Auxiliary device for knee joint pressure measurement

Abstract

An auxiliary device for knee joint pressure measurement, comprising an upper shell (1), a lower shell (2), an intermediate assembly, and a measurement unit. The upper shell (1) and the lower shell (2) are connected to each other and cooperate to form a chamber, and the intermediate assembly is arranged in the chamber. The intermediate assembly comprises a deformable member (3) and a conduction member (11), wherein the deformable member (3) is connected to the lower shell (2), the conduction member (11) is arranged between the deformable member (3) and the upper shell (1), two ends of the conduction member are respectively connected to the upper shell (1) and the deformable member (3), and the conduction member (11) is used for transmitting the pressure exerted on the upper shell (1) to the deformable member (3) such that the deformable member (3) elastically deforms. A space for the elastic deformation of the deformable member (3) is reserved between the deformation member (3) and the lower shell (2). A strain gauge (16) is provided at a detection end of the measurement unit, and the strain gauge (16) is attached to the surface of the deformable member (3) and deforms along with the elastic deformation of the deformable member (3).

Description

An auxiliary device for measuring knee joint pressure Technical Field

[0001] The present invention belongs to the technical field of medical devices, and in particular relates to an auxiliary device for measuring knee joint pressure. Background Art

[0002] In terms of knee joint treatment, total knee replacement is currently one of the more successful surgical methods for treating knee joint diseases. During the operation, a femoral prosthesis is used to replace the femoral surface, and a tibial prosthesis and tibial spacer are used to replace the tibial surface. The contact surface between the femoral prosthesis and the tibial spacer constitutes the postoperative knee joint plane. Total knee replacement can relieve patients' knee pain and greatly improve their quality of life. However, as the knee joint is a complex joint in the human body, the difficulty of total knee replacement surgery is self-evident. In addition to accurate osteotomy, correct ligament release and soft tissue balance are the key to the operation. Therefore, during the operation, special attention should be paid to the release of the soft tissue around the tibial plateau to ensure that the knee joint has appropriate tightness and the pressure on the inside and outside is as equal as possible.

[0003] At present, the auxiliary device for knee joint pressure measurement can be used in conjunction with computing software to measure the resultant force and pressure center position between knee joint prostheses, helping doctors make more accurate judgments and thus select more suitable prostheses, reducing the probability of knee joint pain and deformity after surgery, effectively improving the quality of surgery, and improving the patient's postoperative life.

[0004] In the prior art, auxiliary devices for measuring knee joint pressure typically include a load-bearing column mounted on the upper shell, which presses against a thin film pressure sensor. The force acting on the upper shell is applied to the thin film pressure sensor via the load-bearing column. The thin film pressure sensor detects the force applied by the load-bearing column to calculate the resultant force acting on the upper shell and its center of gravity. However, thin film pressure sensors require custom manufacturing, resulting in high costs. Furthermore, the measurement value fluctuations and creep resistance of thin film pressure sensors are relatively poor. In particular, the relationship between the resistance change and the applied pressure is nonlinear, requiring a high degree of calibration accuracy prior to use, making the production process difficult.

[0005] Summary of the Invention

[0006] The object of the present invention is to provide an auxiliary device for measuring knee joint pressure, so as to solve the problems of high cost caused by the use of thin film pressure sensors in the prior art.

[0007] The technical solution of the present invention is:

[0008] An auxiliary device for measuring knee joint pressure, comprising:

[0009] an upper shell and a lower shell, the upper shell and the lower shell being connected to each other and cooperating to form a chamber;

[0010] an intermediate component disposed in the chamber, comprising a deformable member and a conductive member, wherein the deformable member is connected to the lower shell, and the conductive member is disposed between the deformable member and the upper shell, with its two ends respectively connected to the upper shell and the deformable member, and the conductive member is used to transmit the pressure exerted on the upper cover to the deformable member to cause the deformable member to undergo elastic deformation; a space for the deformable member to undergo elastic deformation is reserved between the deformable member and the lower shell;

[0011] The measuring unit has a detection end which is a strain gauge, and the strain gauge is attached to the surface of the deformable member and deforms with the elastic deformation of the deformable member.

