Constraint type prosthetic knee

Abstract

The present application relates to a tibial prosthesis configured for implantation onto a tibia, the tibial prosthesis comprising: a distal side; a proximal side opposite the distal side; a bore defining an opening on the proximal side; an anterior engagement member on the proximal side; and a rear engagement member on the proximal side, the rear engagement member being located rearward of the front engagement member. The invention also relates to a method. The present application also relates to a prosthetic knee system comprising: a tibial prosthesis comprising: a distal side; a proximal side opposite the distal side; a bore defining an opening on the proximal side; an anterior engagement member on the proximal side; and a rearward engagement member on the proximal side, the rearward engagement member rearward of the forward engagement member; and a tibial bearing configured to couple with the tibial prosthesis, the tibial bearing comprising: a first complementary engagement feature configured to engage with the anterior engagement member of the tibial prosthesis; and a second complementary engagement feature configured to engage with a posterior engagement member of the tibial prosthesis.

Description

[0001] This application is a divisional application of the invention patent application with the application date of December 22, 2023, application number 202311779317.5, and invention name “Constrained Prosthetic Knee”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 434,590, filed December 22, 2022, and U.S. Patent Application No. 18 / 526,737, filed December 1, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0004] The present disclosure relates generally to orthopedic prostheses and, more particularly, to orthopedic prostheses for constrained knee replacement surgery. Background Art

[0005] Orthopedic surgery and prostheses are commonly used to repair or replace damaged bone and tissue in the human body. Generally speaking, the knee consists of a pair of condyles at the distal portion of the femur, whose lower surfaces bear on a correspondingly shaped proximal surface platform of the tibia. The femur and tibia are connected by ligaments such as the posterior cruciate ligament, lateral collateral ligament, medial collateral ligament, and anterior cruciate ligament. These ligaments provide stability to the knee joint.

[0006] Prosthetic knee joints can be divided into constrained (restrictive) and unconstrained (non-restrictive). A constrained prosthetic knee system may include a femoral prosthesis and a tibial prosthesis that are mechanically connected or constrained to each other to limit the relative movement between the femoral prosthesis and the tibial prosthesis. Common mechanisms for such mechanical connection include hinges, straps or other connecting structures. An unconstrained prosthetic knee system includes a femoral prosthesis and a tibial prosthesis that are not mechanically connected. An unconstrained knee utilizes the patient's existing ligaments and other soft tissues to provide joint stability. A constrained prosthetic knee is particularly suitable for patients who have lost ligaments or whose existing ligaments are unable to provide adequate support and stability for the knee. Summary of the Invention

[0007] The present disclosure generally relates to improved constrained knee prostheses, particularly those utilizing hinge posts. Some constrained knee prostheses with hinge posts utilize a design that allows the femoral component (and hinge post) to freely move generally proximally / distally relative to the tibial baseplate and tibial bearing component. The inventors of the present disclosure have recognized a need for a system that provides a prosthesis that can be reconfigured for use in either a mobile bearing system or a fixed bearing system. Such a system may include components that can be assembled to form both a mobile bearing constrained knee prosthesis and a fixed constrained knee prosthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings illustrate various embodiments by way of example. These embodiments are exemplary and are not intended to be exhaustive or exclusive of the embodiments of the presently protected subject matter.

[0009] Figure 1 and Figure 2 A knee joint structure is shown that provides a suitable environment in which a constrained prosthetic assembly according to one example of the present application may be utilized.

[0010] Figure 3 is a perspective view of a constrained knee prosthesis assembly according to one example of the present application.

[0011] Figure 4 yes Figure 3 A cross-sectional view of a constrained knee prosthesis assembly according to an example of the present application.

[0012] Figure 5 1 is a top view of a constrained knee prosthesis according to an example of the present application.

[0013] Figure 6 It is along Figure 5 A partial cross-sectional view of a constrained knee prosthesis assembly according to an example of the present application, taken along line 6-6.

[0014] Figure 7 1 is a top view of an example of a constrained knee prosthesis including a mobile bearing rotated to a first set limit according to an example of the present application.

[0015] Figure 8 is a top view of an example of a constrained knee prosthesis including a mobile bearing rotated to a second set limit according to an example of the present application.

[0016] Figure 9 is a top view of an example of a constrained knee prosthesis including a fixed bearing according to an example of the present application.

[0017] Figure 10 is a top view of an example of a constrained knee prosthesis assembly including a mobile bearing with a press-fit insert according to an example of the present application. DETAILED DESCRIPTION

[0018] The present application relates to a system including a constrained (restrictive) knee prosthesis. The system may include a set of components, such as a tibial tray or base plate, an interlocking member, a femoral component, a hinge post, a polymer box, a sleeve or the like. The set of components may be configured for use with a tibial bearing component. For example, the system may include a mobile tibial bearing component or a fixed tibial bearing component, which may be replaced at the surgeon's discretion. The mobile tibial bearing component may be configured to limit rotation (or movement) about at least one axis compared to the mobile tibial bearing component by engaging with one or more engagement features of the tibial tray. The fixed bearing component may prevent or completely restrict rotation (or movement) about at least one axis by contacting with one or more engagement features of the tibial tray.

[0019] In another example, the system can include a set of components, a mobile tibial bearing component, and a press-fit insert. In such an example, the press-fit insert can be configured to fill a space between the mobile tibial bearing component and one or more engagement features of the tibial tray to further limit or prevent / block rotation or movement of the tibial bearing component relative to the tibial tray about one or more axes.

