Unicompartmental knee pressure sensing device and system

Abstract

The present application provides a pressure sensing device and system for a unicompartmental knee joint, belonging to the field of medical device technology. The device includes: a housing assembly, provided with a sealed receiving cavity; a flexible pressure sensing electrode layer, accommodated in the sealed receiving cavity, for detecting the pressure of the unicompartmental knee joint, and converting the pressure of the unicompartmental knee joint into a sensing capacitance signal, the flexible pressure sensing electrode layer includes a first electrode layer and a second electrode layer arranged in a stacked manner, the second electrode layer is coated with a dielectric layer on the side facing the first electrode layer, the dielectric layer is bonded to the second electrode layer on the side facing the second electrode layer, and a microstructure is formed on the dielectric layer on the side facing the first electrode layer; a signal processing module, accommodated in the sealed receiving cavity, electrically connected to the flexible pressure sensing electrode layer, for converting the sensing capacitance signal into a unicompartmental knee joint pressure value. The present application has good measurement accuracy and signal stability when used in unicompartmental knee replacement.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a pressure sensing device and system for a unicompartmental knee joint. Background Art

[0002] Unicompartmental Knee Arthroplasty (UKA) is a minimally invasive surgery (MIS) that aims to reduce pain and accelerate functional recovery by partially replacing the damaged knee joint surface. In unicompartmental knee arthroplasty, the knee prosthesis usually includes a femoral unicompartmental prosthesis, a tibial prosthesis, and a meniscus liner. The meniscus liner is located between the femoral unicompartmental prosthesis and the tibial prosthesis to stabilize the femoral unicompartmental prosthesis and prevent its displacement. It is also used to transmit the load force of the knee joint to ensure uniform load distribution, thereby maintaining the stability and functionality of the joint.

[0003] The key to this operation is to ensure that the implanted knee prosthesis is balanced in force. If the implanted knee prosthesis is not balanced in force after surgery, it will cause uneven pressure distribution of the femoral prosthesis on the gasket, which will accelerate the wear of the prosthesis, affect the surgical effect, and even require a second operation. In traditional surgery, doctors often rely on subjective judgment for the placement and size selection of meniscus pads, lacking objective measurement methods. In order to solve the above problems, a measuring tool that can accurately evaluate the positioning and size selection of meniscus pads during surgery can be used. For example, pressure sensing electrodes distributed in an array can be set on the contact surface of the femoral unicompartmental prosthesis and the tibial prosthesis to fully capture the pressure distribution characteristics in the knee joint. These sensing electrodes can provide real-time data to help doctors adjust the position and size of the meniscus pad during surgery to ensure the best mechanical balance.

[0004] However, the surface of the existing pressure sensing electrode is not flat. The electrons in the upper and lower uneven electrodes and the ions in the ion gel film will form two double-layer structures affected by pressure. This will cause additional capacitance effects, resulting in signal distortion and reduced measurement accuracy. Therefore, developing a new sensing technology that can effectively improve measurement accuracy has become a technical problem to be solved in the field of unicompartmental knee replacement. Summary of the invention

[0005] The purpose of the present application is to provide a pressure sensing device and system for a unicompartmental knee joint to solve the above-mentioned problems.

[0006] To achieve the above objectives, in a first aspect, the present application provides a pressure sensing device for a unicompartmental knee joint, the pressure sensing device for a unicompartmental knee joint comprising:

[0007] The housing assembly is provided with a sealed receiving cavity;

[0008] A flexible pressure sensing electrode layer is contained in the sealed receiving cavity, and is used to detect the unicompartmental knee joint pressure and convert the unicompartmental knee joint pressure into a sensing capacitance signal, wherein the flexible pressure sensing electrode layer comprises a first electrode layer and a second electrode layer which are stacked, a dielectric layer is coated on a side of the second electrode layer facing the first electrode layer, a side of the dielectric layer facing the second electrode layer is bonded to the second electrode layer, and a microstructure is formed on a side of the dielectric layer facing the first electrode layer;

[0009] The signal processing module is accommodated in the sealed receiving cavity and is electrically connected to the flexible pressure sensing electrode layer. It is used to convert the sensing capacitance signal generated by the flexible pressure sensing electrode layer into a detection voltage signal, and obtain the unicompartmental knee joint pressure value based on the detection voltage signal.

[0010] In some embodiments, the flexible pressure sensing electrode layer includes at least one sensing node, and a dielectric layer is coated at a position corresponding to each sensing node on a side of the second electrode layer facing the first electrode layer.

[0011] In some embodiments, an ion gel solution is coated on a position corresponding to each sensing node on a side of the second electrode layer facing the first electrode layer, and the ion gel solution forms the dielectric layer after being cured.

