or a wire embodiment combined with one or more planar embodiments, or a conical screw embodiment combined with both a wire embodiment and a planar embodiment, etc. Embodiments of the subject devices which include these various configurations are discussed further below.
The devices can be manufactured using any convenient protocol. For example, the subject devices can be produced by molding, stamping, or machining a piece of metal; by bending or mechanical manipulation of wire; by folding or mechanical manipulation of a planar element, such as a ribbon, etc.
As mentioned above, devices of the invention are reduced fracture fixation devices. The devices may be configured for use with a wide variety of different types of reduced fractures. Different types of reduced fractures of interest include, but are not limited to: fractures of the radius, ulna, humerus, femur, tibia, fibula, clavicle, scapula, spine, vertebral body, ribs, pelvis, carpal bones, tarsal bones, metacarpals, metatarsals, etc., and the like.
In some embodiments, the reduced fracture is a reduced distal radius fracture.
The bone fracture 15 illustrated in
Conical Screw Embodiment
In one embodiment, the reduced bone fracture fixation device is configured as a conical screw. The body of the device can be generally in the shape of a cone, i.e., it can generally taper from a wider diameter at the proximal end of the device to a narrow diameter (e.g., a point) at the distal end of the device. In some instances, the conical screw does not have a “head”, that is, the widest portion of a standard screw that engages with a screwdriver (i.e., the conical screw is a headless screw). The body of the conical screw embodiment can be solid or it can be at least partially hollow. As such, at least a portion of the interior volume of the screw may be void space. For example, the device can have an internal passageway through at least a portion of the length of the device, e.g., the distal end of the device. In some instances in which the screw is hollow, the screw is cannulated, such that an internal passageway is defined inside of the screw from one end of the screw to the other, i.e., the screw is tubular. In a cannulated embodiment, the device can have an internal passageway extending the length of the device, e.g., from the proximal portion of the screw to the distal point of the screw.
In embodiments in which the conical screw has an internal passageway or opening, the opening forms a “wall”, i.e., the portion of the conical screw that surrounds the opening. In some embodiments the wall of the screw is continuous around the entire circumference of the conical screw. In some embodiments, one or more portions of the wall can have cut-outs such that the wall has “windows”, or openings, where there is communication between the internal passageway of device and the outside of the body of the device through the opening in the wall. The cut-outs can be any suitable shape (e.g., oval, ellipse, rectangle, etc.) or size, and can have any orientation with respect to the long axis of the device (e.g. longitudinal, diagonal, transverse, etc.)
In other embodiments, the wall of the conical screw is discontinuous at the proximal end of the device, e.g., the wall is formed of one or more segments. In some embodiments, therefore, the conical screw can have one or more extensions, or arm segments.
By “arm segment” is meant a proximal extension of a portion of the body of the device from the distal end of the device. In some embodiments, the subject device can have two or more arm segments, or three or more, or four of more, five or more, etc. The arm segments of a subject device can be separated by various distances. The arm segments can also be of various lengths, which can depend on the overall size and configuration of the device. In some embodiments, one or more individual arm segments can have cut-outs that provide “windows”, or openings formed within them, such that there is communication between the internal passageway of device and the outside of the body of the device through the opening in the arm segment.
For embodiments in which the reduced bone fracture fixation device includes one or more arm segments, the device may further include a first locking element, e.g., a hook, loop, or other feature, on a first arm segment at the proximal end of the device. The device may further include a second locking element, e.g., a hook or other feature, on a second arm segment at the proximal end. The first locking element and the second locking element may be configured to lock together, to constrain a maximum distance between the first arm segment and the second arm segment.
The reduced bone fracture fixation devices can also include one or more bone securing elements. By “bone securing element” is meant an element configured to secure the reduced bone fracture fixation device to bone at the surface of a reduced bone fracture or fracture void, such that the position of the reduced bone fracture device is maintained once it has been placed into the reduced fracture site (in other words, the device retains its position following placement). The bone securing element can be, for example, one or more threads on the outside surface of the device, such as threads on a screw; the bone securing element can also be barbs; hooks; loops; bumps; spurs; footholds; knuckles; coils, anchors; or other features etc.
