WO2017155995A1

WO2017155995A1 - Knee prosthesis with modular tibial inserts

Info

Publication number: WO2017155995A1
Application number: PCT/US2017/021156
Authority: WO
Inventors: Donald Running; Craig Brewer
Original assignee: Genesis Innovation Group, Llc
Priority date: 2016-03-08
Filing date: 2017-03-07
Publication date: 2017-09-14

Abstract

Knee prostheses for use with a femoral component including medial and lateral articular surfaces is provided. The prostheses include a plurality of separate and distinct tibial inserts each including a concave articular surface. The prostheses also include a tibial implant including a stem and a tray portion including a medial portion configured to couple with a first tibial insert and a lateral portion configured to couple with a second tibial insert. The plurality of tibial inserts are each configured to couple to either the medial portion and the lateral portion of the plate portion for articulation with the medial and the lateral articular surfaces of the femoral component, respectively. The first and second tibial inserts and the tray portion are configured such that the first and second tibial inserts can couple to the tray portion at varying positions and/or spacings along a medial-lateral direction.

Description

KNEE PROSTHESIS WITH MODULAR TIBIAL INSERTS

CROSS-REFERENCE TO RELATED APPLICATION

[0101] This application perfects and claims the benefit of U.S. Provisional Patent

Application No. 62/305,256, filed on March 8, 2016, and entitled Knee Prosthesis with Modular Tibial Inserts, which is hereby expressively incorporated herein by reference in its entirety. FIELD OF THE INVENTION

[0102] The present disclosure is generally directed to knee replacement prostheses. More particularly, the present disclosure is directed to a knee replacement prostheses with one or more modular tibial insert.

BACKGROUND OF THE INVENTION

[0103] Total knee replacement (also called knee arthroplasty) typically involves the removal of damaged cartilage surfaces and an amount of underlying bone at the ends of the femur and tibia. The removed cartilage and bone is replaced with prostheses that recreate the surfaces of the joint. These parts may be cemented or "press-fit" into the bone.

[0104] One type of knee replacement system, often referred to as fixed-bearing

prostheses, utilize a femoral component for the distal end of the femur, a stemmed tibial plate for the proximal end of the tibia, and a tibial insert for placement on the tibial plate and articulation with the femoral component. Tibial inserts typically form medial and lateral articular surfaces from a single piece of polyethylene, such as a single piece of UHMWPe. The one-piece tibial insert locks securely to the tibial tray.

[0105] Tibia trays and corresponding inserts are typically offered in numerous different sizes, and tibial inserts are typically offered in differing joint types or configurations, such as cruciate retaining, constrained cruciate retaining, posterior stabilized configurations, and medial pivot option (a conforming or constrained medial articular surface and a less conforming lateral articular surface) configurations, for example. Three or four different inserts are thereby required in inventory to provide the three or four different joint configuration options. If an anatomic (right/left) design is used, these numbers must be doubled.

[0106] When using a typical fixed bearing knee implant, careful attention must be paid with respect to the internal/external rotational alignment of the tibial tray in relation to the femoral implant because the tibial insert is locked in its orientation relative to the tibial tray. The typical tibial insert has an articular surface created into it with a defined anterior/posterior (AP) plane of articulation. If the AP plane of the tibial insert does not align with the AP plane of the femoral flexion, mal-articulation will occur leading to potential damage of the insert and abnormal loading of the femur onto the insert. Studies have shown that the best fitting tibial tray onto a resected tibia surface is the universal shaped (non-right/left specific) tray using a mobile bearing insert. This means that the surgeon can internally/externally rotate the tibial tray to achieve the optimal fit on the resected bone, allowing the mobile bearing to rotate into the AP plane of the femoral articulation.

[0107] Anatomic or right/left tibial trays for fixed bearing knees can provide a more optimal fit onto the resected tibial bone, but often must be rotated to align the tibial insert AP articular plane with the femoral AP plane. Once the anatomic tibial tray rotation is changed, a different, sub-optimal fitting tibial tray must be used to avoid having the tray overhanging the resected bone.

[0108] In some cases, after the surgeon has made all the tibial and femoral cuts and soft tissue releases, they may find that the laxity in the medial or lateral compartments are not equal. In those cases, the surgeon's only options are to leave the patient in this suboptimal condition or attempt to fine tune the soft tissue releases in the "tight" compartment. Neither situation is desirable.

[0109] Therefore, knee replacement prostheses that require less inventory (e.g., less tibial insert and tibial tray inventory), allow for optimal internal/external rotational placement of a tibial tray while still providing proper femoral-tibial tracking through the range of motion (ROM), provide the ability to fine tune varus/valgus soft tissue balancing, and provide the ability to increase or decrease the constraint in the medial and/or lateral compartments are desirable. SUMMARY OF THE INVENTION

[0110] The present disclosure provides knee replacement prostheses and implants that include a modular, multi-piece tibial insert. The tibial insert is formed of separate and distinct components that are universal shaped (non-right/left specific) with concave articular surfaces. The present disclosure thereby provides an individual articular insert for the medial compartment and another for the lateral compartment. However, as the inserts are universal, they are interchangeable between the medial and lateral compartments. Further, the inserts may be configured to provide differing articulations or resulting joint types with a respective femoral component. In this way, differing combinations of inserts can be utilized in the medial and lateral compartments to provide differing desired clinical results.

[0111] The present disclosure also provides for tibial trays and inserts that provide a plurality of medial/lateral locking locations of an insert with respect to the tray along a medial- lateral direction or sides of the tray. Both the medial and lateral portions of the tibial tray may allow for multiple locking locations of the respective insert utilized therewith. The tibial tray may thereby allow for differing medial -lateral spacings and/or positions of the medial and lateral inserts, such as to suit or match differing condyle spacings or positions. [0112] These and other objects, features and advantages of this disclosure will become apparent from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0113] For the purposes of illustrating the knee replacement prostheses and related methods described herein, there is shown herein illustrative embodiments. These illustrative embodiments are in no way limiting in terms of the precise arrangement and operation of the disclosed knee replacement prostheses and related methods and other similar embodiments are envisioned within the spirit and scope of the present disclosure.

[0114] FIG. 1 illustrates an elevational perspective view of an exemplary tibial plate according to the present disclosure.

[0115] FIG. 2 illustrates an enlarged elevational perspective view of the tibial plate of FIG. 1.

[0116] FIG. 3 illustrates another enlarged elevational perspective view of the tibial plate of FIG. 1.

[0117] FIG. 4 illustrates a top view of the tibial plate of FIG. 1.

[0118] FIG. 5 illustrates a bottom view of the tibial plate of FIG. 1.

[0119] FIG. 6 illustrates a left side view of the tibial plate of FIG. 1.

