CRUCIATE-RETAINING KNEE PROSTHESIS
Certain embodiments generally provide an improved tibial base member comprising keel portions that allow one or both cruciate ligaments to be preserved. Other embodiments provide improved lateral and/or medial inserts having a mesial lip that helps relieve and or prevent impingement between the femoral component and the tibial eminence. Other embodiments provide improved femoral components having various chamfers to provide additional clearance with respect to the tibial eminence and posterior cruciate ligament without decreasing bone coverage.
This application is a continuation of U.S. patent application Ser. No. 15/989,733, filed May 25, 2018, which is a divisional of U.S. patent application Ser. No. 14/556,623, filed Dec. 1, 2014, which is a continuation of U.S. patent application Ser. No. 13/016,175, filed Jan. 28, 2011, now U.S. Pat. No. 8,900,316, issued Dec. 2, 2014, which claims priority from U.S. Provisional Application Ser. No. 61/372,556 filed on Aug. 11, 2010, U.S. Provisional Application Ser. No. 61/382,287 filed on Sep. 13, 2010, and U.S. Provisional Application Ser. No. 61/299,835 filed on Jan. 29, 2010. The contents of the prior applications are hereby incorporated by reference.
RELATED FIELDSProstheses for use in knee arthroplasty, such as tibial and/or femoral implants, which may in some instances facilitate the retention of one or both cruciate ligaments.
BACKGROUNDIn total knee arthroplasty, the convention is to resect the entire proximal tibia to create a plateau surface on which a tibial base prosthesis can be implanted. Such conventional resection techniques typically sacrifice one or both of the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) since the resections removed the bony attachment site for those ligaments (the “tibial eminence”). Often, PCL and ACL functions are replaced by the prosthesis, which may utilize a stabilizing post on the tibial insert, and a corresponding receptacle on the femoral component or increased sagittal conformity. While these prostheses generally restore anterior-posterior stability, they may not feel as “natural” as a normal knee and are less tissue-conserving.
If any one or both of the cruciate ligaments are salvageable, it is sometimes desirable (especially for young and active patients) to conserve either or both the ACL and PCL in order to preserve natural biomechanics, range of motion, and feeling.
In current PCL-sparing knee implants, a posterior portion of the tibial insert and/or tibial base member may have a slight cut-out to provide space for the PCL and its attachment site on a remaining portion of the tibial eminence. A surgeon must remain careful not to resect portions of bone adjacent the PCL attachment areas. The ACL is generally sacrificed when using these so-called posterior cruciate-retaining prostheses.
Alternatively, a surgeon may attempt to preserve both the ACL and PCL, which is sometimes accomplished by installing two unicondylar implants. The tibial eminence and cruciate ligaments attached thereto are left intact. The medial and lateral tibial plateau areas are resected and replaced with separate unicondylar tibial trays and corresponding inserts. One disadvantage of implanting two separate unicondylar implants includes the difficulty in properly aligning the two implants in relation to each other. If the two implants are not aligned properly, wear may be accelerated, mechanical axis alignment may be compromised, and femoral motion may feel unnatural to the patient. Surgical implantation time may also be increased due to the added complexity of installing two implants instead of one.
In lieu of two separate unicondylar implants, surgeons have the alternative option of preserving both the ACL and PCL by implanting a single bi-cruciate retaining implant, which comprises a single tibial bearing member (which may be an insert) and/or tibial base member. Prior art bi-cruciate retaining implants are essentially formed of an insert and a base member, each having two unicondylar portions joined by a thin anterior bridge which connects the two. The thin anterior bridges may fail to support the high torsional loading experienced by active patients, and past implants have been known to eventually bend or shear in half over time, requiring premature revision surgery. Even minor bending and shearing experienced by such prior art devices may reduce performance and eventually cause loosening or de-laminating of the implant from the bone an either or both of the medial and lateral sides.
Additional problems with prior bi-cruciate retaining deigns include fracture of the bone adjacent to the area connecting the ACL to the tibia (i.e., the anterior tibial eminence). Such fractures are especially common when bone portions anterior to the ACL attachment point are removed in order to provide enough space for the medial and lateral side portions to be connected by said thin anterior bridge.
