Knee joint pressure balance measurement system based on knee joint pad

Abstract

The present invention relates to the field of knee joint pressure measurement, and provides a knee joint pressure balance measurement system based on a knee joint pad, comprising a tibial pad, a pressure acquisition module, a signal receiving and displaying module, a data processing module and a computer, wherein the pressure acquisition module comprises a left pressure sensor group, a right pressure sensor group and a rigid circuit, wherein the left pressure sensor group and the right pressure sensor group each comprise 15 sensors 1, wherein the sensors 1 are used to collect pressure data of the knee joint in different states, wherein the different states comprise knee flexion at 0°, 30°, 60°, 90°, 120°, 150° and 180°, and wherein the several sensors 1 are integrated in the rigid circuit; the present invention improves the accuracy of knee joint balance by calculating the linear relationship between the input signal and the input pressure of the calibration sensor 1, which can not only increase the service life of the patient's postoperative prosthesis, but also reduce the incidence of postoperative complications and improve the patient's postoperative quality of life.

Description

Technical Field

[0001] The invention relates to the field of knee joint pressure measurement, in particular to a knee joint pressure balance measurement system based on a knee joint pad. Background Art

[0002] Knee osteoarthritis is a common chronic degenerative joint disease, usually caused by long-term joint use, aging, trauma, genetic factors, etc., and the symptoms of knee osteoarthritis include knee pain, swelling, stiffness, limited joint movement, etc.; as the disease progresses, the function of the knee joint gradually weakens and may even lead to difficulty walking; for patients with severe osteoarthritis in the middle and late stages, total knee arthroplasty (TKA) is the first choice for surgical treatment.

[0003] Total knee replacement surgery uses metal, high molecular weight polyethylene, ceramics and other materials to make artificial knee joint prostheses according to the morphology, structure and function of human joints. It is implanted into the human body through surgical techniques to relieve the patient's joint pain and restore joint function. Total knee replacement surgery is often used to treat and improve diseases such as end-stage knee arthritis, knee cartilage necrosis, and knee valgus / valgus deformity. It includes two steps: osteotomy and soft tissue release to restore the force line of the lower limbs and maintain soft tissue balance, thereby achieving knee joint balance. However, imbalance in total knee replacement surgery can cause pain in the patient, wear and loosening of the prosthesis, and may also cause the patient to feel unstable, prone to falling or falling while walking, ultimately affecting the patient's health and the length of time the prosthesis stays in the patient's body.

[0004] Chinese Patent Publication No.: CN113925493A, a knee joint multi-parameter measurement system based on total knee replacement; including: a matrix pressure sensor array is used to place it on the osteotomy plane of the patient's knee joint lower limb during the doctor's operation to obtain a pressure signal; a posture measurement device is used to place it on the osteotomy plane of the patient's knee joint lower limb during the doctor's operation to obtain a posture signal of the lower limb; a contact trajectory measurement device is used to place it on the osteotomy plane of the patient's knee joint lower limb during the doctor's operation to obtain relevant motion trajectory data; the data measured by the matrix pressure sensor array, the posture measurement device and the contact trajectory measurement device are sent to a data processing device, and temporarily replace the tibial pad during the operation, and then take it out after the pressure and posture are balanced, and put in a suitable tibial pad. Although the above scheme uses the absolute value of the linear pair value to determine whether the knee joint is balanced, because the linear relationship before and after the knee joint operation is dynamically changing, there is a possibility of mistakes and errors.

[0005] In summary, the present invention proposes a knee joint pressure balance measurement system based on a knee joint gasket. Summary of the invention

[0006] The present invention provides a knee joint pressure balance measurement system based on a knee joint gasket. The present invention determines the linearity of the left and right knees to solve the problems in the prior art that imbalance in total knee replacement surgery may cause pain to the patient, wear and loosening of the prosthesis, and the like.

[0007] The prior art solutions of the present invention are as follows:

[0008] A knee joint pressure balance measurement system based on a knee joint pad comprises a tibial pad, a pressure acquisition module, a signal receiving and displaying module, a data processing module and a computer, wherein the pressure acquisition module comprises a left pressure sensor group, a right pressure sensor group and a rigid circuit, wherein the left pressure sensor group and the right pressure sensor group each comprise a plurality of sensors 1, and the plurality of sensors 1 form a pressure measurement plane, wherein the sensor 1 is used to collect pressure data of the knee joint in different states, wherein the different states comprise knee flexion at 0°, 30°, 60°, 90°, 120°, 150° and 180°, wherein the plurality of sensors 1 are integrated in the rigid circuit, and the rigid circuit is attached to the tibial pad, wherein the signal receiving and displaying module comprises a capacitance measurement module, a single chip microcomputer and a Bluetooth module, wherein the capacitance measurement module performs analog-to-digital conversion on the data collected by the sensor and sends the data to the single chip microcomputer for processing, wherein the single chip microcomputer packages and organizes the data of the sensor 1 and sends the data to the computer via the Bluetooth module, wherein the data processing module processes and analyzes the data received by the computer, and the computer displays the pressure distribution of the knee joint in real time;

