Implantable artificial knee joint with an integrated artificial joint extensor mechanism

Abstract

An implantable knee prosthesis comprising a femoral stem component, a tibial stem component, and a hinged joint having at least one hinge pivot point and a limited axis of rotation, the implantable knee prosthesis having a prosthetic extensor system configured to simulate the natural movement levels of a patient with an impaired extensor system.

Description

Technical Field

[0001] Cross - Reference to Related Applications The disclosure of this application is based on the disclosure of U.S. Provisional Patent Application Serial No. 62 / 983,560, entitled Implantable Prosthetic Knee Joint with Integrated Extensor Mechanism, filed on February 28, 2020, the entire contents of which are incorporated herein by reference. The disclosure of this application is related to the disclosure of U.S. Provisional Patent Application Serial No. 63 / 049,612, entitled Implantable Prosthetic Knee Joint with Integrated Extensor Mechanism, filed on July 8, 2020, the entire contents of which are incorporated herein by reference.

[0002] Description of Research and Development Sponsored by the Federal Government Not applicable.

[0003] Reference to Appendices Not applicable.

[0004] Technical Field The present invention relates to an implantable total artificial knee joint for patients with a damaged or absent extensor mechanism.

Background Art

[0005] Conventional knee joint replacements, for example, total knee arthroplasty, require an extensile system that, for the purposes of the present disclosure, refers to the muscles, tendons, ligaments, and patella that provide stability to the knee joint and enable a person to extend the knee. In the case of a person who requires a total knee arthroplasty but whose extensile system is not functioning, the most common options are either above-knee amputation with osseointegration or socket technology using an external artificial knee joint, or total fixation (in situ or ex situ) of the knee joint. Either procedure can lead to a decrease in quality of life. However, in the United States, more than 150,000 leg amputations are performed each year. Above-knee (transfemoral) amputations are less frequent than below-knee (tibial) amputations, but above-knee amputations result in the highest levels of functional and disability impairment.

[0006] It is known that the design and configuration of an artificial knee joint determine the degree of voluntary control required of the amputee at various stages of the walking cycle. The primary requirement in knee joint replacement is to design a prosthesis that enables the amputee to walk comfortably and safely without excessive mental or physical effort. During one walking cycle, each leg undergoes a stance phase and one swing phase. The stance phase begins when the heel touches (or strikes) the floor. Subsequently, the sole of the foot contacts the ground. Next, the body weight swings directly over the supporting leg and continues to rotate over the foot (mid-stance). As the mass of the body above the ankle continues to rotate forward, the heel lifts off the ground. After the heel has lifted, the body is moved forward by the gastrocnemius muscle. The cycle ends when the entire foot has risen off the ground. During level walking, a normal human knee rotates through a range of approximately 70° from a position of full extension (0°) at initial and mid-stance to 70° of flexion immediately after toe-off. The artificial knee should enable flexion while compensating for the lack of muscular control regarding both stability and swing control. Therefore, when designing an artificial knee joint, it is desirable to approximate the natural knee joint position and movement as closely as possible.

[0007] The knee joint has two basic movements: flexion and extension in the sagittal plane and internal and external rotation about the vertical axis. The cartilage, meniscus, ligaments, and muscles around the knee respond to substantial stresses during daily activities. If the natural soft tissue stability of the knee is compromised or absent, there is increased laxity in flexion and extension, and a flexion gap imbalance may occur. Therefore, an artificial knee joint should approximate as faithfully as possible the laxity and stability of a normal knee joint.

[0008] To minimize or prevent uncontrolled movement during the swing phase of an external artificial knee joint, a braking device, such as an adjustable braking device, may be provided to bias, adjust, or attenuate to some extent the action of inertial forces during the swing phase. For example, the brake may be continuously engaged and disengaged during the swing phase of walking. SUMMARY OF THE INVENTION

[0009] The present invention is directed to an implantable total artificial knee joint for use in patients who would otherwise require above-knee amputation or total knee immobilization.

[0010] The following drawings form a part of this specification and are included to demonstrate further specific aspects of the present invention. The present invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein. However, neither the detailed description nor the drawings are intended to limit or are provided for the purpose of limiting the scope of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011]

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[0012] The invention disclosed in this specification can have various modifications and alternative forms. However, only some specific embodiments are shown in the drawings as examples and will be described in detail below. The drawings and detailed descriptions of these specific embodiments are not intended to limit the width or scope of the inventive concept or the appended claims in any way. Rather, the drawings and detailed descriptions are provided to illustrate the inventive concept to those skilled in the art and enable those skilled in the art to make and use the inventive concept.

[0013] The above drawings and the following description of specific structures and functions are not presented to limit the scope of the invention or the scope of the claims filed. Rather, the drawings and the description herein are provided to teach those skilled in the art how to make and use the present invention for which patent protection is sought. Those skilled in the art will appreciate that not all features of all commercial embodiments of the present invention are described or shown for clarity and understanding. Those skilled in the art will also appreciate that developing actual commercial embodiments incorporating aspects of the present invention will require many implementation-specific decisions to achieve the ultimate goals of the developers of the commercial embodiments. Such implementation-specific decisions may include, but are not limited to, compliance with system-related, business-related, government-related, and other constraints, and may vary depending on the particular implementation, location, and time. The efforts of the developers may be complex and time-consuming in an absolute sense, but nevertheless, such efforts are routine for those skilled in the art who benefit from this disclosure. It should be understood that the invention disclosed and taught herein is capable of many different modifications and alternative forms. Finally, the use of singular terms such as "a" is not intended to limit the number of items, and the use of relational terms such as "upper", "lower", "left", "right", "above", "below", "under", "over", "sideways", etc. is used to clarify with specific reference to the drawings in the description herein and is not intended to limit the scope of the present invention or the appended claims.