SUMMARYWhen compared to prior art designs, at least some of the embodiments of the cruciate-retaining tibial prostheses described herein provide greater rigidity, torsional and bending stiffness, and resistance to torsional flexing, bending, and/or shearing between medial and lateral tibial portions.
These and other embodiments provide additionally or alternatively a tibial prosthesis for at least partially replacing a proximal portion of a tibia, the tibial prosthesis comprising an inferior surface contact with a resected surface on the proximal portion of the tibia, and a keel for penetration into a cavity formed in the proximal tibia, wherein the keel extends at an inferior-posterior angle away from the inferior surface, wherein the tibial prosthesis defines a central notch extending between, the medial and lateral baseplate portions posterior to the connecting baseplate portion, wherein the central notch has a sufficient width and length to receive a portion of a tibial eminence including an anterior cruciate ligament attachment site and a posterior cruciate ligament attachment site, and wherein the central notch comprises a medial edge and a lateral edge, wherein an angle defined by the medial edge and a base of the anterior keel portion is acute, and wherein an angle defined by the lateral edge and the base of the anterior keel portion is obtuse.
Also disclosed are tibial prostheses wherein a posterior face of the anterior keel portion is offset from a posterior face of the connecting baseplate portion.
Also disclosed are tibial prostheses wherein a superior surface of the tibial prosthesis includes at least one lock member for securing a tibial insert.
Also disclosed are tibial prostheses wherein a superior surface of the tibial prosthesis includes at least two lock members for securing a medial tibial insert and a lateral tibial insert.
Also disclosed are tibial prostheses for at least partially replacing a proximal portion of a tibia, the tibial prosthesis comprising a medial baseplate portion, the medial baseplate portion having a medial inferior surface for contact with a medial resected surface on the proximal portion of the tibia, a lateral baseplate portion, the lateral baseplate portion having an lateral interior surface for contact with a lateral resected surface on the proximal portion of the tibia, a connecting baseplate portion extending between the medial and lateral baseplate portions, wherein the tibial prosthesis is asymmetric about a midline extending in an anterior-posterior direction between the medial and lateral baseplate portions and the medial baseplate portion extends further anteriorly than the lateral baseplate portion.
Also disclosed are tibial prostheses wherein an area defined by the medial baseplate portion in a transverse plane is greater than an area defined by the lateral baseplate portion in the transverse plane.
Also disclosed are tibial prostheses wherein the tibial prosthesis is a bicruciate-retaining tibial prosthesis.
Also disclosed are tibial prostheses wherein the tibial prosthesis defines a notch extending in a generally anterior-posterior direction between the medial and lateral baseplate portions and is positioned posterior to the connecting baseplate portion; and wherein the notch is of sufficient length to receive as least a portion of an eminence of the tibia including an anterior cruciate ligament attachment site and a posterior cruciate ligament attachment site.
Also disclosed are tibial prostheses wherein the notch comprises a medial edge, a lateral edge, and an anterior edge, herein an angle defined by the medial and anterior edges is acute, and wherein an angle defined by the lateral and anterior edges is obtuse.
Also disclosed is a tibial prosthesis for at least partially replacing a proximal portion of a tibia, the tibial prosthesis comprising a medial baseplate portion comprising a medial inferior surface for contact with a medial resected surface on the proximal portion of the tibia, a lateral baseplate portion comprising a lateral inferior surface for contact with a lateral resected surface on the proximal portion of the tibia, a connection baseplate portion extending between the medial and lateral baseplate portions, the connection baseplate portion comprises a connection inferior surface, a keel for penetration into a cavity formed in the proximal tibia, wherein the keel extends at an inferior-posterior angle away from at least one of the medial inferior surface, the lateral inferior surface, and the connection inferior surface.
Also disclosed are tibial, prostheses wherein the keel includes an anterior keel portion, a medial, keel portion, extending from the medial inferior surface, and a lateral keel, portion extending from the lateral inferior surface, wherein the anterior keel portion extends at the inferior-posterior angle away from the connection inferior surface.
