The present disclosure relates to final and provisional implants used in knee arthroplasty, and, in particular, to final and provisional patellar implants for replacing a patellar articular surface and facilitating the proper placement of a patellar implant, respectively.
The knee joint is generally formed by the pair of condyles located at the distal portion of a femur, the tibial plateau located at the proximal end of a tibia and a pair of menisci positioned between the tibial plateau and the femoral condyles. The knee further includes the patella which is secured by the patellar tendon to ride against an anterior portion of the femur during articulation of the knee.
A knee may experience disease or trauma necessitating replacement of all or a portion of the knee with one or more prosthetic knee implants including prosthetic components such as a femoral component to replace the distal end of the femur, a tibial component to replace the proximal end of the tibia, a bearing insert to replace articulating tissue between the femur and the tibia and a patellar articular surface to replace the articulating surface of the patella. During replacement of the patellar articular surface, the patella may be everted to provide access to its posterior surface so that the posterior surface of the patella can be shaped to accommodate placement of a prosthetic patellar component thereon.
Knee prosthesis systems may include different sized femoral components, tibial components, bearing inserts and patellar articular surfaces. Patellar articular surfaces of differing sizes many times utilize differing securement mechanisms so that intraoperatively switching from one size to another necessitates altering the compatible securement features formed in the natural patella which receives the prosthetic patellar articular surface. In certain pre-existing systems, such as the Zimmer Natural Knee II System, a series of differently sized circular patellar prostheses may utilize compatible securement features so that the associated securement features formed in the natural patella do not have to be re-formed when intraoperatively choosing between two different size patellas. The patellas of this system all have a mathematically similar, i.e., circular perimeter shape. The Zimmer Natural Knee II System is shown and described in the Natural-Knee II Primary System Surgical Technique bearing copyright dates of 2004, 2005 and 2009, a copy of which is herewith submitted in an Information Disclosure Statement, the entire disclosure of which is hereby explicitly incorporated by reference herein.
The present disclosure is, in one embodiment, directed to a system of prosthetic patellar components, i.e., patellar prostheses, including first and second prosthetic patellar components having dissimilar perimeter shapes and which are interchangeably usable without altering the securement feature formed on the natural patella. For the purposes of this document, “dissimilar” is used to describe the perimeter shapes of two patellar prostheses which are not 1) mathematically similar, i.e., exactly the same in shape but not necessarily size or 2) substantially mathematically similar, i.e., the same in shape within manufacturing tolerances but not necessarily size. In one embodiment, the first prosthetic patellar component includes a generally circular periphery while the second prosthetic patellar component includes a generally elongate periphery. In certain embodiments, the securement feature of the prosthetic patellar components incorporates a keying feature which allows for securement of the patellar prosthesis to the natural patella in only a single, desired position. The present disclosure is further directed to a provisional patellar implant for facilitating the proper placement of a final patellar implant on a natural patella. “Patellar prosthesis” and “prosthetic patellar component” are used interchangeably throughout this document. Both of these terms can denote either a final or a provisional patellar prosthesis.
In accordance with an aspect of the present disclosure, two patellar components having dissimilar perimeter shapes have identical securement features. For example, a non-circular, generally elongate patellar prosthesis of the present disclosure which is sized and shaped to provide substantial coverage of the superior aspect of the posterior surface of the natural patella includes a plurality of fixation posts extending from the bone contacting surface thereof to facilitate securement of the patellar prosthesis on the natural patella. The fixation posts of the non-circular, generally elongate patellar prosthesis of the present disclosure are sized the same as and arranged in an identical pattern with respect to a plurality of fixation posts extending from the bone contacting surface of a circular patellar prosthesis of the present disclosure so that the two prostheses are interchangeably usable with a natural patella without requiring modification of the attachment surface of the natural patella, i.e., without requiring redrilling of holes to accommodate the fixation posts.
Dissimilar patellar prostheses of the present disclosure further utilize a non-circular arrangement of fixation posts so that they are securable to the natural patella in only a single orientation. The non-circular orientation of the fixation posts is identical for each of the dissimilar prosthetic patellar components so that the dissimilar patellar prostheses are interchangeable as described above.
When implementing a method of replacing the articular surface of a patella in accordance with the present invention, a surgeon may first provide to the patient a first patellar prosthesis having a first patellar prosthesis perimeter shape, secure the first patellar prosthesis to the patella, evaluate the fit and coverage of the patellar prosthesis relative to the patella, thereafter provide a second patellar prosthesis having a second patellar prosthesis perimeter shape which is dissimilar from the first patellar prosthesis perimeter shape, secure the second patellar prosthesis to the patella without forming any additional patella securement features on the patella, evaluate the fit and coverage of the second patellar prosthesis relative to the patella and then choose one of the first patellar prosthesis and the second patellar prosthesis for final implantation based on the aforementioned evaluations. In practicing this method, the “first patellar prosthesis” and “second patellar prosthesis” may be either final or provisional patellar prostheses. Further, in the embodiments of the present invention, the first patellar prosthesis will be a symmetrical patellar prosthesis such as a circular patellar prosthesis, while the second patellar prosthesis will be an asymmetrical patellar prosthesis such as an elongate patellar prosthesis.