[0120] FIG. 7 illustrates a right side view of the tibial plate of FIG. 1.

[0121] FIG. 8 illustrates an elevational back perspective view of another exemplary tibial plate according to the present disclosure.

[0122] FIG. 9 illustrates an elevational front perspective view of the tibial plate of FIG. 8.

[0123] FIG. 10 illustrates an elevational back perspective view of another exemplary tibial plate according to the present disclosure. 0124] FIG. 11 illustrates an elevational front perspective view of the tibial plate of FIG. 10. 0125] FIG. 12 illustrates an elevational back perspective view of an exemplary tibial insert according to the present disclosure.

[0126] FIG. 13 illustrates a bottom back perspective view of the tibial insert of FIG. 13.

[0127] FIG. 14 illustrates an elevational front perspective view of the tibial insert of FIG. 13

[0128] FIG. 15 illustrates a bottom front perspective view of the tibial insert of FIG. 13.

[0129] FIG. 16 illustrates a top view of the tibial insert of FIG. 13.

[0130] FIG. 17 illustrates a bottom view of the tibial insert of FIG. 13.

[0131] FIG. 18 illustrates a back view of the tibial insert of FIG. 13.

[0132] FIG. 19 illustrates a front view of the tibial insert of FIG. 13.

[0133] FIG. 20 illustrates a left side view of the tibial insert of FIG. 13.

[0134] FIG. 21 illustrates a right side view of the tibial insert of FIG. 13.

[0135] FIG. 22 illustrates a top view of a knee replacement prosthesis according the present disclosure comprising a pair of tibial inserts installed on a tibial plate.

[0136] FIG. 23 illustrates a front view of the knee replacement prosthesis of FIG. 22.

[0137] FIG. 24 illustrates a left side view of the knee replacement prosthesis of FIG. 22.

[0138] FIG. 25 illustrates a plurality of exemplary tibial inserts of a knee replacement prosthesis system according to the present disclosure.

[0139] FIG. 26 illustrates a left side view of the plurality of exemplary tibial inserts of FIG. 25.

[0140] FIG. 27 illustrates a perspective view of an exemplary femoral implant according to the present disclosure.

[0141] FIG. 28 illustrates a bottom perspective view of the femoral implant of FIG. 27.

[0142] FIG. 29 illustrates a back elevational view of the femoral implant of FIG. 27. [0143] FIG. 30 illustrates a side view of the femoral implant of FIG. 27.

[0144] FIG. 31 illustrates a bottom view of the femoral implant of FIG. 27.

[0145] FIG. 32 illustrates a top view of the femoral implant of FIG. 27.

DETAILED DESCRIPTION

[0146] When introducing elements of various embodiments of the present invention, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. Any examples of parameters are not exclusive of other parameters of the disclosed embodiments. Components, aspects, features, configurations, arrangements, uses and the like described, illustrated or otherwise disclosed herein with respect to any particular embodiment may similarly be applied to any other embodiment disclosed herein.

[0147] As shown in FIGS. 1-32, embodiments of knee replacement prostheses and related methods and systems for knee replacement according to the present disclosure may comprise or include fixed-bearing prostheses. The prostheses may include a femoral component 12 (see FIGS. 27-32) for coupling to a distal end of a femur, a stemmed tibial plate or implant 14, 114, 214 (see FIGS. 1-11) for coupling to a proximal end of a tibia, and modular tibial inserts 16, 116, 216, 316 (see FIGS. 13-21, 25 and 16) for placement on medial and lateral portions of the tibial plate 14, 114, 214 for articulation with corresponding medial and lateral articulation surfaces 18 of the femoral component 12 (see FIGS. 27-32).

[0148] As shown in FIGS. 1-7, in some embodiments a tibial plate or implant 14 according to the present disclosure may include a plate or tray portion 22 and a stem portion 24 extending from an inferior side of the plate portion 22. The tray portion 22 of the tibial plate 14 may be of a universal design that can be used with either left or right tibia of a patient. For example, the tray portion 22 may be symmetrical about a central plane that divides the tray portion 22 into a medial side or portion and a lateral side or portion. The medial and lateral portions of the tibial portion 22 may be mirror images of each other about the central plane. In this way, the plate portion 22 may be rotated properly to align or fit properly or anatomically on a respective resected tibia to yield the best fit to the tibia, regardless of whether it is a left or right tibia of a patient. The universal tibia tray portion 22 design may reduce tray inventory by half as compared to anatomical designed tibial trays. The tray portion 22 of the tibial plate 14 may include a substantially convex anterior side or portion 28, and a substantially concave posterior side or portion 26, as shown in FIGS. 1-7. The concave portion of the posterior side 26 of the tray portion 22 may be positioned between a pair of convex portions, as shown in FIGS. 1-7. In use, the concave portion of the posterior side 26 of the tray portion 22 may be positioned at or about midline to accommodate tissue, such as the posterior cruciate ligament for example.

[0149] As shown in FIGS. 1-4, 6 and 7, the proximal side of the tray portion 22 may include a planar engagement surface 30 extending at least substantially across the tray portion 22 along a medial-lateral direction. Both the medial and lateral portions of the tray portion 22 may include the planar engagement surface 30. As shown in FIGS. 1-3, the anterior and/or posterior portions of the medial and/or lateral portions of the tray portion 22 may include a respective posterior 32 or anterior 34 lip portion spaced from the planar engagement surface 30. In some embodiments, both the medial and lateral portions of the tray portion 22 may include respective posterior and anterior lip portions 32, 34. The posterior lip portions 32 and anterior lip portions 32 may extend substantially parallel to each other.

[0150] The posterior lip portions 32 may form respective slots, recesses or cavities 36 extending between the respective posterior lip portions 32 and the engagement surface 30, as shown in FIGS. 1-3, 6 and 7. As also shown in FIGS. 1-3, 6 and 7, the anterior lip portions 34 may form respective slots, recesses or cavities 38 extending between the respective anterior lip portions 34 and the engagement surface 30. As shown in FIG. 3, the posterior recesses 36 formed by the posterior lip portions 32 at the posterior portion of the tray portion 22 also extend in the anterior-to-posterior direction to respective side walls 37 that extend between the engagement surface 30 and the respective posterior lip portions 32. Similarly, the anterior recesses 38 formed by the anterior lip portions 34 at the anterior portion of the tray portion 22 also extend in the posterior-to-anterior direction to respective side walls 39 that extend between the engagement surface 30 and the respective anterior lip portions 34, as shown in FIGS. 1 and 2. The posterior recesses 36 and the anterior recesses 38 (and/or the side walls 37, 39 associated therewith) may extend substantially parallel to each other.

