Patent Application
20240016525
The present invention relates to a contoured orthopedic plate for the fixation of bone fractures, with a particular application to fractures of the medial malleolus. The distal portion of the plate includes a curved hook with two prongs intended to wrap the distal portion of the tibia and accept shear-off screws for fixation over the fracture line.
The prior art has advanced in the innovation and use of orthopedic plates and methods of fixation to include plates contoured for specific anatomic areas and typical fracture patterns. This includes long plates, which may be used on the bones of the lower leg, and to fix typical ankle fractures.
One such example is set forth in U.S. Pat. No. 9,631,157 to Medoff et al. which illustrates a contoured plate that is fixed along an outside edge of the tibia, and which includes spiked hooks that wrap and fix the distal prominence of the bone in the event of a fracture. A problem with the plates shown in this reference is that the spikes are fixed with respect to their length and angle, which can lead to problems in achieving fixation or in a proper anchoring of a distal fragment. In addition, the static nature of the location and angle of the hooks leads to problems with fit such that when the hooks are optimally located, the plate contouring is off so that the plate rocks or the hooks are too steeply angled and don't accommodate the distal portion of the corresponding bone segment. Attempts to customize these spikes intraoperatively adds time and complexities to the surgery, which are not welcome.
Other previous solutions have provided complications even more cumbersome and requiring more cutting or customization of off the shelf hardware.
Accordingly, it is an object of the present invention to provide a bone plate that allows for some pre-operative or intraoperative selection, including for example, selecting a screw length and angle, or allowing a surgeon the ability to tailor the dual hook end by bending one or both hooks legs into a greater angle. The terminal hook screws are typically short sharp spike-like screws that act to fix the terminal fragment and hold it in position while it is buttressed by the wrapping portion of the plate. However, it is possible for a surgeon to select a screw length and angle so that they can cross a fracture line if they determine it to be advantageous. This is not possible with the present plates. Moreover, the flexibility of the screw angle and length, and potential ease of customization of the hook leg ends means that a surgeon can let the plate contouring determine the fit, and the screw characteristics can be easily selected to optimize the fixation of the fragment.
Advantageously, the plate further includes a drill guide which mounts from one of the more proximal holes of the plate to overlay the terminal portion of one quarter to three quarters, and more specifically, one third of the length of the plate with a terminal end having guide bores to direct the insertion of the distal shear off or snap off screws which act as prongs in the associated bone. These screws are selected to secure the distal fragment, and along with an optional compression slot, can be used to create compression across a fracture line, such as in the terminal prominence at or around the medial pyramidal process of the tibia. The screws are designed with an extension for holding the screw prior to implantation and to permit the shearing or snapping of the screw from the extension after implantation. The screws also preferably include an anti-backout feature, such as a flange that interacts with the snap-off screw hole surround to inhibit the screw from backing out over time. In addition, preferably, these screws are self-tapping so that they can be inserted without any additional preparation, such as drilling pilot holes.
It is a further object of the present invention to provide a bone plate that can be seated adjacent against a bone as a result of generalized contouring that provides an accommodating interior (i.e., bone facing) surface which includes a gently radiused end portion to resemble the shape of a J inside profile, and a having a terminal dual pronged end which resembles an inverted U. The prongs include fixation holes for locking or non-locking screws which are preferably variable angle screws, that are preferably snap-off or shear-off screws such that the screws have no or relatively little area which protrudes above the surface of the plate prongs around these fixation holes. The plate is further contoured in outline to minimize the material while allowing sufficient material around the fixation holes to provide the necessary plate and plate/screw interface strength.
Further, it is an object to provide a bone plate that includes a long portion having fixation holes that can accommodate locking or non-locking fixation means, such as screws, and preferable variable angle screws. Ideally, the long portion of the plate includes 2 to 8, and preferably 3 to 5 such holes, wherein one of more of the holes may include compression means, such as a compression slot, shown here in the proximal hole.
The present invention comprises a contoured orthopedic plate for fixing bone fractures having a small terminal fragment. The bone plate has a long bone portion or body having a first end, for example, at the proximal end of the plate, a second end, for example at the distal end of the plate, an exterior or top surface which faces away from the bone in use, an interior or bottom surface which faces toward or is adjacent the bone in use, and serpentine side edges which join the exterior and interior surfaces along the long side, a rounded or circular end edge at the proximal end of the plate and a inwardly curved hook that splits into two or more prongs at an angle of 70° to 110°, and preferably 90°+/−5° to the angle of the long plate long axis. The invention also comprises other contours and specific configurations with respect to the terminal curve and contouring and number of fixation holes, as well as the included compression slot.