[0009] The sensor one includes three sensor twos, and the three sensor twos form a pressure measurement plane. Because the linear relationship before and after knee joint surgery is dynamically changing, three pressure sensors are used, and each sensor two has independent parameters. There is a linear relationship between the measurement results, making the measurement results more accurate.

[0010] Furthermore, the three sensors 2 have different physical properties, which results in a comprehensive error when the sensor 2 measures the knee joint. The formula for the comprehensive error is △′=√(△1 2 + △2 2 + △3 2 ), wherein △1, △2, △3 are the errors of the three sensors 2 respectively, and the average value of the weighted values ​​of the three sensors 2 is the weighted value W of sensor 1 (2), and the average value of the pressure values ​​of the three sensors 2 is the pressure value F of sensor 1 (2).

[0011] Furthermore, the data processing module includes a pressure sensor processing method, and the processing method adopted by the pressure sensor is a cubic spline difference algorithm. The cubic spline difference method is a numerical method for data interpolation, which can be used to estimate the values ​​of other positions given a set of known data points. The algorithm utilizes the properties of cubic polynomials and obtains a smooth curve by interpolating the curves between data points.

[0012] Furthermore, the pressure distribution display method is a dynamic two-dimensional or three-dimensional thermal graphics method and a pressure numerical method. The dynamic two-dimensional or three-dimensional thermal graphics method can measure the pressure value of the knee joint gasket contacting the ground by using a sensor, and convert these data into a two-dimensional or three-dimensional graphic display. This method can intuitively display the pressure distribution of the knee joint under different movements and postures, helping doctors and researchers to better understand the distribution of knee joint loads, and the pressure numerical method can convert the pressure value of the knee joint gasket contacting the ground into a numerical value and display it on the screen. This method can provide specific pressure values ​​to help doctors and researchers understand the load of the knee joint more accurately and conduct quantitative analysis.

[0013] Furthermore, there is a linear relationship between the output and input of the sensor 1, and the linear relationship formula is:

[0014] L=|(W1F1+W2F2+...+W n F n ) / (F1+F2+...+F n )|

[0015] Among them, W1 to W n is the weighted value of sensor 1 when knee is bent, F1 to F n is the pressure value of sensor 1 when the knee is bent, and L is the maximum value and threshold value of the balance determined by the absolute value of the linearity value.

[0016] Furthermore, in different states, such as when the knee is flexed at 0°, 30°, 60°, 90°, 120°, 150°, and 180°, the linearity of the left or right pressure sensor group is calculated respectively, and whether the knee joint is in balance is determined by comparing the absolute value of the linearity value. When the knee is flexed at 0°:

[0017] L 0 L =|(W 0 L1 F 0 L1 +W 0 L2 F 0 L2 +...+W 0Ln F 0 Ln ) / (F 0 L1 +F 0 L2 +...+F 0 Ln )|

[0018] L 0 R =|(W 0 R1 F 0 R1 +W 0 R2 F 0 R2 +...+W 0 Rn F 0 Rn ) / (F 0 R1 +F 0 R2 +...+F 0 Rn )|

[0019] L 0 MAX =max(L 0 L , L 0 R )≤L 0 ALL

[0020] Among them, W 0 L1 To W 0 Ln is the weighted value of the left sensor position when the knee is flexed 0°, F 0 L1 To F 0 Ln W is the pressure value of sensor 1 on the left side when the knee is bent at 0°; 0 R1 To W 0 Rn is the weighted value of sensor 1 on the right side when the knee is flexed 0°, F 0 R1 To F 0 Rn is the pressure value of sensor 1 on the right side when the knee is bent at 0°, L 0 L L is the absolute value of the linearity value on the left side of 0° knee flexion, 0 R is the absolute value of the linearity value on the right side when the knee is flexed 0°, L0 MAX The maximum value of balance is determined by the absolute value of the left or right linear value, L 0 ALL When the knee is bent at 0°, the maximum value of the left and right pressure differences is used to determine the threshold.