In a further aspect of the present disclosure, a trial patellar prosthesis includes a single fixation peg which is offset from the center of the patellar trial prosthesis. When using this trial prosthesis, a hole may be formed in the patella which is slightly larger than the single fixation post so that the trial patellar component may rotate about its fixation post during range of motion testing to allow the trial patellar prosthesis to automatically orient itself in a kinematically advantageous position relative to the natural patella. A set of final implants including a final implant which mirrors the trial patellar component, including its offset fixation peg, together with a final patellar implant having a central fixation peg may be utilized together with the aforementioned trial patellar prosthesis as further described hereinbelow.
The invention, in one form thereof, comprises a system of patellar prostheses including a first patellar prosthesis comprising a first patellar prosthesis perimeter defining a first patellar prosthesis perimeter shape and a first patellar prosthesis securement feature having a size and a shape; a second patellar prosthesis comprising a second patellar prosthesis perimeter defining a second patellar prosthesis perimeter shape, the second patellar prosthesis shape dissimilar from said first patellar prosthesis perimeter shape, and a second patellar prosthesis securement feature having the same size and shape as the first patellar prosthesis securement feature, whereby the first patellar prosthesis and the second patellar prosthesis are securable to a natural patella having a patella securement feature compatible with the size and shape shared by the first patellar prosthesis securement feature and the second patellar prosthesis securement feature to allow interchangeable securement of the first patellar prosthesis and the second patellar prosthesis to a natural patella.
The invention, in another form thereof, comprises a method of replacing the articular surface of a patella, including the steps of: providing a first patellar prosthesis comprising a first patellar prosthesis perimeter defining a first patellar prosthesis perimeter shape and a first patellar prosthesis securement feature having a size and a shape; forming a patella securement feature on the patella, the patella securement feature sized and shaped to cooperate with the first patellar prosthesis securement feature to secure the first patellar prosthesis to the patella; securing the first patellar prosthesis to the patella, using the first patellar prosthesis securement feature and the patella securement feature; removing the first patellar prosthesis from the patella; providing a second patellar prosthesis comprising a second patellar prosthesis perimeter defining a second patellar prosthesis perimeter shape, said second patellar prosthesis perimeter shape dissimilar from said first patellar prosthesis perimeter shape; a second patellar prosthesis securement feature having the size and shape of the first patellar prosthesis securement feature; and securing the second patellar prosthesis to the patella using a second patellar prosthesis securement feature and the patella securement feature.
The invention, in a further form thereof, comprises a patellar prosthesis including an articular surface, a base having a securement feature, the securement feature comprising a first fixation post having a first fixation post longitudinal axis intersecting said base at a first point, a second fixation post having a second fixation post longitudinal axis intersecting said base at a second point and a third fixation post having a third fixation post longitudinal axis intersecting said base at a third point, the first fixation post longitudinal axis and the second fixation post longitudinal axis arranged on a pitch circle of radius r, the third fixation post longitudinal axis offset from the pitch circle by a distance O, whereby said first point, said second point and said third point do not define an equilateral triangle.
The invention, in yet another form thereof, comprises a patellar prosthesis including an articular surface defining a dome sized to ride in a sulcus of one of a femur and a femoral and a femoral prosthesis, a bone contacting surface opposite the articular surface, and a securement feature comprising a single fixation post extending from the bone contacting surface, the bone contacting surface including a substantially planar bone contacting surface having no protrusions except for the securement feature extending therefrom, whereby, with the substantially planar bone contacting surface contacting the substantially planar osteotomized surface of a patella and the securement feature positioned in an aperture formed in the patella, the patellar prosthesis is rotatable relative to the patella, the single fixation post positioned such that the patellar prosthesis is rotatable relative to the patella to allow repositioning of the patellar prosthesis relative to the patella during range of motion testing to automatically reposition the patellar prosthesis to optimize patellar tracking during a fall range of motion of a knee joint including the patellar prosthesis.
