Kinematic alignment knee implant system

Abstract

Various embodiments relate to a femoral component for a knee prosthesis optimized for kinematic alignment surgical technique. The component includes an anterior flange having a length of about 40 mm to about 60 mm measured from a distal femoral reference point to an apex of the flange; a lateral flange defining a lateral flange angle of about 8 degrees to about 11 degrees, the angle measured between a line extending along the lateral flange and a line perpendicular to a reference line that connects the farthest distal points of the medial condyle and the lateral condyle; and a trochlear groove formed in the anterior flange. The trochlear groove has a width that remains substantially constant from about 0 degrees of flexion to about 30 degrees of flexion, with a tapering angle of about 1 degree to about 12 degrees.

Description

Atorney Docket No. 447054-000202 PATENTKINEMATIC ALIGNMENT KNEE IMPLANT SYSTEMCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 682,858 filed August 14, 2024, which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates generally to prosthetic knee joint systems and surgical techniques for total knee arthroplasty. More particularly, the present disclosure relates to femoral components and tibial insert components specifically optimized for a kinematic alignment surgical methodology that reproduces patient-specific anatomical features and preserves functional elements.BACKGROUND

[0003] Total knee arthroplasty has been a widely practiced surgical procedure for treating knee osteoarthritis and other degenerative knee conditions for over five decades. The conventional approach, known as mechanical alignment, aims to restore the limb to a neutral mechanical axis by positioning implant components perpendicular to the mechanical axes of the femur and tibia. This methodology has provided reliable pain relief and functional improvement for millions of patients worldwide.

[0004] Despite the clinical success of mechanical alignment techniques, postoperative patient satisfaction rates have remained suboptimal. Indeed, studies indicate that approximately 15- 20% of patients report dissatisfaction following total knee arthroplasty performed using mechanical alignment techniques. Common complaints include residual pain, stiffness, unnatural knee sensation, and limitations in activities of daily living. These outcomes have prompted ongoing research into alternative surgical approaches to beter restore natural knee function and improve patient satisfaction.

[0005] The mechanical alignment approach often involves soft tissue releases, particularly of the medial collateral ligament, to achieve balanced flexion and extension gaps. These releases can disrupt the natural ligamentous structures that contribute to normal knee kinematics. Additionally, the standardized bone cuts used in mechanical alignment may not account for individual anatomical variations in joint line orientation and ligament tension paterns that exist among patients.11622649582.5Atorney Docket No. 447054-000202 PATENT

[0006] Recent advances in understanding knee biomechanics have highlighted the complexity of natural knee motion, which involves differential movement paterns between the medial and lateral compartments during flexion and extension. For example, the medial compartment tends to function as a relatively stable pivot point, while the lateral compartment exhibits greater posterior translation and rotational movement. This asymmetric motion patern contributes to the smooth, natural feel of a healthy knee joint.

[0007] Kinematic alignment has emerged as an alternative surgical philosophy that aims to restore the patient's pre-arthritic joint line orientation and ligament tension paterns. This approach focuses on reproducing individual anatomical features rather than achieving a standardized mechanical axis. Early clinical studies have suggested that kinematic alignment may offer improved patient satisfaction and more natural knee function when compared to traditional mechanical alignment techniques.

[0008] However, existing knee implant designs have been developed primarily for mechanical alignment procedures. When these implants are used with kinematic alignment techniques, various complications, particularly related to patellofemoral tracking and joint stability, can arise. The different bone cuting paterns and component positioning used in kinematic alignment can create mismatches between implant geometry and the intended surgical technique.

[0009] The patellofemoral joint presents particular challenges when conventional implants are used with kinematic alignment. The altered component positioning can affect the trochlear groove orientation and patellar tracking paterns, potentially leading to anterior knee pain, patellar instability, or other complications. Similarly, tibial insert designs optimized for mechanical alignment may not provide appropriate constraint and mobility characteristics for the different joint line orientations used in kinematic alignment.

[0010] There remains a need for implant systems specifically designed to complement kinematic alignment surgical techniques while addressing the unique biomechanical requirements of this approach. Such systems would potentially allow surgeons to more reliably achieve the benefits of kinematic alignment while minimizing the risk of complications associated with implant-technique mismatches.SUMMARY

[0011] In some embodiments, a femoral component for a knee prosthesis optimized for kinematic alignment surgical technique includes an anterior flange having a length ranging21622649582.5Atorney Docket No. 447054-000202 PATENT from about 40 mm to about 60 mm measured from a distal femoral reference point to an apex of the anterior flange; a lateral flange defining a lateral flange angle ranging from about 8 degrees to about 11 degrees, wherein the lateral flange angle is measured between a line extending along the lateral flange and a line perpendicular to a reference line that connects farthest distal points of a medial condyle and a lateral condyle; and a trochlear groove formed in the anterior flange, the trochlear groove having a width that remains substantially constant from about 0 degrees of extension to about 30 degrees of flexion with a tapering angle ranging from about 1 degree to about 12 degrees.

[0012] In some embodiments, the trochlear groove has a trochlear groove angle ranging from about 12.1 degrees to about 18.1 degrees.

[0013] In some embodiments, the medial condyle and the lateral condyle have a single-radius arc design with an arc radius ranging from about 20 mm to about 40 mm corresponding to femoral component size.

[0014] In some embodiments, the single-radius arc design extends from about 0 degrees of flexion to about 90 degrees of flexion, and the medial condyle and the lateral condyle have a continuously variable radius design at degrees of flexion greater than about 90 degrees of flexion.

[0015] In some embodiments, the medial condyle and the lateral condyle are configured to reproduce kinematic alignment third axis motion through differential articulation with a tibial insert, the medial condyle providing high conformity articulation and the lateral condyle providing low conformity articulation to allow axial rotation around a medial pivot point.

[0016] In some embodiments, the femoral component has anteroposterior and mediolateral dimensions configured to prioritize cortical bone coverage for reproduction of a kinematic alignment axis, the femoral component having an anteroposterior to mediolateral aspect ratio within a range of about 0.93 to about 0.98.

[0017] In some embodiments, the femoral component further includes a chamfered lateral margin extending from distal to posterior condylar regions, wherein the chamfered lateral margin prevents overhang beyond an arc defined by an intercondylar midpoint as a center of rotation under valgus placement up to about 6 degrees.

[0018] In some embodiments, the chamfered lateral margin reduces soft tissue irritation during kinematic alignment surgical placement.

[0019] In some embodiments, the femoral component is configured to reproduce all three kinematic alignment axes through a hybrid of medial pivot and medial stabilized techniques.31622649582.5Atorney Docket No. 447054-000202 PATENT

[0020] In some embodiments, the medial condyle is configured to transition from high conformity articulation to controlled mobility at about 90 degrees of flexion; and the lateral condyle is configured to provide substantially unrestricted mobility throughout range of motion.

[0021] In some embodiments, a tibial insert component for a knee prosthesis optimized for kinematic alignment surgical technique includes a medial compartment having a contact surface with a conformity ratio of about 1 : 1.04 relative to a corresponding femoral component surface in a coronal plane, the medial compartment including elevated lips along a medial edge and an intercondylar eminence region, wherein the elevated lips are configured to enhance mediolateral stability during oblique joint line loading; and a lateral compartment having a contact surface with an identical conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in the coronal plane, wherein the lateral compartment includes an elevated lateral lip configured to absorb stress from lateral femoral shift while maintaining uniform load distribution, and wherein the lateral compartment is further configured to allow posterior translation and axial rotation of a lateral femoral condyle.

[0022] In some embodiments the medial compartment has a contact surface that provides full surface contact with a corresponding single-radius femoral component from about 0 degrees to about 90 degrees of flexion.

[0023] In some embodiments, the medial compartment includes an elevated anterior slope and an elevated posterior slope configured to substitute for deficient anterior cruciate ligament and posterior cruciate ligament function.

[0024] In some embodiments, the lateral compartment has a flat insert geometry with an anterior slope configured to accommodate internal rotation up to about 10 degrees in full extension.

[0025] In some embodiments, the lateral compartment has a flat posterior portion without a posterior lip and includes a rounded chamfered posterior edge to prevent edge loading during extreme motion.

[0026] In some embodiments, the elevated lips of the medial compartment are configured to enhance lateral stability and reduce polyethylene wear through uniform load distribution.