Also disclosed are tibial prostheses wherein at least a part of the anterior keel portion extends in a generally medial-lateral direction on the connection baseplate portion, wherein at least a part of the medial keel portion extends in a generally anterior-posterior direction of the medial baseplate portion, and wherein at least a part of the lateral keel portion extends in a generally anterior-posterior direction on the lateral baseplate portion.
Also disclosed are tibial prostheses wherein the anterior keel portion joins the medial and lateral keel portions at areas of increased thickness.
Also disclosed are tibial prostheses wherein the anterior keel portion joins the medial and lateral keel portions at areas of increased width.
Also disclosed are tibial prostheses wherein the connection baseplate portion increases in thickness in an anterior posterior direction.
Also disclosed are tibial prostheses wherein the medial and lateral keel portions decrease in height as the medial and lateral keel portions extend in an anterior to posterior direction.
Also disclosed are tibial prostheses wherein the anterior keel portion extends across the connection baseplate portion in an anterior-medial to a posterior-lateral direction.
Also disclosed are tibial prostheses wherein a posterior face of the anterior keel portion is offset from a posterior face of the connection baseplate portion.
Also disclosed are tibial prostheses wherein the tibial prosthesis defines a central notch extending between the medial and lateral baseplate: portions: posterior to the connection baseplate portion, wherein, the central notch, has a sufficient width, and length to receive a portion of a tibial eminence including an anterior cruciate ligament attachment site and a posterior cruciate ligament attachment site.
Also disclosed are tibial prostheses wherein the central notch comprises a medial edge and a lateral edge, wherein an angle defined by the medial edge and a base of the anterior keel portion is acute; and wherein an angle defined by the lateral edge and the base of the anterior keel portion is obtuse.
Also disclosed are tibial prostheses wherein the tibial prosthesis is asymmetric about a midline extending in an anterior-posterior direction between the medial and lateral baseplate portions and the medial baseplate portion extends further anteriorly than the lateral baseplate portion.
These or other embodiments provide additionally or alternatively a tibial prosthesis for at least partially replacing a proximal portion of a tibia, comprising a tibial articulation surface for articulation with a femoral condylar articulation surface, wherein the tibial articulation surface defines a mesial lip extending in an anterior to posterior direction along a mesial edge of the articulation surface; where in the mesial lip is raised by a height relative to a corresponding central portion of the articulation surface; and wherein the height with which the mesial lip is raised relative to the corresponding central portion decreases in an anterior to posterior direction.
Also disclosed are tibial prostheses wherein the tibial articulation surface is a medial tibial articulation surface and wherein at least a portion of the medial tibial articulation surface is concave in a sagittal plane.
Also disclosed are tibial prostheses wherein an anterior-mesial portion of the medial tibial articulation surface is curved to at least partially conform to the femoral condylar articular surface.
Also disclosed are tibial prostheses wherein a posterior-outer portion, of the medial tibial articulation surface is substantially flat and does not substantially conform to the femoral condylar articular surface.
Also disclosed are tibial prostheses wherein the tibial articulation surface is a lateral tibial articulation surface; and wherein the lateral tibial articulation surface is convex in a sagittal plane.
Also disclosed are tibial prostheses wherein an anterior-mesial portion of the lateral tibial articulation surface is curved to at least partially conform to the femoral condylar articular surface.
Also disclosed are tibial prostheses wherein a posterior-outer portion of the lateral tibial articulation surface is substantially flat and does not substantially conform to the femoral condylar articular surface.
Also disclosed are tibial prostheses wherein the tibial prosthesis is a tibial insert; and wherein the tibial insert further comprises an inferior surface that includes at least one lock member for securing to a tibial baseplate.
Also disclosed is a tibial prosthesis for at least partially replacing a proximal portion of a tibia, comprising a tibial articulation surface for articulation with a femoral condylar articulation surface, wherein the tibial articulation surface defines a mesial lip extending in an anterior to posterior direction along a mesial edge of the articulation surface, wherein the mesial lip is raised by a height relative to a corresponding central portion of the articulation surface, and therein an anterior-mesial portion of the medial tibial articulation surface is curved to at least partially conform to the femoral condylar articular surface, and wherein a posterior-outer portion of the medial tibial articulation surface is substantially flat and does not substantially conform to the femoral condylar articular surface.