[0151] As shown in FIGS. 1-4, the posterior-facing surface or posterior portion of the anterior lip portions 34 (and/or the respective side walls 39 of the anterior recesses 38) may include a plurality of substantially identical indentations 40 (or projections forming indentations 40 therebetween) extending into the anterior lip portions 34 in a posterior-to-anterior direction. The indentations (or projections) 40 of the anterior lip portions 34 may also be spaced, arranged or extend along a medial -lateral direction, as shown in FIGS. 1-4. In this way, the indentations 40 of the anterior lip portions 34 may form a consistent or continuous pattern of indentations 40 extending along a medial-lateral direction. In some embodiments, as shown in FIGS. 1 and 2, the anterior lip portions 34 may include at least five substantially identically-shaped indentations 40 spaced or arranged along a medial -lateral direction. The posterior-facing side walls 39 of the anterior recesses 38 positioned below (e.g., inferiorly) and anteriorly to the anterior lip portions 34 and the indentations 40 therein may be substantially planar or flat, as shown in FIGS. 1 and 2. In other embodiments, the posterior-facing side walls 39 of the anterior recesses 38 may include the indentations 40 or otherwise be non-planar. As explained further below, the indentations 40 of the posterior lip portions 34 may allow for unique medial and lateral tibial inserts to be removably coupled to the tray portion 22 of the tibial plate 14, such as in or at various medial- lateral positions or spacings, such as with respect to each other or a midline of the tray portion 22 or the tibial plate 14 itself (and/or a patient's tibia or femur).

[0152] In some embodiments, the indentations 40 of the anterior lip portions 34 may be arcuate concave indentations, such as circular or spherical concave indentations. In some other embodiments, the indentations 40 of the anterior lip portions 34 may be non-spherical indentations. However, any other shape and/or pattern of indentations 40 may be utilized.

[0153] Similar to the indentations 40 in the anterior lip portions 34, the anterior-facing surface of the side walls 37 of the posterior recesses 36 formed underneath the posterior lip portions 32 (and/or the anterior-facing surface or anterior portion of the posterior lip portions 32) may include a plurality of substantially identical indentations 42 (or projections forming indentations therebetween) extending therein in an anterior-to-posterior direction, as shown in FIG. 3. The indentations (or projections) 42 in the posterior recesses 36 may be spaced, arranged or extend along a medial-lateral direction, as shown in FIG. 3. In some embodiments, as shown in FIG. 3, the anterior-facing surface of the side walls 37 of the posterior recesses 36 positioned underneath the posterior lip portions 32 may include at least four substantially identical -shaped indentations 42 spaced along a medial-lateral direction. In this way, the indentations of the posterior recesses 36 may form a consistent or continuous pattern of indentations 42 extending along a medial-lateral direction. In some embodiments, the indentations 42 of the posterior recesses 36 may be arcuate concave indentations, such as circular indentations. In some other embodiments, the indentations 42 of the posterior recesses 36 may be non-spherical indentations. However, any other shape and/or pattern of the indentations 42 may be utilized. The anterior- facing surface of the posterior lip portions 32 positioned above (e.g., superiorly) and anteriorly to the indentations 42 of the posterior recesses 36 may be substantially linear, planar or flat, as shown in FIGS. 1-4.

[0154] As explained below with respect to FIGS. 12-21, tibial inserts 16 according to the disclosure may include a posterior locking member that includes a posterior lead-in lip that positions or snaps under one of the posterior lip portions 32 and into the associated posterior recess 36 of the tray portion 22 to prevent posterior lift-off of the inserts from the tray portion 22 (e.g., from the engagement surface 30), and an anterior locking member that includes a deflectable anterior lead-in lip that positions or snaps under one of the anterior lip portions 34 and into the associated anterior recesses 38 of the tray portion 22 to prevent anterior lift-off of the inserts from the tray portion 22 (e.g., from the engagement surface 30). Both the anterior and posterior locking members of the inserts 16 may include projections (or indentations forming projections therebetween) that mimic or correspond to the indentations 40, 42 of the anterior and posterior lip portions 32, 34 to fix the inserts along a medial-lateral direction. Further, as the tray portion 22 includes a plurality of the substantially identical-shaped indentations 40, 42 spaced along a medial-lateral direction at the anterior and posterior lip portions 32, 34, the inserts 16 may be fixed to the tray portion 22 at several different medial-lateral locations and/or spacings. As such, the tibial plate 14 may provide for variable spacing along a medial -lateral direction between a medial insert 16 fixed or coupled to the medial portion of the tray portion 22 and a lateral insert 16 fixed or coupled to the lateral portion of the tray portion 22. Similarly, the tibial plate 14 may provide for variable positioning along a medial-lateral direction of a medial insert 16 fixed or coupled to the medial portion of the tray portion 22 and a lateral insert 16 fixed or coupled to the lateral portion of the tray portion 22, such as with respect to a midline of the tray portion 22 or the tibial plate 14 (and/or a patient's tibia or femur). As the tray portion 22 of the exemplary tibial plate 14 of FIGS. 1-7 includes at least five indentations 40 at the anterior lip portions 34 and the at least four indentations 42 at the posterior lip portions 42 (e.g., within the posterior recesses 36), the tray portion 22 may provide at least four different medial-lateral positions of each of the inserts 16 on the tray portion 22 (i.e., at least sixteen different medial- lateral spacings between the inserts 16), such as with respect to each other or respect to a midline of the tray portion 22 or the tibial plate 14 (and/or a patient's tibia or femur). As shown in FIGS. 1-3, the tibial plate 14 may also include an anterior central lip portion 46 extending or spaced from an anterior portion of the engagement surface 30 in a central portion of the tray portion 22 along a medial-lateral direction intermediate of, or positioned between, the medial anterior lip portion 34 and the lateral anterior lip portion 34 (and the associated anterior recesses 38). As shown in FIGS. 1-3, the tibial plate may 14 also include a posterior central lip portion 44 extending or spaced from a posterior portion of the engagement surface 30 in a central portion of the tray portion 22 along a medial -lateral direction intermediate of, or positioned between, the medial posterior lip portion 32 and the lateral posterior lip portion 32 (and the associated posterior recesses 36). The anterior and posterior central lip portions 46, 44 of the central portion of the tray portion 22 may form respective slots, recesses or cavities extending between the respective lip portion 46, 44 and the engagement surface 30, as shown in FIGS. 1-3. The anterior and posterior central lip portions 46, 44 of the central portion of the tray portion 22 may thereby allow for a stabilizing post insert (not shown) to be coupled, locked or fixed to the central portion of the tray portion 22 (via portions positioned within the recesses). The stabilizing post insert (not shown) may extend in the superior direction away from the engagement surface 30 of the tray portion 22 to provide a posterior stabilized tibial plate or implant 14, if desired.