The invention, in yet a further form thereof, comprises a method of positioning a patellar prosthesis on a patella of a knee joint, including the steps of: preparing a patella to receive a first patellar prosthesis, the step of preparing the patella to receive the first patellar prosthesis comprising the steps of osteotomizing the patella to form a substantially planar osteotomized surface of the patella and forming an aperture in the patella; providing a first patellar prosthesis comprising an articular surface defining a dome sized to ride in a sulcus of one of a femur and a femoral prosthesis, a bone contacting surface opposite the articular surface and a securement feature comprising single fixation post extending from the bone contacting surface, the bone contacting surface comprising a substantially planar bone contacting surface having no protrusions except for the securement feature extending therefrom, whereby, with the substantially planar bone contacting surface contacting the substantially planar osteotomized surface of the patella and the securement feature positioned in the aperture formed in the patella, the patellar prosthesis is rotatable relative to the patella, the single fixation post positioned such that the patellar prosthesis is rotatable relative to the patella to allow repositioning of the patella prosthesis relative to the patella during range of motion testing to automatically reposition the patellar prosthesis to optimize patellar tracking during a full range of motion of a knee joint including the patellar prosthesis; positioning the first patellar prosthesis fixation post in the aperture in the patella, the aperture sized to rotatably receive the first patellar prosthesis fixation post; positioning the substantially planar first patellar prosthesis bone contacting surface in contact with the substantially planar osteotomized surface of the patella; conducting a range of motion test of the knee, the first patellar prosthesis free to rotate relative to the patella during the range of motion test; determining a rotational position of the second patellar prosthesis relative to the patella for optimal patella tracking in the knee joint; and securing a final patellar prosthesis in the rotational position determined in the determining step.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring to
To prepare patella P to receive elongate patellar prosthesis 20, an incision is made to expose the knee joint and patella P is everted as shown in
Elongate patellar prosthesis 20 of the present disclosure may be formed, e.g., of ultra high molecular weight polyethylene. Any of the patella prostheses of the present disclosure, including provisional patellar prostheses may be formed of biocompatible materials such as various polymers including ultra high molecular weight polyethylene, ceramic materials and metals such as stainless steel, titanium and cobalt chrome alloys. Further, any of the patellar prostheses including the provisional patella prostheses of the present disclosure may be formed in two piece configurations in which the articular surface is connected to a support member from which the fixations posts extend. The bone contacting side of a patellar prosthesis in accordance with the present invention may include bone ingrowth promoting material such as trabecular metal to facilitate securement of the patellar prosthesis to the patella.
Referring to
Placement of elongate patellar prosthesis 20 on prepared patella P is schematically illustrated in
Referring to
Referring to
Because the configuration of fixation posts 28a′, 28b′ and 28c′ of circular patellar prosthesis 44 is identical to the configuration of fixation posts 28a, 28b and 28c of elongate patellar prosthesis 20, a surgeon may intraoperatively decide to switch from elongate patellar prosthesis 20 to circular patellar prosthesis 44 or visa versa. Advantageously, positioning the group of fixation posts 28a, 28b and 28c such that they are offset relative to the centroid of elongate patellar prosthesis 20 allows for this interchangeability between elongate patellar prosthesis 20 and circular patellar prosthesis 44. Specifically, circular patellar prosthesis 44 of the present disclosure is generally implanted in a position that is medially and superiorly offset relative to the center of patella P, as illustrated in
Referring to
Referring to
Referring to
In accordance with a further embodiment of the present disclosure, an implant may be constructed to mimic trial patellar prosthesis 46 illustrated in
While this invention has been described as having exemplary designs, the present disclosure can be further modified within the spirit and scope of this invention. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the scope of the appended claims.
This application is related to and claims the benefit under Title 35, U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No. 61/420,537, entitled OFFSET PEG PATELLA, filed on Dec. 7, 2010, the entire disclosure of which is hereby expressly incorporated by reference herein.