The present invention also includes a multiple barreled drill guide facilitating the insertion of at least two parallel terminal screws at the distal end of a bone at the correct location. The multiple barreled drill guide has a drill body, that fastens to the plate, such as by a thumb screw device which is secured in a dedicated threaded hole in the plate and which has outrigger slots for k-wires for helping to temporarily hold the plate in place during screw insertion.
The present invention relates to an orthopedic plate and fastener system to aid in the healing of a bone fracture, in particular, at a terminal end of the bone. The plate 10 has a long body portion 12 which extends along a central axis. This body portion 12 includes an exterior surface 14 which faces away from the bone in use, and an opposing interior surface 16 which faces toward the bone in use. These opposing surfaces are joined by a first side edge 18 on a first side and a spaced apart second edge 22 on a second side. One end of the body portion 12 includes a rounded terminal end 20. The opposing end of the body portion 12 is joined to a curved hook end or head 30 which flows from the central axis in a curve which forms an arc of from 60° to 120°, and more preferably from 70° to 105°, or preferably 90°+/−5°. The head 30 comprises at least two prongs 32, 34 which are separated by a u-shaped recess 36 which extends for at least 75%, and preferably about 90% of the arc and is rounded at the apex to avoid stress concentrations. The screw holes in the prongs could be sized to fit a 3-5 mm screw which is advantageously sharp and self-tapping, however, it is also possible to place a lag screw or cannulated lag screw through this slot/space, so it could be good to at least include that it could accept a lag screw.
The prongs 32, 34 each include a through hole 42, 44 which receive fixation means, and preferably screws 50 which are designed to snap or shear at or below the level of the prong exterior surface 52 surrounding the through holes such that the screw remains captured in the through holes but does not provide a sharp edge to interfere with soft tissue exterior to the implant.
The body portion 12 of the plate 10 also includes through holes 62 for fixation means, and preferably screws 70. These through holes 62 advantageously have an interface with the screws 70 which permit variable angle locking, meaning that the screws can be implanted at a conically varying angle of axis with respect to the center axis of the hole, but subsequently locked into position at the selected angle. In this case, the holes have interrupted internal threads 68 to provide for this feature, as they interact with external threads (not shown) on the body portion screws 70.
The plate of the present invention is specifically designed for use with a medial malleolus and is illustrated on this bone in the drawings. The body portion includes 3 regular screw holes 62, although it is understood, that the plate can be provided in varying lengths and with varying numbers of body screw holes 62 preferably from 2 to 8, or 3+/−1, and one or more compression slot 66, which is a terminal through hole in this case. The body portion includes thickened areas around the body screw holes and thinner areas between the screw holes so as to minimize the total plate material and yet provide sufficient strength for the screw holes 62.
The system also includes a drill guide 80 which is configured to overlay the exterior surface 14 of the plate 10, and which is secured to the plate by a thumb screw member 82 which threads into a threaded hole 65 in the plate included for this purpose. This end of the drill guide includes a double barreled channel member which can be used to drill pilot holes for the terminal screws, or preferably to guide them directly as they are inserted through the holes 42, 44 in the prongs 32, 34 of the plate head.
The snap or twist off screws 50 are illustrated in
In use, after exposure of the necessary bone area, the fracture site is cleared and refreshed. Fracture reduction is performed and temporary stabilization is achieved using a K-wire, reduction forceps or a Lobster Claw clamp per the surgeon preference. A drill guide can be used with a hook plate template to locate pilot holes for the plate body screws. After removing the drill guide, the hook plate can be placed over the K-wires and the hook plate can be secured to the bone. A drill guide can be fed over k-wires which extend through the terminal snap off screw holes. The k-wires can be removed and the snap off screws can be implanted into the terminal bone portion. The screws can be snapped off and the flange around the screw head is popped into place in the screw hole to inhibit backing out.
In an additional aspect of the invention the snap off screws are made from a bioabsorbable material. Examples of suitable materials include hydroxyapatite, polylactides, polyglycosides, polydioxanes, magnesium, silicon nitride and human bone.
In accordance with the patent statutes, the best mode and preferred embodiment have been set forth; the scope of the invention is not limited thereto, but rather by the scope of the attached claims.
| Number | Date | Country | |
|---|---|---|---|
| 63388393 | Jul 2022 | US |