[0020] To better understand knee replacement surgery, it may be helpful to understand the relationship between the bones and the bone cuts that can be formed toward the various temporary and permanent prosthetic components within the knee joint. Figure 1 and Figure 2 Several features of the knee joint structure and orientation are shown. Figure 1 , a front view of the lower limb 102 including a femur 104 and a tibia 106 shows various lower limb axes. The femur 104 has an anatomical axis 108 that roughly coincides with its intramedullary canal. The femur 104 also has a mechanical axis 110, or load axis, from the center of the femoral head 112 to the center of the knee joint 114. The angle 116 extending between these two axes varies depending on the patient population, but is roughly between 5-7 degrees (inclusive). Like the femur 104, the tibia 106 also has an anatomical axis that roughly coincides with its intramedullary canal. The mechanical axis 118 of the tibia 106 extends from the center of the knee joint 114 to the center of the ankle region 120 and is roughly collinear with the anatomical axis of the tibia 106.

[0021] The joint line 122 about which the knee joint 114 flexes is approximately parallel to a line passing through the medial and lateral femoral condyles 124 and to the tibial plateau 126. Figure 1106, the joint line 122 may extend at a varus or valgus angle relative to the mechanical axes 110 and 118 of the femur 104 and tibia 106, respectively. Typically, during partial or total knee replacement surgery, a portion of the distal side of the femur 104 or a portion of the proximal side of the tibia 106 is resected parallel or approximately parallel to the joint line 122, thereby being perpendicular to the mechanical axes 110 and 118, as shown at 128 and 130, respectively.

[0022] A typical knee can move between an extended state, in which the longitudinal axis of the femur 104 is substantially parallel to the longitudinal axis of the tibia 106, and a flexed state, in which the longitudinal axes of the femur 104 and tibia 106 are angled approximately 140 degrees relative to each other. In various embodiments, the extended state can be limited to + / - 10 degrees, while the flexed state can be much less than 140 degrees. For example, the flexed state can include a limitation in which the longitudinal axes of the femur 104 and tibia 106 are angled approximately 90 to 140 degrees relative to each other.

[0023] Figure 2 A close-up view of the knee joint 114 and its coordinate system is shown, wherein the medial / lateral axis 202 corresponds approximately to the joint line 122 ( Figure 1 ), the proximal / distal axis 204 corresponds approximately to the mechanical axes 110 and 118 ( Figure 1 ), and the anterior / posterior axis 206 is approximately normal to the other two axes. Arrows can depict the position along each of these axes to represent the positioning of the inserted prosthetic component on the medial / lateral 208, anterior / posterior 210, and proximal / distal 212 sides. Rotation about each axis can also be represented by arrows. Rotation about the proximal / distal axis 204 corresponds anatomically to external rotation of the femoral component, while rotation about the anterior / posterior axis 206 and the medial / lateral axis 202 corresponds to the extension plane inclination and varus / valgus angle of the component, respectively. Based on the proximal tibial notch 130 ( Figure 1 ) can affect the varus / valgus angle 214, the extension plane angle 216, the external rotation 218, or the joint extension gap. Similarly, the distal femoral notch 128 ( Figure 1 ) will also affect the position of the joint line 122, the extension gap, the varus / valgus angle 214 or the extension plane angle 216.

[0024] As used herein, the terms "proximal" and "distal" are to be defined according to commonly understood anatomical interpretations. The term "proximal" refers generally toward the patient's torso, while "distal" refers to the direction opposite to proximal, that is, away from the patient's torso. It should be understood that the terms "proximal" and "distal" are to be interpreted with reference to the patient standing with the knee joint in extension. This is intended to distinguish "proximal" and "distal" from "anterior" and "posterior." As used herein, the terms "anterior" and "posterior" are to be interpreted according to commonly understood anatomical interpretations. Thus, "posterior" refers to the patient's rear, e.g., behind the knee. Similarly, "anterior" refers to the patient's front, e.g., in front of the knee. Thus, "posterior" refers to the direction opposite to "anterior." Similarly, the term "lateral" refers to the direction opposite to "medial." The term "medial / lateral" refers to inside to outside or outside to inside. The term "proximal / distal" refers to near to far or far to near. The term "anterior / posterior" means anterior to posterior or posterior to anterior.

[0025] As used herein, the "perimeter" of the tibial baseplate refers to any perimeter as viewed from a top plan view (e.g., in a generally transverse anatomical plane). Alternatively, the perimeter of the tibial baseplate can also be any perimeter as viewed from a bottom plan view (e.g., in a generally transverse anatomical plane), with the distal surface of the tibial baseplate adapted to contact the resected proximal surface of the tibia.

[0026] The term "micromotion" refers to the small movements that can occur between prosthetic components, such as between the tibial baseplate and the capture element, when forces are applied. These small movements can result from material deformation in one or both of the interacting components, or from the presence of small spaces or gaps between them. Micromotion is distinguished from larger component movements, such as proximal / distal movement of the femoral component relative to the tibial baseplate and tibial bearing component.

[0027] Figure 3 A prosthetic assembly 300 for a constrained knee is shown. Prosthetic assembly 300 may include a tibial baseplate 302, a tibial bearing component 304 (sometimes also referred to as a meniscus component, polymer component, articular component, or bearing), a femoral component 306, and a hinge post 308.

[0028] The tibial bearing component 304 can be coupled to the proximal surface 310 of the tibial baseplate 302 and positioned on top of the proximal surface 310 of the tibial baseplate 302. The tibial bearing component 304 can be formed of a polymer material, such as ultra-high molecular weight polyethylene (UHMWPE) or the like. The tibial bearing component 304 can be configured to articulate with the femoral component 306 in a manner known in the art for use in knee flexion and extension. The femoral component 306 and the tibial baseplate 302 of the prosthetic assembly 300 are mechanically coupled to each other. This is achieved by the hinge post 308 and the Figure 4 Hinge post 308 is coupled to femoral component 306 and is received within recess 309 of tibial bearing component 304 and recess 322 of tibial baseplate 302 ( Figure 4 )Inside.