[0155] As shown in FIGS. 8 and 9, another exemplary tibial plate or implant 114 according to the present disclosure is illustrated. Tibial plate 114 of FIGS. 8 and 9 is substantially the same as the tibial plate 14 of FIGS. 1-7, and therefore like reference numerals preceded by the numeral "1" are used to indicate like features or aspects, and the description thereto with respect to the tibial plate 14 equally applies to the tibial plate 1 14 unless otherwise noted. As shown in FIGS. 8 and 9, the tibial plate 1 14 differs from the tibial plate 14 in that it may include fewer than five anterior indentations 140 at or in the anterior lip portions 134 and/or fewer than four posterior indentations 142 at the posterior lip portions 132 or within the posterior recesses 136. For example, as shown in FIGS. 8 and 9, the tibial plate 114 may include three anterior indentations 140 extending into the anterior lip portions 134 and/or two posterior indentations 142 extending into the side walls 137 of the posterior recesses 136 beneath the posterior lip portions 132. As the tray portion 122 includes a plurality of the anterior and posterior indentations 140, 142 at the anterior and posterior lip portions 134, 132, the tibial plate 114 provides for variable positioning and/or spacing along a medial-lateral direction of a medial insert 116 removably coupled or fixed to the medial portion of the tray portion 122 and a lateral insert 116 fixed to the lateral portion of the tray portion 122, such as with respect to each other or a midline of the tray portion 122 or the tibial plate 114 (and/or a patient's tibia or femur). The tray portion 122 of the tibial plate 114 of FIGS. 8 and 9 may be relatively smaller than the tray portion 122 of the tibial plate 114 of FIGS. 1-7. As the tray portion 122 of the exemplary tibial plate 114 of FIGS. 8 and 9 includes three anterior indentations 140 in the anterior lip portions 134 and two posterior indentations 142 in the posterior recesses 136, the tray portion 122 may provide two different medial-lateral positions of each of the inserts on the tray portion 122 (i.e., at least four different medial-lateral spacings between the inserts and/or medial-lateral locations of the inserts with respect to a midline).

[0156] As shown in FIGS. 10 and 1 1, another tibial plate 214 according to the present disclosure is illustrated. Tibial plate 214 of FIGS. 10 and 11, is substantially the same as the tibial plate 14 of FIGS. 1-7 and tibial plate 114 of FIGS. 8 and 9, and therefore like reference numerals preceded by the numeral "2" are used to indicate like features or aspects, and the description thereto with respect to tibial plate 14 and tibial plate 114 equally applies tibial plate 214 unless otherwise noted. Tibial plate 214 differs from the tibial plate 14 and the tibial plate 114 in that it includes fewer than three anterior indentations 240 extending into the anterior lip portions 234 and/or fewer than two posterior indentations 242 within the recesses 236 formed underneath the posterior lip portions 232. As shown in FIGS. 10 and 11, the tibial plate 214 may include two indentations 240 extending into the anterior lip portions 234 and/or one indentation 242 within the recesses 236 formed underneath the posterior lip portions 232. As the tray portion 222 thereby does not include a plurality of indentations 242 within the recesses 236 formed underneath the posterior lip portions 232, the tibial plate 214 may not provide for variable positioning or spacing of a medial insert 216 fixed or coupled to a medial portion of the tray portion 222 and a lateral insert 216 fixed to a lateral portion of the tibial plate 214 along a medial-lateral direction. However, as explained below, because the tray portion 222 is configured to fix with two separate and distinct inserts (e.g., separate and distinct medial and lateral inserts 216, 216), the tray portion 222 advantageously allows for customization of the tibial plate 214 to provide differing articulation configurations, reduce inventory, provide the ability to fine tune varus/valgus soft tissue balancing, and provide the ability to increase or decrease the geometric constraint in the medial and/or lateral compartments. The tray portion 222 of the tibial plate 214 of FIGS. 10 and 11 may be relatively smaller than the tray portion 22 of the tibial plate 14 of FIGS. 1-7 and the tray portion 122 of the tibial plate 114 of FIGS. 8 and 9.

[0157] As shown in FIGS. 12-21, the present disclosure provides for modular tibial implants or plates that utilize universal tibial inserts or articular components 16 with concave articular or articulation surfaces 50. The individual tibial inserts 16 may be universally-shaped (non-right/left specific). For example, in some embodiments the concave articular surface 50 of the tibial inserts 16 may be symmetric or a mirror image at least in a medial -lateral direction across a midline or diameter of the articular surfaces 50 (e.g., across a midline extending in the anterior-posterior direction). For a particular application, an individual, distinct articular insert 16 may be utilized for the medial side or compartment of a tibial tray portion 22, 122, 222 of a tibial plate or implant 14, 114, 214 and another individual, distinct articular insert 16 may be utilized for the lateral side or compartment of the tibial tray portion 22, 122, 222.

[0158] As described above, the locking or coupling mechanisms of the inserts 16 may be configured to allow for more than one medial/lateral locking location with or on a tibial tray. The inserts 16 may include coupling or locking mechanisms configured to couple or lock the inserts 16 to a plate portion 22, 122, 222 of a tibial plate 14, 114, 214. As shown in FIGS. 13, 15 and 17-21, the inserts 16 may include an engagement surface 60 configured to mate or abut with the engagement surface 30, 130, 230 of the plate portion 22, 122, 222 of a tibial plate 14, 114, 214 when the inserts 16 are coupled or locked therewith (e.g., via the coupling mechanisms and the anterior ad posterior lip portions, as explained further below). In some embodiments, the engagement surface 60 of the inserts 16 (and, potentially, the engagement surface 30, 130, 230 of the plate portion 22, 122, 222) may be planar or include planar portions.

[0159] As shown in FIGS. 13, 15, 17-21, the inserts 16 may include a posterior locking or coupling mechanism or configuration 51 with a medial-lateral extending slot 52 at the posterior side of the inserts 16 for acceptance or mating with the posterior lip 32, 132, 232 of the plate portion 22, 122, 22 of a tibial plate 14, 114, 214 (see FIGS. 3, 9 and 11). Further, as also shown in FIGS. 12, 13, 15, 17, 18, 20 and 21, the posterior locking mechanism 51 of the inserts 16 may include an anterior-to-posterior extending extension 54 with an anterior-to-posterior extending projection 56 extending from a surface of extension 54 positioned below the slot 52 to the engagement surface 60 of the inserts 14 along the inferior-superior direction. The engagement surface 60 of the inserts 16 may mate with or engage the engagement surface 30, 130, 230 of the plate portion 22, 122, 222 of the tibial plate 14, 114, 214. For example, the portions of the engagement surface 60 associated with the extension 54 and the projection 56 of the posterior locking mechanism 51 of the inserts 16 may abut the portion of the engagement surface 30, 130, 230 associated with a posterior recess 36, 136, 236 of the plate portion 22, 122, 222.

