Patent Description:
Orthopedic procedures and prostheses are commonly utilized to repair and/or replace damaged bone and tissue in the human body. For example, a knee arthroplasty can be used to restore natural knee function by repairing damaged or diseased articular surfaces of the femur and/or tibia. An incision is made into the knee joint to expose the bones comprising the joint. Cut guides are used to guide the removal of the articular surfaces that are to be replaced. Prostheses are used to replicate the articular surfaces. Knee prostheses can include a femoral component implanted on the distal end of the femur, which articulates with a tibial bearing component and a tibial component implanted on the proximal end of a tibia to replicate the function of a healthy natural knee. Various types of arthroplasties are known including a total knee arthroplasty, where all of the articulating compartments of the joint are repaired with prosthetic components. <CIT> discloses a tibia platform comprising a metallic lower part and different bearing parts made of plastic which can be anchored to one another at a posterior position via an open hinge joint. The embodiment illustrated in <FIG> of <CIT> defines the preamble of claim <NUM>.

This disclosure pertains generally to tibial systems for a knee arthroplasty including a revision knee arthroplasty. The present inventors have recognized, among other things, that a degree of micro-motion experienced by a tibial bearing component relative to a tibial baseplate can be reduced by providing an additional lockdown feature(s). Reduction of micro-motion can provide better overall durability for the tibial bearing component when assembled with the tibial baseplate. Furthermore, present inventors have recognized that with additional lockdown features, a greater rigidity and torsional strength can be provided to the tibial bearing component. As such, metal reinforcement need not be provided to a spine of the tibial bearing component. Thus, the weight of the tibial bearing component can be reduced.

As used herein, "micro-motion" refers to the small motions that may exist between prosthesis components, such as between the tibial baseplate and the tibial bearing component, respectively, upon application of force. Such small motions may occur as a result of material deformation in one or both of the interacting components, or may result from slight spaces or clearances therebetween, for example. Micro-motion is distinguished from "mobile bearing" applications, which experience relatively larger motions as the tibial bearing component articulates with respect to the tibial baseplate (such as by sliding or rotating) along a desired motion path.

As used herein, a "fixed bearing" tibial prosthesis is a prosthesis in which the tibial bearing component is seated atop the tibial baseplate in a final, locked, and secured position. In this secured position, lift-off of the tibial bearing component from the tibial baseplate as well as transverse movement of the tibial bearing component relative to the tibial baseplate is prevented during natural articulation of the knee. Some micro-motion may exist between the tibial bearing component and tibial baseplate in a fixed bearing prosthesis.

The present invention provides a system for use in a knee arthroplasty, as defined in claim <NUM>. Further optional features of the invention are defined in the dependent claims. Methods are described herein but the methods are not claimed. Described herein is a system for use in a knee arthroplasty comprising: a tibial bearing component having medial and lateral proximal articular surfaces and an opposing distal surface, wherein the tibial bearing component defines at least one recess therein with the recess having an opening at a periphery of the tibial bearing component; a tibial baseplate coupled to the tibial bearing component on a proximal surface thereof and having a distal surface configured to be disposed on a resected proximal surface of a tibia; an insert configured to be disposed within the recess and engage the tibial baseplate and the tibial bearing component; and a fastener retaining the insert to the tibial baseplate.

Optionally the tibial bearing component comprises a posterior-stabilized tibial bearing component with a spine disposed between the medial and lateral proximal articular surfaces.

Optionally the insert comprises: a body having an aperture defined thereby, the aperture receives a head of the fastener; a first foot connected to the body and extending distal therefrom, the first foot having a first side surface engaging the tibial baseplate; and a second foot connected to the body and extending distal therefrom, the second foot spaced from the first foot and having a second side surface engaging the tibial baseplate.

Optionally the insert further comprises a tab extending proximally from the body, the tab engaging the tibial bearing component to retain the insert within the tibial bearing component.

Optionally the body includes a first wing that extends lateral of the first foot and a second wing that extends medial of the second foot.

Optionally the head of the fastener and the aperture share a similar curvature such the fastener is self-centering within the insert.

