CN111419253A - Knee joint soft tissue pressure measuring device, measuring system and measuring method - Google Patents

Abstract

The invention provides a knee joint soft tissue pressure measuring device, a knee joint soft tissue pressure measuring system and a knee joint soft tissue pressure measuring method for human knee joint replacement surgery, which can solve the problem of balancing of the pressure of the inner side and the outer side of a knee joint in the knee joint replacement surgery process and provide reference for the bone cutting amount of a femoral part and the implantation size of a prosthesis. The structure is simple, the cost is low, and the universality is strong; the measurement accuracy and the sensitivity are high, the operation is simple, the display information is rich, the operation of doctors can be greatly facilitated, the operation time is saved, the clinical operation efficiency is improved, and the bleeding amount of patients and the injury to the patients caused by the operation are obviously reduced.

Description

Knee joint soft tissue pressure measurement device, measurement system and measurement method

technical field

The invention belongs to the technical field of medical devices, and in particular relates to a knee joint soft tissue pressure measuring device, a measuring system and a measuring method for human knee joint replacement surgery.

Background technique

As the population ages, the number of patients suffering from knee osteoarthritis is on the rise, and hospitals are performing more and more artificial joint replacements each year. Artificial knee replacement surgery solves the problems of knee joint aging or necrosis and loss of function for patients, relieves the pain of patients, and greatly improves the quality of life of patients.

In its Chinese invention patent application CN105919607A, the applicant disclosed a human knee joint soft tissue pressure and its trajectory measurement system. The force-bearing surface of the shell adopts a concave arc surface, and the pressure sensor adopts a film sensor, which has a complex shape and structure and high power consumption. , low precision, so the clinical effect is not good, it is difficult to be widely used.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects of the prior art, the purpose of the present invention is to provide a knee joint soft tissue pressure measurement device, a measurement system and a measurement method for human knee joint replacement surgery, which can solve the problem of knee joint pressure during knee joint replacement surgery. The balance of lateral pressure, and provide a reference for the amount of osteotomy in the femur and the size of the prosthesis implantation. It has simple structure, low cost and strong compatibility; high measurement accuracy and sensitivity, simple operation and rich display information, which can greatly facilitate the operation of doctors and save operation time, thereby improving the efficiency of clinical operations and significantly reducing the bleeding of patients. amount and the damage caused by surgery.

In order to achieve the above object, in one aspect, the present invention provides a knee joint soft tissue pressure measurement device for human knee joint replacement surgery, comprising a casing, a circuit board and a resistance strain gauge; wherein,

The casing is used for accommodating the circuit board and the resistance strain gauge, and the casing is provided with a force-bearing surface, and the force-bearing surface is a plane;

The circuit board includes a power supply, a microprocessor, an analog-to-digital converter (ADC) and a wireless communication module;

The resistive strain gauge is electrically connected to the circuit board, which is located below the force-bearing surface. Resistive strain gauge is a pressure sensor, a pressure sensor is a device that can sense pressure signals and convert the pressure signals into usable output electrical signals according to certain rules. When the resistive strain gage is under pressure, the output electrical signal is transmitted to the microprocessor and/or analog-to-digital converter on the circuit board for processing.

Further, the casing includes a first casing and a second casing, and the force-bearing surface is located on the upper surface of the first casing.

Further, the force-bearing surface also includes a left force-bearing surface and a right force-bearing surface. The left force-bearing surface and the right force-bearing surface respectively have three force-bearing columns, and the force-bearing columns are located at one end of the cantilever beam. , the cantilever beam deforms, which transmits pressure to the resistive strain gage located under the force-bearing column.

Further, the deformation angle range of the resistance strain gauge is ±3.6°, and the sensitivity is 2.0-2.2.

Further, the triangle formed by the three force columns on the left force surface or the right force surface is an obtuse triangle, and the largest angle among the three angles of the obtuse triangle is α, and 90°<α<110°, It is preferably 95°<α<105°, more preferably 100°; the smallest angle among the three angles is γ, and 15°<γ<35°, preferably 20°<γ<30°, more preferably 25° ; Correspondingly, the other angle of the three angles is β, and 45°<β<65°, preferably 50°<β<60°, more preferably 55°. The side opposite to the largest angle α extends substantially in the direction of the axis of symmetry of the housing. Specifically, the included angle between the side opposite to the maximum angle α and the axis of symmetry of the housing is between 0° and 5°.