[0012] In some embodiments, the first electrode layer is arranged in series laterally and is located on the upper layer of the dielectric layer; the second electrode layer is arranged in series longitudinally and is located on the lower layer of the dielectric layer, and at least one row of electrodes in the first electrode layer and at least one column of electrodes in the second electrode layer are crisscrossed to form the at least one sensing node.

[0013] In some embodiments, the housing assembly includes:

[0014] An upper shell component, comprising a flexible upper shell having a surface shape that fits the unicompartmental knee joint and a hard upper shell disposed inside the flexible upper shell;

[0015] The lower shell component is enclosed with the upper shell component to form the sealed receiving cavity; the flexible pressure sensing electrode layer is accommodated in the sealed receiving cavity on the side facing the upper shell component, and the signal processing module is accommodated in the sealed receiving cavity on the side facing the lower shell component.

[0016] In some embodiments, the pressure sensing device for the unicompartmental knee joint further comprises:

[0017] A pressure transmission component is arranged between the upper shell component and the flexible pressure sensing electrode layer, and is used for transmitting the pressure of the unicompartmental knee joint to the flexible pressure sensing electrode layer.

[0018] In some embodiments, the pressure conduction component includes a force-conducting column fixed to the flexible upper shell corresponding to the position of the sensing node of the flexible pressure sensing electrode layer, and a hard gasket adhered to the side of the flexible pressure sensing electrode layer facing the upper shell component.

[0019] In some embodiments, the pressure sensing device for the unicompartmental knee joint further comprises:

[0020] The inertial sensor units are respectively arranged on the ankle and thigh of the measured object, and are used to collect the leg posture data of the measured object.

[0021] In the second aspect, the present application also proposes a pressure sensing system for a unicompartmental knee joint, the pressure sensing system for a unicompartmental knee joint comprising a pressure sensing device and a receiving device of the unicompartmental knee joint as described in any of the above embodiments, the pressure sensing device of the unicompartmental knee joint and the receiving device being communicatively connected, the receiving device comprising an electromagnetic induction unit and a receiving circuit unit, the electromagnetic induction unit being used to activate the pressure sensing device of the unicompartmental knee joint, the receiving circuit unit being used to receive the unicompartmental knee joint pressure value and leg posture data transmitted by the pressure sensing device of the unicompartmental knee joint, and transmit the unicompartmental knee joint pressure value and the leg posture data to an electronic device.

[0022] In some embodiments, the unicompartmental knee joint pressure sensing system also includes an electronic device, the receiving device is connected to the electronic device, and the electronic device is used to receive the unicompartmental knee joint pressure value and the leg posture data transmitted by the receiving device, and generate unicompartmental knee joint pressure distribution data at different posture angles between the femur and tibia of the subject under test based on the unicompartmental knee joint pressure value and the leg posture data.

[0023] Compared with the prior art, the beneficial effects of this application include:

[0024] In the first aspect, the present application is coated with a dielectric layer on the side of the second electrode layer facing the first electrode layer, so that the dielectric layer and the second electrode layer are completely fitted, eliminating the gap between the two, so that even if the second electrode layer itself is not flat, it will not interfere with the capacitance measurement. In the second aspect, compared with the existing polymer ion gel film capacitance sensor, the force or strain is sensed by the change in the film thickness caused by the change in force or strain, thereby causing the change in capacitance. The response amount of the capacitance change caused by the unit force or strain change is small, and the sensitivity is limited. In the present application, a microstructure is formed on the side of the dielectric layer facing the first electrode layer. When the flexible pressure sensing electrode layer is subjected to the pressure of the unicompartmental knee joint, the contact area of ​​the dielectric layer and the first electrode layer is changed, and the capacitance is changed, so that the sensing of the unicompartmental knee joint pressure has a higher sensitivity. In the third aspect, the integrated signal processing module can capture and process the sensing capacitance signal of the flexible pressure sensing electrode layer in real time, and provide an immediate unicompartmental knee joint pressure value, thereby helping doctors to adjust the position and size of the meniscus pad during surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0026] Figure 1 Schematic diagram of the surface of copper foil electrodes with different roughness under an electron microscope in the prior art;

[0027] Figure 2 It is a schematic diagram of the capacitance equivalent circuit of the uneven electrode and the ion gel film in the prior art;

[0028] Figure 3 It is a schematic structural diagram of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application at a second viewing angle;

[0029] Figure 4 A schematic cross-sectional structure diagram of a flexible pressure sensing electrode layer of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application;

[0030] Figure 5 A schematic diagram of a capacitance equivalent circuit of a flexible pressure sensing electrode layer of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application;

[0031] Figure 6 A schematic diagram of a surface morphology scan of a dielectric layer of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application under an electron microscope;

[0032] Figure 7 A schematic diagram of a single-point coating of a sensing node of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application;

[0033] Figure 8 A schematic diagram of lead connection of a sensing node of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application;

[0034] Fig. 9 It is another schematic diagram of single-point coating of a sensing node of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application;

[0035] Fig.10 It is a schematic structural diagram of a pressure sensing device for a unicompartmental knee joint according to an embodiment of the present application at a third viewing angle;

[0036] Fig.11 Schematic diagram of the overall structure of a pressure sensing system for a unicompartmental knee joint according to an embodiment of the present application.

