Patent Application
20240024125
Not applicable.
Not applicable.
Field of the Invention. The inventions disclosed herein relate to clamps and similar devices used during a total knee arthroplasty to hold or compress a patellar prosthesis and resurfaced patella in position while bone cement cures there between.
Description of the Related Art Total knee arthroplasty (i.e., TKA) involves three components: a femoral component, a tibial component, and a patellar component and numerous surgical tools. For the patellar component, the posterior surface of the existing patella (i.e., the articular side; the side that previously engaged the natural femoral condyles) is resurfaced, such as by sawing, to reduce the thickness of the existing patella and to form a typically planar surface. A patellar prothesis is provided for the total knee replacement and has a posterior or articular surface designed to operatively engage with the prosthetic “condyles” and an anterior surface designed to mate with, couple to, or engage the resurfaced portion of the existing patella.
Many patellar prostheses are secured to the resurfaced patella with adhesive, such as bone cement. Because bone cement requires time to cure or set (for example, 10-20 minutes), a patellar clamping tool is used to apply a compressive force to the patellar prothesis/patella combination to prevent the interface from moving or loosening while the bone cement sets or cures. While the bone cement is setting (and the patellar clamping tool is applied), the knee replacement surgery may be interrupted or at least delayed because of the existence, size, weight, and location of the clamping tool. Further, because clamping tools are typically made of metal, there is a possibility that the tool could scratch, nick, or otherwise damage the femoral or tibial protheses.
U.S. Pat. No. 10,034,774 is entitled Disposable Modular Patella Protector/Clamp and discloses “[a] disposable modular patella protector and clamp [ ], providing the ability for a surgeon to shift the procedure sequence of the implantation of the patella from the end of a total knee replacement procedure to anytime during the procedure by providing a modular clamp that holds and protects the patella prosthesis and prepared patella. The clamp may be positioned in a manner in which it does not obstruct the patella or the prosthesis, allowing the surgeon to attend to other elements of the procedure while the bone cement is allowed to cure.”
U.S. Pat. No. 10,034,679 is entitled Artificial Prosthesis Installation Clamp and Method and discloses “[i]n the use of devices and methods for measuring applied pressure on an article, such as a patella construct during a surgical procedure, a clamp is provided with arms, an optional external spring, an optional internal spring and a torque knob for applying constant and measurable pressure to the article. Embodiments of the clamp include a spring rod engaged with the torque knob for assisting in applying and retaining desired pressure. Spike elements and a bushing insert are secured to the ends of the arms for retaining the article in place during use. The elements are advantageously assembled and disassembled to facilitate thorough and quick cleaning.”
The present inventions are directed to improved patellar clamps that are small, light weight, and do not interfere with the knee replacement surgery while the clamp is in use.
To the extent that the inventions disclosed and enabled herein can be briefly summarized, one of many possible brief summaries may be: A clamp for compressing a cemented patella/prosthesis combination may comprise a first member having a surface adapted to contact an anterior surface of a resurfaced patella; a second member that is separable from the first elongated component and that has a surface with an artifact shaped to engage at least a portion of an articular surface of a patellar prothesis, when the prosthesis is cemented to the resurfaced patella; a tension component coupled to one end or edge of the first or the second member, such that the tension component extends away from the member substantially perpendicularly to the surface of the member to which the tension component is coupled; a retention mechanism associated with the member that does not have the tension component coupled thereto, wherein the retention mechanism comprises an interior surface that engages an exterior surface on the tension component; and wherein when the first member contacts the anterior surface of the resurfaced patella and when the second member engages the articular surface of the patellar prothesis, and when a compressive force is applied between the first and second members, at least a portion of the applied compressive force is retained in the clamp by the retention mechanism reacting against the tension member to lock the retained compressive force across the cemented patella/prothesis combination. Other brief summaries are likely possible.