Further, the length of the cantilever beam is 0.5-2cm, the longitudinal section of the cantilever beam along its length direction is a trapezoid, and its end close to the force-bearing column is thinner, so that the cantilever beam deforms when it is under pressure; One end of the force column is thicker to ensure that the cantilever beam has sufficient strength. The pressure displacement of the cantilever beam at the force column is 0.004-0.006mm/N, preferably 0.005mm/N, that is, when the force column is subjected to 100N pressure, the displacement in the vertical direction is 0.5mm.

Further, the power supply is electrically connected to and supplies power to electronic devices such as microprocessors, analog-to-digital converters, and wireless communication modules on the circuit board. The power source can be a button battery, a dry battery or a rechargeable lithium battery, preferably a button battery.

Further, the microprocessor is an embedded programmable controller, such as FPGA, CPLD, single-chip microcomputer, etc., which is used for analyzing and processing data and controlling other modules on the circuit board.

Further, the wireless communication module is a Bluetooth, WiFi or Zig-Bee communication module, preferably a Bluetooth module.

Further, the circuit board also includes a power switch. Preferably, the power switch adopts a magnetic switch.

In another aspect, the present invention also provides a knee joint soft tissue pressure measurement system for human knee joint replacement surgery, which includes a handle in addition to the above knee joint soft tissue pressure measurement device.

Further, the handle includes a pallet and a handle. There are limit posts on the support plate, which can be matched with limit holes on the shell, so that the knee joint soft tissue pressure measurement device can be quickly installed on the support plate of the handle. The handle is textured to increase friction and make it easier to hold.

Further, the knee joint soft tissue pressure measurement system for human knee joint replacement surgery of the present invention further comprises a knee joint space evaluation block for evaluating the knee joint space size of a patient. There can be multiple knee joint space assessment blocks, each with different thickness specifications, such as 1mm, 2mm, 5mm, 10mm, etc., and can be replaced or used in combination with each other to adapt to the size of the knee joint space of different patients. The uppermost gap evaluation block (that is, the gap evaluation block that touches the femur) can also be designed as a curved surface, with various shapes and specifications to adapt to the shape of the femur of different patients. Clearance The knee joint space evaluation block can also be a split design, that is, it is divided into two left and right unilateral knee joint space evaluation blocks, and the two evaluation blocks can respectively have different thickness specifications.

Further, the lower surface of the knee joint space evaluation block has a groove corresponding to the force-bearing column of the knee joint soft tissue pressure measurement device, which is used to fix the knee joint space evaluation block above the knee joint soft tissue pressure measurement device, and to The pressure of the knee joint soft tissue on the knee joint space evaluation block is transmitted to the force column, which in turn is transmitted to the resistive strain gage located below it.

Further, the knee joint soft tissue pressure measurement system for human knee joint replacement surgery of the present invention further includes a wireless receiving module, a data processing module and a display module.

Further, the data receiving module, the data processing module and the display module are integrated in an intelligent terminal, such as a desktop computer, a notebook computer, a tablet computer or a smart phone and other integrated electronic devices with data receiving, processing and display functions.

In a typical example of using the knee joint soft tissue pressure measurement system of the present invention to measure the knee joint soft tissue pressure of a patient undergoing knee replacement surgery, the knee joint soft tissue pressure measurement device, the knee joint space evaluation block and the holder are first Assembled together, placed on the tibial platform of the patient after osteotomy; the knee joint is moved in the way of flexion and extension. During the movement, the pressure sensor is subjected to the pressure exerted on it by the human femur, and the pressure sensor converts the pressure change into an electrical signal. The electrical signal is amplified by the front-end signal processing circuit, and then converted into a digital signal by an analog-to-digital converter, and then sent to the embedded microprocessor through the SPI communication interface for analysis, processing and control, and then the processed signal is passed through a high-performance The Bluetooth module performs transmission, and the result display and human-computer interaction are performed in the interactive software of the tablet computer. According to the displayed pressure value, the doctor performs femoral osteotomy or soft tissue release with corresponding tools to complete the pressure balance in knee replacement surgery.