[0014] Aspects of the invention disclosed herein may be embodied as an apparatus, system, method, or computer program product. Accordingly, a particular embodiment may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software aspects and hardware aspects in the form of, for example, "circuits", "modules", or "systems". Further, embodiments of the present invention may take the form of a computer program product embodied in one or more computer-readable storage media having computer-readable program code thereon.

[0015] Items, components, functions, or structures in this disclosure may be described or labeled as one or more "modules". For example, but not limited to, a module may be configured as a hardware circuit including off-the-shelf semiconductors such as custom VLSI circuits or gate arrays, logic chips, transistors, or other individual components. A module may also be implemented as a programmable hardware device such as a field-programmable gate array, programmable array logic, programmable logic device, etc. A module may also be configured as software for execution on various types of processors. A module of executable code may include one or more physical or logical blocks of computer instructions that can be compiled as objects, procedures, or functions. The executable files of a module need not be physically placed together, but may include heterogeneous instructions stored in different locations that, when logically combined, constitute the module and achieve a specified purpose or function. A module of executable code may be a single instruction or a number of instructions and may be distributed across several different code segments, between different programs, and across several memory devices. Similarly, data is herein identified and exemplified within a module, may be embodied in any suitable form, and may be compiled within any suitable type of data structure. The data may be collected as a single data set or may be distributed across different locations including different storage devices and may exist, at least in part, simply as electrical signals on a system or network. When a module or a part of a module is implemented in software, the software portion may be stored on one or more computer-readable storage media.

[0016] Throughout this disclosure, references to "one embodiment," "an embodiment," or similar terms mean that the particular feature, structure, or characteristic described in connection with that embodiment is included in at least one of the many possible embodiments of the invention. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to" unless specifically stated otherwise. A listed list of items does not mean that any or all of the items are mutually exclusive and / or mutually inclusive unless specifically stated otherwise. Unless specifically stated otherwise, the terms "a," "an," and "the" also refer to "one or more."

[0017] Furthermore, the described features, structures, or characteristics of one embodiment can be combined with one or more other embodiments in any suitable way. In the following description, numerous specific details are provided in order to provide a thorough understanding of the embodiments of the present disclosure, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc. Those skilled in the art who enjoy the benefits of the present disclosure will understand that the invention can be practiced without one or more of the specific details, or in other ways, components, materials, etc. In other cases, well-known structures, materials, or operations are not illustrated or described in detail to avoid obscuring aspects of the present disclosure.

[0018] The description of the elements in each figure may refer to the elements of the previous drawing. Like numbers refer to like elements in all drawings including alternative embodiments of like elements. In some possible embodiments, the functions / operations / structures shown in the figures may be different from the order shown in the block diagrams and / or operation diagrams. For example, two operations shown as occurring in sequence may actually be executed substantially simultaneously, depending on the relevant functions / operations / structures, or the operations may be executed in the reverse order.

[0019] Generally, the present invention relates to an implantable total artificial knee joint for an individual whose extensor system is impaired or non-functional. For example, without limitation, the artificial joint of the present invention may or may not include an integrated extensor mechanism configured to provide one or more biasing forces to the joint to simulate or approximate normal knee function (e.g., extension) levels, and may include a modified conventional outside partial artificial knee joint. The artificial joint of the present invention may also include an integrated braking mechanism configured to provide one or more constant or variable forces to the joint to simulate or approximate normal knee function levels. Above-knee amputees using socket artificial joints or osseointegration artificial joints may have additional mechanical, hydraulic, or electronic braking and / or extension devices to compensate for a non-functional or absent extensor system. It will be understood that an individual who has received a conventional knee joint replacement with an impaired extensor system cannot walk without fear of falling and cannot ascend steps or stairs. In contrast, the implantable artificial knee joint of the present invention having an integral or integrated extensor mechanism improves a person's ability to walk without fear of knee flexion and / or even ascend stairs, thereby potentially obviating the need for above-knee amputation or arthrodesis.

[0020] Although the present invention is disclosed with respect to the knee joint, it will be understood that the present invention is applicable to other joints, such as the ankle joint, for example.

[0021] Figures 1 and 2 illustrate the components of a typical human knee joint. These drawings illustrate the femur 102, tibia 104, fibula 106, and patella 202. Figure 2 illustrates the patellar ligament 204, quadriceps tendon 206, and patellar retinaculum 208. It is understood that the extensor mechanism of the knee consists of the quadriceps muscle 210, quadriceps tendon 206, patella 202, patellar ligament 204, patellar retinaculum (medial and lateral), and adjacent soft tissues.