In one embodiment of the conical screw configuration, the bone securing element is a spiral thread or ridge that extends along at least a portion of the external surface of the conical screw device. In some instances, the pitch of the thread can be the same, and in some instances, the pitch of the thread may be variable. In these instances, the pitch of the thread (i.e., distance between the threads) may vary as desired. In some instances, the pitch ranges from 1 mm to 1 cm, such as 1.5 mm to 5 mm and including 2 mm to 3 mm. In some embodiments, the pitch may be variable along the length of the screw, e.g., the pitch may be smaller at the distal end, and widen at the proximal end. In some embodiments, the pitch can be single or double start thread. The thread or ridge can in some instances have a sharp peak, as shown in
The subject device can also have various configurations between the threads, e.g., the ‘valley’ or grooves between the threads can be in a V-shape, or a U-shape, etc. Additionally, the depth of the “valley” or conversely, the height of the thread or ridge can also vary along the length of the screw embodiment. For example, the grooves can be shallower at the proximal end in order to provide more surface for contact with the surrounding bone.
The device can have any suitable diameter. In some instances, the diameter ranges from 3 mm to 3 cm, such as from 5 mm to 2.5 cm, or 5 mm to 2 cm. Additionally, the dimensions of the device can vary from one end of the device to the other, e.g., as for example with a conical screw embodiment. In some instances, the length of the device ranges from 3 mm to 6 cm, such as 4 mm to 5 cm, and including 8 mm to 4 cm.
The subject devices can in some embodiments be configured to be delivered to a reduced bone fracture site of interest using one or more tools, such as a guidewire, a grasping tool, a screwdriver, etc. For example, in a cannulated or hollow conical screw embodiment, the device can be deployed to a fracture site using a guidewire. In another example, the device can be positioned in a fracture site by using a tool such as a screwdriver adapted for use with the device (e.g. a hex head, cruciate, Phillips, Torx, or other three-dimensional locking method).
The angle of the conical screw, i.e., the angle formed between the distal point of the cone and the sides or walls of the cone can vary, e.g., in some embodiments the cone can be wider, or have a larger angle, and in other embodiments the cone will be narrower, or have a smaller angle. Accordingly, the volume of the internal open space of the conical screw embodiment will vary with changes in the above described angle. The volume of the internal open space will vary as well as with changes in length of the device, width of the internal passageway, etc.
Wire Embodiments
In another embodiment, the reduced bone fracture fixation device can have a configuration suitable for construction from wire. Wire embodiments of interest include, but are not limited to, those embodiments disclosed in PCT application Serial No. PCT/US10/24753, the disclosure of which is herein incorporated by reference. The wire can, in some embodiments, be formed into loops, coils, hinges, curves, pivots, or be curved or shaped to form a cage of various shapes, etc., or a combination thereof. The shape of the body of the device can therefore be any three-dimensional shape, such that the device can be successfully positioned in a reduced bone fracture. The shape of the subject devices can include, but is not limited to, a trapezoidal, pyramidal, cylindrical, conical, oblong, ovoid, cuboid, rectangular prism, triangular prism, or hexahedral shape, one or more “V” shapes, an “umbrella shape”, etc. The shapes may be symmetric or asymmetric, and in some embodiments a reduced bone fracture fixation device can include more than one shape or can vary in shape.
The cross-sectional configuration of the wire can be any suitable shape, such as round, oval, rectangular, square, etc. The wire can be of any diameter, which can range from 0.2 mm to 4 mm, such as from 0.3 mm to 3 mm, or 0.5 mm to 2.5 mm diameter. The wire may also vary in diameter along the length of the wire, such that the wire can have a smaller or larger diameter in some portions of the wire. For example, the wire may have a reduced or smaller diameter along one or more portions of an arm segment, etc. In some embodiments, the device may be formed of a continuous wire. In other embodiments, the device may be formed of more than wire. The overall dimensions for a reduced bone fracture fixation device for use in a reduced fracture site may have a length, or longest axis, which can range from 3 mm to 6 cm, such as 4 mm to 5 cm, and including 8 mm to 4 cm. Additionally, the dimensions of the device can vary from one end of the device to the other, e.g., as for example with a triangular prism embodiment. As discussed above, the actual dimensions of the reduced fracture fixation device will vary according to the size of the fracture, the size and extent of the fracture site, etc.
