Patent ID: 12207852

DETAILED DESCRIPTION

By way of summary, one embodiment of the present disclosure may feature a fixation system and method for coupling together two bone or bone segments. The fixation system may include a first and a second fixation element (e.g., but not limited to, a screw) and an interconnect. The first and second fixation elements are coupled to a first and second bone, respectively, and each includes a tapered cavity. The interconnect includes a first and a second tapered protrusion configured to be frictionally received in the tapered cavities of the first and second fixation elements, respectively. Once assembled, the frictional forces between the tapered surfaces form a frictional connection which generally locks the position of the first and second fixation elements together with respect to each other (though the fixation system may also be configured to allow some movements relative to each other).

Turning now toFIGS.1and2, one embodiment of a fixation system10is generally illustrated in an unassembled (i.e., exploded) cross-sectional view (seeFIG.1) and an assembled cross-sectional view (seeFIG.2). The fixation system10includes a first and a second fixation element12,14as well as an interconnect16. As described herein, the fixation system10may be used to couple and/or secure to bones and/or bone segments (collectively generally referred to as simply bones for ease of reference) together with respect to each other. The fixation system10may therefore be used to arrange or position the bones in a generally anatomically alignment. As used herein, the term “generally anatomically alignment” is intended to mean a positioning of the bones corresponding to the generally accepted medical definition. The term “generally anatomically alignment” may therefore allow for some deviation based on the patient's overall condition, the skill of the surgeon, and pathology being treated.

In the illustrated embodiment, the first fixation element12is configured as a screw18. According to one embodiment, the screw18includes a body portion20having one or more external threaded portions22configured to threadably engage with a portion of a first bone. The threaded portion22may include a self-taping thread. While the first fixation element12is shown having an external threaded portion22, the body20of the first fixation element12may alternatively (or in addition) include one or more ribs or protrusions configured to engage the bone to secure the first fixation element12to the bone. A portion of the body20may have a tapered configuration which decreases from a first end24(e.g., a proximal end) to a second end26(e.g., a distal end).

At least a portion of the body20(e.g., but not limited to, the proximal end24) defines a first cavity28. The first cavity28may include a generally cylindrical region30having a tapered inner surface/sidewall32. The tapered sidewall32decreases in diameter from the opening34of the cavity28towards the distal end26. As described herein, the opening34of the cavity28is configured to receive a corresponding tapered portion of the interconnect16to form a frictional interference connection/coupling as generally illustrated inFIG.2.

The proximal end24may also include one or more notches36. Consistent with the illustrated embodiment, the screw18may be rotatably driven, i.e., screwed, into the bone using a driver (not shown for clarity) configured to engage the notches36to rotate the screw18. Alternatively (or in addition), the first cavity28may include a keyed region38configured to engage with a corresponding keyed region of the driver to rotate the first fixation element12into the bone.

The second fixation element14is configured to be secured to a second bone and may generally correspond to the first fixation element12. For example, the second fixation element14may be the same as the first fixation element12. Alternatively, the second fixation element14may have a different diameter, length, pitch, taper, length of cannulated passage, and/or the like. The dimensions of the first and second fixation elements12,14will depend on the intended application and related size of the first and second fixation elements12,14dimensions and condition of the first and second bones to be coupled together. For example, the dimensions of the first and second fixation elements12,14may be generally about 5 mm in diameter at the proximal outer diameter, tapering down over the 12 mm length of the screw to a 2.5 mm diameter at the distal outer diameter. The interconnect16may be approximately 2 mm in diameter and may vary from 6 mm to 13 mm in overall length.

The interconnect16is configured to couple the first and second fixation elements12,14, and therefore the first and second bones. The interconnect16includes a first and a second generally cylindrical region38,40each having a tapered external surface/sidewall42,44, respectively. The tapered sidewalls42,44have a taper which generally corresponds to the tapered sidewalls32of the first and second fixation elements12,14, respectively, to form a frictional or interference fit. In particular, when the interconnect16is received within the first and second fixation elements12,14, the precision tapered sidewalls32of the first and second fixation elements12,14abut against the precision tapered sidewalls42,44of the interconnect16so closely that the friction between the sidewalls32,42,44mates the first and second fixation elements12,14to the interconnect16as generally illustrated inFIG.2.

The interconnect16may optionally include one or more shoulders, protrusions, or the like46. The shoulder46extends radially outwardly from the body48of the interconnect16. According to one embodiment, the shoulder46extends circumferentially around the entire perimeter of the body48. Alternatively, the shoulder46may extend radially outwardly around a portion of the body48. The shoulder46may separate the first and second sidewalls42,44as generally illustratedFIG.1and may limit the distance which the interconnect16may be inserted into a cavity28of fixation elements12,14as generally illustrated inFIG.2.