[0022] Figure 3 illustrates an implanted total knee system 300 having a knee joint 302 with an integrated artificial joint extensor mechanism according to the teachings of the present invention. The artificial joint system 300 replaces the end of the femur 102, the upper portion of the tibia 104, or both when the bones 102, 104 have been severely damaged by infection, fracture, or tumor, for example, during a total knee arthroplasty for tumor. The integrated artificial joint extensor mechanism (not shown) makes it possible to avoid cutting or immobilizing the knee joint of an individual whose extensor mechanism is damaged or non-functional, and enhances the ability to walk and / or even to ascend or descend steps and stairs.

[0023] As will be described below, the artificial joint extensor mechanism useful in all of the disclosed embodiments may include a biasing mechanism configured to apply a constant force, a varying force, and / or an adjustable force to one or more components of the artificial joint 302 to bias the joint 302 to an extended position. Suitable biasing mechanisms include coil springs, wafer springs, hydraulic cylinders, pneumatic cylinders, magnets, and linear motors.

[0024] In addition to or instead of the artificial joint extensor mechanism, the artificial knee joint 302 may include a brake or resistance mechanism configured to slow or inhibit the movement (flexion) speed or range of the joint 302. Suitable resistance mechanisms include cam surfaces, interference fit surfaces, magnets, coil springs, wafer springs, hydraulic cylinders, pneumatic cylinders, magnets, and linear motors. It will be understood that the biasing mechanism can also function as a resistance mechanism and vice versa.

[0025] In an exemplary artificial knee system 300, the system 300 has an integral or modular intercondylar femoral stem 304 and an integral or modular intercondylar tibial stem 306. In an artificial joint system having an integral stem, implantation may require disassembly of the joint 302. Alternatively, during implantation, the human knee joint may be hyperextended and the entire artificial joint system 300 may be implanted with the integral stem without disassembling the joint 302. In an artificial joint system 300 having one or more modular stems, the stems are implanted and then the joint 302 is coupled to the one or more modular stems 304, 306.

[0026] FIG. 4 illustrates another embodiment of the present invention that does not require substantial (e.g., about 5 cm or more) removal of bone from the femur 102 or tibia 104 and can thus be used in individuals who have not lost a significant amount of bone due to severe irreparable fractures, infections, or tumors. Most of the artificial joint system 400 illustrated in FIG. 4 is instead received within the bone at the end of the femur 408 and / or the upper portion of the tibia 410. As illustrated, the femoral component 404 of the artificial joint 402 is substantially received within the condyle, and the tibial component 406 of the artificial joint 402 is substantially received within the condyle.

[0027] Joints 302, 402 suitable for use in the present invention include, but are not limited to, a unicentric (single) axis joint that operates as a simple hinge, a polycentric (multi) axis joint having multiple pivot points, a manual friction joint that uses a "brake" to vary resistance to flexion, a constant friction joint that relies on a constant pressure to a surface such as a rotating surface to resist knee flexion, a variable friction joint that uses a fluid control system to control resistance to knee bending, a pneumatic fluid control joint that varies resistance to flexion, a hydraulic fluid control joint configured to control the speed of the knee, a lock joint that can be locked to simulate a fixed knee joint, a posture control joint actuated by body weight, and a computerized or "smart" joint.

[0028] Those skilled in the art having the benefit of this disclosure will appreciate that the present invention may be adapted for use as the joints 302, 402 of the present invention. external It will be appreciated that there are prosthetic knee systems on the market that are configured for use (i.e., not implanted). For example, and without limitation, Ottobock manufactures an above-knee joint that includes a microprocessor-based system known as the C-Leg. One or more of these external joints may form the basic joint used as part of the present invention. Those skilled in the art will appreciate that there are other external prosthetic knees that are suitable for use with the present invention.

[0029] FIG. 5 is a diagram showing the configuration of the present invention. implantable 5 illustrates another of many possible embodiments of a prosthetic knee system 500. The knee joint 502 includes, but is not limited to, a modified polycentric knee joint having two offset hinge points 504 and 506 and a shock pad 508. implantable 5 represents a knee joint. As is known, the pad 508 may be manufactured from a biocompatible, wear-resistant material such as ultra-high molecular weight polyethylene (UHWMPE). implantable Although a total knee joint is illustrated, most implantable It will be appreciated that a total knee replacement may be used.

[0030] The knee joint 502 preferably includes a rotation system configured to allow some rotation about an axis substantially perpendicular to the hinge axis 504 or 506 or substantially parallel to a perpendicular axis. For example, and without limitation, the knee joint 502 may include rotational surfaces 510a and 510b, such as spherical mating surfaces, that allow relative rotation between the knee joint 502 and, for example, a tibial stem 512. Either or both of the surfaces 510a or 510b preferably include a wear-resistant surface, such as UHMWPE, with sufficient lubricity to allow a normal rotational feel under load. Although the rotation point or area is preferably associated with the knee joint 502 below the impact pad 508, it will be understood that the rotation point may also be associated with the knee joint 502 at or above the hinge point 504 or 506.

