Patent Application
20250041069
Total ankle replacement (TAR) requires fixation of the tibial component to the tibia of a patient, and further requires fixation of the talar component to the talar of the patient. Disclosed herein are prosthetic implants that provide a high retention force to aid in preventing loosening after initial implantation.
The present disclosure includes a prosthetic implant for use in TAR surgery. The prosthetic implant of the present disclosure includes an expanding peg or post that allows the surgeon to expand the peg intraoperatively to apply radial pressure resulting in a wedged press fit that provides enhanced time zero fixation. As such, the present disclosure provides multiple fixation methods that allow for increased fixation during initial implantation of both the tibial and talar components in TAR surgery by providing dynamic compression between the prosthetic implant and the mating bone so that the prosthetic implant does not move or migrate after implantation.
The present disclosure provides one or more pegs or posts of the prosthetic implant are secured to the bone of the patient by a press fit between a prepared hole in the bone and the outer diameter of the peg/post. Further, the present disclosure allows the surgeon to apply radial pressure by expanding the peg or post to obtain robust fixation in addition to the press fit. Once the peg or post is positioned in the prepared hole in the bone, an expanding mechanism of the peg or post is moved from a first position to a second position to thereby cause the peg or post to expand either outward in a tapered direction or radially causing the peg to have a mechanical press fit with the mating bone. As such, the present disclosure provides increased fixation during initial implantation until the body has time to heal and osseointegration with the porous ingrowth surface occurs.
Thus, in one aspect, a prosthetic implant includes a body comprising a first side and a second side opposite the first side. The first side comprises a bone contact surface, and the second side is configured to be coupled to an articulation surface. The prosthetic implant also includes a cylindrical stem extending away from the first side of the body. The prosthetic implant also includes an expanding mechanism positioned within the cylindrical stem. Movement of the expanding mechanism from a first position to a second position causes a maximum diameter of the cylindrical stem to change from a first maximum diameter to a second maximum diameter, where the second maximum diameter is greater than the first maximum diameter.
In another aspect, a method can include drilling a channel in a bone, positioning a cylindrical stem of a prosthetic implant into the channel, where the prosthetic implant includes a body comprising a first side and a second side opposite the first side, where the cylindrical stem extends away from the first side, and where the second side is configured to be coupled to an articulation surface, and moving an expanding mechanism positioned within the cylindrical stem from a first position to a second position, thereby causing a maximum diameter of the cylindrical stem to change from a first maximum diameter to a second maximum diameter, where the second maximum diameter is greater than the first maximum diameter.
In another aspect, a prosthetic implant includes a body comprising a first side and a second side opposite the first side, where the first side comprises a bone contact surface and the second side is configured to be coupled to an articulation surface. The prosthetic implant further includes a cylindrical stem spaced away from the first side of the body. The prosthetic implant further includes a rod having a first end and a second end opposite the first end. The first end is coupled to the first side of the body and the second end is coupled to the cylindrical stem. The rod comprises a shape memory or super elastic material. The rod is stretched prior to placement of the cylindrical stem in a channel in a tibia of a patient such that the shape memory or super elastic material of the rod causes the cylindrical stem and the body to be pulled towards each other.
In another aspect, a prosthetic implant includes a body comprising a first side and a second side opposite the first side, where the first side comprises a bone contact surface and the second side is configured to be coupled to an articulation surface. The prosthetic implant further includes a cylindrical stem extending away from the first side of the body. The prosthetic implant further includes a shape memory or super elastic component positioned at least partially within the cylindrical stem. The prosthetic implant further includes a holding mechanism positioned coupled to the shape memory or super elastic component. Removal of the holding mechanism causes the shape memory or super elastic component to retract from a first length to a second length, where the first length is greater than the second length. Retraction of the shape memory or super elastic component from the first length to the second length causes a maximum diameter of the cylindrical stem to change from a first maximum diameter to a second maximum diameter, where the second maximum diameter is greater than the first maximum diameter.
