A system and method for measuring the force line of a lower limb

Abstract

The application provides a lower limb force line measuring system and a measuring method, the measuring system comprises: a femur alignment fixing device and a measuring module, the femur alignment fixing device is used for aligning with a femur and being fixed to a distal end of the femur, the measuring module is fixed to the femur alignment fixing device and is used for measuring angular velocities when the distal end of the femur makes internal-external rotation and makes forward-backward movement, and calculating an internal-external rotation angle and a forward-backward inclination angle of the distal end of the femur according to a formula. Since only the angular velocities when the distal end of the femur moves need to be measured, the measuring module can use a low-cost gyroscope to complete the measurement, and an accelerometer is not needed to participate in the calculation, so that the cumulative error of the calculation is reduced.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a measurement system and method for measuring lower limb force lines. Background Technology

[0002] Currently, the main method for measuring lower limb force lines is to use accelerometers and gyroscopes to collect necessary data, perform trajectory fitting, and then perform calculations based on the fitted curve to obtain the lower limb force lines. However, because sensor errors can significantly affect the calculation results during trajectory fitting, this method is not suitable for low-cost sensors.

[0003] According to patent application CN110974493A, when measuring the femoral tilt angle, a reference coordinate system is established with the three axes of the motion sensor in the navigation unit, and the spatial motion trajectory of the motion sensor is fitted to calculate the coordinate value of the femoral acetabulum. Based on the coordinate value of the acetabulum, the varus / valgus angle and the anteroposterior tilt angle of the femur are calculated.

[0004] The existing solution uses trajectory fitting to measure femoral tilt angle. Since the sensor needs to undergo two integration operations in the trajectory fitting algorithm, the error can easily accumulate, resulting in a large error in the calculated result. Furthermore, because it is very sensitive to the sensor parameters, low-cost sensors cannot be used in this situation. Summary of the Invention

[0005] The purpose of this invention is to provide a measurement system and method for lower limb force lines, which can use a low-cost gyroscope to measure the lower limb force lines and does not require the use of an accelerometer for calculation, thus reducing the cumulative error of the calculation.

[0006] To address the aforementioned technical problems, this invention provides a lower limb force line measurement system, comprising: a femoral alignment and fixation device and a measurement module, wherein...

[0007] The femoral alignment and fixation device is used to align with and fix the distal end of the femur;

[0008] The measuring module is fixed to the femoral alignment and fixation device and is used to measure the angular velocity of the distal femur during varus / valgus and anterior / posterior movements, and to calculate the varus / valgus angle of the distal femur according to the following formula. With camber angle ,

[0009] , ,

[0010] Where, ω X ω Y and ω ZThe angular velocity of the distal femur in the X, Y, and Z directions is perpendicular to each other.

[0011] Optionally, the lower limb force line measurement system further includes a terminal, which is used to display the varus / valgus angle and the anteversion / retroversion angle.

[0012] Optionally, the femoral alignment and fixation device includes: a device body, a Whiteside line auxiliary alignment arrow, a femoral fixation pin, a device fixation hole, and a measurement module fixation groove; wherein,

[0013] The Whiteside line alignment arrow is used to align with the Whiteside line on the femur;

[0014] The femoral fixation pin is inserted from the distal end of the femur in a manner perpendicular to the femur;

[0015] The device fixing hole is used to screw in a screw to fix the femoral alignment and fixation device to the distal end of the femur;

[0016] The measuring module fixing groove is used to fix the measuring module.

[0017] Optionally, the external components of the measurement module include a module body, fixed positioning points for the measurement module, operation buttons, and user indicator lights; wherein,

[0018] The fixed positioning point of the measurement module is used to play a role in positioning and fixing when the measurement module is fixed to the femoral alignment and fixation device;

[0019] The operation buttons are used to turn the measurement module on or off.

[0020] The user indicator light is used to indicate the data acquisition progress of the measurement module.

[0021] Optionally, the measurement module internally includes: an inertial sensor, internal buttons, a microprocessor, a wireless transmission module, internal indicator lights, and a battery; wherein,

[0022] The inertial sensor is used to measure the angular velocity of the distal femur during inversion / valgus and anterior / posterior movements and transmit the data to the microprocessor.