[0031] The rotational system preferably includes, but is not limited to, one or more structures such as a stop configured to limit the relative amount of rotation. For example, the knee joint 502 illustrated in FIG. 5 includes a projection 514 that extends downwardly into the tibial stem 512. The projection 514 may include one or more ears, lugs, or recesses 516 that cooperate with the tibial stem 512 to limit the amount of rotation to, for example, about ±15 degrees. Structures that may be provided to limit the amount or type of movement may be configured to be generally applicable to most patients. By way of non-limiting example, the rotation of the tibia within the implantable artificial knee system of the present invention may be configured to limit its movement to a standard expected of 95 percent of healthy adults. For the purposes of the present invention disclosed herein, other implantable rotational systems are contemplated. Further, external rotary hinge artificial knee joints may be used in conjunction with the present invention. In some embodiments, the resistance to rotation may increase as the amount of rotation increases. Cam surfaces or interference surfaces may be used to produce various amounts of resistance.

[0032] As disclosed elsewhere herein and incorporated for all purposes of this particular embodiment, these rotational problems can be addressed by adjusting the structures that provide stops, limits, and biasing, either before or after implantation. Alternatively, these problems can be addressed beforehand by evaluating the current range of motion and extension of the candidate for arthroplasty. The measured ranges and limits can be configured by initially adjusting or manufacturing to specified tolerances and / or functions.

[0033] The applicant contemplates further embodiments that utilize the features of a "smart" or microprocessor-based artificial joint system. In one of many possible embodiments that may be envisioned by those benefiting from the present disclosure, a "smart" joint may be configured to communicate with wearable sensors such as accelerometers, position sensors, angular sensors, pressure sensors, and / or load sensors to self-regulate the range, limits, and / or function of one or more implanted artificial joints in a particular person and / or particular situation.

[0034] In one non-limiting embodiment illustrated in FIG. 6A, the “smart” artificial knee system 602 can receive input from wearable sensors such as one or more sensors in a person's belt 604a, clothing 604b, shoes 604c, 604d, etc., to set the scope and limits of the system 602. These clothing items have the advantage of being normally worn in a particular position relative to the knee for a particular activity. Placing the sensors on the belt, shoes, and / or clothing is also much less burdensome than wearing sensors that need to be applied to specific locations on the body, such as the opposite knee. However, the invention disclosed herein can utilize sensors removably or permanently attached to the body.

[0035] In this envisioned embodiment, the sensor in the belt 604a can relay a pressure change, such as a contraction of the erector spinae or gluteal muscles that can be a precursor to the swing phase step, when the shoe sensor identifies that the leg is fully extended, for example, when the ipsilateral shoe is at its maximum distance under the “smart” knee 602 and the contralateral shoe is appropriately close when the posture is normal. Small pressure changes detected along the belt can indicate that the wearer is preparing to take a small or normal step. However, larger detected pressure changes can indicate that the wearer is preparing to jump or lunge. The “smart” knee 602 can then process these signals and instantaneously adjust its limits and range in anticipation of this activity.

[0036] In another embodiment, the set of sensors may indicate that shoes 604c, 604d are approaching belt 604a. When belt 604a is substantially vertically above the shoe, the "smart" knee 602 may anticipate that the wearer is squatting or perhaps preparing to sit. However, when the belt is offset from the shoe, the wearer may be anticipated to be preparing to bend the knee. An algorithm can be implemented in the artificial knee 602 to temporarily adjust the friction, resistance, or biasing force for the anticipated movement. Appropriate adjustment of the range, limits, and even biasing of the "smart" knee can be made for these interpreted sensor inputs.

[0037] In yet another envisioned embodiment, the pressure on the front and back of the soles 604c, 604d of the feet related to the distance between the feet may indicate that the wearer is walking or running. A large pressure difference and a long stride length indicate running, which may require a greater extension biasing force than a normal walking stride. Similarly, sensing a lack of sole pressure 604d on one shoe while simultaneously sensing an increase in height may indicate that the wearer needs to make adjustments to climb an inclined or flat step.

[0038] The examples given here relate to sensors in the belt and shoes associated with an artificial knee, but the applicant envisions embodiments with other sensors worn or disposed on the body and used in connection with other implantable extensor joints. Without limitation, these may include appropriate sensors in a wristwatch 612, ring 616, bracelet 612, necklace, piercings, and any other device wearable on the body. Sensors that depend on the distance from the "smart" extensor joint should maintain a relatively stable position with respect to the body or one or more joints that support it. Embodiments of the invention described herein may include, without limitation, sensors that monitor and relay other information such as temperature, gaze direction, respiration, heart rate, etc. (all of which can be used as indicators of future movements that require joint extension).

[0039] The "smart" joint 602 can communicate with nearby sensors through means known to those skilled in the art. These communication paths can include, but are not limited to, near-field communication (NFC) networks, Bluetooth including Bluetooth low energy (BLE), and several other radio frequency paths.

[0040] The applicant assumes that some people may have multiple "smart" joints 602, 614, and that it may be beneficial for the "smart" joints to communicate with each other. As an example, without limitation, the first "smart" knee 502 can function in cooperation with the second smart knee 614. One or more sensors incorporated in the first and second artificial knees can enable each smart knee to monitor the activity (including inactivity) of the other knee for use in a motion algorithm to produce a desired amount of function (e.g., resistance to flexion). As another method, external sensors may be worn adjacent to each knee in clothing such as pants.