In some embodiments, the subject devices constructed from wire can have one or more extensions, or arm segments, i.e., a portion of the body of the device that extends proximally from the distal end of the device. As discussed above, the subject device can have two or more arm segments, or three or more, or four or more, etc. The arm segments of a subject device can be separated by various distances. The arm segments can also be of various lengths, which can depend on the overall size and configuration of the device.
For embodiments in which the reduced bone fracture fixation device includes one or more arm segments, the device may further include a first locking element, e.g., a hook, loop, anchor, or other feature, on a first arm segment at the proximal end of the device. The device may further include a second locking element, e.g., a hook, loop, anchor, or other feature, on a second arm segment at the proximal end. The first locking element and the second locking element may be configured to lock together to constrain a maximum distance between the first arm segment and the second arm segment. The locking elements can in some instances be joined together by an additional process, such as welding, or laser welding. The locking elements can be integral to the arm segments, or they can be separate elements.
The reduced bone fracture fixation devices configured from wire can also include one or more bone securing elements, i.e., an element configured to secure the fixation device to bone at the surface of a reduced bone fracture. The bone securing element can be, for example, barbs; hooks; loops; bumps; spurs; footholds; knuckles; coils, anchors; or other features etc. The bone securing elements can be located in any suitable location on the body of the device. In one embodiment, the bone securing element can located at the proximal end of one or more arm segments.
The reduced bone fracture fixation devices can also include one or more fastening elements. By “fastening element” is meant an element configured to maintain the reduced bone fracture fixation device in an un-deployed configuration prior to positioning the device in a reduced fracture site. The fastening element can also, in some instances, function to maintain the device in a deployed configuration (e.g., by locking an expanded coil in the expanded configuration). In some embodiments, the device can include a release mechanism. By “release mechanism” is meant an element that releases the fastening element to allow the device to deploy (e.g., expand). The release mechanism can be, for example, a button, a switch, etc. A fastening element can be secured to the reduced fracture fixation device, such that the fastening element can be released to allow the reduced fracture fixation device to expand once it has been placed into the reduced fracture site. In some instances, the fastening element can then lock the expanded device in place. The fastening element may be formed integrally with the device, or the fastening element may be a separate element. The fastening element can be any suitable shape, such as a rectangular prism, a clip, a hook, a clasp, a band, etc.
As an example, the reduced fracture fixation device may be in the shape of a small-diameter cylindrical coil, and when a fastening mechanism is released, the fixation device may expand into a larger diameter conical shape (see, e.g.,
The subject devices can be configured to be delivered to a reduced bone fracture site of interest using one or more tools, such as a grasping tool, or a forceps, a guidewire, etc.
According to one embodiment of the present invention, a reduced fracture fixation device may include a resilient hinge, a first arm extending from one end of the hinge, and a second arm extending from another end of the hinge, in which each of the hinge, the first arm, and the second arm includes at least one loop formed from wire. The hinge may be configured to bias the first arm and the second arm away from each other, such that the two arm elements are configured to apply opposing forces on bone of the reduced bone fracture. The hinge and the first and second arm segments can be formed from a single wire, or from multiple wires joined together. A plane defined by the at least one loop of the first arm segment may be substantially parallel to a plane defined by the at least one loop of the second arm segment. A plane defined by the at least one loop of the hinge may be substantially perpendicular to each of a plane defined by the at least one loop of the first arm segment and a plane defined by the at least one loop of the second arm segment. The hinge, the first arm, and the second arm together may substantially form one of a trapezoidal, pyramidal, triangular, conical, oblong, and ovoid shape. In some embodiments, the subject device is not the device disclosed in PCT application Serial No. PCT/US10/24753.
The subject device as shown in
The bone fracture fixation device 51 as shown in
As shown in
In the embodiment shown in
Although the embodiment illustrated in
The hinge 62 may be configured such that the first arm segment 61a and the second arm segment 61b are biased away from each other. By this mechanism, the device 61 may provide additional tension to the fracture and sufficiently fill the void, thereby acting as a three-dimensional reduction device and providing load-sharing. Because the reduced bone fracture fixation device 61 itself acts as the reduction device, additional bone grafts or filler substitutes to fill the metaphyseal void may be unnecessary.