[0023] The internal button is used to connect with the operation button and transmit the switch command to the microprocessor;

[0024] The microprocessor is used to process the angular velocity data to obtain the varus / valgus and anteversion / anteroversion angles of the distal femur;

[0025] The wireless transmission module is used for data transmission between the microprocessor and the terminal;

[0026] The internal indicator light is used to receive instructions from the microprocessor and transmit them to the user indicator light;

[0027] The battery is used to power the microprocessor.

[0028] Optionally, when the distal femur performs varus / valgus movements, the inertial sensor measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω X =0 and ω Y and ω Z Non-zero data is considered valid data; the microprocessor calculates multiple varus / valgus angles of the distal femur according to a formula. The microprocessor performs mean filtering on the computational structure to obtain the actual inward and outward flip angles θ.

[0029] Optionally, when the distal femur moves forward and backward, the inertial sensor measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω Z =0 and ω X and ω Y Non-zero data is considered valid data; the microprocessor calculates the anteroposterior angle of the distal femur according to the formula. The microprocessor performs mean filtering on the calculation results to obtain the actual fore-and-aft angle α.

[0030] Optionally, the inertial sensor measures valid data over a period of time. When the amount of valid data from a single movement of the distal femur is greater than 5%, the user indicator light displays a green light; otherwise, it displays a red light.

[0031] Accordingly, the present invention also provides a method for measuring lower limb force lines, which uses the lower limb force line measurement system described above for measurement, and the measurement method includes the following steps:

[0032] The femoral alignment and fixation device is aligned and fixed at the distal end of the femur;

[0033] The measuring module is fixed to the femoral alignment and fixation device;

[0034] Click the operation button to start the measurement. The distal femur will undergo inversion / valgus motion. The inertial sensor will measure the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω X =0 and ω Y and ωZ Non-zero data is considered valid data. After collecting valid data for a period of time, the microprocessor calculates the varus / valgus angle of the distal femur based on the valid data. ;

[0035] The femur is subjected to an anteroposterior motion, and the inertial sensor measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω Z =0 and ω X and ω Y Non-zero data is considered valid data. After collecting valid data for a period of time, the microprocessor calculates the anteroposterior angle of the distal femur based on the valid data. .

[0036] Optionally, the method for measuring the lower limb force line further includes: the wireless transmission module transmitting the calculation results to the terminal, and the terminal displaying the inversion / exversion angle and the anteversion / anterior tilt angle;

[0037] Methods for aligning and fixing a femoral alignment and fixation device to the distal femur include:

[0038] Align the Whiteside line with the arrow and the Whiteside line on the femur;

[0039] Insert the femoral fixation pin from the distal end of the femur along the direction of the femur;

[0040] Screw the screws into the device fixing holes to fix the femoral alignment and fixation device to the distal end of the femur;

[0041] The method of fixing the measuring module to the femoral alignment and fixation device includes: fixing the measuring module to the measuring module fixing groove.

[0042] Optionally, the inertial sensor measures valid data over a period of time. When the amount of valid data from a single movement of the distal femur is greater than 5%, the user indicator light displays a green light; otherwise, it displays a red light. When the green light is displayed at least three times, the measurement stops.

[0043] In the lower limb force line measurement system and method provided by this invention, the femoral alignment and fixation device is used to align with and fix the distal femur; the measurement module is fixed to the femoral alignment and fixation device and is used to measure the angular velocity of the distal femur during varus / valgus and anterior / posterior movements, and calculate the varus / valgus angle and anterior / posterior angle of the distal femur according to formulas. Since this invention only needs to measure the angular velocity of the distal femur during movement, the measurement module can use a low-cost gyroscope to complete the measurement, eliminating the need for an accelerometer in the calculation, thereby reducing the cumulative error of the calculation. Attached Figure Description

[0044] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention.