[0027] In some embodiments, the flat posterior portion of the lateral compartment is configured to enable posterior translation and axial rotation of a lateral femoral condyle without constraint while preventing localized wear.41622649582.5Atorney Docket No. 447054-000202 PATENT

[0028] In some embodiments, a knee prosthesis system optimized for kinematic alignment surgical technique includes a femoral component having: an anterior flange with a length ranging from about 40 mm to about 60 mm measured from a distal femoral reference point to an apex of the anterior flange; a lateral flange defining a lateral flange angle ranging from about 8 degrees to about 11 degrees, wherein the lateral flange angle is measured between a line extending along the lateral flange and a line perpendicular to a reference line that connects farthest distal points of medial and lateral condyles; a trochlear groove formed in the anterior flange, the trochlear groove having a width that remains substantially constant from about 0 degrees of flexion to about 30 degrees of flexion with a tapering angle ranging from about 1 degree to about 12 degrees; and a tibial insert component having: a medial compartment with a contact surface having a conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in a coronal plane, the medial compartment including elevated lips along a medial edge and an intercondylar eminence region, wherein the elevated lips are configured to enhance mediolateral stability during oblique joint line loading; and a lateral compartment with a contact surface having an identical conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in the coronal plane, wherein the lateral compartment includes an elevated lateral lip configured to absorb stress from lateral femoral shift while maintaining uniform load distribution, and wherein the lateral compartment is further configured to allow posterior translation and axial rotation of a lateral femoral condyle.

[0029] In some embodiments, the femoral component and the tibial insert component are configured to work in combination to reproduce a primary flexion-extension axis, a secondary patellofemoral axis, and a third axial rotation axis, wherein the medial and lateral condyles include a single-radius arc design configured to reproduce the primary flexion-extension axis, wherein the trochlear groove is configured to reproduce the secondary patellofemoral axis, and wherein a differential between the medial compartment and the lateral compartment is configured to reproduce the third axial rotation axis.

[0030] In some embodiments, an anteroposterior to mediolateral aspect ratio of the femoral component and the identical conformity ratio are coordinated to provide balanced load distribution across a joint interface.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the invention and together with the writen51622649582.5Atorney Docket No. 447054-000202 PATENT description serve to explain the principles, characteristics, and features of the invention. Various aspects of at least one example are discussed below with reference to the accompanying drawings, which are not intended to be drawn to scale. In the drawings:

[0032] FIG. 1 depicts the kinematic axes of a knee prosthesis system in accordance with an embodiment.

[0033] FIG. 2 depicts an illustrative femoral component with orthogonal views showing component height in accordance with an embodiment.

[0034] FIG. 3 depicts an example lateral flange angle of the femoral component of FIG. 2 in accordance with an embodiment.

[0035] FIG. 4 depicts illustrative trochlear angle measurements of the femoral component of FIG. 2 in accordance with an embodiment

[0036] FIG. 5 depicts an example trochlear groove and associated contact areas across a range of motion for the femoral component of FIG. 2 in accordance with an embodiment.

[0037] FIG. 6 depicts an illustrative rounded chamfered edge of the femoral component of FIG.2 in accordance with an embodiment.

[0038] FIG. 7 depicts example anteroposterior and mediolateral dimensions for the femoral component of FIG. 2 in accordance with an embodiment.

[0039] FIG. 8A depicts a knee across varying degrees of flexion in accordance with an embodiment.

[0040] FIGS. 8B-8H depict illustrative cross-sectional views of the femoral component of FIG.2 at various flexion angles in accordance with an embodiment.

[0041] FIG. 9 depicts illustrative bone resection views of a femur for knee prosthesis placement in accordance with an embodiment.

[0042] FIG. 10 depicts an example implanted femoral component in accordance with an embodiment.

[0043] FIG. 11 depicts an illustrative comparison of mechanical alignment versus kinematic alignment bone resection in accordance with an embodiment.DETAILED DESCRIPTION

[0044] This disclosure is not limited to the particular systems, devices and methods described, as these may vary. The terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope.61622649582.5Atorney Docket No. 447054-000202 PATENT

[0045] As used in this document, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Those having skill in the art can also translate from the plural form to the singular as is appropriate to the context and / or application. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Nothing in this disclosure is to be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention. As used in this document, the term “comprising” means “including, but not limited to.”

[0046] It will be understood by those within the art that, in general, terms used herein are generally intended as “open” terms (for example, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” et cetera). While various compositions, methods, and devices are described in terms of “comprising” various components or steps (interpreted as meaning “including, but not limited to”), the compositions, methods, and devices also can “consist essentially of’ or “consist of’ the various components and steps, and such terminology should be interpreted as defining essentially closed-member groups.

[0047] In addition, even if a specific number is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (for example, the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, et cetera” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, et cetera). It will be further understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, sample embodiments, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

[0048] In addition, where features of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.71622649582.5Atorney Docket No. 447054-000202 PATENT

[0049] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a writen description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, et cetera. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, et cetera. As will also be understood by one skilled in the art all language such as “up to,” “at least,” and the like include the number recited and refer to ranges that can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.

[0050] The term “about,” as used herein, refers to variations in a numerical quantity that can occur, for example, through measuring or handling procedures in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of compositions or reagents; and the like. Typically, the term “about” as used herein means greater or lesser than the value or range of values stated by 1 / 10 of the stated values, e.g., ±10%. The term “about” also refers to variations that would be recognized by one skilled in the art as being equivalent so long as such variations do not encompass known values practiced by the prior art. Each value or range of values preceded by the term “about” is also intended to encompass the embodiment of the stated absolute value or range of values. Whether or not modified by the term “about,” quantitative values recited in the present disclosure include equivalents to the recited values, e.g., variations in the numerical quantity of such values that can occur, but would be recognized to be equivalents by a person skilled in the art.

[0051] The kinematic alignment surgical technique represents a departure from conventional mechanical alignment approaches in total knee arthroplasty. Kinematic alignment seeks to restore the patient's pre-arthritic joint line and limb alignment by preserving the natural orientation of the joint surfaces. This approach may prioritize the reproduction of individual anatomical characteristics rather than achieving standardized mechanical axes. The kinematic alignment method may aim to maintain the patient's constitutional alignment and joint kinematics, potentially leading to more natural knee function and improved patient satisfaction as compared to mechanical alignment techniques.81622649582.5Atorney Docket No. 447054-000202 PATENT

[0052] A knee prosthesis system optimized for kinematic alignment surgical techniques may incorporate design features that differ substantially from conventional implants. In some cases, the system includes components specifically engineered to accommodate the unique placement angles and anatomical variations encountered in kinematic alignment procedures. The system may comprise a femoral component and a tibial insert component, each designed with geometric characteristics that support the kinematic alignment philosophy. These components may work in combination to reproduce the complex motion paterns of the natural knee while accommodating the specific bone preparation and implant positioning associated with kinematic alignment techniques.

[0053] A femoral component for a knee prosthesis optimized for a kinematic alignment surgical technique may incorporate several distinctive design elements. In some cases, the femoral component features modified dimensional ratios, specialized surface geometries, and altered angular relationships compared to conventional mechanical alignment implants. The femoral component may also include features such as shortened anterior flanges, modified trochlear groove configurations, and chamfered lateral margins to achieve specific benefits associated with kinematic alignment implant placement.

[0054] A tibial insert component for a knee prosthesis optimized for a kinematic alignment surgical technique may feature asymmetric design characteristics between the medial and lateral compartments. In some cases, the medial compartment provides high conformity articulation with elevated lips and slopes to enhance stability and substitute for deficient cruciate ligament function. The lateral compartment may feature a flater, less constrained geometry to allow natural rollback and rotational motion of the lateral femoral condyle. The insert component may be designed to work in conjunction with the femoral component to accommodate the specific loading paterns and motion requirements associated with kinematic alignment placement.

[0055] The system may be configured to reproduce all three kinematic alignment axes including the primary femoral axis, secondary femoral axis, and tibial rotational axis in a unified implant system. The reproduction of these three axes within a single implant system may represent a comprehensive approach to kinematic alignment optimization. In some cases, conventional implants designed for mechanical alignment procedures address only one or two of these axes, potentially limiting their effectiveness in kinematic alignment applications. The approach presented herein may ensure that all aspects of natural knee motion are considered and accommodated within the implant design. This comprehensive axis reproduction may91622649582.5Atorney Docket No. 447054-000202 PATENT contribute to more natural joint kinematics and improved clinical outcomes compared to implants designed primarily for mechanical alignment techniques.

[0056] Kinematic alignment surgical techniques differ from mechanical alignment techniques in their approach to restoring knee joint function. In some cases, mechanical alignment focuses on achieving standardized mechanical axes and neutral limb alignment, often requiring significant bone resection and soft tissue releases to conform to predetermined geometric parameters. Kinematic alignment, by contrast, may preserve the patient's natural joint line orientation and constitutional alignment by maintaining the original bone and cartilage surfaces where possible. This approach may result in less invasive bone preparation and may better preserve the patient's individual anatomical characteristics. The kinematic alignment method may accommodate natural variations in limb alignment and joint geometry, potentially leading to joint mechanics closer to a patient’s physiology as compared to the standardized approach of mechanical alignment.