The interconnect16may also optionally define one or more internal cavities49a,49b. As described herein, the internal cavities49may be configured to receive an alignment device to facilitate alignment of an adjacent fixation element (e.g., the second fixation element14).

Turning now toFIGS.3-8, one embodiment of a method for coupling a first and a second bone together using a fixation system10consistent with at least one embodiment of the present disclosure is generally illustrated. In particular, an end50of a first bone52may be prepared as generally illustrated inFIG.3. For example, a portion of the end50of the bone52may be removed to provide additional space for the fixation system10and/or to align the bone52with respect to the adjacent bones. Optionally, a pilot hole or the like54may be formed in the end50of the bone52. The pilot hole54may be formed using a drill and/or a guide wire (not shown). The pilot hole54in the bone52may be configured to receive a portion of the first fixation element12. For example, the pilot hole54may be configured to receive the first fixation element12and may have a diameter smaller than the outside diameter of the threads22of the first fixation element12to allow the threads22of the first fixation element12to engage the bone52.

After the pilot hole54is formed, the first fixation element12may be rotatably driven (e.g., screwed) into the bone52(for example using a driver) as generally illustrated inFIG.4. Again, it should be noted that the first fixation element12may be secured to the bone52without a pilot hole54. The depth of the first fixation element12within the bone52may be set by rotating the first fixation element12until the first fixation element12is in the desired position. By adjusting the depth of the first fixation element12within the bone52, the fixation system10may be used in a wider variety of applications. For example, adjusting the depth of the first fixation element12may compensate for different amounts of bone preparation (e.g., removal of bone at the end).

After the first fixation element12is secured in the first bone52, a first tapered sidewall42of the interconnect16may be co-axially received in the opening34of the cavity28of the first fixation element12, for example, as generally illustrated inFIGS.5and6. As seen, the sidewall42of the interconnect16may be inserted into the cavity28of the first fixation element12until the shoulder46abuts against the proximal end24of the first fixation element12. Optionally, an alignment device55may be used to locate where the second fixation element14should be secured to the second bone56. For example, the alignment device55may include a pin configured to be received in the cavity49of the interconnect16. The pin55may be secured within the cavity49and extend beyond the interconnect16. The second bone56may then be placed into axial alignment with the pin55. The pin55may include a pointed tip58which may pierce and/or mark the location on the second bone56where the second fixation element14should be secured.

Optionally, the pin55may be secured into the second bone56, and a pilot hole may be formed in the second bone56using a cannulated drill bit advanced over the pin55.

After the location of the second fixation element14has been determined, the second fixation element14may be rotatably driven (e.g., screwed) into the bone56(for example using a driver) as generally illustrated inFIG.7. Again, it should be noted that the second fixation element14may be secured to the bone56without a pilot hole. The depth of the second fixation element14within the bone56may be set by rotating the second fixation element14until the second fixation element14is in the desired position. By adjusting the depth of the second fixation element14within the bone56, the fixation system10may be used in a wider variety of applications. For example, adjusting the depth of the second fixation element14may compensate for different amounts of bone preparation (e.g., removal of bone56at the end).

After the second fixation element14has been secured in the second bone56, the second tapered sidewall44of the interconnect16may be co-axially received in the opening34of the cavity28of the second fixation element14, for example, as generally illustrated inFIG.8. As seen, the sidewall44of the interconnect16may be inserted into the cavity28of the second fixation element14until the shoulder46abuts against the proximal end24of the second fixation element14.

It may be appreciated that the depth of first and second fixation elements12,14may be set independent of each other and independent of the interconnect16. More specifically, while the depth of the first and second fixation elements12,14determines the separation distance between the first and second bones52,56, the first and second fixation elements12,14and the interconnect16are not limited to a specific orientation relative to each other. As such, the separation distance between the first and second bones52,56may be infinitely adjustable.

It should be appreciated that the various steps in the method described herein do not necessarily have to be performed in any specific order. For example, the first and the second fixation elements12,14may be secured in the bones prior to the interconnect16being coupled with either of the fixation elements12,14.

Turning now toFIGS.9aand9b, an exploded view (FIG.9a) and assembled view (FIG.9b) of another embodiment of a fixation system100is generally illustrated. The fixation system100includes a first and a second fixation element112,114as well as an interconnect116. The first and second fixation elements112,114may be similar to any fixation elements described herein. The interconnect116includes a first and a second generally cylindrical region138,140each having a tapered external surface/sidewall142,144, respectively. The tapered sidewalls142,144have a taper which generally corresponds to the tapered sidewalls132of the first and second fixation elements112,114, respectively, to form a frictional or interference fit as generally illustrated inFIG.9band as generally described herein. The interconnect116ofFIGS.9aand9bdoes not have a shoulder.