[0029] Figure 4 An exploded view of prosthetic assembly 300, tibial baseplate 302, tibial bearing component 304, femoral component 306, hinge post 308 is shown, and further illustrating hinge shaft 312, polymer cartridge 314, sleeve 316, shackle 318, and bushing.

[0030] Hinge post 308 is coupled to femoral component 306 via interlock 318, sleeve 316, and hinge shaft 312. A distal portion of interlock 318 is received in recess 309 in tibial bearing component 304 and is threaded or otherwise coupled to hinge post 308. Hinge post 308 extends distally through recess 309 in tibial bearing component 304 and is received in recess 322 in tibial baseplate 302. Recess 322 of tibial baseplate 302, which receives hinge post 308, may be at least partially formed by keel 324 of tibial baseplate 302. Hinge post 308 is movable relative to tibial bearing component 304 or tibial baseplate 302, e.g., rotatable or capable of distraction. Hinge post 308 may be rotatably coupled to femoral component 306 via hinge shaft 312. Thus, when the femoral component 306 and the tibial baseplate 302 are mechanically coupled, the longitudinal axis LA defining the centerline of the hinge post 308 can define the rotation / articular axis ARA for the knee joint.

[0031] When assembled, the interlocking member 318 can be placed between the opposing side walls of the polymer cartridge 314. When assembled onto the hinge shaft 312, the bushing 316 is additionally retained within an aperture on the proximal portion of the interlocking member 318. The interlocking member 318 and the hinge post 308 can be formed from a suitable material, such as a titanium alloy, a cobalt-chromium alloy, or the like, while the bushing 316 and the polymer cartridge 314 can be formed from a different material, such as plastic (e.g., UHMWPE). The bushing 316 can serve as a support between the interlocking member 318 and the hinge shaft 312. The polymer cartridge 314 can serve as a support between the femoral component 306 and the interlocking member 318.

[0032] Figure 4 The prosthesis assembly 300 of FIG. 300 illustrates the components of a system 326 in which the distraction of the knee is not limited by the capture elements or other features of the prosthesis assembly 300. Thus, the components provided by the system 326 are configured for complete distraction when assembled. Thus, as previously described, the soft tissue of the knee is relied upon to limit the distraction between the femoral component 306 and the tibial baseplate 302 and the tibial bearing component 304. The bushing 320 can be configured to be inserted into at least the groove 322 of the tibial baseplate 302. In some examples, the bushing 320 can also be inserted into or through the groove 309 of the tibial bearing component 304. Figure 3 Bushing 320 can be configured to receive at least a portion of hinge post 308. Bushing 320 can serve as a bearing between hinge post 308 and tibial baseplate 302. Hinge post 308 can move generally proximally / distally relative to bushing 320.

[0033] Figure 5 FIG2 is a top view of an example of a mobile-bearing prosthesis (e.g., prosthetic assembly 500) according to an example of the present application. Prosthetic assembly 500 can be configured to be implanted in a patient with a constrained knee. In an example, prosthetic assembly 500 can include a tibial baseplate 502, a tibial insert or bearing component (tibial bearing component 504), and a hinge post 508.

[0034] Tibial baseplate 502 and Figure 3 Similar to the tibial baseplate 302 in FIG. , it can be configured to be inserted into the patient's tibia, for example, Figure 1 The tibial baseplate 502 may include a distal surface 530 (e.g., Figure 6 530) and a proximal surface 532. Proximal surface 532 can be opposite distal surface 530, and perimeter 534 of tibial baseplate 502 can extend between distal surface 530 and proximal surface 532. Proximal surface 532 can include a recess configured to receive hinge post 508. Proximal surface 532 can also include a first engagement feature 540 and a second engagement feature 550.

[0035] The tibial bearing component 504 is similar to Figure 3 The tibial bearing component 304 in the embodiment of the present invention can be configured to be coupled to the tibial baseplate 502 and to rotate about at least a first axis 542, for example, about Figure 2 The distal axis 204 in the tibial bearing component 504 can be externally rotated 218. In an example, the first axis 542 can extend through the centerline of the hinge post 508. The tibial bearing component 504 can include a third engagement feature 560 and a fourth engagement feature 570.

[0036] The first engagement feature 540 can be configured to limit rotation or movement of the tibial bearing component 504 relative to the tibial baseplate 502 about at least a first axis 542. The first engagement feature 540 can include a protrusion 541. The protrusion 541 can extend from the proximal surface 532 of the tibial baseplate 502. Alternatively, other examples of the present application also contemplate that the first engagement feature 540 can be a notch, aperture, or other recess. Figure 5 In the example shown, protrusion 541 can extend from an anterior portion of proximal surface 532 adjacent perimeter 534 and can extend away from distal surface 530. In another example, protrusion 541 can extend from a posterior portion, a medial portion, a lateral portion, or any other portion of proximal surface 532 to limit rotation or movement of tibial bearing component 504 relative to tibial baseplate 502 about at least first axis 542 or a similar axis. First engagement feature 540 can include a first edge 544, a second edge 546, and a third edge 548.

[0037] The first edge 544 can extend posteriorly from the periphery of the tibial baseplate 502. The second edge 546 can also extend posteriorly from the periphery of the tibial baseplate 502. The third edge 548 can extend from the first edge 544 to the second edge 546. The third edge 548 can also include a concave profile 549 such that the thickness of the first engagement feature 540 is reduced in the middle portion compared to the first edge 544 or the second edge 546. In an example, the first edge 544 or the second edge 546 can engage the tibial bearing component 504 to limit further rotation of the tibial bearing component 504 relative to the tibial baseplate 502 about the first axis 542. The interaction between the tibial bearing component 504 and the first edge 544, the second edge 546, and the third edge 548 of the first engagement feature 540 will be described below with reference to FIG. Figure 7 and Figure 8 Discuss in more detail.