[0041] As another example, without limitation, the first "smart" knee 602 can function in cooperation with the ipsilateral "smart" ankle (not shown). In one of many envisioned embodiments, the "smart" joints can adjust their activities. These activities can include, but are not limited to, self-adjustment to reproduce normal and / or expected movements such as walking, climbing, reclining, stretching, and all other movements that people may perform. As a practical example, setting appropriate biasing, range of motion, and extension for the "smart" joint when climbing stairs. In this case, the "smart" ankle can assist in tilting the front of the foot when the "smart" knee moves upward.

[0042] "Smart" joints can communicate with each other in a manner similar to how sensors communicate. However, this may require propagating radio frequency signals from a transmitter inside the body to a receiver also inside the body, which may not be efficient. The applicant assumes that other communication means may be developed in addition to the methods described herein and other methods known to those skilled in the art. Some examples may include, but are not limited to, conductive media such as one or more wires that can be inserted subcutaneously to facilitate such communication.

[0043] These "smart" joints can also receive configuration commands from an external device and transmit data to an external device. In one of many non-limiting assumed embodiments, a person with a "smart" knee can link the "smart" knee to their mobile phone 616 or other similar device using known wireless communication and / or telemetry protocols. The mobile phone 616 or other device can utilize application software designed and configured to interface with the smart knee. For example, a patient can "program" the smart knee to a desired functional level before starting to jog or walk briskly. Similarly, during jogging or walking, the patient can program or reprogram the smart knee as desired.

[0044] As another example, a "smart" knee application can function in conjunction with map features to geographically identify a person's location, predict their direction and speed, and transmit configuration commands to the "smart" knee. For example, if the map features indicate that the person is approaching a steep gradient, the mobile phone can instruct the "smart" knee to set to settings appropriate for climbing ranges, limits, and biases. The ranges, limits, and biases can be maintained there until the map features indicate that the person has moved to a different terrain.

[0045] FIG. 6B illustrates an embodiment of a control system 650 that includes a controller 652, a power system 654, and structural and / or operational components 656 within an artificial joint that can be adjusted or controlled, such as, but not limited to, an artificial joint extensor mechanism and / or an artificial joint resistance mechanism or both. The controller 652 preferably comprises a microprocessor subsystem 658 configured to execute algorithms (software), firmware, and other logical control instructions. The microprocessor subsystem 658 is configured to communicate with a communication subsystem 660 via a bus 668 or the like. The communication subsystem 660 is configured to receive data from one or more internal or external sensors as described above and communicate such data to the microprocessor subsystem 658 via the bus 668. The communication system 660 may also be configured to communicate with an external smart device that executes dedicated application software as described above. It will be understood that the communication protocol implemented and executed by the control system 652 is preferably a combination of a wired protocol and a wireless protocol. For example, without limitation, sensors inside the artificial joint can be connected to the communication subsystem 660 by wire, and sensors outside the artificial joint, such as, but not limited to, the belt sensor 604a, can communicate wirelessly.

[0046] The controller 652 may include a memory subsystem 662 configured to store artificial control and learning algorithms, firmware, and other algorithms 664, as well as sensor data and software data such as generated control instructions. The memory subsystem 662 may preferably comprise a rolling buffer 666 configured to receive raw sensor data. The algorithms executed by the microprocessor 658 can sample the sensor data in the rolling buffer 666 at regular intervals. A communication bus 667 transfers data at least between the microprocessor 658 and the memory subsystem 662.

[0047] The controller 652 and the power subsystem 654 are preferably associated integrally with an artificial joint body or envelope implanted in a human knee joint cavity. For example, the controller 652 and the power subsystem 654 can be packaged to be present in a part of the femoral stem or tibial stem, or in the artificial joint between the stems. Alternatively, the control controller 652 and / or the power subsystem 654 can be implanted at a location within the body separated from the artificial joint and operably connected to the artificial knee 656 through a wired solution. For example, without limitation, the power subsystem 654 can be in a region of the human body that allows for better access for replacement or recharge of the power subsystem 654. Additionally, the power subsystem 654 can include a transcutaneous access port 655 configured to allow for recharge of the power subsystem using a smart needle or other such device. Further, the transcutaneous port 655 can also allow for transcutaneous data transfer to the controller 602.

[0048] Regardless of where the controller 652 and the power subsystem 654 are located, the controller 652 and the power subsystem 654 can be configured to communicate data, power, and power and data to one or more of the artificial joint extensor mechanism 656 and the artificial joint resistance mechanism 656.

[0049] Figure 7 illustrates one of many algorithms or software useful in embodiments of the present invention. Referring without limitation to the embodiments described in FIGS. 6A and 6B, flowchart 702 illustrates the progression of the logic of the top-level algorithm of the smart artificial knee. Smart knees such as 602, 614 include a microprocessor or controller 750 configured to receive information or data from one or more sensors 752 through software or firmware or the like. As described above, these sensors 752 may be external to the artificial joint 766, such as but not limited to the belt sensor 604a, and / or may be internal sensors associated with the artificial joint, such as but not limited to an angular position sensor or an accelerometer. As illustrated in step 704, the controller 750 receives data from one or more of the sensors 752.

[0050] As illustrated in step 706, the controller 750 may also be configured to receive data from an external smart device that executes a dedicated software application associated with the artificial joint 766 through software or firmware or the like. For example, without limitation, the external smart device may include a smartphone 616.