Optionally the opening is at an anterior portion of the periphery of the tibial bearing component and the insert is disposed in the recess such that substantially an entirety of the insert is disposed anterior of the fastener.

Optionally the tibial baseplate includes a rail extending from the proximal surface along a periphery thereof, wherein the rail has a gap in a region of the recess, and wherein with the insert disposed in the recess, at least a portion thereof extends into the gap and engages the rail to limit micro-motion of the tibial bearing component.

Optionally a second aperture is formed in the tibial bearing component and extending from between the medial and lateral proximal articular surfaces to communicate with the recess, wherein the second aperture is configured to receive at least a portion of the fastener, and wherein the second aperture is angled relative to a proximal-distal axis of the tibial bearing component such that second aperture extends both proximal-distal and anterior-posterior.

Optionally the tibial bearing component comprises a posterior-stabilized tibial bearing component with a spine disposed between the medial and lateral proximal articular surfaces, and wherein the fastener is insertable into an anterior portion of the spine.

Optionally the insert comprises: a body having an aperture defined thereby, the aperture configured to receive a head of the fastener; a first foot extending generally distal from the body and having a first side surface engaging the tibial baseplate; and a second foot extending generally distal from the body and spaced from the first foot, the second foot having a second side surface engaging the tibial baseplate.

Optionally the insert further comprises a tab extending proximally from the body and configured to engage the tibial bearing component to retain the insert within the tibial bearing component.

Optionally the opening is at an anterior portion of the periphery of the tibial bearing component and the insert is disposed in the recess when assembled such that substantially an entirety of the insert is disposed anterior of the fastener.

Optionally the tibial baseplate includes a rail extending from the proximal surface along a periphery thereof, wherein the rail has a gap in a region of the recess and forms a part of the opening, and wherein with the insert disposed in the gap the insert is configured to engage the rail to limit micro-motion of the tibial bearing component.

Optionally a second aperture is formed in the tibial bearing component and extending from the medial and lateral proximal articular surfaces to communicate with the recess, wherein the second aperture is configured to receive at least a portion of the fastener, and wherein the second aperture is angled relative to a proximal-distal axis of the tibial bearing component such that second aperture extends both proximal-distal and anterior-posterior.

Further described herein is a method of assembling a tibial prosthesis for a knee arthroplasty, the method can optionally comprise: passing an insert through a peripheral opening and into a recess formed in a tibial bearing component; engaging a portion of the insert with the tibial bearing component while having wings of the insert received in corresponding grooves that are part of the recess; engaging the tibial bearing component with a tibial baseplate; and fastening the insert to the tibial baseplate.

Optionally fastening the insert to the tibial baseplate includes passing a fastener through a proximal surface region located between medial and lateral proximal articular surfaces of the tibial bearing component.

Optionally the method includes engaging a first foot of the insert with a first portion of a rail of the tibial baseplate and engaging a second foot of the insert with a second portion of the rail of the tibial baseplate.

In the drawings, which are not necessarily drawn to scale, like numerals can describe similar components in different views. Like numerals having different letter suffixes can represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various examples discussed in the present document.

The present application relates tibial prostheses, systems, and methods. The systems, for example, include a tibial bearing component, a tibial baseplate, an insert and a fastener.

The present application relates a prosthesis assembly that is for use in a knee arthroplasty and/or as part of a later knee revision surgery. As described herein, the prosthesis assembly can include tibial prosthesis and a femoral prosthesis. This application focuses on aspects of the tibial prosthesis, which include a tibial baseplate, a tibial bearing component, an insert and a fastener. As discussed previously, the tibial prosthesis can be configured to reduce micro-motion between the tibial bearing component and the tibial baseplate. This can improve the durability of the tibial prosthesis. Additional features and benefits of the various examples provided herein will be discussed and/or will be apparent to one of ordinary skill in the art.