Further, the embodiment shown in
When locked together, the two locking elements 65a and 65b form an oblique radial strut between the bone securing elements 66a and 66b. That is, the bone securing elements 66a and 66b and the locking elements 65a and 65b may form a strut that traverses the radial side 63 of the fracture, e.g., from a dorsal, distal side of the fracture (e.g., at location 56a in
As shown in the exemplary embodiment of the reduced bone fracture fixation device 61 of
In another embodiment,
An embodiment in which the reduced bone fracture fixation device is configured as a conical cage formed of wire is shown in
As discussed above, the reduced bone fracture fixation device can also be configured to have both an un-deployed configuration, prior to being placed in the target fracture site, and a deployed configuration once the device is positioned in the fracture site. For example,
The embodiment shown in
Planar Element Embodiments
In another embodiment, the reduced bone fracture fixation device can have a configuration suitable for construction from a planar element. By “planar element” is meant a flat, essentially two-dimensional element, such as a ribbon or sheet. The shape of the subject devices can include, but is not limited to, one or more “V” shapes, a trapezoidal, pyramidal, cylindrical, conical, oblong, ovoid, cuboid, rectangular prism, triangular prism, or hexahedral shape, an “umbrella shape”, etc. The shapes may be symmetric or asymmetric, and in some embodiments a reduced bone fracture fixation device can include more than one shape or can vary in shape. The planar element can also be curved, e.g., in a concave or convex direction, or can be curved or shaped to form a cage of various shapes as disclosed above. In some embodiments, the device may be formed of one or more planar elements, or a combination of one or more planar elements and one or more wire elements.
The shape of the body of the device can therefore be any suitable three-dimensional shape, such that the device can be successfully positioned in a reduced bone fracture. The planar element can be any width, which can range from 3 mm to 6 cm, such as from 4 mm to 4 cm, or 5 mm to 3 cm. In some embodiments, the device may be formed of a continuous planar element. In other embodiments, the device may be formed of more than planar element joined together. The overall dimensions of the device can have a length, or longest axis, which can range from 3 mm to 6 cm, such as 4 mm to 5 cm, and including 8 mm to 4 cm. Additionally, the dimensions of the device can vary from one end of the device to the other, e.g., as for example with a “V”-shaped embodiment. As discussed above, the actual dimensions of the reduced fracture fixation device will vary according to the size of the fracture, the size and extent of the fracture site, etc.
In some embodiments, the subject devices constructed from a planar element can have one or more extensions, or arm segments, i.e., a portion of the body of the device that extends proximally from the distal end of the device. As discussed above, the subject device can have two or more arm segments, or three or more, or four or more, etc. The arm segments of a subject device can be separated by various distances. The arm segments can also be of various lengths, which can depend on the overall size and configuration of the device.
For embodiments in which the reduced bone fracture fixation device includes one or more arm segments, the device may further include a first locking element, e.g., a hook or other feature, on a first arm segment at the proximal end of the device. The device may further include a second locking element, e.g., a hook or other feature, on a second arm segment at the proximal end. The first locking element and the second locking element may be configured to lock together to constrain a maximum distance between the first arm segment and the second arm segment.
The reduced bone fracture fixation devices configured from wire can also include one or more bone securing elements, i.e., an element configured to secure the fixation device to bone at the surface of a reduced bone fracture. The bone securing element can be, for example, barbs; hooks; loops; bumps; spurs; footholds; knuckles; coils, anchors; or other features, etc. The bone securing elements can be located in any suitable location on the body of the device. In one embodiment, the bone securing element can located at the proximal end of one or more arm segments.
The reduced bone fracture fixation devices can also include one or more fastening elements, i.e., an element configured to maintain the reduced bone fracture fixation device in an un-deployed configuration prior to positioning the device in the reduced fracture site. The fastening element can also, in some instances, function to maintain the device in a deployed configuration (e.g., by locking an expanded device in the expanded configuration). In some embodiments, the device can include a release mechanism, e.g., a button, a switch, etc. A fastening element can be secured to the reduced fracture fixation device, such that the fastening element can be released to allow the reduced fracture fixation device to expand once it has been placed into the reduced fracture site. The fastening element may be formed integrally with the device, or the fastening element may be separate. The fastening element can be any suitable shape, such as a rectangular prism, a clip, a hook, a clasp, a band, etc.