In another aspect, the present invention also provides a method for measuring knee joint pressure using the above knee joint soft tissue pressure measurement system, comprising the following steps:

A. Initialize and calibrate the knee soft tissue pressure measurement system:

(1) Establish communication between the knee joint soft tissue pressure measurement device and the intelligent terminal;

(2) Combine the knee joint soft tissue pressure measurement device and the knee joint space evaluation block and place it on the push-pull gauge platform;

(3) Align the indenter of the push-pull gauge with the middle position of the knee joint space evaluation block on one side (for example, the left side), and under multiple different pressures (for example, the first pressure, the second pressure, the third pressure), Collect the different measured AD values (F) and the actual pressure values (x); align the indenter of the push-pull gauge with the middle position of the knee joint space evaluation block on the other side (for example, the right side). Under the pressure (such as the first pressure, the second pressure, the third pressure), the different AD values (F) and the actual pressure value (x) are collected;

(4) Use the linear formula F=Ax+B to fit the above values measured at each pressure point, and solve the A value and B value corresponding to each pressure point, that is, to obtain the calibration value of each pressure point The linear formula of F=Ax+B;

B. Use the knee joint soft tissue pressure measurement system for pressure measurement:

(a) Assemble the knee joint soft tissue pressure measurement device, the knee joint space assessment block and the holder, and place the assembled device on the patient's tibial plateau after osteotomy; according to the femur and the described The gap between the knee joint soft tissue pressure measurement devices, if the thickness of the knee joint space evaluation block is not appropriate, replace the knee joint space evaluation block with different thicknesses until the appropriate thickness of the knee joint space evaluation block is reached;

(b) Exercise the knee joint in the way of flexion and extension, and collect AD values measured at six pressure points in real time during the exercise (F);

(c) Substitute the AD values measured above into the linear formula F=Ax+B after the calibration of the six pressure points respectively, that is, to obtain the pressure value (x) of each pressure point;

(d) Taking the pressure values of the three pressure points on the same side as weights, calculate the weighted average value of the abscissa and the weighted average value of the ordinate of the three pressure points respectively, that is, to obtain the position of the center of gravity of the side. The abscissa value and the ordinate value; and the resultant force on the center of gravity is the sum of the pressure values on the three pressure points;

(e) Display the real-time pressure value of each pressure point, the real-time position of the center of gravity and the resultant force on the center of gravity on the intelligent terminal, and record the position of the center of gravity within a period of time, that is, form a pressure running track.

During the operation, according to the pressure on the inside and outside of the knee joint (that is, on the left and right sides) displayed by the smart terminal, the doctor can choose to use the corresponding osteotomy tool to cut the femur or release the nearby soft tissue until it reaches the inside and outside of the knee joint. pressure balance.

The beneficial technical effects of the present invention are at least reflected in the following aspects:

(1) The pressure sensors in the prior art mostly use thin film sensors, which have low precision, complex circuit design and high cost; the pressure sensor of the present invention uses a resistance strain gauge, which has high precision, simple circuit design and mechanical structure, and high integration. Small size, low cost, and can be made into a disposable product to avoid repeated use, so it is safer.

(2) In the prior art, if three or more pressure sensors are used, the sensors are usually arranged in a symmetrical shape, such as an equilateral or isosceles triangle. This arrangement is to achieve a larger pressure measurement area; The invention creatively arranges three resistive strain gauges (that is, force columns) into a special asymmetric obtuse-angled triangular structure. Although this arrangement reduces the pressure measurement area on the surface, it is actually more in line with the knee joint. Therefore, the effective pressure measurement area is increased, making the measurement results more effective, accurate and comprehensive.

(3) The force-bearing surface of the shell in the prior art usually adopts a concave arc surface to conform to the shape of the patient's femur, but there are individual differences in the shape of the femur of different patients; and the present invention makes the shell of the device (disposable product) subject to The force surface is designed as a plane, and the uppermost gap evaluation block (which can be used repeatedly) is designed as an arc surface. On the one hand, the device is simple in structure, easy to process, low in cost, and more versatile; on the other hand It can also adapt to the shape of the femur of different patients, taking into account the individual needs.

(4) The present invention can simultaneously display pressure magnitude, pressure distribution and pressure running track, and display them in different colors according to different pressure magnitudes, so the information is rich and the degree of visualization is high, which greatly facilitates the operation of doctors.