In another aspect, a prosthetic implant includes a base plate including a first side and a second side opposite the first side. The prosthetic implant further includes an outer core extending away from the first side of the base plate. The outer core is configured to be positioned within a bone. The prosthetic implant further includes an inner core coupled to the base plate and positioned at least partially within the outer core. The prosthetic implant further includes an attachment mechanism coupling the inner core to the outer core. The attachment mechanism allows longitudinal movement of the inner core with respect to the outer core in a first direction while preventing longitudinal movement of the inner core with respect to the outer core in a second direction opposite the first direction.
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In an example, the cylindrical stem 108 includes a plurality of slits 116 between the first end 112 and the second end 114. The plurality of slits 116 may include a first plurality of slits extending from the first end 112 in a direction towards the second end 114 and includes a second plurality of slits extending from the second end 114 in a direction towards the first end 112. The plurality of slits 116 can be substantially parallel with the longitudinal axis of the cylindrical stem 108, as shown in
In use, in one example, the cylindrical stem 108 is configured to be positioned within a channel formed in a tibia of a patient. In another example, the cylindrical stem 108 is configured to be positioned within a channel formed in a talus of a patient.
The prosthetic implant 100 can further include a second cylindrical stem extending away from the first side 104 of the body 102, and a second expanding mechanism positioned within the second cylindrical stem. Similar to the expanding mechanism 110 described above, movement of the second expanding mechanism from a first position to a second position causes a maximum diameter of the second cylindrical stem to change from a first maximum diameter to a second maximum diameter, where the second maximum diameter is greater than the first maximum diameter.
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Methods disclosed herein can be used with any of the embodiments of the prosthetic implant 100 as described herein.
A method includes fixing a prosthetic implant 100 to a bone of a patient. A method can include drilling a channel in a bone. In an example, the channel does not extend entirely through the bone. A method can also include positioning a cylindrical stem 108 of the prosthetic implant 100 into the channel. The prosthetic implant 100 includes a body 102 comprising a first side 104 and a second side 106 opposite the first side 104, the cylindrical stem 108 extends away from the first side 104, and the second side 106 is configured to be coupled to an articulation surface 103. A method can also include moving an expanding mechanism 110 positioned within the cylindrical stem 108 from a first position to a second position, thereby causing a maximum diameter of the cylindrical stem 108 to change from a first maximum diameter to a second maximum diameter, were the second maximum diameter is greater than the first maximum diameter.
In an example, a longitudinal axis of the cylindrical stem 108 is perpendicular to the first side 104 of the body 102. The expanding mechanism 110 can be accessed from the second side 106 of the body 102. The expanding mechanism 110 can move in a direction towards the second side 106 of the body 102 from the first position to the second position to thereby cause the cylindrical stem 108 to change from the first maximum diameter to the second maximum diameter.
In an example, a longitudinal axis of the cylindrical stem 108 is parallel to the first side 104 of the body 102. A diameter of the first end 112 of the cylindrical stem 108 and the diameter of the second end 114 of the cylindrical stem 108 can remain constant when the expanding mechanism 110 moves from the first position to the second position. The maximum diameter of the cylindrical stem can occur between the first end 112 and the second end 114. Alternatively, the maximum diameter of the cylindrical stem 108 can occur at either the first end 112 or at the second end 114.
In an example, the channel is drilled in a tibia of a patient or in a talus of a patient.
In an example, a method further includes drilling a second channel in the bone, positioning a second cylindrical stem of the prosthetic implant into the second channel, where the second cylindrical stem extends away from the first side 104 of the body 102 of the prosthetic implant 100, and moving a second expanding mechanism positioned within the second cylindrical stem from a first position to a second position, thereby causing a maximum diameter of the second cylindrical stem to change from a first maximum diameter to a second maximum diameter, where the second maximum diameter is greater than the first maximum diameter.