[0012] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the strain gauge is a resistance strain gauge.

[0013] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the deformable member is connected to the lower shell via a lifting member to form a space for elastic deformation of the deformable member.

[0014] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the deformable member is an elastomer.

[0015] In a certain embodiment, an auxiliary device for measuring knee joint pressure, the deformable part includes a connecting body and a deformable body, the connecting body is connected to the lower shell, one end of the deformable body is connected to the connecting body, and the other end is a free end, the conductive part is connected to the free end of the deformable body; the strain gauge is fitted and connected to the deformable body.

[0016] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the deformable body and the connecting body are made in one piece, and the strain gauge is fitted and connected to the connection between the deformable body and the connecting body.

[0017] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the deformable member is a strip structure, both ends of the strip structure of the deformable member are respectively connected to the lower shell, and the strain gauge is connected to the middle part of the strip structure of the deformable member.

[0018] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the deformable member is a stainless steel component, a titanium alloy component, or an aluminum alloy component.

[0019] In a certain embodiment of the auxiliary device for measuring knee joint pressure, one of the connections between the conductive member and the upper shell and the deformable member is a fixed connection, and the other is a contact connection.

[0020] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the connection between the upper shell and the lower shell is a non-rigid connection.

[0021] In a certain embodiment, an auxiliary device for measuring knee joint pressure, the upper shell and the lower shell both include a main body part and a side wall part arranged around the main body part, wherein the end face of one of the side wall parts is provided with a groove extending around the circumference, and the end face of the other side wall part is provided with a rib extending around the circumference, the rib extending into the groove and the two side walls of the rib are in contact with the two side walls of the groove.

[0022] In a certain embodiment of the auxiliary device for measuring knee joint pressure, a limiting structure is provided between the upper shell and the lower shell to prevent the upper shell and the lower shell from separating.

[0023] In a certain embodiment of the auxiliary device for measuring knee joint pressure, the upper shell and the lower shell are connected by a flexible telescopic member.

[0024] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0025] During measurement, the auxiliary device for knee joint pressure measurement provided by the present invention is subjected to an external force on the upper shell, which drives the deformable member to undergo elastic deformation through the conductive member, thereby causing the strain gauge attached to the deformable member to deform. Due to the strain effect of the strain gauge, its resistance value will change accordingly, and the change in the strain gauge resistance value is linearly related to the deformation amount. Therefore, the deformation of the strain gauge can be obtained by measuring the resistance value of the strain gauge. The deformation of the strain gauge is caused by the elastic deformation of the deformable member, and the elastic deformation of the deformable member can be obtained from the deformation of the strain gauge. The force applied to the upper shell is applied to the deformable member through the conductive member, causing the deformable member to undergo elastic deformation. Therefore, the force applied by the conductive member to the deformable member can also be obtained from the elastic deformation of the deformable member. The resultant force applied to the upper shell and the center of the resultant force can be calculated based on the position of the conductive member connected to the upper shell and the force applied to the deformable member.

[0026] The auxiliary device for measuring knee joint pressure of the present invention abandons the thin film pressure sensor and adopts a strain gauge as a detection device, thereby reducing costs. At the same time, the resistance change of the thin film pressure sensor is nonlinearly related to the pressure it is subjected to, and the calibration is inaccurate. In addition, the thin film pressure sensor has a large creep property and its own resistance value is offset, which will cause measurement errors. The strain gauge used in the present invention has a linear relationship between its resistance change and its own deformation, and the deformation of the deformable part is also linearly related to its own elastic deformation. Therefore, the strain gauge resistance change value we directly measure is ultimately linearly related to the pressure applied to the deformable part. The pressure can be accurately calculated through pre-calibration, so the measurement of the present invention has high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various other advantages and benefits will become apparent to those skilled in the art by reading the following detailed description of the preferred embodiment.The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention.