[0045] Figure 1 This is a schematic diagram of the module movement with the Y-axis pointing towards the center of the circle, provided in an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the module movement provided by an embodiment of the present invention, in which the Y-axis and the fixed rod form a certain angle in the vertical direction.

[0047] Figure 3 This is a schematic diagram of module movement provided by an embodiment of the present invention, in which the Y-axis and the fixed rod form a certain angle in the horizontal direction.

[0048] Figure 4 This is a schematic diagram of module movement provided by an embodiment of the present invention, showing that the X-axis and the circular plane form a certain angle in the horizontal direction.

[0049] Figure 5 This is a schematic diagram of the femoral alignment and fixation device provided in an embodiment of the present invention.

[0050] Figure 6 This is a schematic diagram of the external structure of a measurement module provided in an embodiment of the present invention.

[0051] Figure 7 This is a block diagram of the internal structure of a measurement module provided in an embodiment of the present invention.

[0052] Figure 8 This is a front view of the distal femur after the measurement module provided in an embodiment of the present invention has been fixed.

[0053] Figure 9 This is an exploded view of the distal femur after the measurement module provided in one embodiment of the present invention has been fixed.

[0054] Figure 10 This is an oblique view of the distal femur after the measurement module provided in an embodiment of the present invention has been fixed.

[0055] Figure 11 This is a schematic diagram of femoral movement during surgery provided in an embodiment of the present invention.

[0056] Reference numerals: 10-Femoral alignment and fixation device; 11-Device body; 12-Whiteside line alignment arrow; 13-Femoral fixation pin; 14-Device fixation hole; 15-Measurement module fixation groove; 16-Osteotomy plate positioning hole; 20-Measurement module; 21-Module body; 22-Measurement module fixing positioning point; 23-Operation button; 24-User indicator light; 201-Inertial sensor; 202-Internal button; 203-Microprocessor; 204-Wireless transmission module; 205-Internal indicator light; 206-Battery. Detailed Implementation

[0057] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.

[0058] As used in this invention, the singular forms “a,” “an,” and “the” include plural objects; the term “or” is generally used to mean “and / or”; the term “a number” is generally used to mean “at least one”; and the term “at least two” is generally used to mean “two or more”. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature, unless otherwise expressly indicated.

[0059] Figure 1 This is a schematic diagram of the module movement with the Y-axis pointing towards the center of the circle according to an embodiment of the present invention. Please refer to it. Figure 1 As shown, a square module is fixed to the center of a circle by a connecting rod. The module can rotate around the center in the plane formed by the XOY axis (e.g., Figure 1 The object moves in a circular plane. Y+ points towards the center of the circle, and X+ remains parallel to the direction of motion. Therefore, during the motion around the center, an angular velocity ω is generated along the Z-axis. Z angular velocity ω along the x-axis X and the angular velocity ω along the Y-axis Y The values ​​are all 0.

[0060] Figure 2 This is a schematic diagram of module movement provided by an embodiment of the present invention, showing that the Y-axis and the fixed rod form a certain angle in the vertical direction. For example... Figure 2As shown, rotating the module along the X-axis will cause the Y-axis to form an angle θ with the fixed rod. Then, moving the module around the center will result in ω being parallel to the X-axis in the direction of motion. X =0, the Y-axis and Z-axis will have angular velocity components, calculated as follows:

[0061] (1)

[0062] Figure 3 This is a schematic diagram of module movement provided by an embodiment of the present invention, showing that the Y-axis and the fixed rod form a certain angle in the horizontal direction. For example... Figure 3 As shown, rotating the module along the Z-axis will cause the Y-axis to form an angle α with the fixed rod. Then, moving the module around the center of the circle, since both the X and Y axes move on a circular plane, ω... X =0, ω Y =0, the Z-axis will have an angular velocity component.