[0038] Third engagement feature 560 can be configured to engage first engagement feature 540 of tibial bearing component 504 to limit rotation of tibial bearing component 504 relative to tibial baseplate 502 about at least first axis 542. Third engagement feature 560 can be an anterior recess that can include first inner wall 562 and second inner wall 564. For example, third engagement feature 560 can be configured to contact third edge 548 of first engagement feature 540 when tibial bearing component 504 is coupled to tibial baseplate 502. The contact between third engagement feature 560 and third edge 548 can help retain tibial bearing component 504 on tibial baseplate 502.

[0039] Second inner wall 564 of third engagement feature 560 can engage first edge 544. First inner wall 562 of third engagement feature 560 can engage second edge 546. Thus, first inner wall 562 and second inner wall 564 of third engagement feature 560 can engage second edge 546 and first edge 544, respectively, to limit rotation of tibial bearing component 504 relative to tibial baseplate 502 about first axis 542 in a clockwise or counterclockwise direction. Figure 5 As shown, third engagement feature 560 can be formed on the anterior portion of tibial bearing component 504, adjacent periphery 534 of tibial baseplate 502. In another example, third engagement feature 560 can be formed in any other portion of tibial bearing component 504 such that third engagement feature 560 can limit rotation of tibial bearing component 504 relative to tibial baseplate 502 about first axis 542. Figure 7 and Figure 8 The interaction between the third engagement feature 560 and the first engagement feature 540 is discussed in greater detail.

[0040] Second engagement feature 550 can be configured to limit movement of tibial bearing component 504 relative to tibial baseplate 502 in at least second direction 552. Movement of tibial bearing component 504 in second direction 552 can be limited by engagement of second engagement feature 550 with tibial bearing component 504. Figure 5 As shown, the second engagement feature 550 may include a protrusion 551 that extends from a central portion of the proximal surface 532, for example, proximal to but spaced from the posterior side of the recess that receives the hinge post 508. In another example, the second engagement feature 550 may extend from a posterior portion, a medial portion, a lateral portion, or any other portion of the proximal surface 532 such that the second engagement feature 550 can limit movement of the tibial bearing component 504 relative to the tibial baseplate 502 in the second direction 552 or a similar direction. Figure 10 and Figure 8 The interaction between tibial bearing component 504 and second engagement feature 550 is discussed in greater detail.

[0041] The fourth engagement feature 570 can be configured to engage the second engagement feature 550 of the tibial bearing component 504 to limit movement of the tibial bearing component 504 relative to the tibial baseplate 502 in at least the second direction 552. The fourth engagement feature 570 can be a wall of a recess formed in the tibial bearing component 504. The recess can be centralized / centered and can also receive the hinge post 508 in addition to the second engagement feature 550. Figure 10 and Figure 8 The interaction between the fourth engagement feature 570 and the second engagement feature 550 is discussed in greater detail.

[0042] like Figure 5 As shown, first engagement feature 540 and second engagement feature 550 of tibial baseplate 502 can be protrusions, while third engagement feature 560 and fourth engagement feature 570 of tibial bearing component 504 can be walls of a groove. In another example, first engagement feature 540 and second engagement feature 550 of tibial baseplate 502 can be grooves, ridges, depressions, or any other formations, or the like, formed in the surface of tibial baseplate 502, while third engagement feature 560 and fourth engagement feature 570 can be protrusions, ridges, extensions, or any other formations, or the like, extending from the surface of tibial bearing component 504.

[0043] Figure 6 It is along Figure 5 A partial cross-sectional view of a constrained knee prosthesis assembly, such as prosthesis assembly 500, according to an example of the present application, taken along line 6-6. Figure 6 As shown, tibial bearing component 504 can be configured to couple to tibial baseplate 502. When tibial bearing component 504 is coupled to tibial baseplate 502, third engagement feature 560 and fourth engagement feature 570 of tibial bearing component 504 can engage first engagement feature 540 and second engagement feature 550, respectively.

[0044] like Figure 6As shown, third engagement feature 560 may include a ridge that can slide under a surface of protrusion 541 that faces distal surface 530 of tibial baseplate 502. Fourth engagement feature 570 may also include a ridge that can slide under a surface of protrusion 551 that faces distal surface 530 of tibial baseplate 502. Thus, during coupling of tibial bearing component 504 to tibial baseplate 502, the ridge of third engagement feature 560 can slide under protrusion 541, and then the ridge of fourth engagement feature 570 can slide under protrusion 551. During coupling, first engagement feature 540 and second engagement feature 550 can be configured to flex away from and toward hinge post 508, respectively, to facilitate coupling of tibial bearing component 504 to tibial baseplate 502. Once coupled, protrusions 541 and 551 can engage the spines of third engagement feature 560 and fourth engagement feature 570 , respectively, to prevent movement of tibial bearing component 504 relative to tibial baseplate 502 in second direction 552 .

[0045] Figure 7 FIG. 1 is a top view of an example of a constrained knee prosthesis (e.g., prosthesis assembly 500) including a movable bearing 704 rotated to a first set limit according to an example of the present application. The movable bearing 704 is similar to the tibial bearing component 504 ( Figure 5 ), can be configured to couple with the tibial baseplate 502. As discussed above, the movable bearing 704 can rotate about at least the first axis 542, which can be along the centerline of the hinge post 508. Figure 7 As shown, movable support 704 can be rotated into orientation 772 .