[0028] FIG1 is a schematic structural diagram of an auxiliary device for measuring knee joint pressure according to Example 1;

[0029] FIG2 is a schematic structural diagram of an auxiliary device for measuring knee joint pressure according to Example 1;

[0030] FIG3 is a schematic structural diagram of an upper shell and a lower shell according to Example 1;

[0031] FIG4 is a schematic structural diagram of a deformable member and a lower shell according to Example 1;

[0032] FIG5 is a schematic structural diagram of another deformable member of Example 1;

[0033] FIG6 is a schematic structural diagram of another deformable member and lower shell of Example 1;

[0034] FIG7 is a schematic structural diagram of another auxiliary device for measuring knee joint pressure according to Example 1;

[0035] FIG8 is a schematic structural diagram of another deformable member and lower shell of Example 1;

[0036] FIG9 is a schematic structural diagram of another deformable member and lower shell of Example 1;

[0037] FIG10 is a schematic structural diagram of another deforming member and a lifting member of Example 1 (only the strain gauge on one deforming body is shown);

[0038] FIG11 is a schematic structural diagram of another deformable member and lower shell of Example 1;

[0039] FIG12 is a schematic structural diagram of an auxiliary device for measuring knee joint pressure according to Example 2;

[0040] FIG13 is a schematic structural diagram of another auxiliary device for measuring knee joint pressure in Example 2.

[0041] Description of reference numerals:

[0042] 1: Upper shell; 2: Lower shell; 3: Deformable part; 4: Circuit module; 5: Slot; 6: Retaining edge; 7: First positioning column; 8: First positioning hole; 9: Buckle; 10: Limit block; 11: Conducting part; 12: Second positioning column; 13: Second positioning hole; 14: Deformable body; 15: Connecting body; 16: Strain gauge; 17: Lifting part; 18: Force-bearing surface; 19: Groove; 20: Soft rubber; 21: Force-bearing plate. DETAILED DESCRIPTION

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other embodiments can be obtained based on these drawings without inventive work.

[0044] To simplify the drawings, only the parts relevant to the present invention are schematically shown in each figure. They do not represent the actual structure of the product. Furthermore, to simplify the drawings and facilitate understanding, in some figures, only one of the components with the same structure or function is schematically depicted or labeled. As used herein, "one" not only means "only one" but also "more than one."

[0045] Example 1

[0046] Referring to Figures 1 to 11, this embodiment provides an auxiliary device for measuring knee joint pressure (hereinafter referred to as the auxiliary device for ease of description), including an upper shell 1, a lower shell 2, an intermediate component and a measuring unit. The upper shell 1 and the lower shell 2 are connected to each other and cooperate to form a chamber, and the intermediate component is arranged in the chamber. The intermediate component includes a deformable member 3 and a conductive member 11. The deformable member 3 is connected to the lower shell 2. The conductive member 11 is arranged between the deformable member 3 and the upper shell 1, and its two ends are respectively connected to the upper shell 1 and the deformable member 3. The conductive member 11 is used to transmit the pressure exerted on the upper cover to the deformable member 3 so that the deformable member 3 undergoes elastic deformation. Among them, a space is reserved between the deformable member 3 and the lower shell 2 for the deformable member 3 to undergo elastic deformation. The detection end of the measuring unit is a strain gauge 16, which is attached to the surface of the deformable member 3 and deforms with the elastic deformation of the deformable member 3.

[0047] When the auxiliary device is measuring, an external force is applied to the upper shell 1, driving the deformable member 3 to undergo elastic deformation through the conductive member 11. This, in turn, causes the strain gauge 16, which is attached to the deformable member 3, to deform. Due to the strain effect of the strain gauge 16, its resistance value changes accordingly. This change in resistance is linearly related to the deformation. Therefore, the deformation of the strain gauge 16 can be determined by measuring its resistance value. The deformation of the strain gauge 16 is caused by the elastic deformation of the deformable member 3, and the deformation of the strain gauge 16 can be used to determine the elastic deformation of the deformable member 3. The force applied to the upper shell 1 is applied to the deformable member 3 through the conductive member 11, causing it to undergo elastic deformation. The elastic modulus of the deformable member 3 is fixed, and pressure calibration during the production process provides a linear relationship between the deformation of the deformable member 3 and the applied pressure. Therefore, during use, the force applied by the conductive member 11 to the deformable member 3 can be calculated based on its elastic deformation. When only one conductive part 11 is provided in a single intermediate component, the pressure value on the upper shell 1 can be calculated through the conductive part 1; when multiple conductive parts 11 are provided in a single intermediate component, the resultant force value and the center of the resultant force on the upper shell 1 can be calculated through the positions at which the multiple conductive parts 11 are connected to the upper shell 1 and the force applied to the deformable part 3 (preferably, multiple conductive parts 11 are provided in a single intermediate component).