With reference toFIGS.10aand10b, an exploded view (FIG.10a) and assembled view (FIG.10b) of yet another embodiment of a fixation system200is generally illustrated. The fixation system200includes a first and a second fixation element212,214as well as an interconnect216. While the interconnect216is illustrated without a shoulder, this is not a limitation of the present disclosure unless specifically claimed as such and the interconnect216may include any interconnect described herein. Optionally, the interconnect216may include a cannulated passage217extending along a longitudinal axis of the interconnect216between both ends. At least one of the fixation elements212,214includes a cannulated passage221. The cannulated passage221extends from the proximal end224(e.g., from the cavity228) to the distal end226. In practice, a guide pin may be inserted into the end of the bone, for example, along the longitudinal axis of the bone. A pilot hole may optionally be formed over a portion of the guide pin, for example using a cannulated drill bit. One or more of the cannulated fixation elements (e.g., cannulated fixation element240) may be advanced over the guide pin such that the guide pin is received within the cannulated passage221and the fixation elements212,214may be secured into the bone as described herein. Optionally, a cannulated interconnect216may also be advanced over the guide pin.

Again, while only one fixation element214is illustrated with cannulated passage221, it should be understood that both fixation elements212,214may include a cannulated passage221. One advantage of having only one cannulated fixation element214is that a guide pin may be inserted into the cavity228of the first fixation element212and may abut against the distal end229. The distal end229may therefore prevent the guide pin from moving beyond the first fixation element212when the second bone is urged against the guide pin.

Alternatively (or in addition), a guide pin may be used which includes a flange extending radially outwardly having a diameter greater than the diameter of the cavity228. The flange may be position a distance away from an end of the guide pin such that a portion of the guide pin is received within the cavity228of the first fixation element212when the flange abuts against the proximal end224of the first fixation element. The flange may therefore prevent the guide pin from advancing though the first fixation element212, even if the first fixation element212is cannulated.

Turning now toFIGS.11a-11d, various view of another embodiment of a fixation system300are generally illustrated. In particular,FIG.11ais an exploded view,FIG.11bis an assembled view,FIG.11cis an exploded cross-sectional view, andFIG.11dis a cross-sectional assembled view of the fixation system300. The fixation system300includes a first and a second fixation element312,314as well as an interconnect316. The first and second fixation elements312,314are similar to any of the fixation elements described herein. The interconnect316may include tapered surfaces338,340which are separated by a flexible region369. The tapered surfaces338,340are configured to engage with the cavities328of the first and second fixation elements312,314as described herein. The flexible region369is configured to allow the first and second fixation elements to move (e.g., bend) with respect to each other such that the two bones secured together by the fixation system300(when assembled) can move. For example, at least a portion of the interconnect316(e.g., at least the flexible region369) may include a superelasticity and/or shape memory material such as, but not limited to, nickel titanium alloys nitinol (e.g., an alloy of nickel and titanium).

The dimensions of the flexible region369may be selected to allow the bending characteristics of the interconnected316to be adjusted. For example, the cross-sectional dimensions, shape, and/or length of the flexible region369may be adjusted to increase the range of motion (e.g., bending) of the fixation system300, the amount of force necessary to bend the fixation system300, and/or the direction(s) in which the fixation system may bend. For example,FIGS.12a-12dgenerally illustrates one embodiment of a fixation system400including a first and a second fixation element412,414and an interconnect416having a flexible region469configured to allow the fixation system400to bend in a generally only one direction (e.g., generally only in a single plane). For example, at least a portion of the flexible region469may have a generally rectangular cross-section having a length running along the longitudinal axis of the interconnect416and a width and height generally perpendicular thereto. The dimensions of the width or the height may be selected to provide directional movement and stability of the interconnect416such that the interconnect416will generally only bend in one direct as a result of the forces in which the fixation system400will experience in a normal or typical application (e.g., the forces that the fixation system400would likely experience when installed in a foot, hand, or the like).

While the fixation system400is illustrated having a generally rectangular cross-section, this is not a limitation of the present disclosure unless specifically claimed as such. For example, at least a portion of the flexible region469may have a generally oval cross-section, one or more longitudinal and/or transverse ribs, grooves, or the like.