[0057] Referring to FIG. 1, kinematic axes of the knee 100 illustrate the complex three- dimensional motion paterns that govern natural knee function. The kinematic axes of the knee 100 are visualized through an anterior view 102 and a medial view 104, which provide complementary perspectives for understanding the spatial relationships between the different rotational axes.

[0058] The kinematic axes of the knee 100 comprise three distinct rotational axes that work in coordination to facilitate natural knee motion. A primary femoral axis 106 may serve as the main flexion-extension axis of the knee joint, extending through the femoral component and defining the primary rotational center for sagital plane motion. The primary femoral axis 106 corresponds to the cylindrical axis described in kinematic alignment theory, representing the axis around which the femur rotates relative to the tibia during flexion and extension. The primary femoral axis 106 may be positioned to pass through the centers of the medial and lateral femoral condyles, creating a stable rotational reference for the majority of knee motion from full extension to approximately ninety degrees of flexion.

[0059] A secondary femoral axis 108 may intersect with the primary femoral axis 106 to define the patellofemoral tracking axis within the kinematic axes of the knee 100. The secondary femoral axis 108 may govern the motion of the patella as the patella engages with the trochlear groove of the femoral component during knee flexion. The secondary femoral axis 108 may be positioned to optimize patellar tracking and minimize lateral patellofemoral ligament tension101622649582.5Atorney Docket No. 447054-000202 PATENT during the early phases of knee flexion, particularly in the range from zero to thirty degrees of flexion where initial patellar engagement occurs.

[0060] A tibial rotational axis 110 may complete the three-axis system within the kinematic axes of the knee 100, providing the reference for axial rotation and rollback motion during knee flexion. As shown in FIG. 1, the tibial rotational axis 110 may be oriented vertically and serve as the axis around which differential motion occurs between the medial and lateral compartments of the knee joint. In some cases, the tibial rotational axis 110 may enable the asymmetric motion patterns characteristic of natural knee kinematics, where the medial compartment functions as a relatively stable pivot point while the lateral compartment undergoes posterior translation and axial rotation. The tibial rotational axis 110 may be positioned to facilitate the rollback motion of the lateral femoral condyle during flexion while maintaining stability in the medial compartment.

[0061] The integration of the primary femoral axis 106, secondary femoral axis 108, and tibial rotational axis 110 within the kinematic axes of the knee 100 may create a comprehensive framework for reproducing natural knee motion in a prosthetic system. In some cases, the three axes may work in combination to accommodate the complex motion paterns that occur during activities of daily living, including walking, stair climbing, and deep flexion activities. The primary femoral axis 106 may provide the foundation for sagital plane motion, while the secondary femoral axis 108 may ensure proper patellofemoral tracking, and the tibial rotational axis 110 may enable the rotational and translational motions that characterize natural knee kinematics. This multi-axis approach may represent a departure from conventional implant designs that focus primarily on a single axis of rotation.

[0062] The spatial relationships between the axes within the kinematic axes of the knee 100 may be maintained through specific geometric features incorporated into the femoral component and tibial insert component. In some cases, the primary femoral axis 106 may be predominantly reproduced through single-radius arc geometry in the sagital plane design of the femoral condyles, providing a consistent rotational center for flexion-extension motion. The secondary femoral axis 108 may be predominantly addressed through specialized trochlear groove configurations that accommodate the natural entry angle and tracking path of the patella during early flexion. The tibial rotational axis 110 may be predominantly facilitated through differential design characteristics between the medial and lateral compartments of the tibial insert, allowing for asymmetric motion paterns that mirror the behavior of the natural knee joint.111622649582.5Atorney Docket No. 447054-000202 PATENT

[0063] Referring to FIG. 2, a femoral component 200 is illustrated through orthogonal views that demonstrate the dimensional characteristics and geometric configuration of the prosthetic device in accordance with some embodiments of this disclosure. The femoral component 200 is shown through an anterior view 202 and a medial view 204, which provide complementary perspectives for understanding the three-dimensional structure and proportional relationships of the component.

[0064] The femoral component 200 may have a height 206 that represents a departure from conventional implant dimensions. In some cases, the component height 206 may be about fortyseven millimeters, which may represent a reduction in height as compared to traditional mechanical alignment implants that typically have a height of about fifty-two millimeters (e .g . , for a size 3 implant). This dimensional reduction in the component height 206 may enable less invasive surgical procedures by reducing the amount of bone resection required during implantation. The reduced component height 206 may also minimize disruption to surrounding soft tissues and may contribute to faster recovery times and reduced postoperative complications.

[0065] The dimensional configuration of the femoral component 200 may incorporate an anterior flange having a length ranging from about thirty-five millimeters to about sixty millimeters as measured from a distal femoral reference point to an apex of the anterior flange. This measurement may be critical for ensuring proper fit and coverage of the prepared bone surface while minimizing invasion into surrounding soft tissues. The reduced anterior flange length compared to conventional implants from 48 mm to 64 mm)may enable preservation of anterior soft tissue structures and may reduce the invasiveness of the surgical procedure.

[0066] In some embodiments, the anterior flange length may be about 35 mm, about 37 mm, about 39 mm, about 41 mm, about 43 mm, about 45 mm, about 47 mm, about 49 mm, about 51 mm, about 53 mm, about 55 mm, about 57 mm, about 59 mm, about 60 mm, or any value or range of values between any two of these values. In some embodiments, the anterior flange length may range from about 40 mm to about 60 mm. In some embodiments, the anterior flange length may range from about 42 mm to about 58 mm. In some embodiments, the anterior flange length may range from about 45 mm to about 55 mm.

[0067] Referring to FIG. 3, the femoral component 200 may incorporate a lateral flange angle 302 that represents a departure from conventional implant angular configurations. The lateral flange angle 302 may be specifically optimized for kinematic alignment surgical placement, where the femoral component 200 may be positioned in a valgus orientation relative to the121622649582.5Atorney Docket No. 447054-000202 PATENT mechanical axis of the femur. In some cases, the lateral flange angle 302 may be within a range of about seven degrees to about eleven degrees, providing a geometric configuration that addresses the coverage challenges associated with valgus positioning in kinematic alignment procedures. This angular range may represent a reduction compared to conventional mechanical alignment implants that typically employ lateral flange angles ranging from twelve degrees to eighteen degrees.

[0068] The measurement of the lateral flange angle 302 may be defined through specific geometric relationships between anatomical reference lines and the lateral flange structure of the femoral component 200. In some cases, the lateral flange angle 302 may be measured between a line extending along the lateral flange and a line perpendicular to a reference line that connects the farthest distal points of the medial condyle and lateral condyle.

[0069] With continued reference to FIG. 3, the lateral flange angle 302 may address specific coverage challenges that occur when the femoral component 200 is positioned in valgus alignment during kinematic alignment procedures. In some cases, conventional implants with larger lateral flange angles experience insufficient coverage of the anterior lateral femur when positioned in the valgus orientation characteristic of kinematic alignment techniques. The reduced lateral flange angle 302 may compensate for the medial shifting of the anterior flange that occurs during valgus positioning, thereby maintaining adequate coverage of the anterior lateral femoral surface. This improved coverage may prevent exposure of prepared bone surfaces and may reduce the risk of soft tissue irritation or mechanical complications associated with inadequate implant coverage.

[0070] The optimization of the lateral flange angle 302 for kinematic alignment placement may contribute to more natural patellofemoral joint articulation compared to conventional mechanical alignment approaches. The lateral flange angle 302 may facilitate proper patellar tracking by providing appropriate lateral guidance during the early phases of knee flexion, particularly in the range from zero to thirty degrees where initial patellar engagement with the trochlear groove occurs. In some cases, the reduced lateral flange angle 302 may help prevent excessive tension on the lateral patellofemoral ligament during early flexion, potentially avoiding the need for invasive soft tissue releases that may be required with conventional implant designs. The angular configuration may also accommodate the unique anatomical characteristics of individual patients with higher precision than conventional technologies, making the femoral component 200 suitable for a broader patient population than conventional implants.131622649582.5Atorney Docket No. 447054-000202 PATENT

[0071] The lateral flange angle 302 may work in coordination with other geometric features of the femoral component 200 to create a comprehensive kinematic alignment optimization.