Description of drawings

1 is a schematic diagram of the assembled state of a knee joint soft tissue pressure measurement device, a knee joint gap evaluation block and a gripper according to a preferred embodiment of the present invention;

2 is a schematic three-dimensional structure diagram of a knee joint soft tissue pressure measurement device according to a preferred embodiment of the present invention;

3 is a schematic diagram of an exploded structure of a knee joint soft tissue pressure measurement device according to a preferred embodiment of the present invention;

4 is a front view and a rear view of a first housing of a knee joint soft tissue pressure measuring device according to a preferred embodiment of the present invention;

5 is a schematic diagram of a cantilever structure of a knee joint soft tissue pressure measurement device according to a preferred embodiment of the present invention;

6 is a schematic three-dimensional structure diagram of the uppermost knee joint space evaluation block according to a preferred embodiment of the present invention;

7 is a schematic three-dimensional structural diagram of a knee joint gap evaluation block according to another preferred embodiment of the present invention;

8 is a front view and a rear view of the knee joint space assessment block of FIG. 7 of the present invention;

9 is a schematic structural diagram of a handle according to a preferred embodiment of the present invention;

10 is a schematic diagram of an interface displayed on a smart terminal by an application program of a knee joint soft tissue pressure measurement system according to a preferred embodiment of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. The following embodiments are implemented on the premise of the technical solutions of the present invention, and provide detailed embodiments and specific operation processes, but the protection scope of the present invention is not limited to the following example.

As shown in Figures 1-9, in a preferred embodiment, the knee joint soft tissue pressure measurement device 1 for human knee joint replacement surgery of the present invention comprises housings 11, 12, a circuit board 15 and a resistance strain gauge 14; The housings 11 and 12 are used to accommodate the circuit board 15 and the resistive strain gauge 14. The housings 11 and 12 include a first housing 11 and a second housing 12. The upper surface of the first housing 11 has a force-bearing surface 13. The force-bearing surface 13 is a plane.

The circuit board 15 includes a power supply, a microprocessor, an analog-to-digital converter and a wireless communication module. The power supply is electrically connected to electronic devices such as microprocessors, analog-to-digital converters, and wireless communication modules on the circuit board 15 and supplies power. The power source is a button battery, which reduces the volume of the circuit board 15 and the circuit integration is high, thereby realizing the miniaturization and low power consumption of the measurement system. The microprocessor is an embedded programmable controller, such as FPGA, CPLD, single-chip microcomputer, etc., which is used for analyzing and processing data and controlling other modules on the circuit board 15 . The wireless communication module is a Bluetooth module. The circuit board 15 also includes a power switch, and the power switch adopts a magnetic switch.

The resistive strain gauge 14 is electrically connected to the circuit board 15 and is located below the force bearing surface 13 . The deformation angle range of the resistive strain gauge 14 is ±3.6°, and the sensitivity is 2.0-2.2.

The force bearing surface 13 includes a left force bearing surface and a right force bearing surface. The left force bearing surface and the right force bearing surface respectively have three force bearing columns 132. The force bearing column 132 is located at one end of the cantilever beam 131. When under pressure, the cantilever beam 131 is deformed, so as to transmit the pressure to the resistive strain gauge 14 located under the force-bearing column 132 .

As shown in FIG. 4 , the triangles ΔABC and ΔDEF formed by the three force-bearing columns A, B, C or D, E, and F on the same force-bearing surface 13 are obtuse-angled triangles. The largest angle of α is 100°; the smallest angle of the three angles is γ and 25°; the other angle of the three angles is β and 55°. The sides BC and EF opposite to the maximum angle α extend substantially in the direction of the axis of symmetry of the housing. Although this special asymmetric obtuse triangle arrangement reduces the pressure measurement area on the surface, it is actually more in line with the ergonomics and pressure division of the knee joint, so it increases the effective pressure measurement area, making the measurement The results are more efficient, precise and comprehensive. According to the usual practice in the prior art, the three force-bearing columns are arranged as symmetrical isosceles ΔA'BC, although the area of ΔA'BC is larger than that of ΔABC (that is, the area of ΔA'BG is larger than that of ΔA'BG). The area of ACG), but the inventor unexpectedly found that due to the special structure of the human knee joint, the actual pressure on the ΔA'BG area is much smaller than the pressure on the ΔACG area during flexion and extension. That is to say, although the area of ΔA'BG is large, a large part of it is invalid, which will affect the accuracy and sensitivity of the measurement results. Therefore, on the basis of a large number of experimental verifications, the inventor found that the use of the special asymmetric obtuse-angled triangular arrangement of the present invention can maximize the effective force-bearing area, thereby making the measurement results of the present invention accurate and sensitive.