[0048] The auxiliary device uses a strain gauge 16 as a detection component, replacing the conventional thin-film pressure sensor. This reduces the cost of the auxiliary device and improves its detection accuracy. Applying force to the deformable member 3 causes it to elastically deform, which in turn causes the strain gauge 16 attached to the deformable member 3 to deform, thereby achieving the detection effect.

[0049] The auxiliary device of this embodiment is further described below.

[0050] Both the upper shell 1 and the lower shell 2 include a main body and sidewalls extending along the periphery of the main body. The two sidewalls are butted together to connect the upper shell 1 and the lower shell 2. The space between the two main body components, enclosed by the butted sidewalls, constitutes the aforementioned chamber. The main body and sidewalls of the upper shell 1 are integrally formed, as are the main body and sidewalls of the lower shell 2. In specific embodiments, the main body and corresponding sidewalls may be connected using other methods, such as gluing, which is not intended to be limiting.

[0051] Since the auxiliary device of this embodiment drives the deformable member 3 to undergo elastic deformation through the conductive member 11 when the upper shell 1 is subjected to force, during this process, the conductive member 11 and the portion of the upper shell 1 connected to the conductive member 11 need to be displaced. If there is a rigid connection between the upper shell 1 and the lower shell 2, part of the pressure on the upper shell 1 will be directly transmitted to the lower shell 2, and the plastic deformation of the upper shell 1 will have a large uncertainty, thereby affecting the final resultant force value and reducing the accuracy of the resultant force center position. For this reason, under preferred circumstances, the upper shell 1 can move freely relative to the lower shell 2, and there is no direct rigid connection between the upper shell 1 and the lower shell 2, so that all the pressure on the upper shell 2 is transmitted to the deformable member 3 through the conductive member 11. Specifically, the connection method between the upper shell 1 and the lower shell 2 preferably adopts a contactless connection or a flexible connection structure.

[0052] In this embodiment, a connection method of a slot 5 and a rib 6 is adopted. Specifically, in the upper shell 1 and the lower shell 2, a slot 5 is provided on the end surface of one side wall portion in a circumferential circle, and a rib 6 is provided on the end surface of the other side wall portion in a circumferential circle. The rib 6 extends into the slot 5 and the two side walls of the rib 6 fit in with the two side walls of the slot 5. Moreover, since the auxiliary device needs to be placed between the knee joints when in use, the shape of the side wall portion in a circumferential circle is to adapt to the knee joint and will not be a regular shape such as an ellipse or a square. Therefore, the arrangement of the slot 5 and the rib 6 also has a positioning function. At the same time, when the upper shell 1 moves relative to the lower shell 2, the rib 6 slides in the slot 5. Since the two side walls of the rib 6 and the two side walls of the slot 5 always fit in during sliding, the structure of the slot 5 and the rib 6 also has a waterproof and dustproof function.

[0053] However, when the upper shell 1 and the lower shell 2 are installed, if the shapes of the slots 5 and the retaining edges 6 are directly used for positioning, it is rather troublesome during actual use. For this reason, the present embodiment further provides a positioning column and a positioning hole structure to facilitate the installation and positioning of the upper shell 1 and the lower shell 2. Specifically, a number of first positioning holes 8 are provided on the inner bottom surface of the upper shell 1 (i.e., the wall surface of the upper shell 1 in the chamber facing the lower shell 2), and a number of corresponding first positioning columns 7 are provided on the inner bottom surface of the lower shell 2 (i.e., the wall surface of the lower shell 2 in the chamber facing the upper shell 1). During the installation process, the upper shell 1 and the lower shell 2 are installed and positioned by inserting the first positioning columns 7 into the corresponding first positioning holes 8. In other embodiments, the first positioning columns 7 may be provided on the upper shell 1, the first positioning holes 8 may be provided on the lower shell 2, or other further positioning methods may be used, which are not limited here.