As used herein, the terms "proximal" and "distal" should be given their generally understood anatomical interpretation. The term "proximal" refers to a direction generally toward the torso of a patient, and "distal" refers to the opposite direction of proximal, i.e., away from the torso of a patient. It should be understood that the use of the terms "proximal" and "distal" should be interpreted as though the patient were standing with the knee joint in extension despite the apparatuses described herein generally being used with the knee joint in flexion. The intent is to differentiate the terms "proximal" and "distal" from the terms "anterior" and "posterior". As used herein, the terms "anterior" and "posterior" should be given their generally understood anatomical interpretation. Thus, "posterior" refers to a rear of the patient, e.g., a back of the knee. Similarly, "anterior" refers to a front of the patient, e.g., a front of the knee. Thus, "posterior" refers to the opposite direction of "anterior". Similarly, the term "lateral" refers to the opposite direction of "medial".

<FIG> and <FIG> illustrate a prosthesis assembly <NUM> that can include a femoral prosthesis <NUM> and a tibial prosthesis <NUM>. In the example of <FIG>, the prosthesis assembly <NUM> is shown in a perspective view with the femoral prosthesis <NUM> articulated relative to the tibial prosthesis <NUM> to <NUM>° of flexion. <FIG> shows the prosthesis assembly <NUM> in a cross-sectional view along a sagittal plane. The sagittal plane extends along the anterior-posterior direction and the proximal-distal direction of the prosthesis assembly <NUM>.

According to the examples provided herein, the prosthesis assembly <NUM> can comprise a posterior stabilized (PS) prosthesis. Thus, the tibial prosthesis can include a spine <NUM> and the femoral prosthesis <NUM> can include a cam <NUM> (<FIG>). The spine <NUM> and the cam <NUM> can designed to cooperate with one another to stabilize femoral prosthesis <NUM> with respect to tibial prosthesis <NUM> in lieu of a posterior cruciate ligament (PCL). However, other prosthesis designs are contemplated including a mid-level constraint (MLC) design, a cruciate retaining (CR) design, and an ultra-congruent (UC) design, for example. The CR and UC designs omit the spine <NUM> and cam <NUM>, such that femoral prosthesis <NUM> defines an intercondylar space between medial and lateral condyles <NUM> and <NUM> (only one shown in <FIG>) that is entirely open and uninterrupted by the cam <NUM>. CR tibial prostheses are generally used in surgical procedures which retain the PCL.

Turning to the components illustrated in <FIG> and/or <FIG>, the tibial prosthesis <NUM> includes a tibial bearing component <NUM>, a tibial baseplate <NUM>, an insert <NUM>, and a fastener <NUM> (<FIG>). The tibial bearing component <NUM> includes the spine <NUM>, a proximal medial articular surface <NUM> and a proximal lateral articular surface <NUM>. The tibial baseplate <NUM> can include a keel <NUM>. Additional components such as a stem <NUM> can be used with the prosthesis assembly <NUM> in some examples.

As shown in <FIG> and <FIG>, the femoral prosthesis <NUM> can be disposed atop and can articulate relative to the tibial prosthesis <NUM>. Such articulation can be between the medial and lateral condyles <NUM> and <NUM> and the proximal medial articular surface <NUM> and the proximal lateral articular surface <NUM>, respectively. The proximal medial articular surface <NUM> and the proximal lateral articular surface <NUM> can be shaped (e.g., curved) to facilitate such articulation during knee joint flexion. The spine <NUM> of the tibial bearing component <NUM> can be centrally located between the proximal medial articular surface <NUM> and the proximal lateral articular surface <NUM> as shown in <FIG>. The spine <NUM> can be configured to engage with the cam <NUM> during flexion as shown in <FIG>. Such engagement provides additional stability that would otherwise be offered by ligaments such as the PCL.

The tibial bearing component <NUM> is secured to the tibial baseplate <NUM> as shown in <FIG> and <FIG>. Such securement can be facilitated by the use of rails, notches, bosses and other features that will be described subsequently. Additionally, as shown in <FIG>, the insert <NUM> and the fastener <NUM> are used to further secure the tibial bearing component <NUM> to the tibial baseplate <NUM> as will be described subsequently.