This proposed brief summary of the inventions is not intended to limit or otherwise affect the scope of what has been disclosed and enabled or limit or otherwise affect the scope of the appended claims. Nothing stated in this Brief Summary of the Invention is intended as a definition of a claim term or phrase or as a disavowal or disclaimer of claim scope.
The following figures form part of the disclosure of inventions and are included to demonstrate further certain aspects of the inventions. The inventions may be better understood by reference to one or more of these figures in combination with the detailed description of certain embodiments presented herein.
While the inventions disclosed herein are susceptible to various modifications and alternative forms, only a few specific embodiments are shown by way of example in the drawings and are described in more detail below. The figures and detailed descriptions of these embodiments are not intended to limit the breadth or scope of the inventive concepts or the appended claims in any manner. Rather, the figures and detailed written descriptions are provided to illustrate the inventive concepts to a person of ordinary skill in the art and to enable such person to make and use the inventive concepts illustrated and taught by the specific embodiments.
The Figures described above, and the written description of specific structures and functions below, are not presented to limit the scope of the inventions disclosed or the scope of the appended claims. Rather, the Figures and written description are provided to teach a person skilled in this art how to make and use the inventions for which patent protection is sought.
A person of skill in this art that has benefit of this disclosure will understand that the inventions are disclosed and taught herein by reference to specific embodiments, and that these specific embodiments are susceptible to numerous and various modifications and alternative forms without departing from the inventions we possess. For example, and not limitation, a person of skill in this art that has benefit of this disclosure will understand that Figures and/or embodiments that use one or more common structures or elements, such as a structure or an element identified by a common reference number, are linked together for all purposes of supporting and enabling our inventions, and that such individual Figures or embodiments are not disparate disclosures. A person of skill in this art that has benefit of this disclosure will recognize and understand the various other embodiments of our inventions having one or more of the structures or elements illustrated and/or described in the various linked embodiments. In other words, not all possible embodiments of our inventions are described or illustrated in this application, and one or more of the claims to our inventions may not be directed to a specific, disclosed example. Nonetheless, a person of skill in this art having benefited from this disclosure will understand that the claims are fully supported by the entirety of this disclosure.
People skilled in this art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related, and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill in this art having benefit of this disclosure.
Further, the use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the scope of what is claimed.
Reference throughout this disclosure to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one of the many possible embodiments of the present inventions. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
During a total knee replacement, the patella 106 is everted from the body such that the posterior surface is effectively facing up toward the surgeon rather than facing down toward the condyles. The patella 106 may be resurfaced by removing, such as by sawing, the posterior surface 126 to create a more or less planar surface. Holes, for example three, are reamed or drilled into the planar surface to orient the patellar prosthesis 126. For patellar prostheses, e.g., prosthesis 126, that require bone cement to secure the prosthesis to the patella 106, a clamp or other compression device is employed to press the prothesis into the planar surface while the bone cement therebetween cures or hardens.
With the foregoing as context, I have invented compression systems for use during knee surgery, such as a total knee arthroplasty, when the patella is resurfaced to accept a cemented patellar prosthesis. The compression systems may comprise a patella member optimized in size, shape, and/or material to contact and apply a compressive force to the anterior surface of the patella; a prothesis member optimized in size, shape and/or material to contact and apply a compressive force to the articular surface of the patellar prothesis; a tension component spanning at least between the patella member and the prosthesis member; and a compression retention mechanism operable with the tension component to hold or lock a compression force applied across the members. The tension component may be located adjacent one end of the members such the compression system resembles the letter “C” or a sideways “U.” It is preferred, but not required that the tension component be substantially perpendicular to either or both of the patella member and the prosthesis member. By “substantially perpendicular,” I mean 90°±15°.
The tension component may be implemented as a unitary structure or as a plurality of structures. The tension component may be formed or made integral with either the patella member or the prosthesis member, or the tension component may be a separate structure or structures from the members. The compression retention mechanism(s) may be formed or made integral with the members, or the compression retention mechanism(s) may be separate structures from the member and tension component(s). The compression retention mechanism may include but does not have to include a release or unlock mechanism.