[0054] A retaining structure is also provided between the upper shell 1 and the lower shell 2 to prevent them from separating. Specifically, a buckle 9 is provided on the inner bottom surface of the upper shell 1, and a retaining block 10 is provided on the inner bottom surface of the lower shell 2. The retaining block 10 cooperates with the inner bottom surface of the lower shell 2 to form a retaining groove. The buckle 9 has a certain degree of elasticity. When the upper and lower shells 1 and 2 are assembled, the buckle 9 elastically deforms, allowing its hook to extend into the retaining groove. The hook of the buckle 9 has a certain amount of movement within the retaining groove, allowing the upper shell 1 to move freely relative to the lower shell 2.

[0055] Two curved surfaces are provided on the outer wall of the upper shell 1, opposite the inner bottom surface. During TKA surgery, these surfaces contact the medial and lateral condyles of the distal femur, respectively. The auxiliary device needs to measure the forces applied to these curved surfaces by the medial and lateral condyles, respectively. Therefore, two corresponding intermediate components are typically located within the chamber. These two intermediate components have similar structures and are typically symmetrically arranged. Therefore, the following detailed description uses one of these components as an example.

[0056] The deformable member 3 includes a connecting body 15 and a deformable member 14. The connecting body 15 is connected to the lower shell 2. One end of the deformable member 14 is connected to the connecting body 15, and the other end is a free end. That is, the deformable member 14 is similar to a cantilever beam structure. The conductive member 11 is connected to the free end of the deformable member 14, and the strain gauge 16 is attached to the deformable member 14. Preferably, the strain gauge 16 should be attached to the position where the deformable member 14 will undergo maximum elastic deformation when subjected to force. Specifically, in this embodiment, the deformable member 14 and the connecting body 15 are integrally formed, and the strain gauge 16 is attached to the connection between the deformable member 14 and the connecting body 15. Of course, in other embodiments, the structure and shape of the deformable member 3 can be various, and are not limited here. For example, the deformable member 3 can have a strip structure, with both ends of the strip structure of the deformable member 3 connected to the lower shell 2 respectively, and the strain gauge 16 and the conductive member 11 are respectively arranged on both sides of the middle portion of the strip structure of the deformable member 3.

[0057] The positioning of the deformable member 3 within the chamber is achieved by aligning the connecting body 15 with the lower shell 2. Specifically, the connecting body 15 is provided with a plurality of second positioning holes 13, and the lower shell 2 is provided with a corresponding plurality of second positioning posts 12. The second positioning posts 12 are inserted into the corresponding second positioning holes 13 to achieve the positioning and installation of the connecting body 15 and the lower shell 2. Of course, in other embodiments, other positioning methods can be used between the connecting body 15 and the lower shell 2, and this is not limited here.

[0058] The deformable part 3 needs to be elastically deformed, so it is preferably an elastomer made of elastic material. The material of the elastomer is preferably stainless steel, and can also be metal materials such as titanium alloy and aluminum alloy. Metal materials have a large elastic modulus, and can withstand a large pressure measurement range under the same structural dimensions.

[0059] The deformable member 3 is connected to the lower shell 2 through the lifting member 17 to form a space for the deformable member 3 to undergo elastic deformation. Specifically, the lifting member 17 can be one or more protrusions integrally formed on the inner bottom surface of the lower shell 2, and the connecting body 15 in the deformable member 3 is adhered to the protrusions. Of course, in other embodiments, the connection method between the lifting member 17 and the deformable member 3 and the lower shell 2 can also be other methods, such as fastener connection, snap connection, etc.; the lifting member 17 can also be connected to other positions of the lower shell 2, such as the side wall portion, etc.; there is no limitation here. Normally, the lifting member 17 and the second positioning column 12 are arranged in one place, and the second positioning column 12 is arranged on the plane of the lifting member 17 facing the upper shell 1. In another optional embodiment, the lifting member 17 can also be connected to the deformable member 3 as shown in Figure 5 to form a whole with it (when the deformable member 3 is made of metal material, the lifting member 17 can also be made of metal material, and the two are connected by welding), and then the lifting member 17 is pasted on the inner bottom surface of the lower shell 2. At this time, the second positioning hole 13 can be set on the lifting member 17 instead of the deformable member 3.