[0046] In orientation 772, movable bearing 704 can be rotated counterclockwise about first axis 542 relative to tibial baseplate 502. For example, movable bearing 704 can be rotated counterclockwise about first axis 542 relative to tibial baseplate 502 until second inner wall 564 of third engagement feature 560 contacts first edge 544 of first engagement feature 540. In such an example, the contact between second inner wall 564 and first edge 544 can prevent movable bearing 704 from further rotating about first axis 542 relative to tibial baseplate 502. Figure 7 As shown, second engagement feature 550 can engage fourth engagement feature 570 to prevent mobile bearing 704 from further rotating about first axis 542 relative to tibial baseplate 502 .

[0047] Figure 8FIG2 is a top view of an example of a constrained knee prosthesis (e.g., prosthesis assembly 500) including a mobile bearing 704 rotated clockwise to a second set limit position according to an example of the present application. Mobile bearing 704 can be rotated clockwise about first axis 542 relative to tibial baseplate 502 to any degree between orientation 772 and orientation 774. Prosthesis assembly 500 with mobile bearing 704 is generally more inclined toward a neutral position between orientation 772 and orientation 774.

[0048] exist Figure 7 In orientation 774, movable bearing 704 can rotate relative to tibial baseplate 502 about first axis 542. For example, movable bearing 704 can rotate relative to tibial baseplate 502 about first axis 542 until first inner wall 562 of third engagement feature 560 contacts second edge 546 of first engagement feature 540. In such an example, the contact between first inner wall 562 and second edge 546 can prevent further rotation of movable bearing 704 relative to tibial baseplate 502 about first axis 542.

[0049] Figure 9 FIG. 1 is a top view of an example of a constrained knee prosthesis (eg, prosthesis assembly 500) including a fixed bearing 904 according to an example of the present application. The fixed bearing 904, such as the tibial bearing component 504 ( Figure 5 ), can be configured to couple with tibial baseplate 502. As discussed above, fixed bearing 904 can prevent rotation or movement of fixed bearing 904 relative to tibial baseplate 502 about first axis 542 and second direction 552.

[0050] Third engagement feature 560 of fixed bearing 904 is configured to surround and contact first engagement feature 540 of tibial baseplate 502 to prevent fixed bearing 904 from moving relative to tibial baseplate 502 about first axis 542. For example, the recess of third engagement feature 560 includes first inner wall 562 and second inner wall 564 along the anterior portion of fixed bearing 904 and is smaller than the recess of third engagement feature 560 on movable bearing 704. Therefore, when fixed bearing 904 is coupled to tibial baseplate 502, first inner wall 562 and second inner wall 564 of third engagement feature 560 of fixed bearing 904 are configured to contact second edge 546 and first edge 544, respectively. Thus, first inner wall 562 and second inner wall 564 of fixed bearing 904 prevent fixed bearing 904 from rotating relative to tibial baseplate 502 about first axis 542.

[0051] Fourth engagement feature 570 of fixed bearing 904 is configured to surround and contact second engagement feature 550 of tibial baseplate 502 to prevent fixed bearing 904 from moving relative to tibial baseplate 502 about second axis 551. Fourth engagement feature 570 may include a flange, a protrusion, a tang, or a rib (rib 972). Rib 972 is configured to surround opposing sides of second engagement feature 550 and protrusion 551 to help prevent fixed bearing 904 from rotating relative to tibial baseplate 502 about first axis 542.

[0052] Figure 10 is a top view of an example of a constrained knee prosthesis assembly (eg, prosthesis assembly 500 ) including a mobile bearing (eg, mobile bearing 704 ) with a press fitting 1070 according to an example of the present application.

[0053] As discussed above, prosthetic assembly 500 can be used as a mobile bearing prosthesis by coupling mobile bearing 704 to tibial baseplate 502. Prosthetic assembly 500 can be used as a fixed bearing prosthesis by coupling fixed bearing 904 to tibial baseplate 502. In another example, prosthetic assembly 500 can be made into a fixed bearing prosthesis by using press fitting 1070. In an example, press fitting 1070 can be configured to be inserted into third engagement feature 560 of mobile bearing 704. In such an example, press fitting 1070 can be configured to fill the space between first inner wall 562 of third engagement feature 560 and second edge 546 of first engagement feature 540, and to fill the gap between second inner wall 564 of third engagement feature 560 and first edge 544 of first engagement feature 540. Thus, press fitting 1070 can effectively convert mobile bearing 704 into a fixed bearing. Thus, mobile bearing 704 can be coupled to tibial baseplate 502 and then press fitting 1070 can be installed onto mobile bearing 704 such that the press fitting engages third engagement feature 560 .

[0054] like Figure 10 As shown, the first engagement feature 540 may include a slot extending from the periphery of the movable support 704. The slot may receive the press fitting 1070 so that the press fitting 1070 slides within the slot and surrounds the first engagement feature 540. Figure 10In the example shown, the press fitting 1070 is configured to fill the entire space between the first edge 544 of the first engagement feature 540 and the second inner wall 564 of the third engagement feature 560, and to fill the entire space between the second edge 546 of the first engagement feature 540 and the first inner wall 562 of the third engagement feature 560. In another example, the press fitting 1070 may be configured to fill any portion of the space between the first edge 544 of the first engagement feature 540 and the second inner wall 564 of the third engagement feature 560, and to fill the space between the second edge 546 of the first engagement feature 540 and the first inner wall 562 of the third engagement feature 560.

[0055] Additional Notes and Examples

[0056] The following non-limiting examples detail certain aspects of the subject matter to address the challenges discussed herein and provide benefits, among other things.