[0072] Referring to FIG. 4, the femoral component 200 may incorporate trochlear groove angle measurements that differ substantially from conventional mechanical alignment implants. The trochlear groove angle configuration may be specifically optimized to compensate for the valgus placement characteristic of kinematic alignment surgical techniques, where the femoral component 200 may be positioned with an average valgus deviation of about two degrees relative to the femoral functional axis. In some cases, this valgus positioning may cause the trochlear groove angle to become steeper compared to the intended design parameters of conventional implants, leading to altered patellofemoral tracking paterns and increased lateral patellofemoral ligament tension. The optimized trochlear groove angle of the femoral component 200 may address these challenges by providing angular specifications that account for the geometric changes associated with valgus implant placement.

[0073] The measurement methodology for determining trochlear groove angles may be established through specific geometric relationships between reference axes and groove geometry. As shown in FIG. 4, a traditional implant trochlear groove primary axis 402 may serve as a baseline reference for conventional implant angular measurements. An implant trochlear groove primary axis 404 may define the actual groove orientation of the femoral component 200, extending along the lateral flange and trochlear groove geometry.

[0074] With continued reference to FIG. 4, a traditional implant trochlear angle 406 may represent the angular configuration typically employed in conventional mechanical alignment implants. The traditional implant trochlear angle 406 may range from six degrees to eight degrees, reflecting the standardized geometric parameters developed for mechanical alignment surgical techniques where implants may be positioned perpendicular to the mechanical axis of the femur. The traditional implant trochlear angle 406 may be inadequate when applied to kinematic alignment procedures due to the valgus positioning that characterizes this surgical approach.

[0075] An implant trochlear angle 408 may represent an optimized angular configuration incorporated into the femoral component 200 for kinematic alignment applications. The implant trochlear angle 408 may range from about 12.1 degrees to about 18.1 degrees, which represents a substantially increased angle as compared to the traditional implant trochlear angle 406 employed in conventional mechanical alignment implants.141622649582.5Atorney Docket No. 447054-000202 PATENT

[0076] In some embodiments, the implant trochlear angle 408 may be about 12.1 degrees, about 12.5 degrees, about 13.0 degrees, about 13.5 degrees, about 14.0 degrees, about 14.5 degrees, about 15.0 degrees, about 15.5 degrees, about 16.0 degrees, about 16.5 degrees, about 17.0 degrees, about 17.5 degrees, about 18.0 degrees, about 18.1 degrees, or any value or range of values between any two of these values. In some embodiments, the implant trochlear angle 408 may range from about 12.1 degrees to about 15.1 degrees. In some embodiments, the implant trochlear angle 408 may range from about 13.0 degrees to about 17.0 degrees. In some embodiments, the implant trochlear angle 408 may range from about 14.0 degrees to about 16.0 degrees.

[0077] The increased angular specification of the implant trochlear angle 408 may compensate for the steepening effect that occurs when the femoral component 200 is positioned in valgus alignment during kinematic alignment procedures. In some cases, the valgus positioning may cause the effective trochlear groove angle to increase beyond the intended design parameters, potentially leading to altered patellar entry trajectories and increased lateral patellofemoral ligament tension during early flexion. The implant trochlear angle 408 may be specifically calibrated to account for this geometric transformation, ensuring that the effective trochlear groove angle remains within physiological ranges even when the femoral component 200 is positioned in the valgus orientation characteristic of kinematic alignment techniques. This angular optimization may enable the femoral component 200 to reproduce smooth patellofemoral joint dynamics that align with natural knee kinematics.

[0078] In some cases, the implant trochlear angle 408 may enable the patella to follow a more natural trajectory during flexion, potentially reducing the load applied to the patellofemoral joint and alleviating anterior knee pain that may be associated with suboptimal patellar tracking. The optimized angular configuration may also reduce the likelihood of lateral patellofemoral ligament tension during the early flexion range from zero to thirty degrees, where initial patellar engagement with the trochlear groove occurs and where tracking irregularities may have the most pronounced effects on joint function and patient comfort.

[0079] Referring to FIG. 5, the femoral component 200 may incorporate a trochlear groove width 504 that represents a departure from conventional implant groove configurations. The trochlear groove width 504 may be specifically designed to accommodate the diverse patellar entry angles and tracking variations that characterize kinematic alignment surgical applications. In some cases, the trochlear groove width 504 may remain substantially constant from zero degrees of extension to thirty degrees of flexion, creating a rectangular contact151622649582.5Atorney Docket No. 447054-000202 PATENT profile that differs substantially from the V-shaped groove geometry employed in conventional mechanical alignment implants. This constant width configuration may provide greater tolerance for individual variations in patellar tracking paterns while reducing the risk of lateral patellofemoral ligament tension during the early phases of knee flexion.

[0080] At about 30 degrees of flexion 508 the trochlear groove geometry may begin to transition from the constant width configuration to a more curved V-shaped profile.

[0081] The trochlear groove width 504 may incorporate specific tapering angles that define the geometric relationships between the medial and lateral ridge structures within the contact area between 0 degrees and 30 degrees of flexion 510. In some cases, the tapering angle may range from about one degree to about twelve degrees, providing a controlled transition from the constant width geometry to the more traditional V-shaped configuration that occurs beyond thirty degrees of flexion. The tapering angle may alternatively range from about five degrees to about ten degrees, offering a more focused angular specification that may optimize patellar tracking characteristics for the majority of kinematic alignment applications. The tapering angle measurements may be taken between the medial and lateral ridge surfaces and the groove floor, establishing the geometric parameters that define the rectangular contact profile within the contact area between 0 degrees and 30 degrees of flexion 510.

[0082] The shallow concave profile created by this wide groove angle may reduce lateral patellofemoral ligament tension during the transition from the contact at 0 degrees of flexion 506 to the contact at 30 degrees of flexion 508, potentially eliminating the need for invasive soft tissue releases that may be required with conventional implant designs.

[0083] The rectangular contact profile established by the trochlear groove width 504 within the contact area between 0 and 30 degrees of flexion 510 may provide functional advantages compared to the V-shaped contact areas employed in conventional mechanical alignment implants. Traditional V-shaped designs may impose a predetermined patellar tracking trajectory that forces the patella to conform to the implant geometry regardless of individual anatomical variations. In some cases, this rigid geometric constraint may lead to increased lateral patellofemoral ligament tension, altered patellar tracking paterns, and potential complications during early flexion activities. The rectangular contact profile of the femoral component 200 may allow the patella to find its natural tracking trajectory within the permissive geometry of the contact area between 0 degrees and 30 degrees of flexion 510, potentially reducing the risk of tracking-related complications and improving overall patellofemoral joint function.161622649582.5Atorney Docket No. 447054-000202 PATENT

[0084] Referring to FIG. 6. the femoral component 200 may incorporate a rounded chamfered edge 606 that addresses specific geometric challenges associated with valgus placement in kinematic alignment surgical procedures. The rounded chamfered edge 606 may extend along the lateral margin of the femoral component 200 from the distal to posterior condylar regions, providing a modified contour that accommodates the angular positioning characteristic of kinematic alignment techniques.

[0085] The geometric configuration of the rounded chamfered edge 606 may be specifically calibrated to prevent overhang beyond an arc defined by an intercondylar midpoint as a center of rotation under valgus placement up to six degrees. In some cases, the intercondylar midpoint may serve as the rotational center for defining the acceptable boundaries of femoral component positioning, with the arc representing the geometric envelope within which the component contours may remain during normal joint motion. When conventional femoral components are positioned in valgus alignment, portions of the lateral margin may extend beyond this rotational arc, creating overhang conditions that can lead to mechanical interference with surrounding soft tissues. The rounded chamfered edge 606 may eliminate these overhang conditions by providing a contoured lateral margin that remains within the rotational arc boundaries

[0086] As shown in FIG. 6, the rounded chamfered edge 606 may provide a smooth transition between the functional articular surfaces of the femoral component 200 and the lateral margin geometry, creating a contoured profile that maintains structural integrity while reducing lateral projection. In some cases, the chamfered lateral margin may be angled to provide maximum clearance in the regions most likely to experience overhang during valgus positioning, while maintaining adequate bone coverage and fixation characteristics in areas where structural support may be needed. The angular configuration of the chamfered lateral margin may be calibrated based on the anticipated range of valgus positioning angles encountered in kinematic alignment procedures, ensuring adequate clearance across the full spectrum of surgical placement scenarios.

[0087] The rounded chamfered edge 606 may provide a smooth, continuous contour that distributes contact forces more evenly across the lateral soft tissue interface, thereby reducing the likelihood of localized pressure points and mechanical irritation. The rounded geometry may also facilitate smoother joint motion by reducing friction and mechanical interference between the femoral component 200 and surrounding soft tissue structures during flexion and extension activities.171622649582.5Atorney Docket No. 447054-000202 PATENT

[0088] Referring to FIG. 7, the femoral component 200 may incorporate specific dimensional relationships that address the geometric challenges associated with kinematic alignment surgical placement.