As an example, the reduced fracture fixation device may be in the shape of a flat triangle formed by one or more planar elements, such that the triangle has a central opening (see, e.g.,
The subject devices can be configured to be delivered to a reduced bone fracture site of interest using one or more tools, such as a grasping tool, plier, clip, forceps, hollow tube cannula, introducer, plunger, sled, and other assistive devices that may deliver, deploy, and/or protect soft tissues in the delivery of the device.
Additional embodiments of reduced bone fracture fixation devices formed from essentially planar elements are shown in
As discussed above, in some embodiments, the device may be formed of a combination of one or more planar elements and one or more wire elements. For example,
In addition, the arm segments of the embodiments as shown in
In some instances, an interchangeable element can provide force on bone of a reduced bone fracture at an additional location on the bone. For example, a subject device can be configured as a planar embodiment with two arm segments, as in
An interchangeable element can be configured to mate with the body of a subject device by using a feature in the body of the device (e.g., the body of the device is configured with one or more slots, notches, grooves, etc.). In some instances, an interchangeable element can be configured to mate with the body of a device by a feature in the interchangeable element (e.g., the interchangeable element can have one or more clips, clasps, hooks, etc.). In some instances both the body of the device and the interchangeable element can be configured to mate by complementary features (e.g, a notch that fits into a slot, or protrusions that interdigitate, etc). In some embodiments, a separate attaching element can be used to mate one or more interchangeable elements to the body of the device (not shown). By “attaching element” is meant an element that securely mates one or more interchangeable elements with a body of the device (e.g., a clip, clasp, band, etc). In some instances, an interchangeable element can be configured to mate with the body of the device such that it overlaps with a portion of the body, e.g., the interchangeable element overlaps the proximal portion of an arm segment, such that the arm segment may remain essentially the same length. In other instances, an interchangeable element can be configured to mate with the body of the device such that it does not overlap with a portion of the body, e.g., the interchangeable element mates with the proximal end of an arm segment such that it extends the length of an arm segment. In some instances, an interchangeable element can be formed of more than one part, e.g., a planar ring and a coiled spring, as shown in
The interchangeable element can have any suitable configuration such that the interchangeable element can provide force on bone of a reduced bone fracture. The interchangeable element can therefore vary in shape, tension, or dimension. For example, the interchangeable element can be in the shape of a spring mounted on a flat washer, as shown in
The reduced bone fracture fixation devices described above can be made of a variety of biocompatible materials or metallic materials that combine strength, flexibility, and fatigue resistance. For example, the fixation device can be formed using at least one of autograft or allograft bone, stainless steel, titanium, a nickel-titanium alloy such as nitinol, a nickel-cobalt alloy, another cobalt alloy, a vanadium alloy, tantalum, chromoly steel or CRMO, PEEK 15 (polyaryletheretherketone), other biocompatible polymers and plastics, and combinations or mixtures thereof. In some embodiments, the reduced bone fracture fixation devices or any portion thereof can include shape memory materials, which are materials that have a temperature induced phase change, e.g., a material that if deformed when cool, returns to its “undeformed”, or original, shape when warmed.
In some embodiments, the fixation device may be coated with a substance, over the entire device or a portion of the surface of the device. In some embodiments, the coating can include a therapeutic agent (e.g., an antibiotic, an anti-inflammatory agent), an agent to promote osteo-integration (e.g., hydroxyapatite), a hardening agent (e.g., titanium nitride), an anodizing treatment, etc. In some embodiments, a fixation device may be coated with a combination of agents, e.g., antibiotics and anti-inflammatory agents; agents or features to promote osteo-integration, etc. In other embodiments, a fixation device may have more than one coating. For example, a reduced bone fracture fixation device can be coated with an antibiotic agent and also have an anodizing treatment applied to the device.
The subject devices can be used in conjunction with various fixation devices as known in the art, such as a K-wire, nails, screws, rods, staples, etc. The reduced bone fracture fixation devices can also be configured to be used with bone graft including autograft or allograft, osteoconductive or osteoinductive synthetic graft, Bone Morphogenetic Proteins (BMPs), or bone cements (e.g., calcium phosphate, calcium sulfate, etc.).
The subject devices and methods can be used in open surgical methods, such that the device may be configured to be implanted with minimal soft tissue invasion and bony disruption. The subject devices and methods can be also be used in minimally invasive surgical, or interventional procedures.