Also disclosed is a tibial prosthesis for at least partially replacing a proximal portion of a tibia, comprising: a tibial articulation surface for articulation with a femoral condylar articulation surface, wherein an anterior-medial portion of the tibial articulation surface at least partially conforms to the femoral condylar articulation surface and a posterior-outer portion of the tibial articulation surface does not substantially conform to the femoral condylar articulation surface.
Also disclosed are tibial prostheses wherein the anterior-mesial portion is curved to at least partially conform to the femoral condylar articulation surface.
Also disclosed are tibial, prostheses wherein the posterior-outer portion, is substantially flat such that the posterior-outer portion does not substantially conform to the femoral condylar articulation surface.
Also disclosed are tibial prostheses wherein the tibial articulation surface is a medial tibial articulation surface; and wherein the medial tibial articulation surface is concave in a sagittal plane.
Also disclosed are tibial prostheses, wherein the tibial articulation surface is a lateral tibial articulation surface; and wherein the lateral tibial articulation surface is convex in a sagittal plane.
According to other embodiments, a tibial prosthesis for at least partially replacing a proximal portion of a tibia is also provided, the tibial prosthesis comprising, a tibial articulation surface for articulation with a femoral condylar articulation surface, wherein the tibial articulation surface defines a mesial lip extending in an anterior to posterior direction along a mesial edge of the articulation surface, wherein the mesial lip is raised a height relative to a corresponding, central portion of the articulation surface, wherein the height with which the mesial lip is raised relative to the corresponding central portion decreases in an anterior to posterior direction, an anterior-mesial portion, of the tibial articulation surface at least partially conforms to the femoral condylar articulation surface and a posterior-outer portion of the tibial articulation surface does not substantially conform to the femoral condylar articulation surface.
Also disclosed are tibial prostheses wherein the anterior-mesial portion is curved to at least partially conform to the femoral condylar articulation surface.
Also disclosed are tibial prostheses wherein the posterior-outer portion is substantially flat such that the posterior-outer portion does not substantially conform to the femoral condylar articulation surface.
Also disclosed tibial prostheses further comprising at least one tibial articulation surface for articulation with a femoral condylar articulation surface of a femoral component, wherein the femoral component comprises a medial condyle and a lateral condyle and wherein at least one of the medial condyle and the lateral condyle comprises a posterolateral chamfer.
Also disclosed are tibial prostheses wherein the at least one tibial articulation surface generally slopes in an anterior-posterior direction.
Also disclosed are tibial prostheses wherein the at least one tibial articulation surface comprises a medial articulation surface and a lateral articulation surface, and wherein a slope of the medial articulation surface in the anterior-posterior direction is different from a slope of the lateral articulation surface in the anterior-posterior direction.
Also disclosed are tibial prostheses wherein the medial articulation surface is associated with a medial insert and the lateral articulation surface is associated with a lateral insert, wherein a thickness of the medial insert at an anterior portion, of the medial insert is different than a thickness of the lateral insert at a posterior portion of the lateral insert.
Also disclosed are tibial prostheses wherein the thickness of the medial insert at the anterior portion of the medial insert is greater than the thickness of the medial, insert at a posterior portion of the medial insert.
Also disclosed are tibial prostheses wherein a thickness of the medial insert at a posterior portion of the medial insert is different than a thickness of the lateral insert at a posterior portion of the lateral insert.
Also disclosed are tibial prostheses wherein the thickness of the lateral insert at the anterior portion of the lateral insert is greater than the thickness of the lateral insert at a posterior portion of the lateral insert.
Also disclosed are tibial prostheses wherein the at least one tibial articulation surface generally slopes in a medial-lateral direction.
Also disclosed are tibial prostheses wherein the at least one tibial articulation surface comprises a medial articulation surface and a lateral articulation surface, and wherein a slope of the medial articulation surface in the medial-lateral direction is different from a slope of the lateral articulation surface in the medial-lateral direction.