[0089] The anteroposterior (AP) dimension 702 may define the front-to-back measurement of the femoral component 200, extending from the anterior flange region to the posterior condylar surfaces. The mediolateral (ML) dimension 704 may establish the side-to-side measurement of the femoral component 200, extending across the width of the condylar surfaces from the medial aspect to the lateral aspect.

[0090] Table 1 illustrates example femoral component sizes and their respective aspect ratios in accordance with an embodiment.Table 1

[0091] The relationship between the AP dimension 702 and the ML dimension 704 may be expressed as an aspect ratio that addresses the specific geometric requirements of kinematic alignment surgical techniques. In some cases, the AP to ML aspect ratio may range from about 0.9114 to about 0.9558 based on the component size.

[0092] In some embodiments, the AP to ML aspect ratio may be about 0.91, about 0.915, about 0.92, about 0.925, about 0.93, about 0.935, about 0.94, about 0.945, about 0.95, about 0.955, about 0.96, or any value or range of values between any two of these values. In some embodiments, the AP to ML aspect ratio may range from about 0.92 to about 0.95. In some embodiments, the AP to ML aspect ratio may range from about 0.93 to about 0.96. In some embodiments, the AP to ML aspect ratio may range from about 0.94 to about 0.955.

[0093] The optimized aspect ratio between the AP dimension 702 and the ML dimension 704 may enable the femoral component 200 to provide adequate cortical bone coverage while accommodating the unique placement angles associated with kinematic alignment procedures. In kinematic alignment, the anterior reference point of the femur is measured at a position about 2 mm higher compared to mechanical alignment, resulting in the femoral component size in kinematic alignment becoming one size larger (equivalent to about 2 mm). When a femoral 181622649582.5Atorney Docket No. 447054-000202 PATENT component designed with the AP / ML ratio for mechanical alignment is used in kinematic alignment, the ML width may extend beyond the bone, resulting in a coverage mismatch. Therefore, the AP / ML ratio design most suitable for kinematic alignment is one in which the AP length is about 2 mm longer than that of the mechanical alignment design, while the ML width is equivalent to that of the mechanical alignment design, achieving the best femoral coverage. The femoral component 200 may have AP and ML dimensions configured to prioritize cortical bone coverage for reproduction of a kinematic alignment axis, thereby ensuring that the implant provides adequate structural support across the prepared bone surfaces. The aspect ratio may be calibrated to provide balanced load distribution across the joint interface while accommodating these kinematic alignment placement angles. This may reduce or prevent stress concentration points that could compromise implant fixation or bone integration.

[0094] Referring to PIG. 8A, the femoral component is illustrated through a radial arrangement that demonstrates the systematic progression of geometric changes occurring throughout the full range of knee motion 800. The radial arrangement may provide a comprehensive visualization of how the cross-sectional profiles change in a coordinated manner as the knee joint transitions through different flexion angles, from the -30 degrees of extension 802 through the 60 degrees of flexion 814 positions.

[0095] Referring to FIGS. 8B-8H, a femoral component across varying degrees of flexion 800 may be illustrated through a series of cross-sectional views that demonstrate the progressive geometric changes, particularly to the trochlear groove, occurring throughout the range of knee motion. The femoral component across varying degrees of flexion 800 may provide a comprehensive visualization of how the femoral component 200 geometry accommodates patellar movement during different phases of knee motion, from hyperextension through deep flexion activities. In some cases, the cross-sectional views may reveal the complex three- dimensional relationships between different regions of the femoral component 200 as the component articulates with the tibial insert during various functional activities. The cross- sectional views of the femoral component across varying degrees of flexion 800 may demonstrate how the optimized geometric features of the femoral component 200 accommodate the kinematic requirements of natural knee motion while maintaining structural integrity and joint stability across the full range of flexion angles.

[0096] The cross-sectional views illustrated in FIGS. 8B-8H may demonstrate the progressive transition from the shallow, dish-shaped groove configuration to the V-shaped groove geometry191622649582.5Atorney Docket No. 447054-000202 PATENT that occurs as the knee moves through its functional range of motion. The trochlear groove geometry evolves from a permissive, wide configuration during early flexion to a more constraining, traditional V-shaped profile during mid-range and deep flexion activities. The systematic progression shown through these cross-sectional views may illustrate how the femoral component 200 accommodates the changing biomechanical requirements of patellar tracking while maintaining joint stability and natural motion paterns throughout the functional range of knee flexion.

[0097] As shown in FIG. 8B, the cross-sectional sequence may begin with a -30 degrees of extension 802 position that represents a hyperextension state beyond the normal resting position of the knee joint. The -30 degrees of extension 802 may demonstrate the geometric configuration of the femoral component 200 when the knee joint extends beyond the neutral standing position, potentially occurring during activities such as walking downhill or transitioning from seated to standing positions. In some cases, the -30 degrees of extension 802 cross-section may reveal how the anterior flange geometry and trochlear groove configuration accommodate patellar positioning during hyperextension activities. The -30 degrees of extension 802 position may also illustrate the spatial relationships between the medial and lateral condylar surfaces and the corresponding tibial insert geometry, demonstrating how the femoral component 200 maintains joint stability and load distribution characteristics even during extreme extension positioning.

[0098] In reference to FIG. 8C, a -15 degrees of extension 804 position may represent an intermediate hyperextension state that occurs during the transition from extreme extension toward the neutral standing position. The -15 degrees of extension 804 cross-section may demonstrate how the femoral component 200 geometry begins to engage with the tibial insert surfaces as the knee joint moves toward the neutral position, illustrating the progressive changes in contact paterns and load distribution characteristics. In some cases, the -15 degrees of extension 804 position may reveal the initial engagement paterns between the trochlear groove and patellar surfaces, showing how the optimized groove geometry accommodates patellar tracking during the transition from hyperextension to neutral positioning. The -15 degrees of extension 804 cross-section may also demonstrate how the femoral component 200 geometry facilitates the transition toward the neutral position where more complex biomechanical interactions will occur.

[0099] As illustrated in FIG. 8D, a 0 degrees of extension 806 position may establish the neutral reference configuration for the femoral component across varying degrees of flexion201622649582.5Atorney Docket No. 447054-000202 PATENT800, representing the standing position where the knee joint achieves full extension without hyperextension. The 0 degrees of extension 806 cross-section may serve as the baseline geometry for understanding how the femoral component 200 accommodates the transition from extension activities to the initiation of flexion motion. In some cases, the 0 degrees of extension 806 position may demonstrate the contact at 0 degrees of extension 506 relationship between the patella and the anterior flange of the femoral component 200, illustrating how the optimized trochlear groove width 504 provides adequate guidance without excessive constraint during the initial phases of patellar engagement. The 0 degrees of extension 806 cross-section may also reveal how the lateral compartment geometry allows internal rotation up to about ten degrees at the lateral condyle during full extension, reproducing the natural screw-home movement of a healthy knee. This internal rotation capability is controlled by the anterior lateral lip, which serves as a rotational stopper, taking over the role of the resected anterior cruciate ligament in providing a strong bracing force in full extension. The spatial relationships between the medial and lateral condylar surfaces and the tibial insert geometry demonstrate how the differential conformity ratios between the medial and lateral compartments contribute to joint stability while allowing these natural motion paterns. The 0 degrees of extension 804 cross-section may also demonstrate how the lateral compartment geometry allows internal femoral rotation up to about ten degrees at the lateral condyle during the extension phase, providing the rotational freedom that characterizes natural knee kinematics during weight-bearing activities.

[0100] In principle, the knee joint may not enter hyperextension when kinematic alignment surgery is performed properly. The range from -30 degrees to 0 degrees may represent a patella protection zone that becomes relevant when the femoral component is placed in a flexed position or in cases of patella alta. While these hyperextension positions may occur in specific clinical scenarios, the primary focus of the cross-sectional analysis may be on the transition zone characteristics that define the trochlear groove geometry during normal functional activities.

[0101] As further shown in FIG. 8E, a 15 degrees of flexion 808 position may represent the early flexion phase where significant changes in patellar tracking and joint loading paterns begin to occur. The 15 degrees of flexion 808 cross-section may demonstrate how the femoral component 200 geometry accommodates the increasing engagement between the patella and the trochlear groove as the knee joint transitions from the neutral position toward active flexion. In some cases, the 15 degrees of flexion 808 position may illustrate how the constant width configuration of the trochlear groove width 504 provides tolerance for individual variations in211622649582.5Atorney Docket No. 447054-000202 PATENT patellar entry angles while maintaining joint stability and guidance characteristics. The 15 degrees of flexion 808 cross-section may also show how the lateral compartment geometry continues to allow rotational freedom at the lateral condyle, enabling the asymmetric motion paterns that characterize natural knee kinematics during the early phases of flexion activities.