[0063] Figure 4 This is a schematic diagram of module movement provided by an embodiment of the present invention, showing that the X-axis forms a certain angle with the circular plane in the horizontal direction. For example... Figure 4 As shown, rotating the module along the Y-axis will cause the X-axis to form an angle β with the circular plane. Then, moving the module around the center of the circle, since the Y-axis moves on the circular plane, ω... Y =0, the X-axis and Z-axis will have angular velocity components, calculated as follows:

[0064] (2)

[0065] From the above, it can be seen that when moving around a circular plane, angle α will not produce angular velocity components along the X and Y axes, while the angular velocity components produced by angles β and θ conform to the following formula:

[0066]

[0067]

[0068]

[0069] From the above formula, we can deduce that:

[0070] (3)

[0071] When ω X When = 0, the following formula can be obtained:

[0072] (4)

[0073] The result of formula (4) is consistent with that of formula (1).

[0074] That is, ω is obtained through measurement. X ω Y ω Z Then the angle θ can be calculated, and the result can be determined when ω X =0 and ω Y and ω Z When a numerical value is available, this data can be used as valid data to calculate the value of θ.

[0075] By analogy with the above principles, moving horizontally around the center of a circle yields the vertical angle of the axis pointing to the center relative to the fixed rod. Therefore, moving vertically around the center of a circle yields the horizontal angle of the axis pointing to the center relative to the fixed rod.

[0076] By analogy, when ω Z When = 0, the following formula can be obtained:

[0077] (5)

[0078] That is, ω is obtained through measurement. X ω Y ω Z Then the angle can be calculated. Determine when ω Z =0 and ω X and ω Y When a numerical value is available, this data can be used as valid data to calculate... The value of .

[0079] Based on the above principles, this invention provides a lower limb force line measurement system, comprising: a femoral alignment and fixation device and a measurement module, wherein the femoral alignment and fixation device is used to align with and fix to the distal end of the femur, and the measurement module is fixed to the femoral alignment and fixation device for measuring the angular velocity of the distal femur during varus / valgus and anterior / posterior movements, and calculating the varus / valgus angle of the distal femur according to the following formula. With camber angle ,

[0080] (1),

[0081] (5),

[0082] Where, ω X ω Y and ω Z The angular velocity of the distal femur in the X, Y, and Z directions is perpendicular to each other.

[0083] The lower limb force line measurement system also includes a terminal, which is used to display the inversion / exversion angle and the anteversion / anterior tilt angle.

[0084] Figure 5 This is a schematic diagram of the femoral alignment and fixation device provided in an embodiment of the present invention. Please refer to it. Figure 5 As shown, the femoral alignment and fixation device 10 includes: a device body 11, a Whiteside line (femoral anterior-posterior axis) auxiliary alignment arrow 12, a femoral fixation pin 13, a device fixation hole 14, and a measurement module fixation groove 15. The Whiteside line auxiliary alignment arrow 12 is used to align with the Whiteside line on the femur. The femoral alignment and fixation device 10 is provided with the Whiteside line auxiliary alignment arrow 12, and the femur is provided with the Whiteside line. Aligning the Whiteside line auxiliary alignment arrow 12 with the Whiteside line includes alignment or overlap between the alignment arrow and the line, thereby achieving alignment between the femoral alignment and fixation device 10 and the femur. The femoral fixation pin 13 is inserted from the distal end of the femur in a direction perpendicular to the femur; the device fixation hole 14 is used to screw in a screw to fix the femoral alignment and fixation device 10 to the distal end of the femur; the measurement module fixation groove 15 is used to fix the measurement module 20. The femoral alignment and fixation device 10 is aligned with the femur by means of the Whiteside line-assisted alignment arrow 12. The alignment refers to matching the position of the femoral alignment and fixation device 10 with the femur and placing the femoral alignment and fixation device 10 on the femur at the predetermined position. The femoral fixation pin 13 and the device fixation hole 14 fix the femoral alignment and fixation device 10 to the femur.

[0085] In this embodiment, the femoral alignment and fixation device 10 further includes: osteotomy plate positioning hole 16, which is subsequently used to fix the osteotomy plate, and the osteotomy is completed by fixing the osteotomy plate according to the degree of the inward and outward flaring angle and the anteroposterior tilt angle.