[0021] The weighted average algorithm is a commonly used data aggregation algorithm, which is suitable for scenarios where data collected by multiple sensors are aggregated. Its basic principle is to weight the data collected by each sensor according to a certain weight, then sum and average them, and finally obtain an aggregated data; for example, for a group of sensors, the weighted average algorithm can aggregate the data collected at different locations into a more accurate pressure value.

[0022] With the knee flexed at 30°:

[0023] L 1 L =|(W 1 L1 F 1 L1 +W 1 L2 F 1 L2 +...+W 1 Ln F 1 Ln ) / (F 1 L1 +F 1 L2 +...+F 1 Ln )|

[0024] L 1 R =|(W 1 R1 F 1 R1 +W 1 R2 F 1 R2 +...+W 1 Rn F 1 Rn ) / (F 1 R1 +F 1 R2 +...+F 1 Rn )|

[0025] L 1 MAX =max(L1 L , L 1 R )≤L 1 ALL

[0026] Among them, W 1 L1 To W 1 Ln is the weighted value of sensor 1 on the left side when the knee is flexed 30°, F 1 L1 To F 1 Ln W is the pressure value of sensor 1 on the left side when the knee is flexed 30°; 1 R1 To W 1 Rn is the weighted value of sensor 1 on the right side when the knee is flexed 30°, F 1 R1 To F 1 Rn is the pressure value of sensor 1 on the right side when the knee is bent at 30°, L 1 L L is the absolute value of the linearity value on the left side at 30° knee flexion. 1 R is the absolute value of the linearity value on the right side when the knee is flexed 30°, L 1 MAX The maximum value of balance is determined by the absolute value of the left or right linear value when the knee is bent at 30°. 1 ALL When the knee is bent at 30°, the maximum value of the left and right pressure differences is used to determine the threshold.

[0027] When the knee is flexed at 90°:

[0028] L 2 L =|(W 2 L1 F 2 L1 +W 2 L2 F 2 L2 +...+W 2 Ln F 2 Ln ) / (F 2 L1 +F 2 L2 +...+F 2 Ln )|

[0029] L 2 R=|(W 2 R1 F 2 R1 +W 2 R2 F 2 R2 +...+W 2 Rn F 2 Rn ) / (F 2 R1 +F 2 R2 +...+F 2 Rn )|

[0030] L 2 MAX =max(L 2 L , L 2 R )≤L 2 ALL

[0031] Among them, W 2 L1 To W 2 Ln is the weighted value of sensor 1 on the left side when the knee is bent 90°, F 2 L1 To F 2 Ln W is the pressure value of sensor 1 on the left side when the knee is bent 90°; 2 R1 To W 2 Rn is the weighted value of sensor 1 on the right side when the knee is bent 90°, F 2 R1 To F 2 Rn is the pressure value of sensor 1 on the right side when the knee is bent 90°, L 2 L L is the absolute value of the linearity value on the left side of 90° knee flexion. 2 R is the absolute value of the linearity value on the right side when the knee is flexed 90°, L 2 MAX The maximum value of balance is determined by the absolute value of the left or right linear value when the knee is bent 90°. 2 ALL When the knee is bent at 90°, the maximum value of the left and right pressure differences is used to determine the threshold.

[0032] When the knee is flexed 150°:

[0033] L 3L =|(W 3 L1 F 3 L1 +W 3 L2 F 3 L2 +...+W 3 Ln F 3 Ln ) / (F 3 L1 +F 3 L2 +...+F 3 Ln )|

[0034] L 3 R =|(W 3 R1 F 3 R1 +W 3 R2 F 3 R2 +...+W 3 Rn F 3 Rn ) / (F 3 R1 +F 3 R2 +...+F 3 Rn )|

[0035] L 3 MAX =max(L 3 L , L 3 R )≤L 3 ALL

[0036] Among them, W 3 L1 To W 3 Ln is the weighted value of sensor 1 on the left side when the knee is flexed 150°, F 3 L1 To F 3 Ln W is the pressure value of sensor 1 on the left side when the knee is flexed 150°; 3 R1 To W 3 Rn is the weighted value of sensor 1 on the right side when the knee is flexed 150°, F 3R1 To F 3 Rn is the pressure value of sensor 1 on the right side when the knee is flexed 150°, L 3 L L is the absolute value of the linearity value on the left side of 150° knee flexion, 3 R is the absolute value of the linearity value on the right side when the knee is flexed 150°, L 3 MAX The maximum value of balance is determined by the absolute value of the left or right linear value when the knee is bent 150°. 3 ALL When the knee is flexed 150°, the maximum value of the left and right pressure differences is used to determine the threshold.