Also disclosed are tibial prostheses wherein the medial articulation surface is associated with a medial insert and the lateral articulation surface is associated with a lateral insert, wherein a thickness of the medial insert at an anterior portion of the medial insert is greater than a thickness of the lateral insert at an anterior portion of the lateral insert, and wherein the thickness of the medial insert at a posterior portion of the medial insert is different than the thickness of the lateral insert at a posterior portion of the lateral insert.
Also disclosed are tibial prostheses wherein the anterior keel portion is positioned anteriorly on the connection inferior surface to engage anterior cortical bone when implanted in a patient.
Also disclosed are femoral components having various chamfers to provide additional clearance with respect to the tibial eminence and PCL without decreasing bone coverage. In some embodiments, the medial and/or lateral condyles of the femoral component comprise a posterolateral chamfer. In some embodiments, an anterior flange of the femoral component may comprise an anterolateral chamfer on the lateral and/or medial sides.
Also disclosed are tibial prostheses further comprising at least one tibial articulation surface for articulation with a femoral condylar articulation surface of a femoral component, wherein the femoral component comprises a medial condyle and a lateral condyle and wherein at least one of the medial condyle and the lateral condyle comprises a posterolateral chamfer.
Further areas of applicability will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating certain embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the invention and together with the written description serve to explain the principles, characteristics, and features of the embodiments. It should be noted that while most or all of the drawings contained herein generally illustrate implants configured for use with a patient's left knee, mirrored implants for use with a patient's right knee and symmetrically configured implants for use with both left and right knees are also envisaged. In the drawings:
The following description is merely exemplary in nature of certain selected embodiments and is in no way intended to limit the invention, its application, or uses.
1. Tibial Base Members
The base member 10 of
As shown, the central cutout portion 8 is generally centered in a medial-lateral direction of the tibial base member 10, which facilitates maintaining the medial/lateral widths of the medial 12a and lateral 12b portions to be generally the same (and, in some embodiments, the medial lateral widths of inserts used in conjunction with the base member 10). In other embodiments, it is not necessary for the medial 12a and lateral 12b portions to be the same in medial/lateral dimensions.
The base member 10 shown in
In some embodiments, the keel portions may extend at an angle between approximately 90 degrees and appropriately 45 degrees with respect to the underside of the base member 10, although more or less pronounced angles are also possible. In some embodiments, the keel portions may extend distally at the same general angle or may extend at a different angles with respect to one another. In some embodiment, the keel portions may be symmetric with respect to one another, or may be asymmetrically configured to suit bony anatomy or for other reasons. Other base member embodiments (discussed below) may have more or less keel portions than the base member 10 of
In the particular embodiment of
The base member of
Tibial base member 10 according to some embodiments may have surface finishes that are optimized for use with cemented or uncemented techniques. In some embodiments, the base members have smooth or polished surfaces, or may have a grit blasted surface finish, or other rough surface finishes and textures such as ridges grooves, steps, flutes, spines, barbs, and combinations thereof. Bottom or distal surfaces of medial portion 12a and lateral portion 12b may also comprise bone ingrowth structures such as a porous ingrowth surfaces with or without hydroxyapatite. In some embodiments, one or more pockets may be provided on the distal or inferior undersurface of base member to accommodate a cement mantle for cemented techniques. The one or more pockets may include means for increasing surface area of contact between the implant and a cement mantle such as a waffle pattern, grooves, ridges, indentations, undercuts, porous portions, protrusions, or bumps 15c, which may be a porous metal material or surface-treated portion of the structure.
The keel portions 14a, 14b, 14c, 16a, and 16b shown in
The base member 10 of
Reinforcement members 28a, 28b are generally cylindrical in shape to facilitate bone preparation. For example, drills or small diameter reamers may be used to prepare the bone to accept the thicker region that form the intersections between the keel portions 24a, 24c, and 24b. Cylindrical and smooth arcuate shapes for the reinforcing member 28a, 28b generally increase the strength at the corners of the cutout between medial 24a and lateral 24b portions, which, in some embodiments, may be high stress areas.