[0102] In reference to FIG. 8F, a 30 degrees of flexion 810 position may establish the transition point where the trochlear groove geometry begins to change from the constant width configuration toward a more constraining profile. The 30 degrees of flexion 810 cross-section may correspond to the contact at 30 degrees of flexion 508 relationship described previously, demonstrating how the femoral component 200 accommodates the shift from permissive early flexion geometry to more guided mid-flexion tracking paterns.

[0103] In reference to FIG. 8G, a 45 degrees of flexion 812 position may represent the midflexion phase where the femoral component 200 geometry provides increased constraint and guidance as compared to the early flexion configurations. The 45 degrees of flexion 812 crosssection may demonstrate how the trochlear groove configuration transitions toward a more traditional V-shaped profile that provides enhanced patellar tracking stability during mid-range flexion activities. In some cases, the 45 degrees of flexion 812 position may illustrate how the single-radius arc design of the medial and lateral condyles provides consistent rotational characteristics during the primary range of knee motion, contributing to the reproduction of the primary femoral axis 106 that governs sagital plane kinematics. The 45 degrees of flexion 812 cross-section may also show how the differential conformity between the medial and lateral compartments enables the asymmetric motion paterns that characterize natural knee function, with the medial compartment providing stability while the lateral compartment allows continued rotational and translational freedom.

[0104] As shown in FIG. 8H, a 60 degrees of flexion 814 position may represent the transition toward deep flexion activities where the femoral component 200 geometry accommodates the increasing demands for joint mobility and rollback motion. The 60 degrees of flexion 814 cross-section may demonstrate how the femoral component 200 maintains joint stability while allowing the posterior translation and axial rotation that characterize natural knee kinematics during deep flexion activities such as stair climbing or rising from seated positions. In some cases, the 60 degrees of flexion 814 position may illustrate how the lateral compartment geometry continues to provide unrestricted mobility throughout the range of motion, enabling the lateral femoral condyle to undergo the posterior rollback and rotational motion that occurs during deep flexion activities. The 60 degrees of flexion 814 cross-section may also show how221622649582.5Atorney Docket No. 447054-000202 PATENT the medial compartment maintains high conformity articulation characteristics that provide joint stability while accommodating the controlled mobility that occurs as the knee approaches the transition point toward the variable radius design that facilitates deeper flexion beyond ninety degrees.

[0105] Referring to FIG. 9, a bone resection 900 of the femur 902 may illustrate the three- dimensional resection surfaces 904 that characterizes kinematic alignment surgical preparation for knee prosthesis placement.

[0106] Referring to FIG. 10, an implanted femoral component 1000 may demonstrate the integration of the femoral component 200 with the prepared bone surfaces following kinematic alignment surgical procedures.

[0107] Referring to FIG. 11, a comparison of example bone resections 1100 is illustrated to present the fundamental differences between conventional mechanical alignment and kinematic alignment surgical approaches in total knee arthroplasty bone preparation. The comparison of bone resections 1100 demonstrates how these two surgical philosophies create substantially different resection configurations that accommodate their respective implant positioning requirements and anatomical preservation strategies. The choice of surgical alignment technique may directly influence the extent of bone removal, the invasiveness of the procedure, and the resulting bone surface geometry that accommodates prosthetic component placement.

[0108] Specifically, the comparison 1100 illustrates a typical mechanical alignment resection 1102 and a kinematic alignment resection 1104 according to the present disclosure. The mechanical alignment resection 1102 may extend a greater distance into the femoral 1106 structure than the kinematic alignment resection 1104, reflecting the standardized cuting approach that aims to achieve predetermined mechanical axes and neutral limb alignment regardless of individual anatomical variations. In some cases, the mechanical alignment resection 1102 may involve more extensive bone removal to accommodate the dimensional requirements of conventional implants that may be designed with standardized geometric parameters rather than patient-specific anatomical considerations. The mechanical alignment resection 1102 demonstrates how conventional surgical techniques prioritize achieving consistent mechanical relationships over preserving individual bone morphology and constitutional alignment characteristics.

[0109] In contrast, the kinematic alignment resection 1104 may represent the bone cutting configuration that characterizes the kinematic alignment surgical approach described in the231622649582.5Atorney Docket No. 447054-000202 PATENT present disclosure. The kinematic alignment resection 1104 may demonstrate a more conservative bone removal approach that preserves individual anatomical characteristics while creating prepared surfaces 1108 of the femur 106 that accommodate the specialized geometric features of the femoral component 200. In some cases, the kinematic alignment resection 1104 may include less extensive bone cuting compared to the mechanical alignment resection 1102, reflecting the kinematic alignment philosophy of maintaining the patient's natural joint line orientation and constitutional alignment. The kinematic alignment resection 1104 may accommodate the reduced component height 206 and optimized dimensional characteristics of the femoral component 200, enabling less invasive surgical preparation while maintaining adequate bone coverage and structural support.

[0110] In some embodiments, the femoral component 200 may include a single-radius arc radius ranging from about 20mm to about 40mm. In some cases, the single-radius arc radius configuration may provide a consistent rotational center that mirrors the biomechanical characteristics of the natural knee joint during the primary range of flexion motion from full extension to approximately ninety degrees of flexion. The arc radius may correspond to femoral component size, providing dimensional scaling that accommodates varying patient anatomies while maintaining the geometric relationships that enable reproduction of natural knee kinematics.[oni] In some embodiments, the radius may be about 20mm, about 22mm, about 24mm, about 26mm, about 28mm, about 30mm, about 32mm, about 34mm, about 36mm, about 38mm, about 40mm, or any value or range of values between any two of these values. In some embodiments, the single-radius arc radius may range from about 20mm to about 30mm. In some embodiments, the single-radius arc radius may range from about 25mm to about 35mm. In some embodiments, the single-radius arc radius may range from about 30mm to about 40mm.

[0112] The geometric configuration of the single-radius arc design may be calibrated to reproduce the primary flexion-extension axis that governs sagittal plane motion during the majority of functional activities encountered in daily living. The primary flexion-extension axis may serve as the rotational center around which the femur moves relative to the tibia during knee flexion and extension, creating a stable biomechanical reference that enables predictable joint motion paterns. In some cases, the single-radius arc design may provide consistent contact relationships between the femoral component and tibial insert surfaces throughout the range from zero degrees of flexion to ninety degrees of flexion, ensuring uniform load241622649582.5Atorney Docket No. 447054-000202 PATENT distribution and stable joint mechanics during weight-bearing activities. The arc radius dimensions may be specifically selected to match the anatomical characteristics of individual patient bone morphology while maintaining the geometric consistency that enables reproduction of natural rotational paterns.

[0113] The single-radius arc design may extend from zero degrees of flexion to ninety degrees of flexion, establishing a consistent geometric relationship that accommodates the primary range of knee motion encountered during most functional activities. During this range, the single-radius configuration may provide stable articulation characteristics that substitute for the anterior cruciate ligament and posterior cruciate ligament functions that may be compromised or rendered absent by total knee arthroplasty procedures. In some cases, the consistent radius may enable predictable joint mechanics that facilitate rehabilitation and functional recovery while providing the biomechanical stability needed for weight-bearing activities and normal gait paterns. The single-radius arc design may accommodate the high conformity articulation requirements of the medial compartment while maintaining geometric compatibility with the differential motion paterns that characterize natural knee function.

[0114] Beyond ninety degrees of flexion, the medial condyle and lateral condyle may transition to a continuously variable radius design that accommodates the changing biomechanical requirements associated with deep flexion activities. The continuously variable radius design may address the anatomical constraints that occur during deep flexion, where maintaining a constant radius may impede natural joint motion and limit the range of flexion that can be achieved. In some cases, the variable radius configuration may enable the posterior rollback motion that characterizes natural knee kinematics during deep flexion activities such as stair climbing, rising from seated positions, or squating movements. The transition from singleradius to variable radius geometry may occur at the ninety-degree flexion boundary, where the biomechanical demands of the joint shift from stability-focused motion to mobility-focused motion that accommodates the complex three-dimensional movements associated with deep flexion activities.

[0115] The integration of single-radius and continuously variable radius design elements may enable the femoral component to incorporate a medial pivot to stabilized concept that combines medial pivot and medial stabilized philosophies within a single prosthetic system. The medial pivot to stabilized concept may provide high conformity and constraint characteristics during the single-radius range from about zero to about ninety degrees of flexion, similar to medial pivot designs that prioritize joint stability and anterior-posterior control. In some cases, the251622649582.5Atorney Docket No. 447054-000202 PATENT transition to continuously variable radius geometry beyond ninety degrees of flexion may enable controlled mobility characteristics similar to medial stabilized designs that prioritize range of motion and natural rollback paterns during deep flexion activities. The medial pivot to stabilized concept may address the limitations of purely medial pivot or purely medial stabilized designs by combining their respective advantages within different phases of the flexion cycle.