[0037] When the knee is flexed 180°:

[0038] L 4 L =|(W 4 L1 F 4 L1 +W 4 L2 F 4 L2 +...+W 4 Ln F 4 Ln ) / (F 4 L1 +F 4 L2 +...+F 4 Ln )|

[0039] L 4 R =|(W 4 R1 F 4 R1 +W 4 R2 F 4 R2 +...+W 4 Rn F 4 Rn ) / (F 4 R1 +F 4 R2 +...+F 4 Rn )|

[0040] L 4 MAX =max(L 4L , L 4 R )≤L 4 ALL

[0041] Among them, W 4 L1 To W 4 Ln is the weighted value of sensor 1 on the left side when the knee is bent 180°, F 4 L1 To F 4 Ln W is the pressure value of sensor 1 on the left side when the knee is bent 180°; 4 R1 To W 4 Rn is the weighted value of sensor 1 on the right side when the knee is flexed 180°, F 4 R1 To F 4 Rn is the pressure value of sensor 1 on the right side when the knee is bent 180°, L 4 L L is the absolute value of the linearity value on the left side of 180° knee flexion. 4 R is the absolute value of the linearity value on the right side when the knee is flexed 180°, L 4 MAX The maximum value of balance is determined by the absolute value of the left or right linear value when the knee is bent 180°. 4 ALL When the knee is bent 180°, the maximum value of the left and right pressure differences is used to determine the threshold.

[0042] If L 0 MAX ≤L 0 ALL ∩L 1 MAX ≤L 1 ALL ∩L 2 MAX ≤L 2 ALL ∩L 3 MAX ≤L 3 ALL ∩L 4 MAX ≤L 4 ALL , it can be judged that the knee joint is in a true balanced state. Otherwise, the knee joint can be balanced by appropriate bone repair or adjustment of the prosthesis position; keep the position unchanged and perform surgical suture.

[0043] A balance judgment method for a knee joint pressure balance measurement system based on a knee joint pad:

[0044] S1, install the knee pad system: first install sensor 2 and sensor 3 inside sensor 1 to form a triangle shape, then measure the comprehensive error of sensor 2 to ensure that the error is less than 1%, then electrically connect sensor 1 to the rigid circuit to form a pressure acquisition module, then place the tibial pad under the knee joint to ensure that it is firmly attached, then connect the pressure acquisition module to the tibial pad, and ensure that sensor 1 is correctly positioned at the pressure acquisition point in different states;

[0045] S2, collecting data: collecting pressure data of the knee joint through sensor 1 of the pressure acquisition module in different states (including knee flexion 0°, 30°, 60°, 90°, 120°, 150° and 180°), and transmitting the data to the signal receiving and display module;

[0046] S3, data processing and analysis: the signal receiving and display module performs analog-to-digital conversion on the data of sensor 1 and sends it to the computer via the Bluetooth module. The data processing module processes and analyzes the data received by the computer and uses the cubic spline difference algorithm to calculate the pressure distribution of the knee joint;

[0047] S4, real-time display of knee joint pressure distribution: The computer displays the knee joint pressure distribution through dynamic two-dimensional or three-dimensional thermal graphics and pressure values, helping doctors and patients understand the balance of the knee joint;

[0048] S5, judging whether the knee joint is in a balanced state: according to the linear relationship formula of sensor 1, the linearity value of the left or right pressure sensor group under different states is calculated, and the absolute value of the linearity value is compared to judge whether the knee joint is in a balanced state. If the linearity value meets the condition, it is judged that the knee joint is in a balanced state. Otherwise, appropriate bone repair or adjustment of the prosthesis position is required to achieve balance;

[0049] S6, fix the position of the knee joint: when the knee joint reaches a balanced state, surgical suture is performed to keep the position unchanged to ensure the balanced state of the knee joint.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. The present invention improves the accuracy of knee joint balance by calculating the linear relationship between the input signal and the input pressure of the calibration sensor 1, which can not only increase the service life of the patient's postoperative prosthesis, but also reduce the incidence of postoperative complications and improve the patient's postoperative quality of life. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1It is a flow chart of the test balance of the overall device of the present invention;

[0053] Figure 2 It is an expanded view of the internal structure of the tibial pad of the present invention.