[0160] The posterior projection 56 of the posterior locking mechanism 51 of the inserts

16 may extend from a posterior-facing surface of the anterior-to-posterior extending extension 54, as shown in FIGS. 13, 17, 18, 20 and 21. The posterior extension 54 and projection 56 of the posterior locking mechanism 51 of the inserts 16 may be configured to mate or extend within the posterior recesses 36, 136, 236 formed beneath the posterior lips portions 32, 132, 232 of the plate portion 22, 122, 222 of the tibial plate 14, 114, 214 (see FIGS. 3, 9 and 11). For example, the posterior slot 52 may be configured to allow the posterior lips portions 32, 132, 232 to extend therein when the engagement surfaces 30, 60 are in engagement or in close proximity to allow the projection 56 and the posterior extension 54 of the posterior locking mechanism 51 of the inserts 16 to slide and/or extend into a posterior recess 36, 136, 236. Further, the posteriorly- extending projection 56 of the posterior extension 54 of the posterior locking mechanism 51 of the inserts 16 may be configured to mate or extend within the indentation(s) 42, 142, 242 of the posterior recesses 36, 136, 236 (e.g., formed by the side wall 37, 137, 237 of the posterior recesses 36, 136, 236 below the posterior lips portions 32, 132, 232) (see FIGS. 3, 9 and 11). The posteriorly-extending projection 56 of the posterior extension 54 may be a mirror image of the indentation(s) 42, 142, 242 of the posterior recesses 36, 136, 236 below the posterior lips portions 32, 132, 232 of the plate portion 22, 122, 222 of the tibial plate 14, 114, 214 (see FIGS. 3, 9 and 11). In this way, the posterior locking mechanism 51 of the inserts 16 may mate or couple with the posterior lip portions 32, 132, 232 and posterior recesses 36, 136, 236 to lock or fix the inserts 16 to the tray portion 22, 122, 222 to prevent lift-off therefrom. Further, the projection 56 of the posterior locking mechanism 51 of the inserts 16 may mate or couple with one of the indentations 42, 142, 242 of the posterior recesses 36, 136, 236 of the tray portion 22, 122, 222 to lock or fix at least the posterior end of the inserts 16 to the tray portion 22, 122, 222 along a medial-lateral direction. As the posterior recesses 36, 136, 236 of the tray portion 22, 122, 222 may include more than one indentation 42, 142, 242, the inserts 16 may be affixed to the tray portion 22, 122, 222 in a variety of medial -lateral locations (i.e., depending upon which indentation 42, 142, 242 the projection 56 is mated with).

[0161] Similar to the posterior side of the inserts 16, the anterior side of the inserts 16 may include an anterior locking or coupling mechanism 61 for mating with the anterior lip portions 34, 134, 234 and anterior recesses 38, 138, 238 of the tray portion 22, 122, 222 of the tibial plate 14, 114, 214, as shown in FIGS. 13, 14, 15, 17 and 19-21. As shown in FIGS. 13-15 and 17, the anterior locking mechanism 61 of the inserts 16 may include a deflectable tab or projection 62. The deflectable tab 62 of the anterior locking mechanism 61 of the inserts 16 may be deflectable at least in the anterior-posterior direction. For example, a gap, space or void 63 may extend between the tab 62 and a body portion of the insert 16 in the anterior-posterior direction, as shown in FIGS. 13, 15 and 17. The gap 63 may also extend along the lateral and medial sides of the tab 62 to the anterior end of the insert 16, as shown in FIG. 17. The gap 63 may extend partially through the insert 16 in an inferior-superior direction. The deflectable tab 62 may include at least one anteriorly-extending projection 64 configured to mate or extend within the indentation(s) 40, 140, 240 of the anterior lips portions 34, 134, 234 of the tray portion 22, 122, 222 of the tibial plate 14, 114, 214 (see FIGS. 1 and 2). The at least one anterior- extending projection 64 of the deflectable tab 62 may extend from an anterior-facing surface or portion of the deflectable tab 62 proximate to the engagement surface 60 of the inserts 14. The at least one anterior-extending projection 64 of the deflectable tab 62 may be a mirror image of the indentation(s) 40, 140, 240 of the anterior lips portions 34, 134, 234 of the tray portion 22, 122, 222 of the tibial plate 14, 114, 214 (see FIGS. 1 and 2). As shown in FIGS. 13, 14, 15, 17 and 19-21, the tab portion 62 of the anterior locking mechanism 61 of the inserts 16 may include at least a pair of anterior-extending projections 64 configured to mate or extend within at least a pair of the indentations 40, 140, 240 of the anterior lip portions 34, 134, 234 of the tray portion 22, 122, 222 of the tibial plate 14, 114, 214 (see FIGS. 1 and 2).

[0162] The at least one anterior-extending projection 64 of the tab portion 62 of the anterior locking mechanism 61 of the inserts 16 may include a first extended portion 66 positioned proximate to the engagement or end surface 60 of the tab portion 62 and inserts 14, as shown in FIGS. 15, 19, 20 and 21. The first extended portion 66 may be positioned anteriorly with respect a second recessed portion 68 of the at least one anterior-extending projection 62 positioned distal to the engagement surface 60 and proximate to the articulation surface 50 of the inserts 14, as shown in FIGS. 15, 19, 20 and 21. In this way, the first extended portion 66 may be positioned proximate to or extend from an inferior free end of the tab portion 62, and the second recessed portion 68 may extend superiorly from the first extended portion 66. Further, the second recessed portion 68 may thereby be positioned posteriorly from the first extended portion 66. The tab portion 62 may include a shelf, lip or anterior-to-posterior extending surface extending between the first extended portion 66 and the second recessed portion 68 of the at least one anterior-extending projection 64 of the tab 62, as shown in FIGS. 19, 20 and 21. [0163] As also shown in FIGS. 15, 17 and 19-21, the tab portion 62 may include an outer angled biasing or bearing surface 70 extending from the inferior engagement or end surface 60 of the tab portion 62. The angled biasing surface 70 of the tab 62 may be angled anteriorly and superiorly as it extends from the engagement or end surface 60 of the tab portion 62 to the first extended portion 66 of the at least one anterior-extending projection 64, as shown in FIGS. 15, 17 and 19-21. In some embodiments, the angled biasing surface 70 of the tab 62 may be planar. In other embodiments, the angled biasing surface 70 of the tab 62 may be non-planar, such as including the shape of the at least one anterior-extending projection 64. The angled biasing surface 70 of the tab 62 may be configured such that when the angled biasing surface 70 is in engagement or abutment with the edge or end of an anterior lip portion 34, 134, 234 of the tray portion 22, 122, 222 of a tibial implant 14, 114, 214 and a downward or inferior force is applied to the insert 16, the angled biasing surface 70 directs the force posteriorly to deflect the tab 62 in at least an anterior-to-posterior direction. In this way, the tab 62 may be deflected to allow the first extended portion 66 of the anterior-extending projection 64 to engage, extend or be positioned within the at least one indentation 40, 140, 240 of the anterior lip portion 34, 134, 234. The insert 16 can then be further translated inferiorly to allow the first extended portion 66 to deflect back anteriorly (along a posterior-to-anterior direction) and into the anterior recess 38, 138, 238 associated with the anterior lip portion 34, 134, 234 and the second recessed portion 68 of the at least one anterior-extending projection 62 to engage, extend or be positioned within the at least one indentation 40, 140, 240 of the anterior lip portion 34, 134, 234.