[0086] Figure 6 This is a schematic diagram of the external structure of a measurement module provided in an embodiment of the present invention. Please refer to it. Figure 6As shown, the external components of the measurement module 20 include a module body 21, a measurement module fixing point 22, an operation button 23, and a user indicator light 24. The measurement module fixing point 22 serves to position and fix the measurement module 20 when it is fixed to the femoral alignment and fixation device 10. In this embodiment, the measurement module fixing point 22 adopts a spring-loaded ball design. The operation button 23 is used to turn the measurement module 20 on or off. The user indicator light 24 indicates the data acquisition progress of the measurement module 20. The user indicator light 24 includes red and green lights; a green light is displayed when the amount of valid data acquired is greater than 5%, and a red light is displayed otherwise.

[0087] Figure 7 This is a block diagram of the internal structure of a measurement module provided in an embodiment of the present invention. Please refer to it. Figure 6 and Figure 7 As shown, the measurement module 20 internally includes: an inertial sensor 201, an internal button 202, a microprocessor 203, a wireless transmission module 204, an internal indicator light 205, and a battery 206. The inertial sensor 201 measures the angular velocity of the distal femur during varaction and anteversion movements and transmits this data to the microprocessor 203. In this embodiment, since only the angular velocity of the distal femur during movement needs to be measured, a low-cost gyroscope can be used; therefore, the inertial sensor 201 is a gyroscope. The internal button 202 connects to the operation button 23 and transmits the switch command to the microprocessor 203. The microprocessor 203 processes the angular velocity data to obtain the varaction and anteversion angles of the distal femur. The wireless transmission module 204 is used for data transmission between the microprocessor 203 and the terminal. The internal indicator light 205 receives the indication from the microprocessor 203 and transmits it to the user indicator light 24. The battery 206 supplies power to the microprocessor 203.

[0088] When the distal femur undergoes inversion / valgus movement, the inertial sensor 201 measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z Where the X, Y, and Z directions are perpendicular to each other, ω X =0 and ω Y and ω Z Non-zero data is considered valid data; the microprocessor 203 calculates multiple varus and valgus angles of the distal femur according to formula (1). The microprocessor 203 performs mean filtering on the calculation results to obtain the actual inward and outward flip angles θ.

[0089] When the distal femur moves back and forth, the inertial sensor 201 measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z Where the X, Y, and Z directions are perpendicular to each other, ω Z =0 and ω X and ω Y Non-zero data is considered valid data; the microprocessor 203 calculates multiple anteroposterior angles of the distal femur according to formula (5). The microprocessor performs mean filtering on the calculation results to obtain the actual fore-and-aft angle α.

[0090] The inertial sensor 201 measures effective data over a period of time, for example, it collects data 200 times per second. When the effective data of a single movement of the distal femur is greater than 5%, the user indicator light 24 displays a green light; otherwise, it displays a red light.

[0091] In the lower limb force line measurement system provided by this invention, the femoral alignment and fixation device 10 is used to align with and fix the distal femur; the measurement module 20 is fixed to the femoral alignment and fixation device 10 and is used to measure the angular velocity of the distal femur during varus / valgus and anterior / posterior movements, and calculate the varus / valgus angle and anterior / posterior angle of the distal femur according to formulas. Since this invention only needs to measure the angular velocity of the distal femur during movement, the measurement module 20 can use a low-cost gyroscope to complete the measurement, eliminating the need for an accelerometer in the calculation, thereby reducing the cumulative error of the calculation.

[0092] Accordingly, the present invention also provides a method for measuring lower limb force lines, employing the lower limb force line measurement system described above, the method comprising the following steps:

[0093] The femoral alignment and fixation device is aligned and fixed at the distal end of the femur;

[0094] The measuring module is fixed to the femoral alignment and fixation device;

[0095] Click the operation button to start the measurement. The distal femur will undergo inversion / valgus motion. The inertial sensor will measure the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω X =0 and ω Y and ω Z Non-zero data is considered valid data. After collecting valid data for a period of time, the microprocessor calculates the inward and outward flanging angles based on the valid data. ;

[0096] The distal femur is subjected to an anteroposterior motion, and the inertial sensor measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω Z =0 and ω X and ω Y Non-zero data is considered valid data. After collecting valid data for a period of time, the microprocessor calculates the tilt angle based on the valid data. .