[0057] Example 1 is a system comprising a prosthetic assembly for a constrained knee, the system comprising: a set of components comprising: a femoral component, an interlocking component extending between a first end portion and a second end portion; a hinge shaft configured to secure the femoral component to the first end portion of the interlocking component; a tibial baseplate having a distal surface, a proximal surface opposite the distal surface, and a perimeter extending between the proximal surfaces, the tibial baseplate comprising a first engagement feature; and a hinge post extending between a first end segment and a second end segment, the first end segment being configured to attach to the second end portion of the interlocking component, the second end segment being configured to be at least partially received by a recess in the tibial baseplate. The system also includes: a movable support configured to be coupled to the tibial baseplate and to rotate about at least a first axis, the first axis being approximately the centerline of the hinge post, the rotation about at least the first axis being limited by at least a first engagement feature of the tibial baseplate; and a fixed support configured to be coupled to the tibial baseplate, the fixed support being limited by at least the first engagement feature of the tibial baseplate and unable to rotate about the first axis; wherein the set of components is configured to be assembled with the movable support or the fixed support.

[0058] In Example 2, the subject matter of Example 1 includes wherein the first engagement feature of the tibial baseplate comprises a first protrusion extending from an anterior portion of the proximal surface away from the distal surface.

[0059] In Example 3, the protected subject matter of Example 2 includes, wherein the first protrusion includes: a first edge extending posteriorly from the periphery of the tibial baseplate; a second edge extending posteriorly from the periphery of the tibial baseplate; and a third edge extending from the first edge to the second edge, the third edge including a concave profile.

[0060] In Example 4, the subject matter of Example 3 includes wherein the tibial baseplate further includes a second engagement feature.

[0061] In Example 5, the subject matter of Example 4 includes, wherein the second engagement feature comprises a second protrusion extending from a central portion of the proximal surface away from the distal surface.

[0062] In Example 6, the protected subject matter of Example 5 includes, wherein the movable support includes a third engagement feature, the third engagement feature being configured to contact a third edge of the first engagement feature when the movable support is coupled to the tibial baseplate, the third engagement feature being further configured to engage with the first edge or the second edge of the first engagement feature when the movable support is rotated about at least the first axis.

[0063] In Example 7, the subject matter of Example 6 includes, wherein engagement of the third engagement feature with the first edge and the second edge of the first engagement feature limits rotation of the movable support.

[0064] In Example 8, the subject matter of Examples 6-7 includes, wherein the third engagement feature is formed in a front portion of the movable support.

[0065] In Example 9, the protected subject matter of Examples 5-8 includes, wherein the movable support includes a fourth engagement feature, the fourth engagement feature being configured to engage with the second engagement feature of the tibial baseplate when the movable support rotates about the second axis relative to the tibial baseplate, and wherein engagement of the fourth engagement feature with the second engagement feature limits rotation of the movable support about the second axis.

[0066] In Example 10, the subject matter of Example 9 includes, wherein the fourth engagement feature is formed in the movable support adjacent to the recess configured to receive the hinge post.

[0067] In Example 11, the subject matter of Example 10 includes, wherein the fourth engagement feature is located on a rear side of the recess configured to receive the hinge post.

[0068] In Example 12, the subject matter of Examples 9-11 includes wherein rotation of the mobile support about the second axis includes adduction and abduction of the prosthetic component.

[0069] In Example 13, the subject matter of Examples 4-12 includes, wherein the fixation bearing is configured to engage the first engagement feature of the tibial baseplate when the fixation bearing is coupled to the tibial baseplate.

[0070] In Example 14, the subject matter of Example 13 includes, wherein the fixed support includes a third engagement feature that contacts the first edge, the second edge, and the third edge of the first engagement feature to prevent the movable support from rotating about at least the first axis.

[0071] In Example 15, the subject matter of Examples 13-14 includes wherein the fixation bearing includes a fourth engagement feature formed in a central portion of the fixation bearing that contacts the second engagement feature of the tibial baseplate when the fixation bearing is coupled to the tibial baseplate.

[0072] In Example 16, the subject matter of Example 15 includes, wherein the fourth engagement feature comprises a pair of ribs that engage the second engagement feature on opposite sides of the second engagement feature.

[0073] Example 17 is a system comprising a prosthetic assembly for a constrained knee, wherein the system comprises: a tibial baseplate having a distal surface and a proximal surface opposite the distal surface, the proximal surface being configured to receive a hinge post, the tibial baseplate including a first engagement feature; a movable support configured to couple to the tibial baseplate and rotate about at least a first axis, the first axis being approximately the centerline of the hinge post, the rotation about at least the first axis being limited by at least the first engagement feature; and a fixed support configured to couple to the tibial baseplate, the fixed support being limited by at least the first engagement feature of the tibial baseplate and unable to rotate about the first axis; wherein the tibial baseplate is configured to be assembled with the movable support or the fixed support.

[0074] In Example 18, the subject matter of Example 17 includes wherein the first engagement feature of the tibial baseplate comprises a first protrusion extending from an anterior portion of the proximal surface away from the distal surface.

[0075] In Example 19, the protected subject matter of Example 18 includes, wherein the first protrusion includes: a first edge extending posteriorly from a periphery of the tibial baseplate, the periphery of the tibial baseplate being defined by a distal surface and a proximal surface of the tibial baseplate; a second edge extending posteriorly from the periphery of the tibial baseplate; and a third edge extending from the first edge to the second edge, the third edge including a concave profile.

[0076] In Example 20, the subject matter of Example 19 includes wherein the tibial baseplate further includes a second engagement feature.

[0077] In Example 21, the subject matter of Example 20 includes, wherein the second engagement feature comprises a second protrusion extending from a central portion of the proximal surface away from the distal surface.

[0078] In Example 22, the protected subject matter of Example 21 includes, wherein the movable support includes a third engagement feature, the third engagement feature being configured to contact a third edge of the first engagement feature when the movable support is coupled to the tibial baseplate, the third engagement feature being further configured to engage with the first edge or the second edge of the first engagement feature when the movable support is rotated about at least the first axis.