As best shown in
As also shown in
As best shown, in
In the embodiment shown in
As shown best in
In some embodiments, such as the one illustrated in
As shown in
Moreover, as with other embodiments, heightened walls or eminence lip portions 89a, 89b, 89c along the medial and lateral sides of the eminence cutout area (see, e.g.
The anterior connecting portion 82c may define a generally trapezoidal sagittal shape, both in sagittal cross section (see, e.g.
In this particular embodiment, the anterior connecting portion 82c of the tibial base member 80 is sloped so as to be thicker (superior-inferior dimension) towards the posterior, which, in some embodiments, may increase strength of the base member 80 proximate the edge of the eminence cutout, while still providing more flexibility on anterior portions of the base member 80 for even stress distribution when the base member 80 is loaded posteriorly. For example, if one of the medial portion 82a or lateral portion 82b is loaded posteriorly more than the other (e.g., in deep flexion), then torsional forces may arise in the anterior portion 82c. In such situations, the flexibility created from a thinner anterior part of the anterior portion 82c more evenly distributes torsional stresses, and the thicker posterior portion of the anterior portion 82c and raised anterior eminence lip 89c provides extra strength and rigidity.
Returning to
While not shown, the upper surfaces of the tibial base member 80 may be configured for use with mobile bearings. In other words, the medial and lateral locking portions, in certain embodiments, may be provided with a means for securing the medial and lateral inserts to the base member, while allowing some finite rotational movement of the inserts. Such means may include, for instance, a male to female connection such as a peg-in-hole configuration or a circular undercut that locks the inserts in 5 degrees of freedom, while still allowing controlled rotation of the inserts relative to the base member. Other means may be provided, such as tracks and followers, which allow controlled translation of the inserts in any one or more of the anterior-posterior and medial-lateral directions.
In some embodiments, the relative anterior keel portion length and angle can be optimized based on data collected. It has been found that given a mixed anterior keel portion length, increasing the angle of the anterior keel portion from vertical generally increases the amount that the anterior keel portion undercuts the anterior tibial eminence, and that too much angle can reduce strength of the base member. If too much of the anterior keel portion undercuts the eminence, the eminence mas also be compromised. Some of the embodiments of the tibial base member were achieved through a combination of optimizing the shapes to distribute stress more efficiently throughout the base member, refining the target strength by analyzing previous tibial base member designs which were known to fracture, and running computer simulations in an iterative fashion. Input received during cadaver labs was used to identify the amount of and areas for bone removal which were acceptable from an anatomical perspective, and such information was also used to determine the optimal number, geometries, and orientation of keel portions for increased strength, and improved initial fixation in various embodiments. The inventors took into consideration manufacturing the same tibial base member design from various materials with high and low fatigue resistance in order to increase the robustness of the design regardless of material strength and properties.
The particular shape of the entire keel selected, combined with the angle of the anterior keel portion, which is in some embodiments is approximately 70 degrees, essentially creates a “sell-anchoring” feature. In other words, since the anterior keel portion undercuts she cancellous bone (relative to the proximal tibial plateau), it provides hold down forces to counteract pull-out forces.
Also disclosed are methods of unpinning a tibial prosthesis. The method includes the steps of determining a resection depth, determining a preferred spatial orientation for the prosthesis, resecting the medial and lateral tibial plateau bone portions without compromising the tibial eminence and ACL/PCL attached thereto, broaching necessary receiving portions for acceptance of one or more fixation features provided on the underside of the tibial prosthesis, and installing the tibial prosthesis using cemented or cementless techniques.
2. Tibial Inserts
The above described and other embodiments provide improved tibial inserts, such as medial insert 110 and lateral invert 120 illustrated in
The lateral insert 120 of
As shown in the embodiments of
As shown in the embodiments of
Like the lateral insert, medial insert 110 also includes a mesial lip 118 and a circumferential chamfer 119 (e.g.