[0051] As illustrated in step 708, the data, whether sensor data, application data, or both, can be analyzed or processed by the artificial joint control algorithm 756, which may or may not include a machine learning function or an artificial intelligence learning function. It will be understood by those skilled in the art benefiting from the present disclosure that the artificial joint control algorithm 756 can be configured and implemented to adjust, modify, or control one or more structural and operational characteristics or functions of the artificial knee.

[0052] In step 710, the memory system 758 of the controller 750 can be updated with some or all of the sensor 752 data and / or status information generated by the artificial joint control algorithm and / or learning algorithm.

[0053] In step 712, the artificial joint control algorithm 756 may generate one or more control instructions 760 from the sensor data 752, the application data 754, and / or the learning data. The one or more control instructions 760 may be configured to be received by one or more adjustable or controllable structures or features of the artificial joint, such as but not limited to the artificial joint extensor mechanism and / or the artificial joint resistance mechanism.

[0054] In step 714, one or more structural 762 or operational 764 features or functions of the artificial knee 766 are adjusted, changed, or controlled using the one or more control instructions 768.

[0055] The algorithm may be configured to loop back 770 to step 708 to analyze new (e.g., temporally new) data from various data sources to determine whether further changes to the structural features 762 and / or operational features 764 of the artificial joint are required or desired. For example, but not limited to, if one or more sensor data indicate an inactive period over a predetermined period, the algorithm 756 may conclude that the patient is sleeping or resting, and the artificial joint and the controller 750 may enter a sleep or inactive mode to conserve power resources.

[0056] Returning to the description of other embodiments of the present invention, in FIG. 5 implantable artificialThe knee joint is illustrated with a femoral stem 518 and a tibial stem 512. Either or both of the stems 512, 518 may be manufactured integrally with the associated knee joint 502 components or may be separate or modular components. In the case of an integral stem, the knee joint 502 (i.e., the stem) can be implanted without assembling one or both of the hinge points 504, 506 and then the knee joint 502 can be assembled after the stem is set. Alternatively, in the case of an integral stem, the human knee joint may be able to hyperextend to accommodate implantation of the artificial joint system. It is also contemplated that one stem is integrated with the knee joint and the other stem is modular or separable. The stems 512 and 518 can be provided in various lengths and configurations for a variety of possible patients, whether modular, integral, or a combination thereof. For example, without limitation, the stems 512 and / or 518 can include press-fit stems of various diameters that are straight, grooved, and / or curved, with or without a porous region 520 joined thereto.

[0057] As previously disclosed and incorporated into this embodiment, the knee joint 502 preferably includes a biasing mechanism that can be a controllable biasing mechanism in a smart embodiment that biases the joint to an extended position. The biasing force (i.e., the force that extends the knee joint) is preferably overcome by inertia during the swing phase of walking. It will be understood that an excessive extension biasing force simulates a locked knee joint. Various extension biasing forces can be provided for various activity levels. For example, an active person may require a greater extension biasing force than a person who is prone to sitting.

[0058] In one non-limiting exemplary embodiment, a stem may be attached and a knee joint installed for an active person. As a person (such as a young person) ages, their lifestyle changes and the contralateral knee may produce a different extension biasing force than the replaced knee. In that case, the modular knee can be exchanged for one with a smaller biasing force, thereby accommodating the contralateral knee and the recipient's lifestyle.

[0059] Certain embodiments of the knee joint 502 are contemplated to have an adjustable or variable extension biasing force. For example, without limitation, after implantation, a small tool can be surgically inserted into the knee joint 502 to adjust the biasing force, such as by rotating a screw or other component within the knee joint 502. As another non-limiting example, a non-surgical example can include an external device configured to electronically link to a microprocessor or logic circuit within the knee joint 502 by means such as magnetic coupling, Bluetooth, or other short-range wireless communication protocols to adjust one or more biasing forces or adjust the operability of the extensor mechanism. For example, a linear motor may be part of the artificial knee, and a controller within the knee joint may adjust the motor, for example, to adjust the biasing force or braking force. Alternatively, an adjustable rotary orifice may be controlled or adjusted for a hydraulic or pneumatic biasing or braking system.

[0060] Each of these non-surgical examples has advantages, but a practical solution needs to prevent unexpected or accidental adjustments. For example, adjustments made through magnetic coupling should not be susceptible to accidental changes when the subject is exposed to a magnetic field that would otherwise not be perceptible. Similarly, a Bluetooth interface should not be accessible to unauthorized and / or unauthenticated interference.

[0061] Common device authentication and authorization mechanisms known to those skilled in the art can be applied to the data communication interface. As an example, a computerized or "smart" joint can be manufactured using a secret cryptographic key and one or more public keys of the manufacturer. Since it can be configured to use only encrypted communication, a person desiring to communicate with the "smart" joint needs to use a device with a key signed by the manufacturer.

[0062] Along these lines, the magnetically actuated adjustment mechanism is kept in a locked state until an authorized and / or authenticated signal is received through the data communication link. Alternatively, one of ordinary skill in the art may utilize multiple magnetic fields to lock and unlock the magnetically actuated adjustment mechanism. In one non-limiting example, a fixed magnetic field of a particular intensity oriented in one direction unlocks the mechanism and a movable magnet may be associated with the mechanism to effect adjustment. Removal of the fixed and oriented magnetic fields allows the lock to be reapplied.