A benefit of the fixation systems300,400is that they may allow for some degree of flexibility when used to couple to adjacent bones which originally were coupled together by way of a joint. In the fixation systems300,400, the interconnects316,416may have a separation length (i.e., distance between the first and second fixation elements when assembled) which is greater than the separation length of the other embodiments described herein. The larger separation length may facilitate bending of the fixation systems when assembled. The fixation systems may have a diameter of approximately 0.5 to 4 mm, an overall length of between approximately 5 to 20 mm, and may bend up to an angle between 10 degrees to 60 degrees.

Turning now toFIG.13, yet another embodiment of a fixation system500consistent with the present disclosure is generally illustrated. The fixation system500includes a first and a second fixation element512,514and an interconnect516. At least one of the fixation elements512,514includes a generally cylindrical protrusion598extending outwardly from the proximal end524. The generally cylindrical protrusion598has a tapered external surface599. The interconnect516includes at least one tapered generally cylindrical cavity528having a tapered internal surface530configured to frictional engage the corresponding tapered external surfaces599of protrusions599of the corresponding fixation elements512,514. While the fixation system500is illustrated in which interconnect516includes a first and a second tapered generally cylindrical cavity528and the interconnect includes a first and a second tapered generally cylindrical protrusion598, it should be understood that either of the fixation elements512,514may include a tapered cavity as described herein and the corresponding end of the interconnect516may have a tapered protrusion as described herein.

The fixations systems described herein may be used to couple any two bones. For example, a fixation system600consistent herewith may be used to couple two or more bones602,604in a foot606as generally illustrated inFIG.14. A fixation system700consistent herewith may also be used to couple to or more bones702,704in a hand706as generally illustrated inFIG.15. It should be understood, however, that these are merely illustrative examples and that the fixation systems described herein are not limited to feet606and/or hands706unless specifically claimed as such.

It should be appreciated that various features of the different embodiments described herein may be combined together. For example, the interconnect may be eliminated such that that the two fixation elements may be directly coupled to each other, for example, using a tapered interference connection as described herein.

According to one aspect, the present disclosure features a fixation system for coupling a first and a second portion of bone together. The fixation system includes a first fixation element, a second fixation element, and an interconnect. The first fixation element includes an external surface configured to engage the first portion of bone and a first tapered mating surface. The second fixation element includes an external surface configured to engage the second portion of bone and a second tapered mating surface. The interconnect includes a first and a second tapered surface disposed at generally opposite ends. The first and the second tapered surfaces are configured to frictionally engage the first and the second tapered mating surfaces of the first and the second element, respectively, to form frictional interference connections therebetween.

According to another aspect, the present disclosure features a fixation system for coupling a first and a second portion of bone together including a first fixation element, a second fixation element, and an interconnect. The first fixation element includes a first body having an external surface configured to engage the first portion of bone. The first body defines a first generally cylindrical protrusion having a tapered external surface. The second fixation element includes a second body having an external surface configured to engage the second portion of bone. The second body defines a second generally cylindrical protrusion having a tapered external surface. The interconnect includes a first and a second tapered generally cylindrical cavity having a tapered internal surface configured to frictionally engage the tapered external surfaces of the first and the second protrusions.

According to yet another aspect, the present disclosure features a fixation system for coupling a first and a second portion of bone together including a first fixation element, a second fixation element, and an interconnect. The first fixation element includes a first body having an external surface configured to engage the first portion of bone. The first body defines a first generally cylindrical cavity having a tapered internal surface. The second fixation element includes a second body having an external surface configured to engage the second portion of bone. The second body defines a second generally cylindrical cavity having a tapered internal surface. The interconnect includes a first and a second tapered generally cylindrical protrusion having a tapered external surface configured to frictionally engage the tapered internal surfaces of the first and the second cavities.

While the principles of the present disclosure have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. The features and aspects described with reference to particular embodiments disclosed herein are susceptible to combination and/or application with various other embodiments described herein. Such combinations and/or applications of such described features and aspects to such other embodiments are contemplated herein. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.

All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified, unless clearly indicated to the contrary.

All references, patents and patent applications and publications that are cited or referred to in this application are incorporated in their entirety herein by reference.

While the principles of the present disclosure have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. The features and aspects described with reference to particular embodiments disclosed herein are susceptible to combination and/or application with various other embodiments described herein. Such combinations and/or applications of such described features and aspects to such other embodiments are contemplated herein. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described (or portions thereof), and it is recognized that various modifications are possible within the scope of the claims. Accordingly, the claims are intended to cover all such equivalents. Various features, aspects, and embodiments have been described herein. The features, aspects, and embodiments are susceptible to combination with one another as well as to variation and modification, as will be understood by those having skill in the art. The present disclosure should, therefore, be considered to encompass such combinations, variations, and modifications.