As shown in
In some instances, a plurality of different posterior slope angle options may be provided to tibial inserts 110 and/or 120. In one embodiment, inserts such as 110 and/or 120 are thinned posteriorly by different amounts so as to effectively rotate the articular surfaces by a flexion-extension angle relative to the bottom surfaces of the inserts 110, 120 and provide more posterior slope. Such an option may, in some embodiments, allow a surgeon to selectively adjust joint laxity when the knee is in flexion. For instance, several pairs of medial 110 and lateral 120 inserts may be provided, each pair differing in posterior slope from the other pairs by a specified number of degrees between about 1-4 degrees, for instance 2 degrees. Other options may include pairing medial 110 and lateral 120 inserts, wherein the posterior slope of the medial insert 110 differs from the posterior slope of the lateral insert 120. Such options may generally allow the flexion space to be adjusted without necessarily requiring a re-cut of tibial bone 220. Multiple dullness options for each of the medial 110 and lateral 120 inserts are also provided for the abovementioned options to afford proper ligament balance. Various combinations and configurations of insert thicknesses, medial-lateral slope, and anterior-posterior slope may be utilized to suit the particular anatomical needs of an individual patient. The options of multiple thickness, medial-lateral slope, and anterior-posterior slope may also be configured in the tibial base plate to provide these configurations while using a single insert.
In some embodiments, the articular geometries of the medial 110 and lateral 120 inserts may be provided by a single cruciate-containing insert 500, which, as shown in
In other embodiments, medial 110 and lateral 120 inserts may be provided, each having different posterior slope angles or thicknesses, and may be utilized in various combinations in order to address different medial and lateral collateral ligament balancing needs. In some instances, a set of inserts 110, 120 including a plurality of sizes may be provided in a surgical implant kit, wherein a general angle between a bottom plane of a particular insert 110, 120 and its corresponding articulating surface varies between inserts. This angle may increase or decrease in either or both, of an anterior-posterior direction and a medial-lateral direction independently or collectively. Providing multiple posterior slope options may advantageously reduce the need for re-cutting the tibia 220.
As another alternate to using separate tibial inserts 110, 120, a tibial base member 1500 shown in
3. Femoral Components
Also provided are improved femoral components. For example, the femoral component 400 shown in
Similarly, medial posterior condyle 408 may compose on its inner surface a posterolateral chamfer 410, shown in
As shown in
Various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from, the scope of the invention, and therefore, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. For example, the novel features of the tibial inserts disclosed may be readily applied to instrumentation such as tibial insert trials, as well as implants designed to be implanted. Thus, the breadth and scope of the invention should not be limited by any of the above-described exemplary embodiments, but should be instead defined only in accordance with any claims which may be appended hereto and their equivalents.
Claims
1. A tibial prosthesis, comprising:
- a medial insert comprising a medial articulation surface and a medial bottom surface, the medial articulation surface for articulation with a medial portion of a femoral condylar articulation surface and the medial bottom surface for receipt by a medial portion of a tibial base member, wherein the medial articulation surface comprises a medial posterior portion with a medial posterior slope relative to the medial bottom surface; and
- a lateral insert comprising a lateral articulation surface and a lateral bottom surface, the lateral articulation surface for articulation with a lateral portion of the femoral condylar articulation surface and the lateral bottom surface for receipt by a lateral portion of the tibial base member, wherein the lateral articulation surface comprises a lateral posterior portion with a lateral posterior slope relative to the medial bottom surface.
2. The tibial prosthesis of claim 1, wherein the medial posterior slope and the lateral posterior slope are equal.
3. The tibial prosthesis of claim 1, wherein the medial posterior slope and the lateral posterior slope are different.
4. The tibial prosthesis of claim 1, wherein the medial posterior slope is negative in an anterior-posterior direction of the medial insert.
5. The tibial prosthesis of claim 1, wherein the lateral posterior slope is negative in an anterior-posterior direction of the lateral insert.
6. The tibial prosthesis of claim 1, wherein the medial posterior slope increases in an anterior-posterior direction of the medial insert.
7. The tibial prosthesis of claim 1, wherein the medial posterior slope decreases in an anterior-posterior direction of the medial insert.
8. The tibial prosthesis of claim 1, wherein the lateral posterior slope increases in an anterior-posterior direction of the lateral insert.
9. The tibial prosthesis of claim 1, wherein the lateral posterior slope decreases in an anterior-posterior direction of the lateral insert.