[0164] In some embodiments, to affix an insert 16 to a tray portion 22, 122, 222 of a tibial plate 14, 114, 214, the posterior locking mechanism 51 of the insert 16 may initially be coupled with a medial or lateral posterior lip portion 32, 132, 232 and associated recess 36, 136, 236, as explained above. Specifically, the posterior lip portion 32, 132, 232 may be positioned within the slot 52, the posterior extension 54 may be positioned within the recess 36, 136, 236, and the posteriorly-extending projection 56 of the posterior extension 54 may be positioned within an indentation 42, 142, 242 of the recess 36, 136, 236. The angled biasing surface 70 of the tab 62 of the anterior locking mechanism 61 may then be aligned and mated with the respective medial or lateral anterior lip portion 34, 134, 234. In such an arrangement, the at least one anterior-extending projection 64 of the tab portion 62 may be substantially aligned with at least one corresponding indentation 40, 140, 240 of the anterior lip portion 34, 134, 234. With the angled biasing surface 70 engaging the posterior edge of the anterior lip portion 34, 134, 234, the insert 16 may be forced inferiorly to cause the angled surface 70 of the tab 62 to deflect the tab 62 posteriorly, and thereby slide or translate along the edge of the anterior lip portion 34, 134, 234 posteriorly, as described above.

[0165] Once the insert 16 is forced inferiorly such that the tab 62 is deflected and the extended portion 66 of the at least one anterior-extending projection 64 of the tab 62 is positioned below (e.g., inferiorly) the respective anterior lip portion 34, 134, 234 and aligned with the associated anterior recess 38, 138, 238, the tab 62 may elastically deflect back in the posterior-to-anterior direction such that the extended portion 66 of the at least one anterior- extending projection 64 of the tab 62 extends into the anterior recess 38, 138, 238 formed below (e.g., inferiorly) the anterior lip portion 34, 134, 234. With the extended portion 66 of the at least one anterior-extending projection 64 of the tab 62 extending into the respective anterior recess 38, 138, 238 below the anterior lip portion 34, 134, 234, the anterior-posterior extending lip extending between the extended portion 66 and the recessed portion 68 of the at least one anterior-extending projection 64 of the tab 62 may lock or affix the engagement surface 60 of the insert 16 to the engagement surface 30 of the tray portion 22, 122, 222 to lock or fix at least the anterior side or portion of the insert 16 to the tray portion 22, 122, 222 to prevent lift-off therefrom in an inferior-superior direction, and translation along a medial-lateral and posterior- anterior directions. Further, the extension 54 and the at least one projection 56 of the posterior locking mechanism 51 of the insert 16 may mate or couple within the posterior recess 36, 136, 236 and the at least one of the indentation 42, 142, 242 therein, respectively, such that the respective posterior lip portion 32, 132, 232 of the tray portion 22, 122, 222 is positioned within the slot 52, to lock or fix at least the posterior side or portion of the insert 16 to the tray portion 22, 122, 222 to prevent lift-off therefrom along an inferior-superior direction, and translation along medial -lateral and posterior-anterior directions. As the anterior lip portions 34, 134, 234 may include a plurality of indentations 40, 140, 240 and the posterior recesses 36, 136, 236 may include a plurality of indentations 42, 142, 242, the inserts 16 may be affixed to the tray portion 22, 122, 22 in a variety of medial-lateral locations (i.e., depending upon which anterior projections 64 of the anterior locking mechanism 61 and the posterior projections 56 of the posterior locking mechanism 51 are mated with the anterior indentations 40, 140, 240 and posterior indentations 42, 142, 242, respectively).

[0166] FIGS. 22-25 illustrate an exemplary assembly of a pair of separate and distinct medial and lateral inserts 316, 316 fixed or coupled with a tibial plate 314 via the anterior and posterior locking mechanisms of the inserts 316. The tibial plate 314 is substantially the same as the tibial plate 14 of FIGS. 1-7, tibial plate 114 of FIGS. 8 and 9, and tibial plate 214 of FIGS. 10 and 11, and therefore like reference numerals preceded by the numeral "3" are used to indicate like features or aspects, and the description thereto equally applies to tibial plate 314 unless otherwise noted. Similarly, the inserts 316 are substantially the same as the insert 16 of FIGS. 12-21, and therefore like reference numerals preceded by the numeral "3" are used to indicate like features or aspects, and the description thereto equally applies to inserts 316 unless otherwise noted. [0167] As shown in FIGS. 22-25, a medial insert 316 is coupled to the medial portion of the tray portion 322 of the tibial plate 314 via anterior and posterior locking mechanisms thereof, and a lateral insert 316 is coupled to the lateral portion of the tray portion 322 of the tibial plate 314 via anterior and posterior locking mechanisms thereof. As shown in FIGS. 22 and 23, a particular medial -lateral positioning and/or spacing of the anterior and posterior inserts 316 was chosen. However, as described above, a different medial-lateral positioning and/or spacing of the inserts 316 may have been chosen and/or the positioning and/or spacing may be modified or changed from such a spacing. Further, as explained below, although FIGS. 22 and 23 illustrate substantially identical medial and lateral inserts 316, the inserts 316 may differ from one another (such being sized differently and/or including differently configured articular surfaces 316).

[0168] As shown in FIGS. 22 and 23 and as described above, the articular surface 350 of the inserts 316 may be concave. In some embodiments, the concave articular surface 350 of the inserts 316 may be spherical or otherwise shaped such that they are void of a distinct AP plane of articulation or rotation. Therefore, the AP plane of the tibial tray portion 322 does not have to be internally/externally rotated to align precisely with the femoral AP rotational plane of a patient. This allows the tibial tray portion 322 to be a universal tray design, which, when rotated properly, typically yields the best fit to the tibia of the patient.