After implantation, the subject devices can maintain reduction of a fracture by acting as a cortical strut and a three-dimensional reduction device filling the metaphyseal void. The reduced bone fracture fixation device provides sufficient resistance to forces to maintain reduction of a fracture (e.g., compressive and torsional forces, which can pull the bone out of alignment during the fracture healing phase). In the case of a distal radius fracture, the healing process typically lasts from 4 to 8 weeks.
The reduced bone fracture fixation device can also provide load-sharing healing of the fracture site. Reduced and maintained fractures will heal even if some defect cavitation has occurred from the fracture itself, since the fracture has direct exposure to bone marrow elements with active bone cells (osteoblasts, osteoclasts, osteocytes, and other blood elements known to influence bone healing and remodeling) provided the fracture remains reasonably stable. Additionally, the subject devices do not require a second procedure for removal of the device, e.g., as required with conventional plate and screw fixation. However, these devices can be removed either in the acute setting due to unforeseen factors such as infection by direct manipulation and extraction. The devices can also be removed even in the setting of a healed fracture by either compression and unscrewing in the conical screw design, or controlled corticotomy with wireform compression, cutting, and removal. In the latter cases, the overall healed fracture integrity is maintain in a three-dimensional phase.
Further, the subject devices may include slight over-distraction of the arm segments such that slight compression by the surrounding soft tissues results when the device is implanted into a bone or fracture void, providing further resistance to motion.
The subject devices find use in methods for repair of a bone fracture. The subject devices can be used in an open surgical procedure, a minimally invasive surgical procedure, or in some embodiments, an interventional procedure.
Methods of using a reduced bone fracture fixation device can include identifying a subject with a bone fracture, reducing the bone fracture, and then introducing into the reduced bone fracture a device comprising a body dimensioned to be positioned in the reduced bone fracture. The subject devices can be inserted into a bone or fracture void, such that body of the device cooperates to tension the bone or fracture void. For example, the reduced bone fracture fixation device may be configured as a conical screw embodiment, with a distal point, and external thread, and a first and a second arm segment at the proximal end of the device.
Methods of reducing a fracture can include a closed or open reduction, as is known to those of ordinary skill in the art (e.g., such as can be found in Campbell's Operative Orthopaedics, S. Terry Canale, Editor; or Operative Techniques in Orthopaedic Surgery, Sam Wiesel, Editor in Chief; Hand Surgery, Editors: Richard Berger & Arnold-Peter Weiss, Lippincott, Williams & Wilkins, 2004; Rockwood and Green's Fractures in Adults; or any suitable online resource such as Orthopaedic Knowledge Online (OKO), etc.)
Following reduction of a fracture, methods can include verification of the position and alignment of the fracture fragments, e.g., using an imaging method, such as an x-ray or portable intra-operative mini-fluoroscopy, etc.
Methods of introducing the subject devices into a reduced fracture site can include the selection of the correct size and/or configuration of the subject device. Selection of an appropriate device can be performed by medical personnel, e.g., a surgeon, prior to a procedure or during the procedure, and can include evaluation of imaging studies (e.g., x-ray, CT, MRI), measurements taken of the fracture site, measurements obtained of the fracture site in the operating or procedure room, etc.
Methods of the subject invention can also include the use of any suitable tools for assisting in the use of the device. Such tools may include, e.g., forceps, tweezers, clamps, graspers, applicators, screwdrivers adapted for use with the device (e.g. a form fit shape such as a hex, cruciate, Torx, or Phillips design), guidewires, sheaths, catheters, and any specially-designed tools.
The device may be implanted through an incision providing access to the bone or fracture void. For example, for a distal radial fracture, the incision may be volar-radial, i.e., the Henry approach, or dorsal-radial between the first and second dorsal compartments. The fracture may be approached around the first dorsal compartment, releasing the distal-most fibers of the brachioradialis if necessary, and accommodating the instrumentation for distraction and reduction. This procedure may be performed with manual reduction. Although the exemplary embodiments disclosed herein refer to implanting the device within a distal radial fracture, it is understood that the device may be implanted in other bone fractures, voids, or defects of other bones, e.g., vertebral bodies, calcaneous, etc. as discussed above.