10. The tibial prosthesis of claim 1, wherein the medial posterior slope and the lateral posterior slope are configured to provide balance between a medial collateral ligament and a lateral collateral ligament.
11. A tibial prosthesis implant kit, comprising:
- a first pair of inserts comprising: a first medial insert comprising a first medial articulation surface and a first medial bottom surface, the first medial articulation surface for articulation with a medial portion of a femoral condylar articulation surface and the first medial bottom surface for receipt by a medial portion of a tibial base member, wherein the first medial articulation surface comprises a first medial posterior portion with a first medial posterior slope relative to the first medial bottom surface; and a first lateral insert comprising a first lateral articulation surface and a first lateral bottom surface, the first lateral articulation surface for articulation with a lateral portion of the femoral condylar articulation surface and the first lateral bottom surface for receipt by a lateral portion of the tibial base member, wherein the first lateral articulation surface comprises a first lateral posterior portion with a first lateral posterior slope relative to the medial bottom surface; wherein the first medial posterior slope and the first lateral posterior slope are configured to provide a first amount of flexion space; and
- a second pair of inserts comprising: a second medial insert comprising a second medial articulation surface and a second medial bottom surface, the second medial articulation surface for articulation with the medial portion of the femoral condylar articulation surface and the second medial bottom surface for receipt by the medial portion of the tibial base member, wherein the second medial articulation surface comprises a second medial posterior portion with a second medial posterior slope relative to the second medial bottom surface; and a second lateral insert comprising a second lateral articulation surface and a second lateral bottom surface, the second lateral articulation surface for articulation with the lateral portion of the femoral condylar articulation surface and the second lateral bottom surface for receipt by the lateral portion of the tibial base member, wherein the second lateral articulation surface comprises a second lateral posterior portion with a second lateral posterior slope relative to the medial bottom surface; wherein the second medial posterior slope and the second lateral posterior slope are configured to provide a second amount of flexion space different from the first amount of flexion space.
12. The tibial prosthesis implant kit of claim 11, wherein the first medial posterior slope is a set number of degrees more than the second medial posterior slope and the first lateral posterior slope is the set number of degrees more than the second lateral posterior slope.
13. The tibial prosthesis implant kit of claim 11, wherein the first medial posterior slope and the first lateral posterior slope are equal.
14. The tibial prosthesis implant kit of claim 11, wherein the first medial posterior slope and the first lateral posterior slope are different.
15. The tibial prosthesis implant kit of claim 11, wherein the second medial posterior slope and the second lateral posterior slope are equal.
16. The tibial prosthesis implant kit of claim 11, wherein the second medial posterior slope and the second lateral posterior slope are different.
17. The tibial prosthesis implant kit of claim 11, wherein the first medial posterior slope is negative in an anterior-posterior direction of the first medial insert and the second medial posterior slope is negative in an anterior-posterior direction of the second medial insert.
18. The tibial prosthesis implant kit of claim 11, wherein the first lateral posterior slope is negative in an anterior-posterior direction of the first lateral insert and the second lateral posterior slope is negative in an anterior-posterior direction of the second lateral insert.
19. The tibial prosthesis implant kit of claim 11, wherein the first medial posterior slope increases in an anterior-posterior direction of the first medial insert and the second medial posterior slope increases in an anterior-posterior direction of the second medial insert.
20. The tibial prosthesis implant kit of claim 11, wherein the first medial posterior slope decreases in an anterior-posterior direction of the first medial insert and the second medial posterior slope decreases in an anterior-posterior direction of the second medial insert.
Type: Application
Filed: Nov 26, 2019
Publication Date: May 7, 2020
Inventors: Nathaniel Milton Lenz (Germantown, TN), Richard Michael Smith (Memphis, TN), Zachary Christopher Wilkinson (Germantown, TN), Brian William McKinnon (Bartlett, TN), Abraham Biglari Salehi (Bartlett, TN), Jonathan Kirk Nielsen (Dana Point, CA), Michael D. Ries (Tiburon, CA), Gerald J. Jerry (St. Clair, MI)
Application Number: 16/696,360