[0116] The medial pivot to stabilized concept may enable the femoral component to provide stability when needed during weight-bearing and functional activities while allowing natural rollback motion during deep flexion movements that require greater joint mobility. During the single-radius phase from about zero to ninety degrees of flexion, the medial compartment may function as a stable pivot point that provides anterior-posterior constraint and rotational stability, while the lateral compartment may allow controlled motion that accommodates the natural asymmetry of knee kinematics. In some cases, the transition to variable radius geometry beyond ninety degrees may enable both the medial and lateral compartments to undergo posterior translation and rotational motion that mirrors the three-dimensional movement paterns of the natural knee joint during deep flexion activities.

[0117] The femoral component may be configured to reproduce all three kinematic alignment axes through a hybrid of medial pivot and medial stabilized techniques, integrating the stability advantages of medial pivot designs with the mobility characteristics of medial stabilized designs within different phases of the flexion cycle. The hybrid approach may provide medial pivot characteristics during the primary flexion range from about zero to approximately ninety degrees, where high conformity and constraint may be beneficial for joint stability and cruciate ligament substitution. In some cases, the hybrid design may transition to medial stabilized characteristics beyond ninety degrees of flexion, where controlled mobility may be advantageous for accommodating deep flexion activities and natural rollback paterns. The medial pivot and medial stabilized techniques may be combined within a single prosthetic system that adapts its biomechanical behavior based on the flexion angle and functional demands, providing stability when needed during weight-bearing activities while enabling mobility during deep flexion movements.

[0118] The constraint characteristics and medial pivot to stabilized concept may be realized through the coordinated interaction between the convex sagital plane geometry of the femoral component and the corresponding concave geometry of the tibial insert. The femoral component's single-radius arc design from zero to ninety degrees of flexion may create a261622649582.5Atorney Docket No. 447054-000202 PATENT consistent convex surface that articulates with the high conformity concave surfaces of the tibial insert's medial compartment. In some cases, this geometric relationship may establish intimate contact between the components with a contact conformity ratio of 1 : 1 from 0° to 90°, enabling the tibial insert to provide anterior-posterior constraint and rotational stability that substitutes for deficient cruciate ligament function. This 1: 1 conformity ratio may be valuable for reproducing the anterior-posterior stability of the natural knee joint within the range where cruciate ligament substitution is required. The medial compartment's elevated lips and conformity ratio of about 1 : 1 may work in conjunction with the femoral component's consistent radius to create a stable pivot point that resists excessive translation while maintaining controlled rotational motion around the medial axis.

[0119] The transition to the medial stabilized characteristics beyond ninety degrees of flexion may be facilitated by the femoral component's shift to continuously variable radius geometry, which may alter the contact relationships with the tibial insert surfaces. As the femoral component transitions from single-radius to variable radius design, the changing convex geometry may enable greater freedom of motion within the concave surfaces of both the medial and lateral compartments of the tibial insert. In some cases, the lateral compartment's flater geometry and reduced constraint characteristics may accommodate the posterior rollback and axial rotation that occurs during deep flexion, while the medial compartment may continue to provide stability through its elevated features and conforming surfaces. This geometric coordination between the femoral component's evolving convex profile and the tibial insert's asymmetric concave design may enable the seamless transition from high constraint medial pivot behavior to controlled mobility medial stabilized behavior, creating a unified system that adapts its biomechanical characteristics based on the flexion angle and functional demands of the joint.

[0120] In a total knee arthroplasty, a tibial insert component may also be implanted. The tibial insert component for a knee prosthesis optimized for kinematic alignment surgical techniques may incorporate asymmetric design characteristics that address the loading paterns and motion requirements associated with kinematic alignment implant placement. The tibial insert component may feature differential conformity ratios and geometric configurations between the medial and lateral compartments that accommodate the unique biomechanical demands encountered when femoral components are positioned in valgus alignment up to about six degrees. In some cases, the tibial insert component may be specifically engineered to work in coordination with the femoral component to reproduce the complex three-dimensional motion271622649582.5Atorney Docket No. 447054-000202 PATENT paterns that characterize natural knee kinematics while providing the stability and load distribution characteristics needed for long-term implant performance. The asymmetric design approach may enable the tibial insert component to accommodate the differential motion paterns between the medial and lateral compartments, where the medial compartment functions as a stable pivot point while the lateral compartment undergoes posterior translation and axial rotation during functional activities.

[0121] The medial compartment may incorporate a contact surface with a conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in a coronal plane, providing high conformity articulation characteristics that enhance joint stability and load distribution across the medial aspect of the knee joint. The conformity ratio of about 1: 1.04 may create intimate contact relationships between the femoral component and the tibial insert surfaces, enabling uniform stress distribution and reducing localized pressure concentrations that could contribute to polyethylene wear or mechanical failure over time. In some cases, the medial compartment contact surface may alternatively incorporate a conformity ratio of about 1: 1, providing even higher conformity characteristics that may be suitable for specific patient populations or surgical scenarios where maximum constraint and stability may be desired. The high conformity design of the medial compartment may substitute for the anterior cruciate ligament and posterior cruciate ligament function that may be compromised or absent following total knee arthroplasty procedures, providing anterior-posterior constraint and rotational stability throughout the primary range of knee motion.

[0122] The medial compartment may include elevated lips along a medial edge and an intercondylar eminence region, creating structural features that enhance the constraint characteristics and provide mechanical boundaries that guide joint motion during functional activities. The elevated lips along the medial edge may extend upward from the base surface of the tibial insert component, creating raised barriers that prevent excessive medial translation of the femoral component during loading activities and joint motion. In some cases, the elevated lips may be contoured to match the curvature of the corresponding femoral component surfaces, ensuring intimate contact relationships that maximize load distribution while providing the mechanical constraint needed to maintain joint stability. The intercondylar eminence region may incorporate elevated features that interact with the intercondylar notch of the femoral component, providing additional constraint in the anterior-posterior direction and contributing to the overall stability characteristics of the medial compartment articulation.281622649582.5Atorney Docket No. 447054-000202 PATENT

[0123] The elevated lips may be configured to enhance mediolateral stability during oblique joint line loading, addressing the complex loading paterns that occur when the knee joint experiences forces that are not aligned with the primary anatomical axes. Oblique joint line loading may occur during activities such as cuting movements, pivoting maneuvers, or uneven terrain navigation, where the knee joint experiences combined loading in multiple directions simultaneously. In some cases, the elevated lips may provide mechanical resistance to lateral displacement of the femoral component, ensuring that the j oint maintains proper alignment and load distribution even when subjected to complex loading scenarios that could otherwise compromise joint stability. The mediolateral stability enhancement provided by the elevated lips may be particularly beneficial in kinematic alignment applications, where the valgus positioning of the femoral component may create altered loading paterns compared to conventional mechanical alignment approaches.

[0124] The lateral compartment may incorporate a contact surface with an identical conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in the coronal plane, providing symmetric conformity characteristics between the medial and lateral compartments that enable balanced load distribution across the joint interface. The identical conformity ratio may ensure that both compartments provide similar contact area characteristics and stress distribution paterns, preventing preferential loading of one compartment over the other during weight-bearing activities. In some cases, the lateral compartment may alternatively incorporate a low-conformity design with a conformity ratio of about 1: 1.3, providing reduced constraint characteristics that may be suitable for applications where greater freedom of motion may be desired in the lateral compartment. The lateral compartment contact surface configuration may accommodate the posterior translation and axial rotation that characterizes natural lateral compartment kinematics while maintaining adequate contact relationships for load transmission and joint stability.

[0125] The lateral compartment may include an elevated lateral lip configured to absorb stress from lateral femoral shift while maintaining uniform load distribution across the contact interface. The elevated lateral lip may extend upward from the lateral edge of the tibial insert component, creating a raised barrier that provides mechanical resistance to excessive lateral displacement of the femoral component during functional activities. In some cases, the elevated lateral lip may be specifically contoured to accommodate the valgus positioning angles that characterize kinematic alignment implant placement, ensuring that the lip provides adequate constraint without creating mechanical interference or impingement during normal joint291622649582.5Atorney Docket No. 447054-000202 PATENT motion. The stress absorption characteristics of the elevated lateral lip may help prevent localized pressure concentrations that could contribute to polyethylene wear or mechanical failure, while the uniform load distribution may enhance the long-term durability of the tibial insert component.