[0054] In the figure:

[0055] 1. Tibial pad; 2. Sensor 1. DETAILED DESCRIPTION

[0056] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0057] like Figure 1 As shown, the present invention provides a knee joint pressure balance measurement system based on a knee joint pad, comprising a tibial pad 1, a pressure acquisition module, a signal receiving and displaying module, a data processing module and a computer, wherein the pressure acquisition module comprises a left pressure sensor group, a right pressure sensor group and a rigid circuit, wherein the left pressure sensor group and the right pressure sensor group each comprise a plurality of sensors 2, and the plurality of sensors 2 form a pressure measurement plane, wherein the sensors 2 are used to collect pressure data of the knee joint in different states, wherein the different states comprise knee flexion at 0°, 30°, 60°, 90°, 120°, 150° and 180°, wherein the plurality of sensors 2 are integrated in a rigid circuit, and the rigid circuit is attached to the tibial pad 1, wherein the signal receiving and displaying module comprises a capacitance measurement module, a single chip microcomputer and a Bluetooth module, wherein the capacitance measurement module performs analog-to-digital conversion on the data collected by the sensor and sends the data to the single chip microcomputer for processing, wherein the single chip microcomputer packages and organizes the data of the sensors 2 and sends the data to the computer via the Bluetooth module, wherein the data processing module processes and analyzes the data received by the computer, and the computer displays the pressure distribution of the knee joint in real time;

[0058] The sensor 1 2 includes three sensors 2, and the three sensors 2 form a pressure measurement plane, the pressure measurement plane is an equilateral triangle, and the sensor 2 is a pressure sensor.

[0059] Embodiment 1:

[0060] like Figure 1 As shown, in this embodiment, first, the tibial pad 1 is placed in an appropriate position of the knee joint and fits tightly with the surface of the knee joint. Sensor 1 2 is integrated into a rigid circuit and then attached to the tibial pad 1. These sensors 1 2 are used to collect pressure data of the knee joint in different states, including knee flexion 0°, 30°, 60°, 90°, 120°, 150° and 180°. The collected data is transmitted to the signal receiving and display module through the rigid circuit.

[0061] The signal receiving and display module includes a capacitance measurement module, a single-chip microcomputer, a Bluetooth module and a computer. The capacitance measurement module converts the analog data collected by sensor 2 into a digital signal and transmits it to the single-chip microcomputer for processing. The single-chip microcomputer packages and organizes the sensor 2 data and sends it to the computer via Bluetooth. The received data is processed and analyzed by the data processing module. The data processing module uses the cubic spline difference algorithm and the photoelectric volumetric pulse wave method to interpolate the data respectively to obtain a smooth curve. Then, based on the interpolated data, the data processing module calculates the pressure distribution of the knee joint. The computer can display the pressure distribution of the knee joint in real time, and then the doctor judges whether it is balanced according to the pressure distribution under different states.

[0062] It should be noted that there are two display methods, including dynamic two-dimensional or three-dimensional thermal graphics and pressure numerical methods. The dynamic two-dimensional or three-dimensional thermal graphics method uses a sensor to measure the pressure value of the knee pad in contact with the ground, and converts this data into a two-dimensional or three-dimensional graphic display. This method can intuitively display the pressure distribution of the knee joint under different movements and postures, helping doctors and researchers to better understand the distribution of knee joint load. The pressure numerical method converts the pressure value of the knee pad in contact with the ground into a numerical value and displays it on the screen. Based on the measured pressure distribution, balance judgment can be made. At the same time, this method can provide specific pressure values ​​to help doctors and researchers understand the load of the knee joint more accurately and conduct quantitative analysis.

[0063] Cubic spline interpolation is a numerical method for data interpolation. It can be used to estimate the values ​​at other locations given a set of known data points. The algorithm uses the properties of cubic polynomials to obtain a smooth curve by interpolating the curve between data points.

[0064] Balance judgment is based on the pressure distribution in different states, including knee flexion 0°, 30°, 60°, 90°, 120°, 150° and 180°. According to the weighted value and pressure value of sensor 2, the corresponding linearity value is calculated. The linearity value is compared with the maximum value of the absolute value balance judgment. If both are less than or equal to the maximum value, the knee joint is judged to be in a true balance state. If the conditions are not met, it is necessary to balance the knee joint by appropriate bone repair or adjustment of the prosthesis position.

[0065] It should be noted that there may be errors in sensor 2, so when using it, it is necessary to test it with sensor 2, and the formula for the comprehensive error is △′=√(△1 2 + △2 2 + △3 2), where △1, △2, and △3 are the errors of sensor 2 respectively. Generally speaking, for high-precision pressure sensors, the comprehensive error is usually below 1%. When the comprehensive error of sensor 2 is less than 1%, sensor 2 is suitable for measuring knee joint pressure balance. If it is greater than 1%, sensor 2 should be replaced.

[0066] In order to ensure the accuracy of measurement, a certain distance needs to be maintained between sensors 2 to avoid mutual interference. However, because sensors 2 are placed on the gasket, the size of the gasket limits the number of sensors 2 that can be prevented.