As shown in <FIG>, the insert <NUM> is disposed within a recess <NUM> of the tibial bearing component <NUM> atop a proximal surface <NUM> of the tibial baseplate <NUM> when assembled. The fastener <NUM> can extend at least partially through an aperture <NUM> into the recess <NUM> and can engage the insert <NUM> along a head portion thereof. The fastener <NUM> additionally extends to fasten to the tibial baseplate <NUM> along a threaded portion as illustrated and described subsequently. As will be further discussed subsequently, features of the insert <NUM>, fastener <NUM>, tibial baseplate <NUM> and tibial bearing component <NUM> reduce micro-motion of the tibial bearing component <NUM> relative to the tibial baseplate <NUM>.

In addition to the proximal surface <NUM>, the tibial baseplate <NUM> has a distal surface <NUM> configured to interface with and abut a resected surface of the tibia (not shown). The keel <NUM> extends generally distal of the distal surface <NUM> according to the example of <FIG> and <FIG>. The keel <NUM> can be configured to be received in a corresponding recess within the tibia to facilitate fixation of the tibial baseplate <NUM> to the tibia. However, according to other examples the tibial baseplate <NUM> can use additional or other features (i.e. features additional to or other than the keel <NUM>) to facilitate fixation to the tibia including bone cement, spikes, augments and/or pegs. Thus, the keel <NUM> and stem <NUM> need not be utilized in all examples.

<FIG> shows a second example of a prosthesis assembly <NUM> of similar construction to the prosthesis assembly <NUM> of <FIG> and <FIG>. However, in <FIG> the location of the aperture <NUM> has been altered relative to the aperture <NUM>. The aperture <NUM> does not pass through the spine <NUM> in the embodiment of <FIG> but is disposed anterior thereof. In contrast, the aperture <NUM> passed through an anterior portion of the spine <NUM> as shown in <FIG> and <FIG>. Thus, it is contemplated that the aperture <NUM>, <NUM> can be disposed in a plurality of positions including passing through at least a portion of the spine, anterior of the spine or posterior of the spine.

<FIG> additionally shows the femoral prosthesis <NUM> articulated to an extension position relative to the tibial prosthesis <NUM>. In such position, the cam <NUM> can be disposed out of contact with the spine <NUM>.

Thus, as shown in one or more of <FIG>, <FIG> and <FIG>, the tibial bearing component <NUM> has medial and lateral proximal articular surfaces <NUM>, <NUM> (<FIG>) and an opposing distal surface <NUM> (<FIG>). The tibial bearing component <NUM> defines at least one recess <NUM> therein with the recess <NUM> having an opening at a periphery of the tibial bearing component <NUM>. The tibial baseplate <NUM> is coupled to the tibial bearing component <NUM> on the proximal surface <NUM> thereof and has a distal surface <NUM> configured to be disposed on a resected proximal surface of a tibia. The insert <NUM> is configured to be disposed within the recess <NUM> and can engage the tibial baseplate <NUM> and the tibial bearing component <NUM>. The fastener <NUM> is insertable into the tibial bearing component <NUM> and is configured to retain the insert <NUM> to the tibial baseplate <NUM>.

<FIG> illustrate a method <NUM> by which the tibial prosthesis <NUM> can be assembled. The method <NUM> includes passing the insert <NUM> through a peripheral opening <NUM> and into the recess <NUM> formed in the tibial bearing component <NUM> as shown in <FIG>. The method engages a portion (e.g., tab <NUM> in <FIG>) of the insert <NUM> with the tibial bearing component <NUM> while having first and second wings (described and number subsequently in reference to <FIG>) of the insert <NUM> received in corresponding grooves (described and number subsequently in reference to <FIG>) that are part of the recess <NUM>. A tool can be used in some instances to facilitate passing the insert <NUM> and engagement as described above. The tool can also facilitate removal of the insert <NUM> from the recess <NUM> in some examples.

The method <NUM> can engage the tibial bearing component <NUM> with the tibial baseplate <NUM> as shown in <FIG>. This can initially be accomplished with engagement features such as dovetail boss, rails, notches or the like as will be illustrated and described subsequently. The insert <NUM> can be fastened to the tibial baseplate <NUM> as is initially demonstrated in <FIG> by passing the fastener <NUM> through the aperture <NUM> and into the recess <NUM> to engage the insert <NUM>. The fastener <NUM> can then be rotated to thread with the tibial baseplate <NUM> to secure the insert <NUM> to the tibial baseplate <NUM> and thereby secure the tibial bearing component <NUM> to the tibial baseplate <NUM>.