Number | Name | Date | Kind |
---|---|---|---|
3927423 | Swanson | Dec 1975 | A |
4944756 | Kenna | Jul 1990 | A |
5011496 | Forte et al. | Apr 1991 | A |
5133758 | Hollister | Jul 1992 | A |
5246460 | Goodfellow et al. | Sep 1993 | A |
5326361 | Hollister | Jul 1994 | A |
5507820 | Pappas | Apr 1996 | A |
5580353 | Mendes et al. | Dec 1996 | A |
5593450 | Scott et al. | Jan 1997 | A |
5609640 | Johnson | Mar 1997 | A |
5609644 | Ashby et al. | Mar 1997 | A |
5702465 | Burkinshaw | Dec 1997 | A |
5723016 | Minns et al. | Mar 1998 | A |
5728162 | Eckhoff | Mar 1998 | A |
5824099 | Mendes et al. | Oct 1998 | A |
5871539 | Pappas | Feb 1999 | A |
5871540 | Weissman et al. | Feb 1999 | A |
6074425 | Pappas | Jun 2000 | A |
6616696 | Merchant | Sep 2003 | B1 |
6709460 | Merchant | Mar 2004 | B2 |
6802864 | Tornier | Oct 2004 | B2 |
7160328 | Rockwood et al. | Jan 2007 | B2 |
7878989 | McMinn | Feb 2011 | B2 |
20030120346 | Mercinek et al. | Jun 2003 | A1 |
20050143830 | Marcinek et al. | Jun 2005 | A1 |
20050165492 | Fritz | Jul 2005 | A1 |
20050222685 | Hayden et al. | Oct 2005 | A1 |
20050267584 | Burdulis, Jr. et al. | Dec 2005 | A1 |
20070021838 | Dugas et al. | Jan 2007 | A1 |
20070100459 | Rhodes | May 2007 | A1 |
20070150066 | McMinn | Jun 2007 | A1 |
20070198022 | Lang et al. | Aug 2007 | A1 |
20080243258 | Sancheti | Oct 2008 | A1 |
20080281426 | Fitz et al. | Nov 2008 | A1 |
20080288080 | Sancheti | Nov 2008 | A1 |
20080300689 | McKinnon et al. | Dec 2008 | A1 |
20090036993 | Metzger | Feb 2009 | A1 |
20090222103 | Fitz et al. | Sep 2009 | A1 |
20090226068 | Fitz et al. | Sep 2009 | A1 |
20090326661 | Wright et al. | Dec 2009 | A1 |
20090326662 | Goldstein et al. | Dec 2009 | A1 |
20100125338 | Fitz | May 2010 | A1 |
Number | Date | Country |
---|---|---|
2472669 | Dec 2005 | CA |
0613667 | Sep 1994 | EP |
0613667 | Sep 1994 | EP |
0676182 | Oct 1995 | EP |
0681817 | Nov 1995 | EP |
0705580 | Apr 1996 | EP |
0728450 | Aug 1996 | EP |
0728450 | Aug 1996 | EP |
0736292 | Oct 1996 | EP |
1308142 | May 2003 | EP |
1308142 | May 2003 | EP |
1557144 | Jul 2005 | EP |
1557144 | Jul 2005 | EP |
1582184 | Oct 2005 | EP |
1582184 | Oct 2005 | EP |
1862150 | Dec 2007 | EP |
1862150 | Dec 2007 | EP |
2140836 | Jan 2010 | EP |
2140837 | Jan 2010 | EP |
2140837 | Jan 2010 | EP |
WO9014805 | Dec 1990 | WO |
WO9104715 | Apr 1991 | WO |
WO9203109 | Mar 1992 | WO |
WO9218069 | Oct 1992 | WO |
WO9300871 | Jan 1993 | WO |
WO9422396 | Oct 1994 | WO |
WO9422397 | Oct 1994 | WO |
WO-9514445 | Jun 1995 | WO |
WO-9725006 | Jul 1997 | WO |
WO9725006 | Jul 1997 | WO |
WO9742914 | Nov 1997 | WO |
WO-9742914 | Nov 1997 | WO |
WO9806343 | Feb 1998 | WO |
WO0170143 | Sep 2001 | WO |
WO03013338 | Feb 2003 | WO |
WO-03013338 | Feb 2003 | WO |
WO-03013339 | Feb 2003 | WO |
WO03013339 | Feb 2003 | WO |
WO2004110319 | Dec 2004 | WO |
WO-2004110319 | Dec 2004 | WO |
WO2007102951 | Sep 2007 | WO |
WO2009018365 | Feb 2009 | WO |
WO-2009018365 | Feb 2009 | WO |
WO2009111626 | Sep 2009 | WO |
Entry |
---|
The partial search report/invitation to pay add'l fees mailed Mar. 7, 2012 in related International Application No. PCT/ US2011/063562. |
“International Application Serial No. PCT/US2011/063562, International Preliminary Report on Patentability mailed Jun. 20, 2013”, 11 pgs. |
“Patellar Component Medialization in Total Knee Arthroplasty”, Aaron A. Hofmann, MD et al., The Journal of Arthroplasty vol. 12 No. 2, Feb. 1997, pp. 155-160. |
“The Effect of Patellar Button Placement and Femoral Component Design on Patellar Tracking in Total Knee Arthroplasty”, Ichiro Yoshii, MD et al., Clinical Orthopaedics and Related Research No. 275, Feb. 1992, pp. 211-219. |
“The effect of component placement on knee kinetics after arthroplasty with an unconstrained prosthesis”, M.C. Miller et al., Journal of Orthopaedic Research 19, 2001, pp. 614-620. |
The International Search Report and Written Opinion mailed May 3, 2012 in related International Application No. PCT/US2011/063562. |
Zimmer Natural-Knee II Primary System Surgical Technique, Zimmer Inc., 2004, 2005, 2009. |
Number | Date | Country | |
---|---|---|---|
20120179264 A1 | Jul 2012 | US |
Number | Date | Country | |
---|---|---|---|
61420537 | Dec 2010 | US |