[0037] Explanation of the accompanying drawings: 100, pressure sensing device for unicompartmental knee joint; 1, shell assembly; 10, upper shell assembly; 101, flexible upper shell; 102, hard upper shell; 103, pressure conduction assembly; 1031, force guide column; 1032, hard gasket; 2, flexible pressure sensing electrode layer; 21, first electrode layer; 22, second electrode layer; 23, sensing node; 24, dielectric layer; 3, signal processing module; 4, inertial sensing unit; 20, lower shell assembly; 200, receiving device; 300, electronic device. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0039] All terms (including technical and scientific terms) used in this application have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used here should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0040] For example, the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first electrode layer may be referred to as a second electrode layer, and similarly, a second electrode layer may be referred to as a first electrode layer. Both the first electrode layer and the second electrode layer are electrode layers, but they are not the same electrode layer.

[0041] For another example, the terms “include”, “comprising”, etc. used in this application indicate the existence of features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0042] As mentioned above, the prior art suggests the use of a measurement tool that can accurately evaluate the positioning and size selection of the meniscus pad during surgery. For example, pressure sensing electrodes distributed in an array can be set on the contact surface of the femoral unicompartmental prosthesis and the tibial prosthesis to fully capture the pressure distribution characteristics within the knee joint. These sensing electrodes can provide real-time data to help doctors adjust the position and size of the meniscus pad during surgery to ensure the best mechanical balance. However, smooth surface electrodes are more expensive. Figure 1 The uneven low-cost electrode shown in the figure, the electrons in the upper and lower uneven electrodes and the ions in the ion gel film will form a Figure 2 The two double electric layer structures affected by pressure are shown. This causes an additional capacitance effect, resulting in signal distortion and reduced measurement accuracy. Therefore, developing a new sensing technology that can effectively improve measurement accuracy has become a technical problem to be solved in the field of unicompartmental knee replacement. To this end, the present application proposes a pressure sensing device and system for a unicompartmental knee joint, which has good measurement accuracy and signal stability for use in unicompartmental knee replacement.

[0043] like Figure 3 As shown, the pressure sensing device 100 for the unicompartmental knee joint proposed in the present application comprises:

[0044] The housing assembly 1 is provided with a sealed receiving chamber;

[0045] The flexible pressure sensing electrode layer 2 is accommodated in the sealed receiving cavity, and is used to detect the unicompartmental knee joint pressure and convert the unicompartmental knee joint pressure into a sensing capacitance signal. The flexible pressure sensing electrode layer 2 includes a first electrode layer 21 and a second electrode layer 22 which are stacked. A dielectric layer 24 is coated on a side of the second electrode layer 22 facing the first electrode layer 21, and a side of the dielectric layer 24 facing the second electrode layer 22 is bonded to the second electrode layer 22. A microstructure is formed on a side of the dielectric layer 24 facing the first electrode layer 21.

[0046] The signal processing module 3 is accommodated in the sealed receiving cavity and is electrically connected to the flexible pressure sensing electrode layer 2. It is used to convert the sensing capacitance signal generated by the flexible pressure sensing electrode layer 2 into a detection voltage signal, and obtain the unicompartmental knee joint pressure value based on the detection voltage signal.

[0047] In this embodiment, the housing component 1 refers to the part that constitutes the external structure and internal support of the pressure sensing device 100 for the unicompartmental knee joint, and provides a space for installation and protection of other components in the device. Specifically, a sealed receiving cavity is formed inside the housing component 1, and the sealed receiving cavity is used to accommodate key components such as the flexible pressure sensing electrode layer 2 and the signal processing module 3.

[0048] In some embodiments, the housing assembly 1 includes:

[0049] The upper shell component 10 comprises a flexible upper shell 101 having a surface shape that fits the unicompartmental knee joint and a hard upper shell 102 disposed inside the flexible upper shell 101;

[0050] The lower shell component 20 is enclosed with the upper shell component 10 to form a sealed receiving cavity; the flexible pressure sensing electrode layer 2 is accommodated in the sealed receiving cavity on a side facing the upper shell component 10, and the signal processing module 3 is accommodated in the sealed receiving cavity on a side facing the lower shell component 20;