As will be discussed and illustrated in reference to further FIGURES subsequently, fastening the insert <NUM> to the tibial baseplate <NUM> can include passing the fastener <NUM> through a region located between medial and lateral proximal articular surfaces <NUM>, <NUM> of the tibial bearing component <NUM> (the location of the aperture <NUM>) as shown in <FIG>. The method <NUM> can also engage a first foot of the insert with a first portion of a rail of the tibial baseplate and can engage a second foot of the insert with a second portion of the rail of the tibial baseplate as will be discussed subsequently in reference to <FIG>.

<FIG> shows the assembled tibial prosthesis <NUM>. <FIG> is an enlarged view of an anterior portion of the tibial baseplate <NUM>, the tibial bearing component <NUM> and the insert <NUM>.

As is best shown in <FIG>, the insert <NUM> can be positioned in the recess <NUM> and can be configured to engage portions of the tibial baseplate <NUM>. More particularly, the insert <NUM> can include a body <NUM>, a first foot 304A and a second foot 304B as shown in <FIG>, <FIG>. A tab <NUM> can project proximal of the body <NUM> as shown in <FIG>. The body <NUM> can include first and second wings 308A and 308B that extend outward of the first foot 304A and second foot 304B, respectively. According to one example, the first wing 308A extends lateral of the first foot 304A and the second wing 308B extends medial of the second foot 304B.

As shown in <FIG>, the opening <NUM> can be located at an anterior portion <NUM> of a periphery <NUM> of the tibial bearing component <NUM>. The insert <NUM> can be disposed in the recess <NUM> such that substantially an entirety or all of the insert <NUM> is disposed therein. Additionally, when disposed in the recess <NUM>, substantially an entirety of the insert <NUM> can be disposed anterior of the fastener <NUM> (<FIG> and <FIG>).

As shown in <FIG>, the tibial baseplate <NUM> can include a rail <NUM> extending from the proximal surface <NUM> along the periphery <NUM>. The rail <NUM> has a gap <NUM>. The gap <NUM> can be part of the opening <NUM>, and therefore, can comprise part of the recess <NUM>. In some examples, part of the rail <NUM> and gap <NUM> can be disposed anterior of the recess <NUM> and opening <NUM>. The example of <FIG> illustrates that with the insert <NUM> disposed in the recess <NUM>, at least a portion of the insert <NUM> extends into the gap <NUM> and engages the rail <NUM> (e.g. along the medial and lateral side surfaces of the first foot 304A and second foot 304B as shown subsequently in <FIG>). Such engagement, along with engagement of the insert <NUM> against the proximal surface <NUM>, can limit micro-motion of the tibial bearing component <NUM> relative to the tibial baseplate <NUM> with securement of the fastener <NUM>.

As shown in <FIG>, the first and second wings 308A and 308B are configured to be received in corresponding grooves 312A and 312B that are part of the recess <NUM>. The grooves 312A and 212B are shaped similar to the wings 308A and 308B. The wings 308A and 308B can be disposed on and engage projections 314A, 314B that form a distal portion of the grooves 312A and 312B.

Turning to <FIG>, the body <NUM> can have an aperture <NUM> defined thereby. The aperture <NUM> can be configured to receive a head of the fastener <NUM> as was previously illustrated in <FIG> and <FIG>. More particularly, according to some examples the aperture <NUM> can be hemispherical in shape along a portion thereof so as to facilitate centering of the fastener <NUM> during insertion. The hemispherical shape can also minimize stretch loss of the fastener <NUM> due to settling of the fastener <NUM> during use. In some examples, such as that of <FIG>, an axis A of the aperture <NUM> can be angled relative to a proximal-distal axis PDA of the insert <NUM>. This causes the fastener <NUM> to be angled in a direction in addition to the proximal-distal direction such as the anterior-posterior direction.