[0079] In Example 23, the subject matter of Example 22 includes, wherein engagement of the third engagement feature with the first edge and the second edge of the first engagement feature limits rotation of the movable support.

[0080] In Example 24, the subject matter of Examples 22-23 includes, wherein the third engagement feature is formed in a front portion of the movable support.

[0081] In Example 25, the protected subject matter of Examples 21-24 includes, wherein the movable support includes a fourth engagement feature, the fourth engagement feature is configured to engage with the second engagement feature of the tibial baseplate when the movable support rotates about the second axis relative to the tibial baseplate, and wherein engagement of the fourth engagement feature and the second engagement feature limits rotation of the movable support about the second axis.

[0082] In Example 26, the subject matter of Example 25 includes, wherein the fourth engagement feature is formed in the movable support adjacent to the recess configured to receive the hinge post.

[0083] In Example 27, the protected subject matter of Example 26 includes, wherein the fourth engagement feature is located on a rear side of the recess configured to receive the hinge post.

[0084] In Example 28, the subject matter of Examples 25-27 includes wherein rotation of the mobile support about the second axis includes adduction and abduction of the prosthetic component.

[0085] In Example 29, the subject matter of Examples 20-28 includes, wherein the fixation bearing is configured to engage the first engagement feature of the tibial baseplate when the fixation bearing is coupled to the tibial baseplate.

[0086] In Example 30, the subject matter of Example 29 includes, wherein the fixed support includes a third engagement feature that contacts the first edge, the second edge, and the third edge of the first engagement feature to prevent the movable support from rotating about at least the first axis.

[0087] In Example 31, the subject matter of Examples 29-30 includes wherein the fixation bearing includes a fourth engagement feature formed in a central portion of the fixation bearing that contacts the second engagement feature of the tibial baseplate when the fixation bearing is coupled to the tibial baseplate.

[0088] In Example 32, the subject matter of Example 31 includes, wherein the fourth engagement feature includes a pair of ribs that engage the second engagement feature on opposite sides of the second engagement feature.

[0089] Example 33 is an apparatus comprising the device of any one of Examples 1-32.

[0090] Example 34 is a system implementing any one of Examples 1-32.

[0091] Example 35 is a method of implementing any one of Examples 1-32.

[0092] Example 36 is a system, method, or apparatus including any element of any of Examples 1-32.

[0093] The above detailed description refers to the accompanying drawings, which form a part of the detailed description. The accompanying drawings illustrate specific embodiments that can be implemented in a diagrammatic manner. These embodiments are also referred to as "examples" in this article. In addition to the content shown or described, these examples may also include other content. However, the inventors of the present application have also considered examples that only provide those elements shown or described. In addition, the inventors of the present application have also considered examples using any combination or arrangement of those elements shown or described (or one or more aspects thereof), whether for a specific example (or one or more aspects thereof) or for other examples shown or described herein (or one or more aspects thereof).

[0094] All publications, patents, and patent documents mentioned in this application are incorporated herein by reference in their entirety, as if individually incorporated by reference. In the event of any inconsistency between the present application and the usage in the referenced documents, the usage in the referenced documents shall be deemed supplemental to that in this document; for irreconcilable inconsistencies, the usage in this application shall control.

[0095] In this document, the use of the terms "a" or "an" is the same as common usage in patent documents, including one or more, and is independent of any other instances or uses of "at least one" or "one or more". In this document, the term "or" is used to refer to non-exclusiveness, thus, "A or B" includes "A but not B", "B but not A", and "A and B", unless otherwise indicated. In the appended claims, the terms "including" and "in..." are used as the plain English / Chinese equivalents of the corresponding terms "comprising" and "wherein". In addition, in the following claims, the terms "including" and "comprising" are open-ended, that is, if a system, apparatus, article or method includes elements other than the elements listed after the term in a claim, it is still deemed to fall within the scope of the claim. In addition, 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.

[0096] As used herein, the term "approximately" means approximately, within the range of, roughly, or approximately. When the term "approximately" is used in conjunction with a numerical range, it modifies the range by extending the upper and lower boundaries of the specified numerical value. Generally speaking, the term "approximately" is used herein to modify a numerical value with a deviation of 10% above or below the stated numerical value. In one aspect, the term "approximately" refers to plus or minus 10% of the numerical value used. Thus, "approximately 50%" refers to 45%-55%. Numerical ranges recited herein by endpoints include all numbers and fractions within that range. For example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, 4.24, and 5. Similarly, numerical ranges recited herein by endpoints also include subranges contained within that range. For example, 1 to 5 includes 1-1.5, 1.5-2, 2-2.75, 2.75-3, 3-3.90, 3.90-4, 4-4.24, 4.24-5, 2-5, 3-5, 1-4, and 2-4. It is also to be understood that all numbers and fractions thereof are assumed to be modified by the word "about."

[0097] The above description is intended to be illustrative and is not restrictive. For example, the above examples (or one or more aspects thereof) may be used in combination with each other. A person of ordinary skill in the art may also use other embodiments after reading the above description. The abstract is intended to allow the reader to quickly determine the nature of the technical disclosure, and when submitting the abstract, it should be understood that the abstract will not be used to interpret or limit the scope or meaning of the claims. In addition, in the above detailed description, various features may be combined together to simplify the disclosure. This should not be interpreted as meaning that features that are not required to be disclosed are essential to any claim. On the contrary, the subject matter of creative protection may not lie in all the features of a particular disclosed embodiment. Therefore, the following claims are hereby incorporated into the detailed description, and each claim exists independently as a separate embodiment. The scope of the specific embodiment should be determined by reference to the appended claims and all equivalent scopes enjoyed by these claims.