As shown in FIG. 5 , the length L of the cantilever beam 131 is 0.5-2 cm, and the longitudinal section of the cantilever beam 131 along its length direction is a trapezoid, which is thinner at the end close to the force-bearing column 132 so that the cantilever beam 131 is under pressure. The deformation S occurs when f; and the end far from the force-bearing column 132 is thicker to ensure that the cantilever beam 131 has sufficient strength. The displacement of the cantilever beam 131 to the pressure f at the force-bearing column 132 is 0.005mm/N, that is, when the force-bearing column 132 is subjected to a pressure f of 100N, the displacement S in the vertical direction is 0.5mm.

The knee joint soft tissue pressure measurement system for human knee joint replacement surgery of the present invention further includes a handle 2 in addition to the above knee joint soft tissue pressure measurement device 1 . The handle 2 includes a pallet 21 and a handle 22 . The support plate 21 has a limit post 23 which can be matched with the limit hole 16 on the first shell 11 , so that the knee joint soft tissue pressure measurement device 2 can be quickly installed on the support plate 21 of the gripper 2 . There are textures on the handle 22 to increase friction and facilitate holding.

The knee joint soft tissue pressure measurement system for human knee joint replacement surgery of the present invention further includes a knee joint space evaluation block 3 for evaluating the knee joint space size of a patient. There can be multiple knee joint space assessment blocks 3, each with different thickness specifications, such as 1mm, 2mm, 5mm, 10mm, etc., and can be replaced or used in combination with each other to adapt to the size of the knee joint space of different patients. As shown in FIG. 6 , in a preferred embodiment, the uppermost gap evaluation block 3 can also be designed as an arc surface, and has various specifications of different shapes, so as to adapt to the shape of the femur of different patients. The knee joint space evaluation block 3 may also be of a split design (not shown in the figure), that is, it is divided into two left and right unilateral knee joint space evaluation blocks, and the two evaluation blocks may have different thickness specifications respectively.

The lower surface of the knee joint space evaluation block 3 has a groove 33 corresponding to the force-bearing column 132 of the knee joint soft tissue pressure measurement device 1 , and is used for fixing the knee joint space evaluation block 3 above the knee joint soft tissue pressure measurement device 1 . , and transmits the pressure of the knee joint soft tissue on the knee joint space evaluation block 3 to the force bearing column 132 , and then transmits it to the resistive strain gauge 14 located below it. The left and right sides 31 and 32 of the knee joint space evaluation block 3 are respectively provided with a positioning hole 34 for connecting with other knee joint space evaluation blocks 3 and used in combination to adapt to the conditions of different patients.

The knee joint soft tissue pressure measurement system for human knee joint replacement surgery of the present invention further comprises a wireless receiving module, a data processing module and a display module. The data receiving module, data processing module and display module are integrated in an intelligent terminal, which is a tablet computer in this embodiment, and its application program interface is shown in Figure 9, which can display the six pressure columns 132 during the measurement process in real time. The pressure value received, the real-time pressure position (center of gravity position), the pressure trajectory within a period of time (the center of gravity trajectory), and the resultant pressure value on one side are displayed in different colors, so the information is rich and the degree of visualization is high. It greatly facilitates the operation of the doctor.

When using the knee joint soft tissue pressure measurement system of this embodiment to measure the knee joint soft tissue pressure of a patient undergoing knee replacement surgery, a knee joint soft tissue pressure measurement device 1 , a knee joint gap evaluation block 3 and a gripper 2 are assembled together (As shown in Figure 1), placed on the tibial plateau of the patient after osteotomy; the knee joint is moved in the way of flexion and extension. During the movement, the pressure sensor is subjected to the pressure exerted on it by the human femur, and the pressure sensor converts the pressure change. The electrical signal is amplified by the front-end signal processing circuit, and then converted into a digital signal by an analog-to-digital converter, and then sent to the embedded microprocessor through the SPI communication interface for analysis, processing and control, and then the processed signal Transmission is performed through a high-performance Bluetooth module, and results display and human-computer interaction are performed in the interactive software of the tablet computer. According to the displayed pressure value, the doctor performs femoral osteotomy or soft tissue release with corresponding tools to complete the pressure balance in knee replacement surgery.