[0067] It should be noted that both the left pressure sensor group and the right pressure sensor group include multiple sensors 2, and the multiple sensors 2 form a pressure measurement plane, which can more accurately measure the pressure distribution in the plane, and at the same time ensure that the pressure measurement in the entire plane is uniform and accurate, and each sensor 2 can independently measure the pressure at its location, thereby improving the reliability and accuracy of the measurement.

[0068] When the knee is flexed to 0°:

[0069] L 0 L =|(W 0 L1 F 0 L1 +W 0 L2 F 0 L2 +...+W 0 Ln F 0 Ln ) / (F 0 L1 +F 0 L2 +...+F 0 Ln )|

[0070] L 0 R =|(W 0 R1 F 0 R1 +W 0 R2 F 0 R2 +...+W 0 Rn F 0 Rn ) / (F 0 R1 +F 0 R2 +...+F0 Rn )|

[0071] L 0 MAX =max(L 0 L , L 0 R )≤L 0 ALL

[0072] Among them, W 0 L1 To W 0 Ln is the weighted value of sensor 2 on the left side when the knee is bent at 0°, F 0 L1 To F 0 Ln W is the pressure value of sensor 2 on the left side when the knee is bent at 0°; 0 R1 To W 0 Rn is the weighted value of sensor 2 on the right side when the knee is bent at 0°, F 0 R1 To F 0 Rn is the pressure value of sensor 2 on the right side when the knee is bent at 0°, L 0 L L is the absolute value of the linearity value on the left side of 0° knee flexion, 0 R is the absolute value of the linearity value on the right side when the knee is flexed 0°, L 0 ALL When the knee is flexed 0°, the maximum value of the left and right pressure difference is used to determine the threshold;

[0073] With the knee flexed at 30°:

[0074] L 1 L =|(W 1 L1 F 1 L1 +W 1 L2 F 1 L2 +...+W 1 Ln F 1 Ln ) / (F 1 L1 +F 1 L2 +...+F 1 Ln )|

[0075] L 1 R =|(W 1 R1 F 1 R1 +W 1 R2 F 1 R2 +...+W 1 Rn F 1 Rn ) / (F 1 R1 +F 1 R2 +...+F 1 Rn )|

[0076] L 1 MAX =max(L 1 L , L 1 R )≤L 1 ALL

[0077] Among them, W 1 L1 To W 1 Ln is the weighted value of sensor 2 on the left side when the knee is flexed 30°, F 1 L1 To F 1 Ln W is the pressure value of sensor 2 on the left side when the knee is bent at 30°; 1 R1 To W 1 Rn is the weighted value of sensor 2 on the right side when the knee is flexed 30°, F 1 R1 To F 1 Rn is the pressure value of sensor 2 on the right side when the knee is bent at 30°, L 1 L L is the absolute value of the linearity value on the left side at 30° knee flexion. 1 R is the absolute value of the linearity value on the right side when the knee is flexed 30°, L 1 ALL When the knee is flexed 30°, the maximum value of the left and right pressure difference is used to determine the threshold;

[0078] When the knee is flexed at 90°:

[0079] L 2 L =|(W 2L1 F 2 L1 +W 2 L2 F 2 L2 +...+W 2 Ln F 2 Ln ) / (F 2 L1 +F 2 L2 +...+F 2 Ln )|

[0080] L 2 R =|(W 2 R1 F 2 R1 +W 2 R2 F 2 R2 +...+W 2 Rn F 2 Rn ) / (F 2 R1 +F 2 R2 +...+F 2 Rn )|

[0081] L 2 MAX =max(L 2 L , L 2 R )≤L 2 ALL

[0082] Among them, W 2 L1 To W 2 Ln is the weighted value of sensor 2 on the left side when the knee is bent 90°, F 2 L1 To F 2 Ln W is the pressure value of sensor 2 on the left side when the knee is bent 90°; 2 R1 To W 2 Rn is the weighted value of sensor 2 on the right side when the knee is bent 90°, F 2 R1 To F 2Rn is the pressure value of sensor 2 on the right side when the knee is bent 90°, L 2 L L is the absolute value of the linearity value on the left side of 90° knee flexion, 2 R is the absolute value of the linearity value on the right side when the knee is flexed 90°, L 2 ALL When the knee is bent 90°, the maximum value of the left and right pressure difference is used to determine the threshold;

[0083] When the knee is flexed 150°:

[0084] L 3 L =|(W 3 L1 F 3 L1 +W 3 L2 F 3 L2 +...+W 3 Ln F 3 Ln ) / (F 3 L1 +F 3 L2 +...+F 3 Ln )|

[0085] L 3 R =|(W 3 R1 F 3 R1 +W 3 R2 F 3 R2 +...+W 3 Rn F 3 Rn ) / (F 3 R1 +F 3 R2 +...+F 3 Rn )|

[0086] L 3 MAX =max(L 3 L , L 3 R )≤L 3 ALL

[0087] Among them, W 3 L1 To W 3 Ln is the weighted value of sensor 2 on the left side when the knee is flexed 150°, F 3 L1 To F 3 Ln W is the pressure value of sensor 2 on the left side when the knee is flexed 150°; 3 R1 To W 3 Rn is the weighted value of sensor 2 on the right side when the knee is flexed 150°, F 3 R1 To F 3 Rn is the pressure value of sensor 2 on the right side when the knee is bent 150°, L 3 L L is the absolute value of the linearity value on the left side of 150° knee flexion, 3 R is the absolute value of the linearity value on the right side when the knee is flexed 150°, L 3 ALL When the knee is flexed 150°, the maximum value of the left and right pressure differences is used to determine the threshold;

[0088] When the knee is flexed 180°:

[0089] L 4 L =|(W 4 L1 F 4 L1 +W 4 L2 F 4 L2 +...+W 4 Ln F 4 Ln ) / (F 4 L1 +F 4 L2 +...+F 4 Ln )|

[0090] L 4 R =|(W 4 R1 F 4 R1 +W 4 R2 F 4 R2 +...+W 4Rn F 4 Rn ) / (F 4 R1 +F 4 R2 +...+F 4 Rn )|

[0091] L 4 MAX =max(L 4 L , L 4 R )≤L 4 ALL

[0092] Among them, W 4 L1 To W 4 Ln is the weighted value of sensor 2 on the left side when the knee is bent 180°, F 4 L1 To F 4 Ln W is the pressure value of sensor 2 on the left side when the knee is bent 180°; 4 R1 To W 4 Rn is the weighted value of sensor 2 on the right side when the knee is bent 180°, F 4 R1 To F 4 Rn is the pressure value of sensor 2 on the right side when the knee is bent 180°, L 4 L L is the absolute value of the linearity value on the left side of 180° knee flexion. 4 R is the absolute value of the linearity value on the right side when the knee is flexed 180°, L 4 ALL When the knee is bent 180°, the maximum value of the left and right pressure differences is used to determine the threshold;

[0093] If L 0 MAX ≤L 0 ALL ∩L 1 MAX ≤L 1 ALL ∩L 2 MAX ≤L 2 ALL ∩L 3 MAX ≤L 3 ALL ∩L4 MAX ≤L 4 ALL , it can be judged that the knee joint is in a true balanced state. Otherwise, the knee joint can be balanced by appropriate bone repair or adjustment of the prosthesis position; keep the position unchanged and perform surgical suture.

[0094] A balance judgment method for a knee joint pressure balance measurement system based on a knee joint pad:

[0095] S1, install the knee pad system: first install sensor 2 and sensor 3 inside sensor 1 2 to form a triangular shape, then measure the comprehensive error of sensor 2 to ensure that the error is less than 1%, then electrically connect sensor 1 2 to the rigid circuit to form a pressure acquisition module, then place tibial pad 1 under the knee joint to ensure that it is firmly attached, then connect the pressure acquisition module to tibial pad 1, and ensure that sensor 1 2 is correctly positioned at the pressure acquisition point in different states;

[0096] S2, data collection: in different states (including knee flexion 0°, 30°, 60°, 90°, 120°, 150° and 180°), the pressure data of the knee joint is collected through the sensor 2 of the pressure acquisition module, and the data is transmitted to the signal receiving and display module;

[0097] S3, data processing and analysis: the signal receiving and display module performs analog-to-digital conversion on the data of sensor 2 and sends it to the computer through the Bluetooth module. The data processing module processes and analyzes the data received by the computer and uses the cubic spline difference algorithm to calculate the pressure distribution of the knee joint;

[0098] S4, real-time display of knee joint pressure distribution: The computer displays the knee joint pressure distribution through dynamic two-dimensional or three-dimensional thermal graphics and pressure values, helping doctors and patients understand the balance of the knee joint;

[0099] S5, judging whether the knee joint is in a balanced state: according to the linear relationship formula of sensor-2, the linearity value of the left or right pressure sensor group under different states is calculated, and the absolute value of the linearity value is compared to judge whether the knee joint is in a balanced state. If the linearity value meets the condition, it is judged that the knee joint is in a balanced state, otherwise, appropriate bone repair or adjustment of the prosthesis position is required to achieve balance;

[0100] S6, fix the position of the knee joint: when the knee joint reaches a balanced state, surgical suture is performed to keep the position unchanged to ensure the balanced state of the knee joint.