[0051] The flexible upper shell 101 in this embodiment is in direct contact with the soft tissue inside the unicompartmental knee joint, and its surface shape design needs to be highly fitted to the inner surface of the unicompartmental knee joint to ensure good contact between the device and the knee joint. The material of the flexible upper shell 101 can be soft and biocompatible silicone, TPU (thermoplastic polyurethane) or other medical-grade elastic materials. The hard upper shell 102 is located on the inner side of the flexible upper shell 101 to provide structural support and protection for the device. The material of the hard upper shell 102 can be medical-grade PC (polycarbonate) and is made by injection molding. As a feasible implementation method for connecting the flexible upper shell 101 and the hard upper shell 102, the flexible upper shell 101 and the hard upper shell 102 are formed into a whole through a secondary encapsulation process, which not only maintains the softness of the part in contact with the skin, but also provides the rigidity required for the internal structure.

[0052] The lower shell component 20 in this embodiment cooperates with the upper shell component 10 to form a closed and sealed receiving chamber for accommodating the flexible pressure sensing electrode layer 2 and the signal processing module 3. The lower shell component 20 can be made of stainless steel to play a rigid supporting role, supporting the electrode plate of the signal processing module 3 to prevent the electrode plate from being deformed by force, thereby interfering with pressure measurement.

[0053] As some feasible implementation methods for connecting the upper shell component 10 and the lower shell component 20, the upper shell component 10 and the lower shell component 20 can be assembled together by means of a biocompatible adhesive (such as UV glue solidified by UV light, etc.) or a mechanical connection method (such as snaps, screws, etc.) to form a closed shell to protect the internal electronic components.

[0054] In this embodiment, the flexible pressure sensing electrode layer 2 includes a first electrode layer 21 and a second electrode layer 22 which are stacked. The electrodes in the first electrode layer 21 and the second electrode layer 22 are made of conductive materials such as metal foil or conductive polymer, such as silver paste, carbon paste, nickel paste screen-printed electrodes, copper foil, etc. Figure 4 As shown, the side of the second electrode layer 22 facing the first electrode layer 21 is coated with a dielectric layer 24, and the dielectric layer 24 can be an ion gel film. The side of the dielectric layer 24 facing the second electrode layer 22 is attached to the second electrode layer 22, and the side of the dielectric layer 24 facing the first electrode layer 21 is formed with a microstructure, thereby forming the following Figure 5 The equivalent capacitance structure shown, wherein the side of the first electrode layer 21 facing the dielectric layer 24 is relatively flat with the dielectric layer 24, the relatively flat first electrode layer 21 and the side of the dielectric layer 24 having a microstructure form a pressure-modulated double-layer capacitance structure, the electrode surface of the second electrode layer 22 used to coat the dielectric layer 24 may be uneven, but because the second electrode layer 22 is tightly fitted with the dielectric layer 24, a relatively large fixed double-layer capacitance structure can be formed. When the unicompartmental knee joint pressure acts on the flexible pressure sensing electrode layer 2, the contact area between the first electrode layer 21 and the dielectric layer 24 is changed, the sensed capacitance signal changes, and the second electrode layer 22 is always tightly fitted with the dielectric layer 24, and the capacitance is fixed, so it will not interfere with the sensed capacitance signal generated by the contact between the first electrode layer 21 and the dielectric layer 24, thereby obtaining a more accurate measurement result.

[0055] In one embodiment, coating the dielectric layer 24 on the side of the second electrode layer 22 facing the first electrode layer 21 may include coating the dielectric layer 24 on the entire side of the second electrode layer 22 facing the first electrode layer 21 .

[0056] In one embodiment, Figure 7 As shown, the flexible pressure sensing electrode layer 2 includes at least one sensing node 23, and a dielectric layer 24 is coated at a position corresponding to each sensing node 23 on the side of the second electrode layer 22 facing the first electrode layer 21. On the one hand, since the dielectric layer 24 is only coated on a specific sensing node 23, rather than the entire surface of the second electrode layer 22, the electric fields between different nodes have little mutual influence. The signal crosstalk between adjacent nodes is reduced, the independence and accuracy of each node are ensured, the signal ambiguity or misjudgment caused by the overall coating is avoided, and the measurement accuracy and resolution are improved. On the other hand, compared with the overall coating, the single-point coating process is relatively simple and easy to control, and can improve production efficiency and reduce manufacturing difficulty and manufacturing cost.

[0057] In some embodiments, an ion gel solution is coated on a position corresponding to each sensing node 23 on a side of the second electrode layer 22 facing the first electrode layer 21 , and the ion gel solution is cured to form a dielectric layer 24 .