The first foot 304A can be connected to the body <NUM> and can extend distal therefrom in a direction generally perpendicular to that of wing 308A. As shown in <FIG>, in addition to a distal surface 322A, the first foot 304A can have a lateral side surface 324A engaging the tibial baseplate <NUM> when assembled as illustrated and described above in reference to <FIG>. Similarly, the second foot 304B can be connected to the body <NUM> and can extend distal therefrom. The second foot 304B can be spaced from the first foot 304A. The second foot 304B can have a distal surface 322B and can have a medial side surface 324B engaging the tibial baseplate <NUM> when assembled as illustrated and described above in reference to <FIG>.

The tab <NUM> can extend proximally from the body <NUM> and can engage the tibial bearing component <NUM> to temporarily retain the insert <NUM> within the tibial bearing component <NUM> such as illustrated in <FIG> of the method <NUM>. More particularly, the tab <NUM> has an anterior face <NUM> (<FIG>) that engages a corresponding surface of the tibial bearing component <NUM> so as not to allow the insert <NUM> to be withdrawn from the recess <NUM> such as in the posterior-to-anterior direction (an opposing direction to the direction of insertion of the insert <NUM> into the recess <NUM> as shown in <FIG>).

<FIG> shows an example of the fastener <NUM> in greater detail. The fastener <NUM> can have a head portion <NUM> and a threaded portion <NUM>. <FIG> provides an enlargement of the threaded portion <NUM>. As discussed with regard to the insert <NUM> of <FIG>, the head portion <NUM> can share as a similar curvature as the aperture <NUM>. For example, the head portion <NUM> can be provided with a hemispherical configuration similar to that of the aperture <NUM> so as to facilitate centering of the screw during insertion (e.g. the conformity of the hemispherical head and the insert can be anywhere between a <NUM>:<NUM> and a <NUM>:<NUM> ratio, inclusive). Such configuration can also minimize stretch loss due to the fastener settling. A neck region <NUM> between the head portion <NUM> and the thread portion can have a necked down area with a diameter smaller than a minor diameter of the threaded portion <NUM>. This can prevent notching of the neck region <NUM> during fabrication.

As shown in <FIG>, the threaded portion <NUM> can include rounded root radii and the minor diameter can be relative to a major diameter to improve the strength of the fastener relative to that of a standard thread.

<FIG> show a tibial bearing component <NUM> similar in construction to that of tibial bearing component <NUM> save that the disposition of an aperture <NUM> such so as to extend through at least an anterior portion of the spine <NUM>. Thus, an anterior portion <NUM> of the spine <NUM> has a cut-out <NUM> as shown in <FIG>. All other features of the tibial bearing component <NUM> are similar to or identical to those of the tibial bearing component <NUM> as previously described.

As shown in <FIG>, the spine <NUM> can be centrally located between the medial articular surface <NUM> and the lateral articular surface <NUM>. A posterior region <NUM> of the spine <NUM> can have a radius such that the posterior region <NUM> is convexly shaped in a medial-lateral direction when viewed in a transverse plane. In contrast, the anterior portion <NUM> can be substantially flat when viewed in the transverse plane.

<FIG> shows a plan view of the distal surface <NUM> of the tibial bearing component <NUM>. <FIG> additionally shows the recess <NUM>. It should be noted that although the recess <NUM> and corresponding insert <NUM> are shown positioned at the anterior region and extending to an anterior periphery of the tibial bearing component <NUM> and the tibial baseplate <NUM> in the examples provided, in other embodiments the recess <NUM> and insert <NUM> can be disposed in other locations of the tibial bearing component <NUM> and the tibial baseplate <NUM>. Additionally, although a substantially anterior-posterior insertion direction for the insert <NUM> into the recess <NUM> was illustrated and described, in other examples the insertion direction can be in another direction (e.g., medial-lateral, proximal-distal) or combinations of directions (e.g., medial-lateral and anterior-posterior).

<FIG> also illustrates additional connection mechanisms such as a double dovetail notch <NUM> and peripheral notches 510A and 510B these features are configured to attach to a double dovetail boss <NUM> and undercut rails 514A, 514B, respectively of the tibial baseplate <NUM> as shown in <FIG>. Upon assembly, the tibial bearing component <NUM>, <NUM>, <NUM> can be advanced along a path, such that tibial bearing component <NUM>, <NUM>, <NUM> moves along a generally anterior-to-posterior path as the double dovetail notch <NUM> begins to engage with the double dovetail boss <NUM> and the peripheral notches 510A and 510B begin to engage with the undercut rails 514A, 514B. Further posterior movement of the tibial bearing component <NUM> causes a tight interfitting engagement between these features. As is discussed and illustrated further in reference to <FIG>, further engagement and securement of the tibial bearing component <NUM>, <NUM>, <NUM> to the tibial baseplate <NUM> is facilitated by the insert <NUM> and the fastener <NUM>.