[0060] When designing the deformable part 3, the buckle 9, the first positioning column 7 and other components, attention should be paid to avoidance to prevent interference and failure to install. If necessary, avoidance grooves, avoidance holes, etc. can be opened on the deformable body 14 of the deformable part 3 for avoidance.

[0061] The conductive member 11 is preferably a conductive column, with its two ends connected to the upper shell 1 and the deformable member 3, respectively. Of the connections between the conductive column and the upper shell 1 and the deformable member 3, one is a fixed connection, and the other is a contact connection. In this embodiment, one end of the conductive column is fixedly connected to the inner bottom surface of the upper shell 1 (specifically, it can be integrally formed or fixedly connected by bonding, etc.), while the other end of the conductive column is in contact with the free end of the deformable body 14. The specific connection is between the end face of the conductive column and the force-bearing surface 18 on the free end of the deformable body 14. In this embodiment, the end face of the conductive column and the force-bearing surface 18 on the free end of the deformable body 14 are both planar; in other embodiments, the end face of the conductive column and the force-bearing surface 18 on the free end of the deformable body 14 can have other shapes, such as spherical surfaces. In another optional embodiment, the conductive column can be fixedly connected to the free end of the deformable body 14, and the force-bearing surface 18 opposite thereto can be set on the inner bottom surface of the upper shell 1, and the force-bearing surface 18 and the end surface of the conductive column corresponding to the force-bearing surface 18 can both be planes or spherical surfaces or other shapes.

[0062] The measurement unit includes a circuit module 4 and multiple strain gauges 16. The strain gauges 16 are electrically connected to the circuit module 4 via wires. The circuit module 4 can detect the current value in the current loop where each strain gauge 16 is located and feed this current value back to an external receiving end via a signal. The number of strain gauges 16 corresponds to the number of deformable bodies 14, with a strain gauge 16 provided at the connection between each deformable body 14 and the connecting body 15. A deformable member 3 includes multiple deformable bodies 14, and the arrangement of multiple strain gauges 16 can increase the accuracy of the final calculated resultant force value and the position of the resultant force on the upper shell 1. There is no limit to the number of strain gauges 16 and deformable bodies 14. Preferably, in this embodiment, three deformable bodies 14 are connected to the connecting body 15 of a deformable member 3, and the contact points of the free ends of the three deformable bodies 14 with the conductive pillars form a triangular configuration. The strain gauges 16 can preferably be resistance strain gauges.

[0063] The auxiliary device needs to be calibrated to obtain a calibration curve. Specifically, different pressures are applied to the force-bearing surface 18 of the deformable body 14 to obtain the current value in the current loop where the corresponding strain gauge 16 is located, and a corresponding calibration curve is formed. As a result, when the auxiliary device is used during surgery, it can obtain the pressure applied by the corresponding conductive part 11 to the deformable part 3 based on the current value obtained by detection, and then calculate the resultant force value and the center of the resultant force of the pressure on the upper shell 1 in combination with the parameters such as the position of the conductive part 11 on the upper shell 1 and the shape of the upper shell 1. Since the deformable part 3 undergoes elastic deformation when it is subjected to the pressure applied by the conductive part 11, when the same deformable part 3 is subjected to the same pressure at the same position, the specific deformation of the elastic deformation produced is consistent (while plastic deformation is uncontrollable, and the deformation will almost be different each time), thereby ensuring the accuracy of the measurement.