[0097] The method for measuring the lower limb force line further includes: the wireless transmission module transmitting the calculation results to the terminal, and the terminal displaying the inward and outward tilt angles and the forward and backward tilt angles.

[0098] First, please refer to Figure 5 As shown, the femoral alignment and fixation device 10 is aligned and fixed to the distal femur. Specifically, the Whiteside line auxiliary alignment arrow 12 is aligned with the Whiteside line on the femur; the femoral fixation pin 13 is inserted from the distal femur perpendicular to the femur; and the screw is screwed into the device fixation hole 14 to fix the femoral alignment and fixation device 10 to the distal femur.

[0099] Next, please refer to Figure 5 and Figure 6 As shown, the measuring module 20 is fixed to the femoral alignment and fixation device 10. Specifically, the measuring module 20 is fixed to the measuring module fixing groove 15. The positional relationship after fixing can be referred to... Figures 8 to 10 As shown.

[0100] Next, please refer to Figures 5 to 11 As shown, click operation button 23 to start the measurement, and make the distal femur perform inversion / valgus movements (refer to...). Figure 11 (1) During the movement, internal and external rotation should be avoided as much as possible. The angular velocity ω of the distal femur in the X, Y and Z directions is measured using an inertial sensor 201. X ω Y and ω Z , will ω X =0 and ω Y and ω Z Non-zero data is considered valid data. After collecting valid data for a period of time, the microprocessor 203 calculates the inner and outer flaring angles based on the valid data and formula (1). .

[0101] The microprocessor 203 calculates multiple inner and outer flaring angles based on valid data and formula (1). Then, the calculation results are filtered by mean to obtain the actual inward and outward flaring angles. .

[0102] Please compare. Figure 11 and Figures 1 to 4 Among them, the femur refers to Figure 11 The femur is located with its proximal end near the pelvis and its distal end near the knee. The femoral alignment and fixation device 10 is fixed to the distal end of the femur. The measuring module 20 is equivalent to... Figures 1 to 4 The module in the middle, the femur is equivalent to Figures 1 to 4 The connecting rod in the middle, the proximal femur is equivalent to Figures 1 to 4 The center of the circle. According to... Figures 1 to 4 Based on the principle analysis, the inner and outer flaring angles can be calculated according to the following formula (1). The fore-and-aft angles can be calculated using the following formula (5). .

[0103] (1)

[0104] (5)

[0105] Next, please refer to Figures 5 to 11 As shown, the distal femur is moved back and forth (refer to...). Figure 11 (2) During the movement, internal and external rotation should be avoided as much as possible. The inertial sensor 201 measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω Z =0 and ω X and ω Y Non-zero data is considered valid data. After collecting valid data for a period of time, the microprocessor 203 calculates the tilt angle based on the valid data and formula (5). The microprocessor 203 calculates multiple tilt angles based on valid data and formula (5). Then, the calculation results are filtered by mean to obtain the actual fore-and-aft angles. .

[0106] During the movement, the measurement module 20 collects data 200 times per second. When the effective data volume of a single movement is greater than 5%, the user indicator light 24 displays a green light; otherwise, it displays a red light. When the green light is displayed at least 3 times (preferably 5 times), the measurement can be stopped.

[0107] Finally, the wireless transmission module 204 transmits the calculation results to the terminal, which displays the calculation results, showing the degrees of the inward and outward tilt angles and the forward and backward tilt angles, and fixes the osteotomy plate according to the degrees to complete the osteotomy.

[0108] In the method for measuring lower limb force lines provided by this invention, the femoral alignment and fixation device 10 is fixed to the distal femur; the measurement module 20 is fixed to the femoral alignment and fixation device 10; the distal femur is subjected to varus / valgus and anterior / posterior movements, respectively; the inertial sensor 201 measures the angular velocity of the distal femur in the X, Y, and Z directions; and the microprocessor calculates the varus / valgus angle. With camber angle Since this invention only needs to measure the angular velocity of the distal femur during movement, the measurement module 20 can use a low-cost gyroscope to complete the measurement, eliminating the need for an accelerometer in the calculation, thereby reducing the cumulative error of the calculation.