[0058] Specifically, in one embodiment, the ion gel solution can be obtained by uniformly mixing a PVDF polymer, an ionic liquid, a wetting agent, a solvent and a filler. The PVDF polymer can include a first PVDF polymer and a second PVDF polymer, for example, the first PVDF polymer includes PVDF, and the second PVDF polymer includes PVDF-HFP. The anions of the ionic liquid include at least one of hexafluorophosphate anion, tetrafluoroborate anion, bistrifluoromethanesulfonyl imide anion, trifluoromethanesulfonate anion, acetate anion, dicyanamide anion, bromide anion, ethyl sulfate anion, and hydrogen sulfide anion, and the cations of the ionic liquid include at least one of 1-ethyl 3-methylimidazolium cation, 1-butyl 3-methylimidazolium cation, 1-hexyl 3-methylimidazolium cation, and 1-octyl 3-methylimidazolium cation. The wetting agent includes dimethyl carbonate; the solvent includes at least one of acetone, N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, and tetrahydrofuran. The filler comprises at least one of nano iron oxide, nano ferroferric oxide, nano aluminum oxide, nano calcium carbonate, nano zinc oxide, nano tin oxide, nano cerium oxide and fumed silicon dioxide.

[0059] In this embodiment, the first PVDF polymer has high crystallinity and high content, and can spontaneously form a microstructure (spherical or quasi-spherical structure). The second PVDF polymer has low crystallinity and low content. In the process of film formation, it participates less in the process of forming a polymer skeleton of a spherical or quasi-spherical structure, plays a role in bonding the spherical or quasi-spherical structure formed by the first PVDF polymer, and can form a stable polymer ion gel particle layer. Adding fillers to the ion gel solution can promote the spontaneous formation of a polymer ion gel particle layer, improve the consistency of the concave-convex structure of one side of the ion gel film (dielectric layer 24), and avoid inconsistent strength, resilience and sensitivity of different points of the gel film. As an example, the specific preparation method of the ion gel solution can refer to the previous patents CN119060387A and CN119060476A, but it should be noted that the ion gel solution in this application can also be prepared using other ingredients, and this application does not impose any restrictions on this.

[0060] Furthermore, an ion gel solution obtained by uniformly mixing PVDF polymer, ionic liquid, wetting agent, solvent and filler is coated at the position corresponding to each sensing node 23 on the side of the second electrode layer 22 facing the first electrode layer 21. The ion gel solution is formed on the second electrode layer 22 to obtain a wet film. The ion gel film obtained after curing is the dielectric layer 24 required in this embodiment. The dielectric layer 24 in this embodiment has the following structure on the side facing the first electrode layer 21: Figure 6The concavoconvex microstructure shown is caused by the spherical or quasi-spherical polymer ion gel particles in the polymer ion gel particle layer formed by spontaneous crystallization. This embodiment does not limit the film forming method, for example, it can be a self-leveling method, spraying method, spin coating method, scraping method and other film forming methods.

[0061] In some embodiments, the curing treatment includes flash drying and baking in sequence, and specifically, the flash drying time may be 1 min to 1500 min, the baking temperature may be 10° C. to 300° C., and the baking time may be 10 h to 500 h. Flash drying rapidly evaporates the solvent and wetting agent, causing the gel film to lose fluidity and eliminate microbubbles in the wet film. Baking completely evaporates the solvent, and flash drying causes the film liquid to lose fluidity in a short time.

[0062] It should be noted that the first electrode layer 21 and the second electrode layer 22 in the present application are only for the convenience of distinguishing the description. The ion gel solution can also be coated on the side of the first electrode layer 21 facing the second electrode layer 22, which will not affect the technical effect of the present application.

[0063] In some embodiments, Figure 7 As shown, the first electrode layer 21 and the second electrode layer 22 respectively include a substrate (the substrate can be an insulating material such as PI, PET, etc.) and an array-arranged (circular) electrode. Figure 8 As shown, the electrodes in the first electrode layer 21 and the electrodes in the second electrode layer 22 are connected in series through leads. Each first electrode in the first electrode layer 21 has a second electrode in the second electrode layer 22 corresponding to the position of the first electrode, and the first electrode and the second electrode overlap to form a sensing node 23. Specifically, the substrate can be PET with a thickness of 30-50um, and the electrodes are screen-printed using silver paste, carbon paste, or nickel paste, with a resistance value within 5 ohms. Figure 7 The dot position in is the sensing node 23.

[0064] In some embodiments, Fig. 9 As shown, the first electrode layer 21 is arranged in series in a horizontal direction and is located on the upper layer of the dielectric layer 24; the second electrode layer 22 is arranged in series in a vertical direction and is located on the lower layer of the dielectric layer 24, and at least one row of electrodes in the first electrode layer 21 and at least one column of electrodes in the second electrode layer 22 are crisscrossed to form at least one sensing node 23. This arrangement enables the sensing node 23 to achieve high-density data acquisition in a limited space, and the wiring method is simple, which helps to improve production efficiency.