[0064] During a TKA procedure, the assistive device is placed between the knee joints, with the lower shell 2 resting on the tibial plateau and the upper shell 1 contacting the medial and lateral condyles of the distal femur. The relative movement of the femur and tibia compresses the left and right curved surfaces of the upper shell 1, causing it to move downward relative to the lower shell 2. This, in turn, drives the conductive column to compress the free end of the deformable body 14, causing elastic deformation of the deformable element 3, primarily the deformable body 14. This, in turn, causes the strain gauge 16 to deform, which in turn changes the resistance of the strain gauge 16, resulting in a change in the current in the current loop. This change in current is detected by the circuit module 4. Based on the strain effect of the strain gauge 16, the change in resistance of the strain gauge 16 is linearly related to its deformation. Since the current in the current loop is linearly related to the resistance, the deformation of the deformable body 14 is also linearly related to the pressure it is subjected to. Therefore, the pressure on the deformable body 14 can be accurately calculated based on the current change detected by the circuit module 4. The resultant force and center point of the pressure on one side can be calculated by using the pressure values ​​applied to multiple deformable bodies 14 on a single side (i.e., multiple deformable bodies 14 in a single intermediate assembly). At the same time, since there is a certain amount of free movement between the upper shell 1 and the lower shell 2, the pressure on the upper shell 1 can be fully transmitted to the deformable body 14 through the conductive part 11. The measured force value is consistent with the actual force value, and the measurement result is intuitive and reliable.

[0065] Several other embodiments are provided below:

[0066] In another feasible embodiment, as shown in FIG7 , the deformable member 3 includes a plurality of independent deformable bodies 14, each of which is supported and connected at both ends by a lifting member 17 connected to the inner bottom surface of the lower shell 2. In this way, the manufacturing cost of the deformable member 3 can be lower, but because the deformable body 14 is supported at both ends, the measurement accuracy of the auxiliary device is poor and the installation process is complicated. A force-bearing surface 18 is provided on the upper surface of the middle portion of each deformable body 14, and a strain gauge 16 is adhered to the lower surface of the middle portion of the deformable body 14. A conductive member 11 is provided at the corresponding position of the upper shell 1 to press on the force-bearing surface 18 of the deformable body 14, causing the deformable body 14 to deform, thereby causing the strain gauge 16 below it to deform.

[0067] In another feasible embodiment, as shown in FIG8 , the deformable member 3 includes a plurality of deformable bodies 14. One end of all the deformable bodies 14 in the same deformable member 3 converges to a point (that is, the deformable bodies 14 are connected together). The convergence point and the other end of the deformable body 14 are supported and connected by a lifting member 17 connected to the inner bottom surface of the lower shell 2. The force-bearing surface 18 and the strain gauge 16 are respectively arranged on the upper and lower surfaces of the middle portion of the deformable body 14. With this structure, the manufacturing cost of the deformable member 3 is low and the installation is simple, but the auxiliary device also has the problem of poor measurement accuracy, and the range of the center of the resultant force that can be measured is small.

[0068] In another feasible embodiment, as shown in FIG9 , the deformable member 3 is a C-shaped planar strip structure.

[0069] In another feasible embodiment, as shown in Figure 10, the deformable member 3 includes a connecting body 15 and multiple deformable bodies 14, one end of the multiple deformable bodies 14 is connected to the connecting body 15 located in the middle, and the other end is a free end. The deformable body 14 has a protrusion, and a strain gauge 16 is pasted on the upper part, front part and side part of the protrusion respectively, which can measure the three-dimensional stress condition of the deformable body 14 and can more realistically reflect the comprehensive stress state of the deformable body 14.

[0070] In another feasible embodiment, as shown in Figure 11, the lifting member 17 is not provided, and the connecting body 15 in the deformable member 3 is directly adhered to the inner bottom surface of the lower shell 2, and a groove 19 is also provided on the inner bottom surface of the lower shell 2 for the deformable body 14 in the deformable member 3 to undergo elastic deformation.

[0071] Example 2

[0072] Referring to Figures 12 and 13 , this embodiment provides an auxiliary device for knee joint pressure measurement based on Example 1. In this embodiment, to achieve a higher level of protection, the connection between the upper shell 1 and the lower shell 2 is improved. Instead of providing a slot 5 and a rib 6 , the upper shell 1 and the lower shell 2 are connected via a flexible telescopic member.

[0073] Specifically, the flexible telescopic member may be made of soft rubber 20 .