Claims

1. A tibial prosthesis configured for implantation into a tibia, the tibial prosthesis comprising: distal; proximal side as opposed to distal side; a hole defining an opening on the proximal side; a front engagement member on the proximal side; as well as A rear engagement member on the proximal side, the rear engagement member being located rearward of the front engagement member.

2. The tibial prosthesis according to claim 1, wherein: The front engagement member extends upwardly from the proximal side, the front engagement member includes a proximal portion, and wherein the front engagement member includes a protrusion extending from the proximal portion toward the rear side.

3. The tibial prosthesis according to claim 2, wherein: The protrusion is spaced above the proximal side.

4. The tibial prosthesis according to any one of claims 1 to 3, comprising: a perimeter extending between the proximal and distal sides; The front engaging member extends from the front portion of the periphery toward the rear side.

5. The tibial prosthesis according to claim 4, wherein: The rear engagement member is positioned adjacent to the rear edge of the aperture, and wherein the rear engagement member extends upwardly from the proximal side and rearwardly away from the rear edge of the aperture.

6. The tibial prosthesis according to claim 4, wherein: The rear engagement member is located between the aperture and the rear portion of the perimeter, and wherein the rear engagement member extends upwardly from the proximal side and rearwardly away from the rear edge of the aperture.

7. The tibial prosthesis according to claim 4, wherein: The front engaging member comprises: a first edge extending from the perimeter toward the rear side; a second edge extending from the perimeter toward the rear side; and A third edge extends between the first edge and the second edge, the third edge having a concave profile.

8. The tibial prosthesis according to claim 7, wherein: The concave profile of the third edge is configured to provide a reduced thickness of the front engagement member.

9. The tibial prosthesis according to claim 1 or 2, comprising: a perimeter extending between the proximal and distal sides; The front engagement member is spaced rearwardly from the front portion of the perimeter and extends rearwardly toward the front edge of the aperture.

10. The tibial prosthesis according to claim 9, wherein: The rear engagement member is positioned adjacent to the rear edge of the aperture, and wherein the rear engagement member extends upwardly from the proximal side and rearwardly away from the rear edge of the aperture.

11. The tibial prosthesis according to claim 9, wherein: The rear engagement member is located between the aperture and the rear portion of the perimeter, and wherein the rear engagement member extends upwardly from the proximal side and rearwardly away from the rear edge of the aperture.

12. The tibial prosthesis according to claim 9, wherein: The front engaging member comprises: a first edge extending from the perimeter toward the rear side; a second edge extending from the perimeter toward the rear side; A third edge extends between the first edge and the second edge, the third edge having a concave profile.

13. The tibial prosthesis according to claim 12, wherein: The concave profile of the third edge is configured to provide a reduced thickness of the front engagement member.

14. The tibial prosthesis according to claim 12, wherein: The anterior engagement member is configured to receive the press fitting, and wherein the anterior engagement member and the press fitting are configured to engage a mobile bearing coupled to the tibial prosthesis to inhibit or limit rotation of the mobile bearing relative to the tibial prosthesis.

15. The tibial prosthesis according to any one of claims 1 to 3, wherein: The anterior and posterior engagement members are configured to engage with complementary features of the tibial bearing to limit or inhibit rotation of the tibial bearing relative to the tibial prosthesis, wherein the aperture is configured to receive the hinge post, and wherein the posterior engagement member is positioned to limit anterior-posterior movement of the tibial bearing relative to the tibial prosthesis when the hinge post is received in the aperture.

16. A prosthetic knee system comprising: A tibial prosthesis comprising: distal; proximal side as opposed to distal side; a hole defining an opening on the proximal side; a front engagement member on the proximal side; and a rear engagement member on the proximal side, the rear engagement member being located rearward of the front engagement member; and A tibial bearing configured to couple with a tibial prosthesis, the tibial bearing comprising: a first complementary engagement feature configured to engage an anterior engagement member of the tibial prosthesis; and A second complementary engagement feature is configured to engage with a posterior engagement member of the tibial prosthesis.

17. The prosthetic knee system of claim 16, wherein: The tibial bearing includes a mobile bearing configured to rotate relative to the tibial prosthesis within a range about a proximal-distal axis when coupled with the tibial prosthesis.

18. The prosthetic knee system of claim 17, wherein: The tibial bearing includes a fixed bearing configured to limit or inhibit rotation relative to the tibial prosthesis about a proximal-distal axis when coupled to the tibial prosthesis, wherein the tibial prosthesis is configured to selectively receive the mobile bearing or the fixed bearing, and wherein at least one of the anterior engagement member or the posterior engagement member is configured to engage with a first complementary engagement feature or a second complementary engagement feature, respectively, of the fixed bearing to limit or inhibit lifting of the fixed bearing relative to the tibial prosthesis.

19. The prosthetic knee system according to any one of claims 16 to 18, wherein: The distal side of the tibial prosthesis includes a tibial crest, wherein the aperture extends into the tibial crest, and wherein the prosthetic knee system further comprises a hinge post configured to be received within the aperture of the tibial prosthesis and coupled to the femoral component to form a hinged knee prosthesis.

20. The prosthetic knee system of any one of claims 16-18, wherein: an anterior engaging member of the tibial prosthesis extending proximally and superiorly, the anterior engaging member including a proximal portion, and wherein the anterior engaging member includes a protrusion extending posteriorly from the proximal portion; The first complementary engagement feature of the tibial bearing comprises a recess configured to receive the protrusion; The posterior engaging member of the tibial prosthesis includes an upwardly extending protrusion; and The second complementary engagement feature of the tibial bearing includes a corresponding recess configured to receive the upwardly extending projection.

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