The compression systems may be fabricated from any medical grade material, including metals, polymers (plastics), ceramics, composites, and combinations thereof. It is preferred that the compression system be fabricated from a lightweight material that will not harm or scratch the other knee replacement components, such as the femoral and tibial components. It is also preferred that the compression system be a one-time use, disposable component, which purpose may inform the material selection. It is also preferred that the compression system have a low profile.
The compression system may be removed from the patella/prosthesis combination, such as when the bone cement has cured, set, or hardened, by releasing or unlocking the retention mechanism to remove the applied compression, or by physically spreading the members (and potentially elastically deforming the tension component) to dislodge the compression system from the patella/prosthesis combination.
In use, the compression system may be slid or installed over a patella/prosthesis combination such that the prosthesis member contacts the articular surface 126 of the prosthesis 124, and the patella member contacts the anterior surface of the patella 106. The user may then squeeze or compress the members, manually or with a tool, to apply a compressive force to the patella/prosthesis combination. The compression retention mechanism is structured to resist releasing the compressive force to maintain the integrity of the cemented interface while the bone cement cures. When the bone cement has cured, the release mechanism, if utilized, may be activated, such as by depressing or pulling with a finger or an instrument, to release the retention mechanism and thereby release the compressive force. Alternately, the members may be spread apart (such as by elastically or plastically deforming the tension component) and removed from the patella/prothesis combination. The compression system may then be removed from the patient and discarded or collected for sterilization and reuse.
It is preferred, but not required, that any exposed portion of the tension component extends outwardly from the everted patella toward the surgeon rather than inwardly toward the knee. Additionally, in some embodiments, it may be preferred to fabricate the tension components from a material that can be cut so that the extending portions may be removed after the compression force has been applied.
Turning now to a description of some, but not all, possible embodiments of my inventions,
The patella member 302 comprises a pair of tension components 308a and 308b, which are sized and shaped to operatively engage the respective receptacles 307a and 307b. Each tension component 308 comprises a plurality of slots 316 formed on the outer surface of the tension component 308. It is preferred that the plurality of slots 316 be spaced to accommodate the thickness of most patella/prothesis combinations, which range from about 0.6 inches (15 mm) to about 1.2 inches (30 mm).
As illustrated, the dogs 312 are biased into slots 316 in the tension components 308 to lock the members, 302, 304 in relative position. The release 318 can be pressed to move the dogs 312 out of locking engagement with the slots 316.
In use, the compression system 300 may be placed or slid over a patella/prosthesis combination such that the prosthesis member 304 contacts the articular surface 126 of the prosthesis 124, and the patella member 302 contacts the patella 106. The user may then depress the release 318 to move the dogs out of the way and manually squeeze or otherwise compress the members 302, 304 to apply a compressive force to the patella/prosthesis combination having bone cement at the interface. Alternately, the slots 312 may be structured so that they only lockingly engage the dogs when the members 302, 304 are attempting to move away from each other. For tension components having unidirectional locking slots 316, the use need not depress the release 318 while squeezing the members. 302, 304. When the bone cement has cured or when the compression system 300 is desired to be removed, the release 310 may be activated, such as by depressing with a finger or an instrument, to release the dogs 312a and 312b and thereby release the compressive force. The compression system 300 may then be removed from the patient and discarded or collected for sterilization and reuse.
Depending upon the material from which the members 302, 304 are fabricated, the members, such as the prosthesis member 304, may slide or move with respect to the articular surface 126 of the prosthesis 124. To prevent or retard such movement, the compression system 300 may comprise a sleeve 314 sized and shaped to slide over the prosthesis member 304 to create a groove or channel to restrain the prothesis against movement. Alternately, the prosthesis member 304 may comprise a depression, groove, channel or other surface feature formed into or on the member 304 to prevent or reduce movement of the patella/prosthesis combination with the compression system 300.