[0074] As shown in Figure 12, a circle of corrugated soft rubber 20 is set between the upper shell 1 and the lower shell 2. The soft rubber 20 is sealed with the upper shell 1 and the lower shell 2. The soft rubber 20 can be deformed freely, so that the upper shell 1 and the lower shell 2 have a certain amount of free movement, thereby achieving a higher level of protection without affecting the actual pressure value (that is, the upper shell 1 will not undergo plastic deformation, resulting in part of the pressure being absorbed).

[0075] Furthermore, as shown in Figure 13, the upper shell 1 can be separated into two left and right force-bearing plates 21. Both left and right force-bearing plates 21 are connected to the lower shell 2 via a soft adhesive 20. This allows the left and right force-bearing plates 21 to move relative to the lower shell 2 independently of each other, thereby achieving independent force measurement on both sides without interference. The soft adhesive 20 can be connected to the two force-bearing plates 21 and the lower shell 2 by injection molding, gluing, plasma welding, laser welding, etc.

[0076] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. An auxiliary device for measuring knee joint pressure, characterized in that: include: An upper shell and a lower shell, the upper shell and the lower shell are connected to each other and cooperate to form a chamber; an intermediate component, arranged in the chamber, comprising a deformable member and a conductive member, wherein the deformable member is connected to the lower shell, the conductive member is arranged between the deformable member and the upper shell, and its two ends are respectively connected to the upper shell and the deformable member, and the conductive member is used to transmit the pressure exerted on the upper cover to the deformable member so that the deformable member undergoes elastic deformation; a space for the deformable member to undergo elastic deformation is reserved between the deformable member and the lower shell; The measuring unit has a detection end which is a strain gauge, and the strain gauge is attached to the surface of the deformable member and deforms with the elastic deformation of the deformable member.

2. The auxiliary device for measuring knee joint pressure according to claim 1, characterized in that: The strain gauge is a resistance strain gauge.

3. The auxiliary device for measuring knee joint pressure according to claim 1, characterized in that: The deformable member is connected to the lower shell via a lifting member to form a space for the deformable member to undergo elastic deformation.

4. The auxiliary device for measuring knee joint pressure according to claim 1, characterized in that: The deformable member is an elastic body.

5. The auxiliary device for measuring knee joint pressure according to claim 1, characterized in that: The deformable member includes a connecting body and a deformable body, the connecting body is connected to the lower shell, one end of the deformable body is connected to the connecting body, and the other end is a free end, the conductive member is connected to the free end of the deformable body; the strain gauge is fitted and connected to the deformable body.

6. The auxiliary device for measuring knee joint pressure according to claim 5, characterized in that: The deformation body and the connection body are made in one piece, and the strain gauge is fitted and connected to the connection between the deformation body and the connection body.

7. The auxiliary device for knee joint pressure measurement according to claim 1, characterized in that: The deformable member is a strip-shaped structure, both ends of the strip-shaped structure of the deformable member are respectively connected to the lower shell, and the strain gauge is connected to the middle part of the strip-shaped structure of the deformable member.

8. The auxiliary device for knee joint pressure measurement according to claim 1, characterized in that: The deformable member is a stainless steel component, a titanium alloy component or an aluminum alloy component.

9. The auxiliary device for measuring knee joint pressure according to claim 1, characterized in that: Among the connections between the conductive member, the upper shell and the deformable member, one is a fixed connection and the other is a contact connection.

10. The auxiliary device for measuring knee joint pressure according to claim 1, characterized in that: The connection between the upper shell and the lower shell is a non-rigid connection.

11. The auxiliary device for measuring knee joint pressure according to claim 10, characterized in that: The upper shell and the lower shell both include a main body portion and a side wall portion arranged around the main body portion, wherein a groove extending around the circumference is provided on the end face of one of the side wall portions, and a rib extending around the circumference is provided on the end face of the other side wall portion, wherein the rib extends into the groove and the two side walls of the rib are in contact with the two side walls of the groove.

12. The auxiliary device for knee joint pressure measurement according to claim 11, characterized in that: A limiting structure is provided between the upper shell and the lower shell to prevent the upper shell and the lower shell from being separated.

13. The auxiliary device for measuring knee joint pressure according to claim 10, characterized in that: The upper shell and the lower shell are connected via a flexible telescopic member.

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