[0109] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A system for measuring the force line of a lower extremity, characterized in that include: The femoral alignment and fixation device and the measuring module, among which, The femoral alignment and fixation device is used to align with and fix the distal end of the femur; The measuring module is fixed to the femoral alignment and fixation device and is used to measure the angular velocity of the distal femur during varus / valgus and anterior / posterior movements, and to calculate the varus / valgus angle of the distal femur according to the following formula. With camber angle , ， ， Where, ω X ω Y and ω Z The angular velocities of the distal femur in the X, Y, and Z directions are perpendicular to each other; the distal femur rotates about the X-axis, and the Y-axis forms an inversion / exversion angle with the femur. The distal femur rotates about the Z-axis, and the Y-axis forms an anteroposterior angle with the femur. .

2. The lower limb force line measurement system as described in claim 1, characterized in that, The lower limb force line measurement system further includes a terminal, which is used to display the inversion / exversion angle and the anteversion / anterior tilt angle.

3. The lower limb force line measurement system as described in claim 2, characterized in that, The femoral alignment and fixation device includes: a device body, a Whiteside line auxiliary alignment arrow, a femoral fixation pin, a device fixation hole, and a measurement module fixation groove; wherein... The Whiteside line alignment arrow is used to align with the Whiteside line on the femur; The femoral fixation pin is inserted from the distal end of the femur in a direction perpendicular to the femur; The device fixing hole is used to screw in a screw to fix the femoral alignment and fixation device to the distal end of the femur; The measuring module fixing groove is used to fix the measuring module.

4. The lower limb force line measurement system as described in claim 3, characterized in that, The external components of the measurement module include the module body, fixed positioning points for the measurement module, operation buttons, and user indicator lights; wherein, The fixed positioning point of the measurement module is used to play a role in positioning and fixing when the measurement module is fixed to the femoral alignment and fixation device; The operation buttons are used to turn the measurement module on or off. The user indicator light is used to indicate the data acquisition progress of the measurement module.

5. The lower limb force line measurement system as described in claim 4, characterized in that, The measurement module internally includes: an inertial sensor, internal buttons, a microprocessor, a wireless transmission module, internal indicator lights, and a battery; wherein, The inertial sensor is used to measure the angular velocity of the distal femur during inversion / valgus and anterior / posterior movements and transmit the data to the microprocessor. The internal button is used to connect with the operation button and transmit the switch command to the microprocessor; The microprocessor is used to process the angular velocity data to obtain the varus / valgus and anteversion / anteroversion angles of the distal femur; The wireless transmission module is used for data transmission between the microprocessor and the terminal; The internal indicator light is used to receive instructions from the microprocessor and transmit them to the user indicator light; The battery is used to power the microprocessor.

6. The lower limb force line measurement system as described in claim 5, characterized in that, When the distal femur undergoes inversion / valgus movement, the inertial sensor measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω X =0 and ω Y and ω Z Non-zero data is considered valid data; the microprocessor calculates multiple varus / valgus angles of the distal femur according to a formula. The microprocessor performs mean filtering on the calculation results to obtain the actual inward and outward flip angles θ.

7. The lower limb force line measurement system as described in claim 5, characterized in that, When the distal femur moves back and forth, the inertial sensor measures the angular velocity ω of the distal femur in the X, Y, and Z directions. X ω Y and ω Z , will ω Z =0 and ω X and ω Y Non-zero data is considered valid data; the microprocessor calculates multiple anteroposterior tilt angles of the distal femur according to a formula. The microprocessor performs mean filtering on the calculation results to obtain the actual fore-and-aft angle α.

8. The lower limb force line measurement system as described in claim 6 or 7, characterized in that, The inertial sensor measures valid data over a period of time. When the amount of valid data from a single movement of the distal femur is greater than 5%, the user indicator light will display a green light; otherwise, it will display a red light.

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