[0101] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A knee joint pressure balance measurement system based on a knee joint pad, comprising a tibial pad (1), a pressure acquisition module, a signal receiving and displaying module, a data processing module and a computer, characterized in that: The pressure acquisition module comprises a left pressure sensor group, a right pressure sensor group and a rigid circuit. The left pressure sensor group and the right pressure sensor group each comprise a plurality of sensors one (2), and the plurality of sensors one (2) form a pressure measurement plane. The sensor one (2) is used to collect pressure data of the knee joint in different states, and the different states include knee flexion at 0°, 30°, 60°, 90°, 120°, 150° and 180°. The plurality of sensors one (2) are integrated in the rigid circuit, and the rigid circuit is attached to the tibial pad (1). The signal receiving and displaying module comprises a capacitance measurement module, a single chip microcomputer and a Bluetooth module. The capacitance measurement module performs analog-to-digital conversion on the data collected by the sensor and sends the data to the single chip microcomputer for processing. The single chip microcomputer packages and organizes the data of the sensor one (2) and sends it to the computer via the Bluetooth module. The data processing module processes and analyzes the data received by the computer, and the computer displays the pressure distribution of the knee joint in real time. The sensor 1 (2) includes three sensors 2, and the three sensors 2 form a pressure measurement plane, and the sensor 2 is a pressure sensor; The three sensors 2 have different physical properties, which leads to a comprehensive error in the measurement of the knee joint by the sensor 2. The formula of the comprehensive error is △ / =√(△1 2 +△2 2 +△3 2 ), wherein △1, △2, △3 are the errors of the three sensors 2 respectively, and the average value of the weighted values ​​of the three sensors 2 is the weighted value W of the sensor 1 (2), and the average value of the pressure values ​​of the three sensors 2 is the pressure value F of the sensor 1 (2); There is a linear relationship between the output and input of the sensor 1 (2), and the linear relationship formula is: L=|(W1F1+W2F2+...+W n F n ) / (F1+F2+...+F n )| Among them, W1 to W n is the weighted value of sensor one (2) position when the knee is bent, F1 to F n is the pressure value of sensor 1 (2) when the knee is bent, and L is the maximum value and threshold value for judging balance using the absolute value of the linearity value when the knee is bent.

2. A knee joint pressure balance measurement system based on a knee joint pad as claimed in claim 1, characterized in that: The data processing module includes a pressure sensor processing method, and the processing method adopted by the pressure sensor is a cubic spline difference algorithm.

3. A knee joint pressure balance measurement system based on a knee joint pad as claimed in claim 1, characterized in that: The pressure distribution is displayed in the form of dynamic two-dimensional or three-dimensional thermal graphics and pressure values.

4. A knee joint pressure balance measurement system based on a knee joint pad as claimed in claim 1, characterized in that: Under different conditions, the linearity of the left or right pressure sensor group is calculated respectively.

5. A knee joint pressure balance measurement system based on a knee joint pad as claimed in claim 4, characterized in that: With the knee flexed at 0°: L 0 L =|(W 0 L1 F 0 L1 +W 0 L2 F 0 L2 +...+W 0 Ln F 0 Ln ) / (F 0 L1 +F 0 L2 +...+F 0 Ln )| L 0 R =|(W 0 R1 F 0 R1 +W 0 R2 F 0 R2 +...+W 0 Rn F 0 Rn ) / (F 0 R1 +F 0 R2 +...+F 0 Rn )| L 0MAX =max(L 0 L ,L 0 R )≤L 0 ALL Among them, W 0 L1 To W 0 Ln is the weighted value of the left sensor one (2) position when the knee is flexed 0°, F 0 L1 To F 0 Ln W is the pressure value of sensor 1 (2) on the left side when the knee is flexed to 0°; 0 R1 To W 0 Rn is the weighted value of sensor 1 (2) on the right side when the knee is flexed to 0°, F 0 R1 To F 0 Rn is the pressure value of sensor 1 (2) on the right side when the knee is flexed to 0°, L 0 L L is the absolute value of the linearity value on the left side of 0° knee flexion, 0 R is the absolute value of the linearity value on the right side when the knee is flexed 0°, L 0 MAX The maximum value of balance is determined by the absolute value of the left or right linear value, L 0 ALL When the knee is bent at 0°, the maximum value of the left and right pressure differences is used to determine the threshold.

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