[0169] As described above, the articular surface 350 of the inserts 316 may articulate and bear against corresponding medial or lateral articular surfaces 18 of a femoral insert 12 (e.g., representing femoral condyles), as shown in FIGS. 27-32. While the locking mechanisms and/or articular surface 350 features of the medial and lateral inserts 316, 316 may be identical, a plurality of differing inserts 316 may be provided and/or a pair of differing inserts 316 may be used in the medial and lateral portions of a tibial plate 314, as shown in FIGS. 25 and 26. The modular nature of the prosthesis thereby allows any medial and lateral tibial inserts 316 to be utilized (e.g., tibial inserts 316 of any size (e.g., thickness), shape, and/or articular surface 350). For example, particular tibial inserts 316 may be utilized to suit a particular femoral insert 18, as shown in FIGS. 27-32. As another example, particular inserts 316 may be utilized to form a particular articulation with a femoral insert 18. As yet another example, particular inserts 316 may be utilized to equalize soft tissue tension. As another example, particular inserts 316 may be utilized for differing sized patients.

[0170] For example, as shown in FIGS 25 and 26, differing inserts 316a-316d may be provided and utilized with the medial and lateral portions of the tibial portion 322 of the tibial plate 314, or two of the same or identical inserts 316a-316d may be utilized with the medial and lateral portions of the tibial portion 322 of the tibial plate 314. The inserts 316a-316d may differ with respect to the size and/or shape of the boundary of the concave articular surfaces 350. In some embodiments, the inserts 316a-316d may differ with respect to the radius of curvature of the superior concave articular surface 350. In some embodiments, the inserts 316a-316d may differ with respect to the position of the apex of the concave articular surface 350 (which, in some embodiments, may be spherical). In some embodiments, the inserts 316a-316d may differ with respect to the proximal height of the apex of the concave articular surface 350 from the engagement surface 330 of the tray portion 322 of the tibial plate 314. However, the above listed examples of potential structural differences between the inserts 316a-316d, such as to provide differing clinical outcomes, are not exhaustive. The inserts 316a-316d may structurally differ from one another in any way (while being configured to affix to the tibial tray portion 322 and/or including a concave articular surface 350), such as to provide a particular clinical outcome or for a particular patient. Although the inserts 316a-316d may structurally differ from one another in some way, the inserts 316a-316d may all be configured to affix or couple to a tibial tray portion 322 in the same way. In this way, the knee prosthesis utilizing the tibial tray portion 322 may be modular and be configurable for a particular patient.

[0171] As noted above, in some embodiments a plurality or kit of inserts 316a- 316d may be provided, and at least some of the inserts 316a-316d may differ from each other with respect to the curvature of the superior concave articular surface 350. Two substantially identical inserts 316a-316d may be utilized with the medial and lateral portions of a tray portion 322, or inserts 316a-316d with differing concave curvatures of the articulation surfaces 350 (such as along the anterior-posterior and/or medial -lateral planes) may be utilized with the medial and lateral portions of a tray portion 322, for example. As another example, inserts 316a-316d with spherical articulation surfaces 350 of differing radius of curvatures (or the same radius of curvatures) may be utilized with the medial and lateral portions of a tray portion 322. Similarly, the articular surfaces 18 of a femur or a femoral implant (i.e., the condyles) 12 may include or be defined by at least one radius of curvature, as shown in FIGS. 27-32. The radius of curvature of the articular surfaces 18 of femoral implants 12 may vary, and the medial and lateral condylar radius of curvature 18 may be the same or different for a particular femoral implant 12. In this way, a particular combination of the radii of curvature of medial and lateral inserts 316a-316d and the corresponding radii of curvature of the medial and lateral articular surfaces 18 of a femoral implant 12 may be selected to provide a particular joint articulation.

[0172] For example, as shown in FIGS. 25 and 26, a plurality of tibial inserts 316a-316d

(e.g., at least four tibial inserts 316a-316d) may be provided with four differing radius of curvatures of the superior concave articular surface. The insert 316a may have or include a smallest radius of curvature of the articular surface 350, a radius of curvature of the insert 316b may be greater than a radius of the insert 316a, a radius of curvature of the insert 316c may be greater than a radius of the insert 316b, and the insert 316d may have a largest radius of curvature, as shown in FIGS. 25 and 26. The articular surfaces 18 of the femoral implant 12, as shown in FIGS. 37-32, may similarly vary from implant 12 to implant 12. In some knee prosthesis embodiments, a plurality of femoral implants 12 may be provided that include differing articular surfaces 18, such as at least four femoral implants 12 with radii of curvature of the articular surfaces 18 corresponding to the at least four inserts 316a-316d of FIGS. 25 and 26. Further, the medial-lateral condylar articular surface spacing of the femoral implants 12 may differ. For example, the femoral implant 12 with a smallest radius of curvature of the articular surfaces 18 may include the smallest spacing of the articular surfaces 18 in a medial-lateral direction, and the femoral implant 12 with a largest radius of curvature of the articular surfaces 18 may include the largest spacing between the articular surfaces 18 in a medial-lateral direction. However, the femoral implants 12 may have other combinations of the spacing and radius of curvature (e.g., in both the anterior-posterior and the medial lateral directions) of the articular surfaces 18. Further, while at least four inserts 316a-316d and at least four corresponding femoral implants 12 are described above, fewer than four inserts 316a-316d and corresponding femoral implants 12 may be provided or utilized, or more than four inserts 316a- 316d and corresponding femoral implants 12 may be provided or utilized according to the present disclosure.

[0173] In some embodiments, the femoral implants 12 with a smallest radius of curvature of the articular surfaces 18 may have the greatest level of constraint when used with the insert 316a that the articular concave surface 350 with a smallest radius of curvature. Inserts 316 with articular concave surfaces 350 with radius of curvatures greater than the smallest insert 316a may be used (i.e., insert 316b, insert 316c, insert 316d, etc.) with the smallest femoral implant 12, but such inserts 316 may provide progressively less constraint, for example. Further, whichever insert 316a-316d is utilized, it must be locked or coupled into the proper medial -lateral spacing and/or position on the tibial tray portion 322 for a particular femoral implant 12, such as with respect to the other insert 316a-316d or a midline of the tray portion 322 or the tibial plate 314 (and/or a patient's tibia or femur).