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In an example, the maximum diameter of the cylindrical stem 308 occurs between the first end 314 and the second end 316 of the cylindrical stem 308. In one such example, a diameter of the first end 314 of the cylindrical stem 208 and a diameter of the second end 316 of the cylindrical stem 308 remain constant when the holding mechanism 312 retracts from the first length to the second length. In an example, the cylindrical stem 308 includes a plurality of slits positioned between the first end 314 and the second end 316. The plurality of slits can help enable the cylindrical stem 308 to change from the first maximum diameter to the second maximum diameter as the shape memory or super elastic component 310 retracts from the first length to the second length.
In an example, the first end 318 of the shape memory or super elastic component 310 is fixedly coupled to the cylindrical stem 308, and the second end 320 of the shape memory or super elastic component 310 is coupled to an opening wedge 322. In such an example, retraction of the shape memory or super elastic component 310 from the first length to the second length causes the opening wedge 322 to move towards the first end 318 of the shape memory or super elastic component 310 to thereby cause the maximum diameter of the cylindrical stem 208 to change from the first maximum diameter to the second maximum diameter.
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It should be understood that arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g. machines, interfaces, functions, orders, and groupings of functions, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location, or other structural elements described as independent structures may be combined.
While various aspects and examples have been disclosed herein, other aspects and examples will be apparent to those skilled in the art. The various aspects and examples disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular examples only, and is not intended to be limiting.
Example methods and systems are described herein. It should be understood that the words “example,” “exemplary,” and “illustrative” are used herein to mean “serving as an example, instance, or illustration.” Any example or feature described herein as being an “example,” being “exemplary,” or being “illustrative” is not necessarily to be construed as preferred or advantageous over other examples or features. The examples described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
Furthermore, the particular arrangements shown in the Figures should not be viewed as limiting. It should be understood that other examples may include more or less of each element shown in a given Figure. Further, some of the illustrated elements may be combined or omitted. Yet further, an example may include elements that are not illustrated in the Figures.
In the following description, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts, which may be practiced without some or all of these particulars. In other instances, details of known devices and/or processes have been omitted to avoid unnecessarily obscuring the disclosure. While some concepts will be described in conjunction with specific examples, it will be understood that these examples are not intended to be limiting.
As used herein, “coupled” means associated directly as well as indirectly. For example, a member A may be directly associated with a member B, or may be indirectly associated therewith, e.g., via another member C. It will be understood that not all relationships among the various disclosed elements are necessarily represented.
Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, e.g., a “second” item does not require or preclude the existence of, e.g., a “first” or lower-numbered item, and/or, e.g., a “third” or higher-numbered item.
Reference herein to “one embodiment” or “one example” means that one or more feature, structure, or characteristic described in connection with the example is included in at least one implementation. The phrases “one embodiment” or “one example” in various places in the specification may or may not be referring to the same example.
As used herein, a system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is indeed capable of performing the specified function without any alteration, rather than merely having potential to perform the specified function after further modification. In other words, the system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the specified function. As used herein, “configured to” denotes existing characteristics of a system, apparatus, structure, article, element, component, or hardware which enable the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, a system, apparatus, structure, article, element, component, or hardware described as being “configured to” perform a particular function may additionally or alternatively be described as being “adapted to” and/or as being “operative to” perform that function.
The limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112 (f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
By the term “about,” “approximately,” or “substantially” with reference to amounts or measurement values described herein, it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. For example, in one embodiment, the term “about” can refer to ±5% of a given value.
Illustrative, non-exhaustive examples, which may or may not be claimed, of the subject matter according the present disclosure are provided below.
This application claims the benefit of priority to (i) U.S. Provisional Application No. 63/285,827 entitled “Fixation Methods for Total Ankle Arthroplasty,” filed on Dec. 3, 2021, and (ii) U.S. Provisional Application No. 63/286,713 entitled “Dynamic Fixation Methods for Total Ankle Replacement,” filed on Dec. 7, 2021, the contents of each of which are hereby incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/051676 | 12/2/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63285827 | Dec 2021 | US | |
| 63286713 | Dec 2021 | US |