[0065] In this embodiment, the signal processing module 3 is fastened to the flexible pressure sensing electrode layer 2 through the adhesive layer 3, and is electrically connected to at least one sensing node 23 in the flexible pressure sensing electrode layer 2, and is responsible for converting the sensing capacitance signal from each sensing node 23 into a detection voltage signal, and then obtaining the sensing capacitance value of the sensing node 23 corresponding to the detection voltage signal based on the analog-to-digital conversion calculation of the detection voltage signal, and obtaining the true pressure value of the sensing node 23 based on the pressure calibration function of the sensing node 23. The specific implementation of the signal processing module 3 can be found in the previous patent CN118961003B, and the content of the patent is introduced into this application, and this application will not be repeated here.

[0066] In the pressure sensing device 100 for the unicompartmental knee joint proposed in the embodiment of the present application, on the first aspect, the present application is coated with a dielectric layer 24 on the side of the second electrode layer 22 facing the first electrode layer 21, so that the dielectric layer 24 is completely fitted with the second electrode layer 22, eliminating the gap between the two, so that even if the second electrode layer 22 itself is uneven, it will not interfere with the capacitance measurement. On the second aspect, compared with the existing polymer ion gel film capacitance sensor, which relies on the change of force or strain to cause the change of film thickness, thereby causing the change of capacitance to sense force or strain, the response amount of the capacitance change caused by the unit force or strain change is small, and the sensitivity is limited. In the present application, a microstructure is formed on the side of the dielectric layer 24 facing the first electrode layer 21. When the flexible pressure sensing electrode layer 2 is subjected to the pressure of the unicompartmental knee joint, the contact area between the dielectric layer 24 and the first electrode layer 21 is changed, and the capacitance is changed, so that the sensing of the pressure of the unicompartmental knee joint has a higher sensitivity. Thirdly, the integrated signal processing module 3 can capture and process the sensing capacitance signal of the flexible pressure sensing electrode layer 2 in real time, and provide an instant unicompartmental knee joint pressure value, thereby helping the doctor to adjust the position and size of the meniscus pad during surgery.

[0067] In one embodiment, Fig.10 As shown, the pressure sensing device 100 for the unicompartmental knee joint further includes:

[0068] The pressure transmission component 103 is disposed between the upper shell component 10 and the flexible pressure sensing electrode layer 2 , and is used for transmitting the unicompartmental knee joint pressure to the flexible pressure sensing electrode layer 2 .

[0069] In some embodiments, the pressure conduction component 103 includes a force-conducting column 1031 fixed to the flexible upper shell 101 and corresponding to the position of the sensing node 23 of the flexible pressure sensing electrode layer 2, and a hard gasket 1032 adhered to the side of the flexible pressure sensing electrode layer 2 facing the upper shell component 10.

[0070] The force-guiding column 1031 is a structure fixed on the flexible upper shell 101, and its number and position correspond one-to-one to the position of the sensing node 23 in the flexible pressure sensing electrode layer 2. The function of each force-guiding column 1031 is to effectively transfer the pressure from the inside of the knee joint to the corresponding sensing node 23, thereby ensuring that the flexible pressure sensing electrode layer 2 can accurately detect the pressure change.

[0071] As a feasible implementation method of forming the force-guiding column 1031, the force-guiding column 1031 and the flexible upper shell 101 can be integrally formed by precision injection molding or mold molding. The shape and size of the force-guiding column 1031 can be designed according to the mechanical environment inside the knee joint and the size of the flexible pressure sensing electrode layer 2, such as cylindrical or conical, to ensure uniformity and accuracy of pressure transmission, which is not limited in this embodiment.

[0072] The hard gasket 1032 can be attached to the side of the flexible pressure sensing electrode layer 2 facing the upper shell component 10 by means of epoxy resin, silicone or other adhesives suitable for fixing electronic components, and the number and position of the hard gasket 1032 correspond to the position of the sensing node 23 in the flexible pressure sensing electrode layer 2. That is, the hard gasket 1032 is located between the flexible pressure sensing electrode layer 2 and the force guiding column 1031, which can effectively protect the flexible pressure sensing electrode layer 2 from mechanical damage and extend the service life of the flexible pressure sensing electrode layer 2. The hard gasket 1032 can be a metal gasket made of high-strength and corrosion-resistant materials such as medical-grade stainless steel and titanium alloy, which can maintain long-term stability in the in vivo environment, thereby extending the service life of the entire unicompartmental knee joint pressure sensing device 100.

[0073] In addition, experimental tests show that the hard gasket 1032 can not only protect the flexible pressure sensing electrode layer 2, but also improve the sensitivity of the sensing node 23. This is because the hard gasket 1032 has good rigidity and can more effectively transmit and disperse pressure, so that the sensing node 23 can more accurately detect the pressure change of the unicompartmental knee joint.