[0126] The lateral compartment may be further configured to allow posterior translation and axial rotation of a lateral femoral condyle, accommodating the complex three-dimensional motion paterns that characterize natural lateral compartment kinematics during functional activities. The posterior translation capability may enable the lateral femoral condyle to move posteriorly relative to the tibial surface during knee flexion, reproducing the rollback motion that occurs naturally during activities such as stair climbing, rising from seated positions, or deep flexion movements. In some cases, the axial rotation capability may allow the lateral femoral condyle to undergo internal and external rotation around the medial pivot point, enabling the screw-home mechanism and rotational paterns that define natural knee kinematics during various functional activities. The combination of posterior translation and axial rotation capabilities may enable the lateral compartment to accommodate the asymmetric motion paterns that characterize the kinematic alignment third axis motion while maintaining adequate contact relationships for load transmission and joint stability.

[0127] The elevated lips of the medial compartment may be configured to enhance lateral stability and reduce polyethylene wear through uniform load distribution across the contact surfaces. The lateral stability enhancement may prevent excessive side-to-side motion of the femoral component during functional activities, maintaining proper joint alignment and reducing the risk of instability or dislocation. In some cases, the uniform load distribution provided by the elevated lips may reduce stress concentrations that could contribute to accelerated polyethylene wear, potentially extending the service life of the tibial insert component and reducing the likelihood of revision surgery due to wear-related complications. Polyethylene wear reduction may be particularly beneficial in kinematic alignment applications, where the altered loading paterns associated with valgus positioning of the femur and varus positioning of the tibia may create different stress distribution characteristics compared to conventional mechanical alignment approaches. The varus alignment of the tibia, the weight-bearing side, may present a significant challenge in kinematic alignment. As a result, the uniform load distribution provided by the elevated lips may be especially beneficial for maintaining implant longevity and performance.301622649582.5Atorney Docket No. 447054-000202 PATENT

[0128] While various illustrative embodiments incorporating the principles of the present teachings have been disclosed, the present teachings are not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the present teachings and use its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which these teachings pertain.

[0129] In the above detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the present disclosure are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject mater presented herein. It will be readily understood that various features of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0130] The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various features. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions . It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0131] Various of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.311622649582.5

Claims

Atorney Docket No. 447054-000202 PATENTCLAIMSWhat Is Claimed Is:

1. A femoral component for a knee prosthesis optimized for kinematic alignment surgical technique, comprising: an anterior flange having a length ranging from about 40 mm to about 60 mm measured from a distal femoral reference point to an apex of the anterior flange; a lateral flange defining a lateral flange angle ranging from about 8 degrees to about 11 degrees, wherein the lateral flange angle is measured between a line extending along the lateral flange and a line perpendicular to a reference line that connects farthest distal points of a medial condyle and a lateral condyle; and a trochlear groove formed in the anterior flange, the trochlear groove having a width that remains substantially constant from about 0 degrees of extension to about 30 degrees of flexion with a tapering angle ranging from about 1 degree to about 12 degrees.

2. The femoral component of claim 1, wherein the trochlear groove has a trochlear groove angle ranging from about 12.1 degrees to about 18.1 degrees.

3. The femoral component of claim 1, wherein the medial condyle and the lateral condyle have a single-radius arc design with an arc radius ranging from about 20 mm to about 40 mm corresponding to femoral component size.

4. The femoral component of claim 3, wherein the single-radius arc design extends from about 0 degrees of flexion to about 90 degrees of flexion, and the medial condyle and the lateral condyle have a continuously variable radius design at degrees of flexion greater than about 90 degrees of flexion.

5. The femoral component of claim 1, wherein the medial condyle and the lateral condyle are configured to reproduce kinematic alignment third axis motion through differential articulation with a tibial insert, the medial condyle providing high conformity articulation and the lateral condyle providing low conformity articulation to allow axial rotation around a medial pivot point.321622649582.5Atorney Docket No. 447054-000202 PATENT6. The femoral component of claim 1, wherein the femoral component has anteroposterior and mediolateral dimensions configured to prioritize cortical bone coverage for reproduction of a kinematic alignment axis, the femoral component having an anteroposterior to mediolateral aspect ratio within a range of about 0.93 to about 0.98.

7. The femoral component of claim 1, further comprising a chamfered lateral margin extending from distal to posterior condylar regions, wherein the chamfered lateral margin prevents overhang beyond an arc defined by an intercondylar midpoint as a center of rotation under valgus placement up to about 6 degrees.

8. The femoral component of claim 7, wherein the chamfered lateral margin reduces soft tissue irritation during kinematic alignment surgical placement.

9. The femoral component of claim 1, wherein the femoral component is configured to reproduce all three kinematic alignment axes through a hybrid of medial pivot and medial stabilized techniques.

10. The femoral component of claim 1, wherein: the medial condyle is configured to transition from high conformity articulation to controlled mobility at about 90 degrees of flexion; and the lateral condyle is configured to provide substantially unrestricted mobility throughout range of motion.

11. A tibial insert component for a knee prosthesis optimized for kinematic alignment surgical technique, comprising: a medial compartment having a contact surface with a conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in a coronal plane, the medial compartment including elevated lips along a medial edge and an intercondylar eminence region, wherein the elevated lips are configured to enhance mediolateral stability during oblique joint line loading; and a lateral compartment having a contact surface with an identical conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in the coronal plane, wherein the lateral compartment includes an elevated lateral lip configured to absorb stress331622649582.5Atorney Docket No. 447054-000202 PATENT from lateral femoral shift while maintaining uniform load distribution, and wherein the lateral compartment is further configured to allow posterior translation and axial rotation of a lateral femoral condyle.

12. The tibial insert component of claim 11, wherein the medial compartment has a contact surface that provides full surface contact with a corresponding single-radius femoral component from about 0 degrees to about 90 degrees of flexion.

13. The tibial insert component of claim 11, wherein the medial compartment includes an elevated anterior slope and an elevated posterior slope configured to substitute for deficient anterior cruciate ligament and posterior cruciate ligament function.

14. The tibial insert component of claim 11, wherein the lateral compartment has a flat insert geometry with an anterior slope configured to accommodate internal rotation up to about 10 degrees in full extension.

15. The tibial insert component of claim 11, wherein the lateral compartment has a flat posterior portion without a posterior lip and includes a rounded chamfered posterior edge to prevent edge loading during extreme motion.

16. The tibial insert component of claim 11, wherein the elevated lips of the medial compartment are configured to enhance lateral stability and reduce polyethylene wear through uniform load distribution.

17. The tibial insert component of claim 11, wherein the flat posterior portion of the lateral compartment is configured to enable posterior translation and axial rotation of a lateral femoral condyle without constraint while preventing localized wear.

18. A knee prosthesis system optimized for kinematic alignment surgical technique, comprising: a femoral component having: an anterior flange with a length ranging from about 40 mm to about 60 mm measured from a distal femoral reference point to an apex of the anterior flange;341622649582.5Atorney Docket No. 447054-000202 PATENT a lateral flange defining a lateral flange angle ranging from about 8 degrees to about 11 degrees, wherein the lateral flange angle is measured between a line extending along the lateral flange and a line perpendicular to a reference line that connects farthest distal points of medial and lateral condyles; a trochlear groove formed in the anterior flange, the trochlear groove having a width that remains substantially constant from about 0 degrees of flexion to about 30 degrees of flexion with a tapering angle ranging from about 1 degree to about 12 degrees; and a tibial insert component having: a medial compartment with a contact surface having a conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in a coronal plane, the medial compartment including elevated lips along a medial edge and an intercondylar eminence region, wherein the elevated lips are configured to enhance mediolateral stability during oblique joint line loading; and a lateral compartment with a contact surface having an identical conformity ratio of about 1: 1.04 relative to a corresponding femoral component surface in the coronal plane, wherein the lateral compartment includes an elevated lateral lip configured to absorb stress from lateral femoral shift while maintaining uniform load distribution, and wherein the lateral compartment is further configured to allow posterior translation and axial rotation of a lateral femoral condyle.

19. The knee prosthesis system of claim 18, wherein the femoral component and the tibial insert component are configured to work in combination to reproduce a primary flexionextension axis, a secondary patellofemoral axis, and a third axial rotation axis, wherein the medial and lateral condyles comprise a single-radius arc design configured to reproduce the primary flexion-extension axis, wherein the trochlear groove is configured to reproduce the secondary patellofemoral axis, and wherein a differential between the medial compartment and the lateral compartment is configured to reproduce the third axial rotation axis.

20. The knee prosthesis system of claim 18, wherein an anteroposterior to mediolateral aspect ratio of the femoral component and the identical conformity ratio are coordinated to provide balanced load distribution across a joint interface.351622649582.5

Images