[0063] The extension biasing component may include a torsion spring integrated into one or more of hinges 504, 506. For example, the torsion spring may be fixed to the outer components 522, 524 of the knee joint 502 and fixed to the lever component 526 through a spline or the like. The natural state of the spring is an extended state, and the amount of return biasing force increases as the amount of flexion increases. This may be an amount of return biasing force that increases linearly, but the applicant contemplates embodiments in which, in one of many non-limiting examples, the return biasing force is non-linear such that it reaches a maximum at the central point of the arc and maintains that force for the remainder of the arc. In this exemplary embodiment, the return to the extended state does not become stronger with an increase in the arc. Alternatively, the extension biasing component may include a hydraulic system, a pneumatic system, a magnetic system, or a mechanical system. In yet another contemplated embodiment, these extension biasing components may be combined. As described above, the natural state of the spring in which the amount of return biasing force increases with an increase in the amount of flexion may be combined with a magnetic component that cancels a portion of the return biasing force to provide a restricted or controlled return play, by way of non-limiting example.

[0064] The extension biasing component may include a brake that releasably "locks" the knee joint in an extended position but is overcome by the play forces associated with normal or active walking.

[0065] Figure 8 shows a conventional external total knee prosthesis 、 rotation according to the present inventionimplantable to do Illustrates one of many embodiments for conversion to an artificial knee joint. A spherical rotating surface 802 may be formed on, for example, a tibial stem or a femoral stem and may include a central recess 804 into which a protrusion 806 from the knee joint may extend. The protrusion 806 may include a lug 808 or alternatively a recess (not shown). The recess 804 may include two stops 810 that limit the amount of rotation of the knee joint relative to the hip or foot by interacting with the lug or recess 808. It is preferable that the load generated by the knee joint is reacted by a pad, a spherical surface, or both, rather than the protrusion 806. Those skilled in the art benefiting from the present disclosure will understand for the purposes of the present invention that conventional external other rotational systems may be implemented in the knee joint.

[0066] In an envisioned embodiment, but not limited to, the stops 810 may be adjacent to the central axis of the protrusion 806, such as within a raceway, rotatable therearound, and biased toward a particular orientation. In this envisioned embodiment, the rotation of the protrusion 806 within the rotating surface 802 does not reach a rigid fixed point but can slow down gradually as it rotates. That is, as the protrusion 806 rotates clockwise in FIG. 8, the protrusion 806 faces the left stop 810. However, rather than stopping the rotation, the resistance to further clockwise rotation from the biasing applied to the cooperating stop 810 can be gradually increased. In this example, the cooperating stop 810 can have a limit beyond which further rotation is not allowed, and thus, as the protrusion 806 rotates, the protrusion 806 gradually encounters resistance up to the stopping point.

[0067] FIG. 9 is implantable for total knee replacement in an individual who may have a damaged or absent extensor mechanism in the original position such that externalFigure 902 illustrates one embodiment of the invention in which the knee joint 902 has been modified in accordance with the teachings of the present disclosure. In this illustration, the knee joint 902 is polycentric, and the femur (not shown) can rotate within a range of motion of approximately 30 degrees, such as ±15 degrees, relative to the tibia (not shown) at the knee joint 902. Further, FIG. 9 illustrates that the femur stem 904, which may be integrated with or modular to the knee joint 902, includes a central channel 906 that can house biasing elements such as a spring having a linear or non-linear spring constant, a pneumatic piston sealed to the channel wall, and / or a hydraulic piston sealed to the channel wall. Similarly, the knee joint components 908 and 910 may include magnets configured to bias the knee joint 902 to an extended position through gravity. The breakthrough force required to overcome the attractive or repulsive force of the magnets can be designed to allow flexion during normal activities or any future activity level.

[0068] Channel 906 is illustrated as being associated with the femur stem 904, but it will be understood that channel 906 can be associated with the tibia stem 912, along with the rotational socket 914. Alternatively, the rotational socket 914 can be associated with a stem that does not house channel 906.

[0069] Alternatively or in addition, channel 906 can house one or more components of the control system 650 as described above.

[0070] The prosthetic joints 402, 502, 602, 902, and other embodiments of the invention disclosed herein may and preferably include a biosheath, cover, or encapsulation 950 that separates the movable components of the prosthetic joint from the surrounding soft tissue and vascular structures. For example, without limitation, suitable biosheaths can include silicon, silicon oxide, silicon nitride, stainless steel mesh, or other biocompatible materials. It will be understood that the biosheath, when implemented, should be flexible or deformable enough to accommodate at least the desired range of flexion and rotation and to provide the desired amount of separation, encapsulation, or protection of the movable components.

[0071] Other and further embodiments using one or more aspects of the present invention described above can be devised without departing from the spirit of the present invention. Further, various methods and method embodiments of manufacturing and assembling the system, and positional specifications, can be included in combination with each other to create variations of the disclosed methods and embodiments. References to elements in the singular may include elements in the plural and vice versa.