For implantation of the device within a distal radial bone or fracture void, the distal end of the device may be inserted first so that it becomes positioned on an ulnar side of the fracture, or the device may be inserted in any other orientation. In an embodiment in which the device includes a hinge which biases the first and second arm segments away from each other, the arms may be compressed together during implantation in order to decrease the insertion profile of the device. During implantation, the first arm segment may be oriented so that it is near the dorsal (larger) side of the fracture, and the second arm segment may be oriented so that it is near the volar (smaller) side of the fracture. After the device has been inserted into and properly located within the bone or fracture void, the compression on the arms may be released.
The device may also include bone securing elements and locking elements. After implantation, the bone securing elements may attach to bone adjacent the bone or fracture void, thereby securing the device within the bone or fracture void. For example, the bone securing element may attach to bone on a distal side of the bone or fracture void, and the bone securing element may attach to bone on a proximal side of the bone or fracture void, or vice versa. In addition, locking elements may engage with each other in order to constrain a maximum distance between the first arm segment and the second arm segment within the bone or fracture void.
In some instances, methods of treating a reduced fracture can include using the subject devices with additional elements, including fixation elements, or synthetic bone graft, or any suitable bone cement. For example, a fracture of the proximal tibia may be successfully reduced and treated with a device of the subject invention (e.g., a device with a conical screw configuration) however there may be an additional bone fragment or fragments that can be positioned with a fixation device, such as a K-wire, plates, or pin. In another example, a fracture of the proximal humerus may be successfully reduced and treated with a device of the subject invention (e.g., a device with a cylindrical coil configuration), however the fracture void may be large enough to require “filler” in the form of bone graft including autograft or allograft, synthetic graft, or bone cements (e.g., calcium phosphate, calcium sulfate, etc.). In yet another example, a compression fracture of a vertebral body may be successfully reduced and treated with a device of the subject invention (e.g., a pyramid-shaped device as in
After the reduced bone fracture has been treated as described above, methods of treating the reduced fracture generally include a period of immobilization, e.g., with a splint or cast. In some instances, the period of immobilization can range from one week to 3 months, such as from two weeks to 2 months, or 1 month to 8 weeks. In embodiments in which an additional fixation device has been employed, the fixation device may need to be removed.
Methods of Manufacture
Methods of manufacturing the reduced bone fracture fixation device may include methods of forming the subject devices from a wire, include forming a resilient hinge by at least one loop, forming the first arm segment by at least one loop at one end of the hinge, and forming the second arm segment by at least one loop at the other end of the hinge. The reduced bone fracture fixation device may include a resilient hinge, a first arm segment attached to one end of the hinge, and a second arm segment attached to another end of the hinge, in which each of the hinge, the first arm segment, and the second arm segment includes at least one loop formed from wire.
For example,
As illustrated in
The bone securing elements 156a and 156b may be formed as one or more loops, bumps, barbs, spurs, footholds, knuckles, coils, or other features to secure the device within a bone or fracture void. In addition, the locking elements 155a and 155b may be formed as hooks or other features to interlock or constrain the free proximal ends of the first and second arm segments 151a and 151b.
From the partially formed configuration shown in
In addition to bending or mechanical manipulation of wire, in some embodiments the reduced fracture fixation device can be formed by other techniques or methods, such as molding, stamping, machining, extrusion, scoring, or any other techniques or combination of techniques suitable for the particular material used. In some embodiments, the subject device can be formed from a planar element, as shown below.
Methods of manufacturing the reduced bone fracture fixation device may also include methods of forming the subject devices from a planar element.
Another embodiment of the method of making the subject device is shown in
Methods of manufacturing the reduced bone fracture fixation device may include applying one or more coatings to all or a portion of the device, as discussed above. Such coatings include but are not limited to therapeutic agents, osteo-integration agents, hardening agents, anodizing treatments, etc.
Accordingly, the device may be formed so as to be implanted with minimal soft tissue invasion and bony disruption. Also, the device may be formed to restore metaphyseal and cortical collapse of a bone or fracture void. Further, the device may be formed to directly tension a bone or fracture void while maintaining reduction.
The description of the present invention is provided herein in certain instances with reference to a subject or patient. As used herein, the terms “subject” and “patient” refer to a living entity such as an animal. In certain embodiments, the animals are “mammals” or “mammalian,” where these terms are used broadly to describe organisms which are within the class mammalia, including the orders carnivore (e.g., dogs and cats), rodentia (e.g., mice, guinea pigs, and rats), lagomorpha (e.g., rabbits) and primates (e.g., humans, chimpanzees, and monkeys). In certain embodiments, the subjects, e.g., patients, are humans.