As was previously shown in reference to <FIG> and <FIG>, the aperture <NUM>, <NUM>, <NUM> can be configured to receive at least a portion of the fastener <NUM> (<FIG> and <FIG>) therein. Indeed, upon assembly a head portion of the fastener <NUM> may remain in the aperture <NUM>, <NUM>, <NUM>. According to the example of <FIG>, the aperture <NUM> can be angled (along axis B) relative to a proximal-distal axis (not shown) of the tibial bearing component <NUM> such that the aperture <NUM> extends both proximal-distal and anterior-posterior. The angle can be in a manner similar or identical to that provided for the aperture <NUM> of the insert <NUM> as previously discussed. In other examples, the aperture and/or aperture of the insert <NUM> can be angled in any manner desired not just in the proximal-distal and anterior-posterior manner illustrated.

<FIG> and <FIG> illustrate the recess <NUM> in further detail including the grooves 312A and 312B (<FIG> and <FIG> also show a notch <NUM> that can form a part of the recess <NUM>. The notch <NUM> can be positioned anterior of the aperture <NUM> along a proximal portion of the recess <NUM>. The notch <NUM> is configured to receive the tab <NUM> (<FIG>) when the insert <NUM> is received in the recess <NUM>. An anterior surface <NUM> that forms a part of the notch <NUM> is configured to engage the anterior face <NUM> (<FIG>) of the insert <NUM>. This engagement can temporarily restrict movement of the insert <NUM> such that the insert cannot easily be withdrawn from the recess <NUM> such as in the posterior-to-anterior direction (an opposing direction to the direction of insertion of the insert <NUM> into the recess <NUM> as shown in <FIG>).

<FIG> and <FIG> show the tibial baseplate <NUM>. In particular, <FIG> shows the proximal surface <NUM> of the tibial baseplate <NUM>. <FIG> shows a plan view of a proximal portion of the tibial baseplate <NUM>. Additional features shown include the rail <NUM> extending from the proximal surface <NUM> along the periphery <NUM>. The rail <NUM> has the gap <NUM> as previously discussed in reference to <FIG>. The gap <NUM> can be part of the opening <NUM>, and therefore, can comprise part of the recess <NUM>. As shown in <FIG>, the tibial baseplate <NUM> can also include the double dovetail boss <NUM> and the undercut rails 514A, 514B as previously discussed.

The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) can be used in combination with each other. Other examples can be used, such as by one of ordinary skill in the art upon reviewing the above description. Also, in the above detailed description, various features can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed example. Thus, the following claims are hereby incorporated into the detailed description as examples or embodiments, with each claim standing on its own as a separate example, and it is contemplated that such examples can be combined with each other in various combinations or permutations.

Claim 1:
A system for use in a knee arthroplasty comprising:
a tibial bearing component (<NUM>) having medial and lateral proximal articular surfaces (<NUM>,<NUM>) and an opposing distal surface, wherein the tibial bearing component defines at least one recess (<NUM>) therein with the recess having an opening (<NUM>) at a periphery of the tibial bearing component (<NUM>);
a tibial baseplate (<NUM>) configured to receive the tibial bearing component on a proximal surface (<NUM>) thereof and having a distal surface (<NUM>) configured to be disposed on a resected proximal surface of a tibia; and
an insert (<NUM>) disposable through the opening and into the recess, the insert configured to engage the tibial baseplate (<NUM>) and the tibial bearing component (<NUM>) when the insert, the tibial baseplate and the tibial bearing component are assembled together; characterised in that the system further comprises
a fastener (<NUM>) insertable into the tibial bearing component and configured to retain the insert (<NUM>) to the tibial baseplate (<NUM>).