[0072] The order of steps can occur in various orders unless otherwise particularly limited. The various steps described herein can be combined with other steps, interrelated with the described steps, and / or divided into multiple steps. Similarly, elements are described functionally and can be embodied as separate components or combined into components with multiple functions.

[0073] The present invention has been described in connection with preferred and other embodiments, but not all embodiments of the present invention have been described. Obvious modifications and changes to the described embodiments are available to those skilled in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the present invention as contemplated by the applicant. Rather, in accordance with patent law, the applicant intends to fully protect all such modifications and improvements that fall within the equivalent scope or range of the following claims.

[0074] Finally, the appended claims and what they teach to those skilled in the art are incorporated into this disclosure for all purposes.

Claims

1. An implantable artificial knee joint, comprising an intermedullary femoral stem portion configured to be implanted in the femur, and a femoral component configured to replace at least the end portion of the femur, a tibial component comprising an intermedullary tibial stem portion configured to be implanted in the tibia associated with the femur, a flexion joint formed by operatively coupling the femoral component and the tibial component, the flexion joint having a certain range of flexion of the tibia with respect to the femur, an artificial joint extensor mechanism operatively coupled to the flexion joint and configured to bias the implanted artificial knee joint to an extended position to simulate the natural knee movement level of an individual whose extensor mechanism is impaired when the implantable artificial knee joint is implanted in the human body, comprising, wherein the artificial joint extensor mechanism includes a constant friction joint that depends on a certain pressure on the rotation surface to resist knee flexion, an artificial knee joint.

2. The artificial knee joint according to claim 1, wherein the artificial joint extensor mechanism includes one or more of a spring system, a magnet system, a hydraulic system, or a pneumatic system.

3. The artificial knee joint according to claim 1, wherein the flexion joint is configured to also allow a certain range of rotation of the tibia with respect to the femur.

4. The artificial knee joint according to claim 1, wherein the artificial joint extensor mechanism includes a flexion resistance system having at least one friction surface configured to provide an increased amount of resistance to flexion.

5. The artificial knee joint according to claim 3, further comprising a rotation resistance system having at least one friction surface configured to provide an increased amount of resistance to rotation in any direction from the central orientation.

6. The artificial knee joint according to claim 1, wherein the flexion joint is a unicondylar joint configured to operate as a simple hinge or a polycentric joint having a plurality of pivot points.

7. The artificial knee joint according to claim 1, wherein at least a part of the flexion joint is encapsulated within a bioseal.

8. The artificial knee joint according to claim 1, wherein the intercondylar femoral stem portion is removably coupled to the femoral component for the purpose of implanting the artificial knee joint.

9. The artificial knee joint according to claim 1, wherein the intercondylar tibial stem portion is removably coupled to the tibial component for the purpose of implanting the artificial knee joint.

10. The artificial knee joint according to claim 1, wherein the intercondylar femoral stem portion is integrated with the femoral component, the intercondylar tibial stem portion is integrated with the tibial component, and the flexion joint is configured to be assembled after implantation of the femoral component and the tibial component.

11. The artificial knee joint according to claim 1, wherein the intercondylar femoral stem portion is integrated with the femoral component, the intercondylar tibial stem portion is integrated with the tibial component, and the artificial knee joint is configured to be implanted without disassembling the flexion joint.

12. The artificial knee joint according to claim 1, wherein the artificial joint extensor mechanism includes a fluid cylinder configured to bias the flexion joint toward 0° flexion.

13. The artificial knee joint according to claim 12, wherein the fluid in the fluid cylinder is a liquid or a gas.

14. The artificial knee joint according to claim 13, wherein the artificial joint extensor mechanism is configured to control the flexion speed.

15. The artificial knee joint according to claim 1, wherein the artificial joint extensor mechanism includes a locking joint configured to simulate a fixed knee joint.

16. The artificial knee joint according to claim 1, wherein the flexion joint includes a posture control joint actuated by body weight.

17. An implantable artificial knee joint, comprising an intermedullary femoral stem portion configured to be implanted in the femur, and a femoral component configured to replace at least the end portion of the femur, comprising an intermedullary tibial stem portion configured to be implanted in the tibia operatively associated with the femur, and a tibial component configured to replace at least the upper portion of the tibia, a flexion joint formed by operatively coupling the femoral component and the tibial component, having a certain range of flexion of the tibia with respect to the femur, and also having a certain range of rotation between the femoral component and the tibial component, an artificial joint extensor mechanism operatively coupled to the flexion joint, configured to bias the implanted artificial knee joint to an extended position and resist flexion to simulate the natural knee movement level of an individual with a damaged extensor mechanism, and including one or more of a spring system, a magnet system, a hydraulic system, or a pneumatic system, a biosheath encapsulating the flexion joint configured to separate the movable part of the flexion joint from the surrounding tissue, comprising, wherein the artificial joint extensor mechanism includes a constant friction joint that depends on a certain pressure on the rotation surface to resist knee flexion. Artificial knee joint.

18. The artificial knee joint according to claim 17, wherein the flexion joint is a monoaxial joint configured to operate as a simple hinge, or a multi-axial joint having a plurality of pivot points.

19. The artificial knee joint according to claim 17, wherein either or both of the femoral intermedullary stem portion and the tibial intermedullary stem portion are removably coupled to the femoral component and the tibial component for the purpose of implanting the artificial knee joint.

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