Kits
Also provided are kits that at least include the subject devices. The subject kits at least include a reduced bone fracture fixation device of the subject invention and instructions for how to use the device in a procedure.
In some embodiments, the kits can include a set of two or more reduced bone fracture fixation devices. In other embodiments, a set of devices can include at least three reduced bone fracture fixation devices, e.g., four or more, five or more, six or more, etc.
In some embodiments, a set of reduced bone fracture fixation devices includes two or more devices in which at least two of the bone fracture fixation devices are of different sizes. For example, in one embodiment a set of three reduced bone fracture fixation devices can be provided in a “small” size; a “medium” size; and a “large” size, which can vary in length along the longest axis of the device. The set of reduced bone fracture fixation devices can also be provided as a set of devices configured for a particular fracture site; e.g. proximal tibia, proximal humerus, hip, etc. In other embodiments, a set of devices e.g., for the distal radius, can be provided with both different sizes, and different configurations, in which some configurations might be more suited for a particular fracture site than other configurations.
In some instances, devices of different size, or devices for different sites may be labeled in any suitable manner to distinguish one size from another, or to distinguish a device for one site from another. For example, a “small” size wrist fracture fixation device can have an anodized treatment imparting a red color to the device, while the “medium” size fracture fixation device can have an anodized treatment imparting a blue color to the device.
In some instances, a kit can include one or more devices with one or more interchangeable elements, such that the interchangeable element that is best suited for a particular fracture site (e.g., optimal shape, size, degree of tension, etc.) can be selected and attached to the body of the device. The kit can also include a sizing and/or measuring tool, which can be disposable, for determining a desired size or configuration of bone fracture fixation device by measuring one or more distances, such as the distance between the surfaces of reduced fracture, the extent of the fracture, etc. The measuring tool can be any suitable measuring device, such as a sizer, a template, a caliper, a sterile disposable flexible tape measure, etc.
The kit can also include one or more tools configured to position a reduced bone fracture fixation device in a reduced bone fracture. The positioning tools can be disposable. Such tools may include, e.g., forceps, tweezers, clamps, graspers, applicators, screwdrivers adapted for use with the device (e.g. a form fit tip using for example a hex, cruciate, Torx, or Phillips design), guidewires, sheaths, catheters, and any specially-designed tools.
Other elements which can be included in the kit include any suitable bone cement (e.g., calcium phosphate cement), synthetic bone graft, BMP, PMMA (polymethylmethacrylate) cement, etc., or, which can be used with subject devices at the fracture site. The kits can also include one or more separate fixation elements, such as a K-wire, plates, etc.
The instructions for using the devices as discussed above are generally recorded on a suitable recording medium. For example, the instructions may be printed on a substrate, such as paper or plastic, etc. As such, the instructions may be present in the kits as a package insert, in the labeling of the container of the kit or components thereof (i.e. associated with the packaging or subpackaging) etc. In other embodiments, the instructions are present as an electronic storage data file present on a suitable computer readable storage medium, e.g., CD-ROM, diskette, etc. The instructions may take any form, including complete instructions for how to use the device or as a website address with which instructions posted on the internet may be accessed.
All publications and patent applications cited in this specification are herein incorporated by reference as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention.
Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.
Pursuant to 35 U.S.C. §119 (e), this application claims priority to U.S. Provisional Application Ser. No. 61/494,294 filed on Jun. 7, 2011; U.S. Provisional Patent Application Ser. No. 61/382,331, filed on Sep. 13, 2010; U.S. Provisional Patent Application Ser. No. 61/375,700, filed on Aug. 20, 2010; the disclosures of which are herein incorporated by reference. This application is also a continuation in part application of PCT application Serial No. PCT/US10/24753 filed on Feb. 19, 2010; which application claims priority to U.S. Provisional Patent Application Ser. No. 61/208,279, filed on Feb. 21, 2009; the disclosures of which applications are herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61494294 | Jun 2011 | US | |
| 61382331 | Sep 2010 | US | |
| 61375700 | Aug 2010 | US | |
| 61208279 | Feb 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2010/024753 | Feb 2010 | US |
| Child | 13211122 | US |