The method for measuring knee joint pressure using the knee joint soft tissue pressure measurement system of this embodiment includes the following steps:

A. Initialize and calibrate the knee soft tissue pressure measurement system:

(1) establishing the communication between the knee joint soft tissue pressure measurement device 1 and the intelligent terminal;

(2) Combine the knee joint soft tissue pressure measurement device 1 and the knee joint space evaluation block 3 and place them on the push-pull force gauge platform;

(3) Align the indenter of the push-pull gauge with the middle position of the left knee joint gap evaluation block 31, and collect the pressure under the pressures of 0N, 45N, and 90N (ie, the first pressure, the second pressure, and the third pressure), respectively. Different measured AD values (F) and actual pressure values (x); align the indenter of the push-pull gauge with the middle position of the right knee joint gap evaluation block 32, under the pressures of 0N, 45N, and 90N, respectively , collect the different AD values (F) and actual pressure values (x) measured;

(4) Use the linear formula F=Ax+B to fit the above numerical points measured at each pressure point in the F-x coordinate axis, and solve the A value and B value corresponding to each pressure point, that is, get The linear formula F=Ax+B after calibration of each pressure point;

B. Use the knee joint soft tissue pressure measurement system for pressure measurement:

(a) Assemble the knee joint soft tissue pressure measurement device, the knee joint space assessment block and the holder, and place the assembled device on the patient's tibial plateau after osteotomy; according to the femur and the described The gap between the knee joint soft tissue pressure measurement devices, if the thickness of the knee joint space evaluation block is not appropriate, replace the knee joint space evaluation block with different thicknesses until the appropriate thickness of the knee joint space evaluation block is reached;

(b) Exercise the knee joint in the way of flexion and extension, and collect AD values measured at six pressure points in real time during the exercise (F);

(c) Substitute the AD values measured above into the linear formula F=Ax+B after the calibration of the six pressure points respectively, that is, to obtain the pressure value (x) of each pressure point;

(d) Taking the pressure values of the three pressure points on the same side as weights, calculate the weighted average value of the abscissa and the weighted average value of the ordinate of the three pressure points respectively, that is, to obtain the position of the center of gravity of the side. The abscissa value and the ordinate value; and the resultant force on the center of gravity is the sum of the pressure values on the three pressure points;

(e) Display the real-time pressure value of each pressure point, the real-time position of the center of gravity and the resultant force on the center of gravity on the intelligent terminal, and record the position of the center of gravity within a period of time, that is, form a pressure running track.

During the operation, according to the pressure on the inside and outside of the knee joint (that is, on the left and right sides) displayed by the smart terminal, the doctor can choose to use the corresponding osteotomy tool to cut the femur or release the nearby soft tissue until it reaches the inside and outside of the knee joint. pressure balance.

The preferred embodiments of the present invention have been described in detail above. It should be understood that many modifications and changes can be made according to the concept of the present invention by those skilled in the art without creative efforts. Therefore, any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited tests on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims (10)

1. A knee joint soft tissue pressure measuring device for human knee joint replacement surgery is characterized by comprising a shell, a circuit board and a resistance type strain gauge; wherein,

the shell is used for accommodating the circuit board and the resistance type strain gauge, and a stress surface is arranged on the shell and is a plane;

the circuit board comprises a power supply, a microprocessor, an analog-to-digital converter and a wireless communication module;

the resistance type strain gauge is electrically connected with the circuit board and is positioned below the stress surface.

2. The knee joint soft tissue pressure measurement device of claim 1, wherein the housing comprises a first housing and a second housing, the force bearing surface being located on an upper surface of the first housing; the stress surface comprises a left stress surface and a right stress surface, the left stress surface and the right stress surface are respectively provided with three stress columns, the stress columns are located at one ends of cantilever beams, and when the stress columns bear pressure, the cantilever beams deform so as to conduct the pressure to the resistance-type strain gauges located below the stress columns.

3. The knee joint soft tissue pressure measurement device according to claim 2, wherein the deformation angle range of the resistance type strain gauge is ± 3.6 degrees, and the sensitivity is 2.0-2.2.