[0074] In this embodiment, through the synergistic effect of the force guiding column 1031 and the hard gasket 1032, the pressure conduction component 103 can ensure that the pressure inside the knee joint is accurately and evenly transmitted to each sensing node 23 of the flexible pressure sensing electrode layer 2, thereby improving the accuracy and reliability of unicompartmental knee joint pressure sensing.

[0075] In one embodiment, Fig.11 As shown, the pressure sensing device 100 for the unicompartmental knee joint further includes:

[0076] The inertial sensor unit 4 (IMU) is respectively configured on the ankle and thigh of the object under test, and is used to collect the leg posture data of the object under test, and transmit the leg posture data to the receiving device 200 or the electronic device 300 in a wireless communication manner (such as Bluetooth, Wi-Fi, zigbee, etc.).

[0077] In some embodiments, the inertial sensing unit 4 includes at least one accelerometer and at least one gyroscope, which are used to measure the static posture information and dynamic rotation information of the object under test, and fuse the static posture information and dynamic rotation information to obtain the leg posture data of the object under test.

[0078] Specifically, the accelerometer is used to measure the linear acceleration of the object under test in the directions of the three axes of space (usually the X, Y, and Z axes), thereby obtaining static posture information to distinguish the user's motion state (such as stillness or leg bending). The gyroscope is used to measure the angular velocity of the object under test in the directions of the three axes of space, thereby obtaining dynamic rotation information, that is, the rotation of the femur and tibia of the object under test during the leg bending process, so as to accurately capture the changes in the leg posture of the object under test. The leg posture data of the object under test is obtained by fusing the static posture information and the dynamic rotation information.

[0079] In one embodiment, Fig.11 As shown, an embodiment of the present application also proposes a pressure sensing system for a unicompartmental knee joint, the pressure sensing system for a unicompartmental knee joint comprising a pressure sensing device 100 and a receiving device 200 of a unicompartmental knee joint as described in any of the above embodiments, the pressure sensing device 100 of the unicompartmental knee joint and the receiving device 200 are communicatively connected, the receiving device 200 comprises an electromagnetic induction unit and a receiving circuit unit, the electromagnetic induction unit is used to activate the pressure sensing device 100 of the unicompartmental knee joint, the receiving circuit unit is used to receive the unicompartmental knee joint pressure value and leg posture data transmitted by the pressure sensing device 100 of the unicompartmental knee joint, and transmit the unicompartmental knee joint pressure value and the leg posture data to an electronic device 300.

[0080] In some embodiments, the receiving device 200 can transmit the unicompartmental knee joint pressure value and leg posture data to the electronic device 300 via a wireless communication module (such as Bluetooth, Wi-Fi, zigbee, etc.), a wired transmission method (such as a serial port, a USB port, an Ethernet, etc.) or a storage method (such as a TF card, an SD card, a FLASH storage chip, etc.).

[0081] In one embodiment, Fig.11As shown, the pressure sensing system of the unicompartmental knee joint further includes an electronic device 300, which may be a smart phone, a tablet computer, a portable medical terminal, a laptop computer, an embedded computer, a wearable device, a dedicated medical monitor or a cloud server, etc. The receiving device 200 is connected to the electronic device 300, and the electronic device 300 is used to receive the unicompartmental knee joint pressure value and the leg posture data transmitted by the receiving device 200, and generate the unicompartmental knee joint pressure distribution data under different posture angles between the femur and the tibia of the measured object based on the unicompartmental knee joint pressure value and the leg posture data.

[0082] In some embodiments, a reference coordinate system can be established in three-dimensional space, with the femur or tibia as a reference. The posture change of the leg in the coordinate system is determined by the leg posture data. Specifically, the relative posture angle between the femur and the tibia is calculated based on the static posture information (acceleration) and dynamic posture information (angular velocity) in the leg posture data.

[0083] Furthermore, according to the position distribution of each sensing node 23, the pressure value of each sensing node 23 is mapped to the corresponding two-dimensional plane position to form a unicompartmental knee joint pressure distribution map. The unicompartmental knee joint pressure distribution maps corresponding to each posture angle are combined to form a three-dimensional data set.