[0174] In this way, the plurality of inserts 316a-316d with differing curvatures of the articulation surface 350 may be utilized by a surgeon or other user to create any one of multiple types of articulations by selecting a particular modular insert 316a-316d for the medial and/or lateral side of the tray portion 322 of the tibial plate 314 (and with respect to the particular femoral implant 12 being utilized). If a constrained, cruciate retaining prosthesis is desired, for example, the user may use two similar inserts 316 that are designed for the particular femoral implant 12 chosen, for example. This results in a preferred more constrained or conforming fit. If a standard, cruciate retaining type of articulation is desired, the user may select two components from any larger sized insert 316 (i.e., an insert with a superior articular surface 350 with a larger radius of curvature), for example. If a medial pivot articulation is desired, the user may select an insert 316 designed for the femur for the medial compartment and a larger size for the lateral compartment (i.e., an insert 316 with a superior articular surface 350 with a larger radius of curvature), for example. If a posterior stabilized type of articulation is desired, the user may select two inserts 316 designed for that femur and the proper posterior stabilized spine insert, for example. As another example, if a user encounters unequal soft tissue tension, the user may select thinner or thicker inserts 316 for the medial and/or lateral compartments to achieve proper tension.

[0175] It is to be understood that the above description is intended to be illustrative, and not restrictive. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments, they are by no means limiting and are merely exemplary. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the various embodiments should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Also, the term "operably connected" is used herein to refer to both connections resulting from separate, distinct components being directly or indirectly coupled and components being integrally formed (i.e., monolithic). Further, 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, sixth paragraph, unless and until such claim limitations expressly use the phrase "means for" followed by a statement of function void of further structure. It is to be understood that not necessarily all such objects or advantages described above may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. [0176] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the disclosure may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

[0177] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

CLAIMS We claim:

1. A tibial prosthesis for use with a femoral component including medial and lateral articular surfaces, the prosthesis comprising:

a plurality of separate and distinct tibial inserts each including a concave articular surface; and

a tibial implant including a stem and a tray portion including a medial portion configured to couple with a first tibial insert of the plurality of tibial inserts and a lateral portion configured to couple with a second tibial insert of the plurality of tibial inserts,

wherein the plurality of tibial inserts are each configured to couple to either the medial portion and the lateral portion of the plate portion for articulation with the medial and the lateral articular surfaces of the femoral component, respectively.

2. The prosthesis of claim 1, wherein at least one of the plurality of tibial inserts includes a spherical concave articular surface.

3. The prosthesis of claim 2, wherein the plurality of tibial inserts include at least one tibial insert with a spherical concave articular surface defined by a first radius of curvature, and at least one tibial insert with a spherical concave articular surface defined by a second radius of curvature that is different than the first radius of curvature.

4. The prosthesis of claim 1, wherein the plurality of tibial inserts include at least one tibial insert with a concave articular surface including a first radius of curvature, and at least one tibial insert with a concave articular surface including a second radius of curvature that is different than the first radius of curvature.

5. The prosthesis of claim 1, wherein the plurality of tibial inserts include an anterior locking mechanism at an anterior side of the inserts and a posterior locking mechanism at a posterior side of the inserts.

6. The prosthesis of claim 5, wherein the medial and lateral portions of the tray portion of the tibial implant each include anterior and posterior lip portions configured to couple with the anterior and posterior locking mechanisms of the tibial inserts, respectively.

7. The prosthesis of claim 6, wherein the anterior lip portions are positioned proximate to an anterior side of the tray portion and the posterior lip portions are positioned proximate to a posterior side of the tray portion.

8. The prosthesis of claim 7, wherein the tray portion of the tibial implant includes an engagement surface, and wherein the anterior and posterior lip portions are spaced from the engagement surface to form anterior and posterior recesses therebetween.

9. The prosthesis of claim 8, wherein the anterior and posterior locking mechanisms are configured to mate within the anterior and posterior recesses, respectively.

10. The prosthesis of claim 9, wherein at least one of the anterior and posterior recesses includes at least one indentation therein, and wherein at least one of the anterior and posterior locking mechanisms includes an extension portion with at least one projection configured to extend into the at least one of the anterior and posterior recesses such that the at least one projection mates with the at least one indentation to couple the at least one insert in a first medial-lateral positon.

11. The prosthesis of claim 10, wherein the at least one of the anterior and posterior recesses includes a plurality of indentations therein spaced along a medial-lateral direction to couple the at least one insert in one of a plurality of differing medial -lateral positons.

12. The prosthesis of claim 9, wherein at least one of the anterior and posterior lip portions include at least one indentation, and wherein at least one of the anterior and posterior locking mechanisms includes a deflectable tab portion with at least one projection configured to mate with the at least one indentation to couple the at least one insert in a first medial -lateral positon.

13. The prosthesis of claim 12, wherein the deflectable tab portion of at least one of the anterior and posterior locking mechanisms includes a recessed portion including the at least one projection and an extended portion configured to extend into the respective anterior or posterior recesses.

14. The prosthesis of claim 13, wherein the extended portion is proximate to an inferior end of the deflectable tab portion, and wherein the deflectable tab portion includes an angled biasing surface extending posteriorly or anteriorly between the extended portion and the free end of the inferior end of the deflectable tab portion.

15. The prosthesis of claim 1, wherein the plurality of tibial inserts include tibial inserts with concave articular surfaces defining differing outer peripheries.

16. The prosthesis of claim 1, wherein the tray portion of the tibial implant includes a first engagement surface, wherein the plurality of tibial inserts include a second engagement surface that engages the first engagement surface when the tibial implants are couple with the tray portion, and wherein the plurality of tibial inserts include tibial inserts with differing thicknesses between the concave articular surfaces and the second engagement surfaces.

17. A tibial prosthesis for use with a femoral component including medial and lateral articular surfaces, the prosthesis comprising:

a medial tibial insert including a concave articular surface for articulation with the medial articular surface of the femoral component;

a lateral tibial insert including a concave articular surface for articulation with the lateral articular surface of the femoral component, the lateral tibial insert being separate and distinct from the medial tibial insert; and

a tibial implant including a stem and a plate portion including a medial portion and a lateral portion,

wherein the medial and lateral portions of the plate are configured such that the medial and lateral tibial inserts are able to couple to the medial and lateral portions of the plate, respectively, at varying spacings therebetween in the medial-lateral direction.

18. The prosthesis of claim 17, wherein the medial and lateral tibial inserts are each configured to couple to the medial and lateral portions of the plate, respectively, at varying medial-lateral locations with respect to a center midline.

19. The prosthesis of claim 17, wherein the medial and lateral tibial inserts each include an anterior locking mechanism at an anterior side of the inserts and a posterior locking mechanism at a posterior side of the inserts.

20. The prosthesis of claim 19, wherein the medial and lateral portions of the tray portion of the tibial implant each include anterior and posterior lip portions configured to couple with the anterior and posterior locking mechanisms of the medial and lateral tibial inserts, respectively.