System 400 also comprises a prosthesis member 404 having a surface feature for engaging the articular surface 126 of the prosthesis 124.
Similar to the system 300, the system 400 may comprise a retention mechanism to lock in the compressive force. One type of retention system that may be used with this and other embodiments comprises spaced holes 410 in the tension components 402. It will be appreciated that the holes 410 are preferably spaced at discrete intervals along the tension components to accommodate patella/prosthesis combination of varying thicknesses.
In use, once the user has placed the system 400 on the patella/prosthesis combination, the user may manually squeeze or use a tool to squeeze the system 400 to apply compression to the combination. To retain the compression, the user may simply insert a suture needle into the appropriate hole in each tension component so that the body of the needles react against a surface of the member 404 to retain the compressive force To release the compression and remove the system 400, the user simply has to remove the suture needles such as with a forceps or hemostat.
Receptacle 406b illustrates an alternate embodiment in which a plurality of individual, embedded barbs 506 are disposed on the inner surface of the receptacle 406b such that the barbs allow the tension component 402b to pass through in one direction but not pass in the opposite direction, which opposite direction would release the applied compressive force.
In use, a compression system utilizing a retention mechanism 500, such as compression system 400, may be removed from the patient by simply spreading the members away from each other thereby elastically and/or plastically deforming (e.g., bending) the tension components 402a and 402b to allow the system to be removed. It is contemplated that for embodiments without a release mechanism, a tab, ring, or other structure may be provided at the end of member 404 opposite the tension components 402 to aid grasping and spreading the members 402, 404.
It will be appreciated that the retention member 700 may be formed integrally with or secured to a member, preferably the prosthesis member, such as illustrated in
Alternately, retention mechanism 700 may be a structure independent of the member, and in that iteration may take the form of a push nut. In use, after the user has squeezed or clamped the compression system, the retention member 700 may be pushed down the exposed tension component until the retention member contacts the patella or prosthesis member to retain the compressive force.
Furthermore, the member 700 may comprise internal threads that cooperate with corresponding threads on the tension members. In use, after the user has squeezed or clamped the compression system, the threaded retention member 700 may be screwed on to the exposed tension component until the threaded retention member 700 contacts the patella or prosthesis member to retain the compressive force. Exterior surface treatment, such as knurling, may benefit the retention members 700.
The retention mechanism 800 may be formed integrally with the patella/prosthesis member, in which case after the user has operably installed the system on the patella/prosthesis combination and compressed the same, the user may slide the compression lock 804 from the unlocked to the locked condition. When desired, the user may unlock the compression lock 804 by sliding it to the unlocked condition.
Alternately, the retention mechanism(s) 800 may a separate structure from the patella and prosthesis member, in which case in which case after the user has operably installed the system on the patella/prosthesis combination and compressed the same, the user may slide the compression lock 804 to the appropriate position on the exposed portion of the tension component and active the compression lock so that the dog 904 engages a slot 808 in the one or more tension components, thereby retaining the applied compressive force. The compressive force may be released by moving the lock 804 in the opposite direction.
While the foregoing embodiments are illustrated for simplicity with rectilinearly shape components, it is contemplated that either or both of the patella and prothesis members may be rounded, curved or otherwise shaped to better engage and evenly compress the cemented patella/prosthesis combination.
Those persons of skill having the benefit of this disclosure will now understand and be enabled to produce embodiments of my inventions using one or more of or combining aspects of one or more of the features in the previously disclosed embodiments and those features and aspects taught by these embodiments.
Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of my invention. Further, the various methods and embodiments of the methods of manufacture and assembly of the system, as well as location specifications, can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice versa.
The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.
The inventions have been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by me, but rather, in conformity with the patent laws, I intend to protect fully all such modifications and improvements that come within the scope or range of equivalent of the following claims.
This application for patent claims benefit of and priority to United States Non-Provisional application filed on Jul. 22, 2022, and having Ser. No. 63/369,140, the contents which are incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63369140 | Jul 2022 | US |