[0084] In summary, the pressure sensing device and system of the unicompartmental knee joint of the embodiment of the present application, on the one hand, can provide high-resolution unicompartmental knee joint pressure monitoring through a flexible pressure sensing electrode layer. On the other hand, by coating a dielectric layer at the position corresponding to each sensing node on the side of the second electrode layer facing the first electrode layer, the pressure sensing sensitivity can be effectively improved, and interference and crosstalk can be reduced. On the third hand, the leg posture data obtained by the inertial sensing unit can be used to calculate the relative posture angle between the femur and the tibia, providing a reliable basis for the pressure distribution analysis of the unicompartmental knee joint. On the fourth hand, the receiving device is connected to an electronic device for transmitting the unicompartmental knee joint pressure value and leg posture data. It can realize real-time data transmission, ensure signal stability and integrity, and support remote monitoring and data analysis.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0086] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A pressure sensing device for a unicompartmental knee joint, characterized in that: The pressure sensing device of the unicompartmental knee joint comprises: The housing assembly is provided with a sealed receiving cavity; A flexible pressure sensing electrode layer is accommodated in the sealed receiving cavity, and is used to detect the unicompartmental knee joint pressure and convert the unicompartmental knee joint pressure into a sensing capacitance signal. The flexible pressure sensing electrode layer includes a first electrode layer and a second electrode layer that are stacked. At least one row of electrodes in the first electrode layer and at least one column of electrodes in the second electrode layer are crisscrossed to form a plurality of sensing nodes. An ion gel solution obtained by uniformly mixing a PVDF polymer, an ionic liquid, a wetting agent, a solvent and a filler is coated at a position corresponding to each sensing node on a side of the second electrode layer facing the first electrode layer. The ion gel solution is cured to form a dielectric layer, so that the dielectric layer is only coated on each sensing node, rather than on the entire surface of the second electrode layer. The side of the dielectric layer facing the second electrode layer is completely in contact with the uneven electrode surface of the second electrode layer to eliminate the gap between the two, thereby forming a fixed double-layer capacitor structure. A microstructure is formed on the side of the dielectric layer facing the first electrode layer, thereby forming a pressure-modulated double-layer capacitor structure. The signal processing module is accommodated in the sealed receiving cavity and is electrically connected to the flexible pressure sensing electrode layer. It is used to convert the sensing capacitance signal generated by the flexible pressure sensing electrode layer into a detection voltage signal, and obtain the unicompartmental knee joint pressure value based on the detection voltage signal.

2. The pressure sensing device for a unicompartmental knee joint according to claim 1, characterized in that: The first electrode layer is arranged in series in a transverse manner and is located on the upper layer of the dielectric layer; the second electrode layer is arranged in series in a longitudinal manner and is located on the lower layer of the dielectric layer.

3. The pressure sensing device for a unicompartmental knee joint according to claim 1, characterized in that: The housing assembly comprises: An upper shell component, comprising a flexible upper shell having a surface shape that fits the unicompartmental knee joint and a hard upper shell disposed inside the flexible upper shell; The lower shell component is enclosed with the upper shell component to form the sealed receiving cavity; the flexible pressure sensing electrode layer is accommodated in the sealed receiving cavity on the side facing the upper shell component, and the signal processing module is accommodated in the sealed receiving cavity on the side facing the lower shell component.

4. The pressure sensing device for a unicompartmental knee joint according to claim 3, characterized in that: The pressure sensing device for the unicompartmental knee joint further comprises: A pressure transmission component is arranged between the upper shell component and the flexible pressure sensing electrode layer, and is used for transmitting the pressure of the unicompartmental knee joint to the flexible pressure sensing electrode layer.

5. The pressure sensing device for a unicompartmental knee joint according to claim 4, characterized in that: The pressure transmission component includes a force-conducting column fixed to the flexible upper shell and corresponding to the position of the sensing node of the flexible pressure sensing electrode layer, and a hard gasket adhered to the side of the flexible pressure sensing electrode layer facing the upper shell component.

6. The pressure sensing device for a unicompartmental knee joint according to claim 1, characterized in that: The pressure sensing device for the unicompartmental knee joint further comprises: The inertial sensor units are respectively arranged on the ankle and thigh of the measured object to collect the leg posture data of the measured object.

7. A pressure sensing system for a unicompartmental knee joint, characterized in that: The pressure sensing system of the unicompartmental knee joint comprises a pressure sensing device and a receiving device of the unicompartmental knee joint as described in any one of claims 1 to 6, the pressure sensing device of the unicompartmental knee joint and the receiving device are communicatively connected, the receiving device comprises an electromagnetic induction unit and a receiving circuit unit, the electromagnetic induction unit is used to activate the pressure sensing device of the unicompartmental knee joint, the receiving circuit unit is used to receive the unicompartmental knee joint pressure value and leg posture data transmitted by the pressure sensing device of the unicompartmental knee joint, and transmit the unicompartmental knee joint pressure value and the leg posture data to an electronic device.

8. The pressure sensing system for a unicompartmental knee joint according to claim 7, characterized in that: The unicompartmental knee joint pressure sensing system also includes an electronic device, to which the receiving device is connected. The electronic device is used to receive the unicompartmental knee joint pressure value and the leg posture data transmitted by the receiving device, and generate unicompartmental knee joint pressure distribution data at different posture angles between the femur and tibia of the subject under test based on the unicompartmental knee joint pressure value and the leg posture data.

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