4. The knee joint soft tissue pressure measurement device according to claim 2, wherein the triangle formed by the three force-bearing columns on the left force-bearing surface or the right force-bearing surface is an obtuse triangle, the largest angle of the three angles of the obtuse triangle is α, 90 degrees < α <110 degrees, the smallest angle of the three angles is gamma, 15 degrees < gamma <35 degrees, the other angle of the three angles is β, and 45 degrees < β <65 degrees, and the side opposite to the largest angle α extends approximately along the symmetry axis of the shell.

5. The device for measuring the soft tissue pressure of the knee joint as claimed in claim 2, wherein the length of the cantilever beam is 0.5-2 cm, and the pressure displacement of the cantilever beam at the stress column is 0.004-0.006 mm/N.

6. A knee joint soft tissue pressure measuring system for human knee joint replacement surgery is characterized in that,

the knee soft tissue pressure measurement system comprises the knee soft tissue pressure measurement device of claim 2;

the knee joint soft tissue pressure measuring system also comprises a holder and a knee joint clearance evaluating block;

the knee joint soft tissue pressure measuring system further comprises a wireless receiving module, a data processing module and a display module.

7. The knee joint soft tissue pressure measurement system of claim 6, wherein the holder comprises a plate and a handle; the supporting plate is provided with a limiting column which can be matched with a limiting hole on the shell; the handle is provided with grains.

8. The knee joint soft tissue pressure measuring system according to claim 6, wherein the lower surface of the knee joint gap evaluation block has a groove corresponding to the stress column of the knee joint soft tissue pressure measuring device for fixing the knee joint gap evaluation block above the knee joint soft tissue pressure measuring device and transmitting the pressure of the knee joint soft tissue on the knee joint gap evaluation block to the stress column and further to the resistive strain gauge located therebelow.

9. The knee joint soft tissue pressure measurement system according to claim 6, wherein the data receiving module, the data processing module and the display module are integrated into an integrated intelligent terminal with data receiving, processing and displaying functions.

10. A method of measuring knee joint pressure using the knee joint soft tissue pressure measurement system of claim 9, comprising the steps of:

A. performing initial calibration on the knee joint soft tissue pressure measurement system:

(1) establishing communication between the knee joint soft tissue pressure measuring device and the intelligent terminal;

(2) the knee joint soft tissue pressure measuring device and the knee joint clearance evaluating block are combined and then placed on a push-pull dynamometer platform;

(3) aligning a pressure head of a push-pull dynamometer to the middle position of one side of the knee joint clearance evaluation block, and collecting measured values under different first pressure, second pressure and third pressure; aligning the pressure head of the push-pull dynamometer to the middle position of the other side of the knee joint clearance evaluation block, and collecting different AD values (F) and actual pressure values (x) of six pressure points measured under different first pressure, second pressure and third pressure;

(4) fitting the measured values at each pressure point by using a linear formula F (Ax + B), and solving an A value and a B value corresponding to each pressure point to obtain the linear formula F (Ax + B) after each pressure point is calibrated;

B. performing pressure measurements using the knee joint soft tissue pressure measurement system:

(a) assembling the knee joint soft tissue pressure measuring device, the knee joint clearance evaluating block and the holder together, and placing the assembled device on a tibial plateau of a patient after osteotomy; according to the gap between the femur and the knee joint soft tissue pressure measuring device, if the thickness of the knee joint gap evaluation block is not proper, the knee joint gap evaluation blocks with different thicknesses are replaced until the proper thickness of the knee joint gap evaluation block is reached;

(b) the knee joint is moved in a flexion and extension mode, and AD values (F) measured by six pressure points are collected in real time in the movement process;

(c) respectively substituting the measured AD values into a linear formula F which is obtained by calibrating six pressure points and is equal to Ax + B to obtain a pressure value (x) borne by each pressure point;

(d) respectively calculating the weighted average value of the abscissa and the weighted average value of the ordinate of the three pressure points by taking the pressure values borne by the three pressure points on the same single side as weights, and obtaining the abscissa value and the ordinate value of the gravity center position of the single side; the resultant force borne by the gravity center point is the sum of the pressure values borne by the three pressure points;

(e) and displaying the real-time pressure value of each pressure point, the real-time position of the gravity center point and the resultant force applied to the gravity center point on the intelligent terminal, and recording the position of the gravity center point within a period of time to form a pressure running track.

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