Knee joint prosthesis durability test pretreatment method and device

Abstract

The invention belongs to the technical field of orthopedic implants, and discloses a knee joint prosthesis durability test pretreatment method and device.According to the technical scheme, the knee joint prosthesis durability test pretreatment method comprises the steps that S1, a thighbone component is aligned and installed on a testing machine, the thighbone component is located at the maximum buckling angle on the sagittal plane, and the buckling angle comprises a caster angle; s2, the femoral component is placed at the position which makes contact with the liner and is close to the rear edge of the liner, the internal rotation angle, the buckling angle and the rear inclination angle are accurately adjusted, the loading dynamic fatigue test needs to be carried out after the internal rotation angle, the buckling angle and the rear inclination angle are preprocessed, the preprocessed angles are prone to change in the testing machine installation process, and therefore the testing accuracy is greatly improved. The pretreatment device and the loading device are integrally treated, so that the problem of complex angle pretreatment pain points is solved, the mounting and loading difficulties of the test are also solved, and the accuracy of the test method and the result can be ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of orthopedic implants, and in particular relates to a pretreatment method and device for durability testing of knee joint prostheses. Background Art

[0002] The knee joint is the largest and most complex joint in the human body. Damage to any of its main components will cause abnormal knee movement. Over time, the cartilage and meniscus will wear and degenerate, forming osteoarthritis, which will affect people's daily life. The commonly used method is to perform knee prosthesis replacement surgery. For knee joints with serious lesions, total knee replacement surgery is used. As artificial knee replacement becomes a very common surgical procedure, research related to knee prostheses has also attracted more and more attention. When a knee prosthesis is implanted in the human body, it will be subjected to the biological kinematics of the human body, such as simple running, jumping, turning and other movements. However, the influence of movement patterns under high flexion angles should also be considered, such as the kinematics of squatting or kneeling. It should be considered whether the knee prosthesis has the ability to resist deformation and damage under high flexion conditions, and whether it can withstand a series of dynamic fatigue performance tests with a relatively high number of cycles. At the same time, it should be considered that under high flexion conditions, the tibial pad is under the greatest pressure. The material of this material is generally ultra-high molecular weight polyethylene, which is combined with the femoral condyle component made of metal or ceramic to undergo friction and wear. Therefore, there is an urgent need for a pretreatment method and device to verify the ability of the tibial pad to resist deformation in combination with the femoral condyle. Summary of the invention

[0003] In order to solve the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a knee joint prosthesis durability test pretreatment method and device to solve the problems mentioned in the background technology.

[0004] The technical solutions adopted by the knee joint prosthesis durability test pretreatment method and device to solve the technical problems are: Provides a pre-processing method for knee prosthesis durability testing, including: S1. Align and install the femoral component on the testing machine so that it is in the maximum flexion angle in the sagittal plane, and the flexion angle includes the posterior tilt angle; S2. Place the femoral component in contact with the liner and close to the posterior edge of the liner. S3, align all components in the rotational equilibrium position to set the maximum flexion angle, in which the femoral component, liner, and tibial tray are aligned in the coronal plane according to the desired equilibrium alignment; S4, rotation alignment; S5, keep the anterior and posterior center lines of the femoral component and the liner component always in line, and simulate the tibial tray to internally rotate 20° relative to the femoral component; S6. Set the loading force line through the centerline of the femoral component and intersect at the contact point or its posterior side.

[0005] Furthermore, in step 1, the femoral component is installed according to the test method in ASTM F2083-2012.

[0006] Furthermore, in the step 2, the contact points between the specified components are recorded.

[0007] Furthermore, in step 2, the anterior-posterior displacement can allow the femur to flex and rotate to a specified angle without generating impact between the femur and the tibia.

[0008] Furthermore, in step 5, on the liner-fixed system, only one condyle will be at the maximum posterior contact point after simulating internal rotation, and the other condyle should be close to the center of the liner. In order to make both femoral condyles contact the liner before loading, it is necessary to change the valgus and valgus positioning of the tibial component. In order to ensure appropriate flexion and correct force line, it is also necessary to rotate the femoral component to achieve the 20° requirement.

[0009] On the other hand, the present invention also provides a pretreatment device for implementing the above-mentioned pretreatment method, including a knee prosthesis femoral component embedding fixture and a knee prosthesis tibial tray embedding fixture, the knee prosthesis femoral component embedding fixture is driven by a femoral component flexion angle servo motor, the femoral component flexion angle servo motor is fixedly installed on a testing machine, a femoral component flexion angle sensor is fixedly installed on the testing machine, the femoral component flexion angle sensor is coaxially fixedly connected to the knee prosthesis femoral component embedding fixture; the knee prosthesis tibial tray embedding fixture is driven by a tibial tray posterior tilt angle servo motor, the tibial tray posterior tilt angle servo motor is fixedly installed on the testing machine, the testing machine A tibial tray posterior inclination angle sensor is installed correspondingly on the upper side, and the tibial tray posterior inclination angle sensor is coaxially fixedly connected with the tibial tray embedding fixture of the knee prosthesis. A tibial tray and femoral component internal rotation angle linear push rod is arranged below the tibial tray embedding fixture of the knee prosthesis. One end of the tibial tray and femoral component internal rotation angle linear push rod is fixed to the bottom plate of the testing machine through a slipknot, and the other end is connected to the tibial tray embedding fixture of the knee prosthesis through a slipknot. The tibial tray embedding fixture of the knee prosthesis is fixed to the bottom plate of the testing machine through a set of thrust bearings. When the tibial tray and femoral component internal rotation angle linear push rod is pushed out or retracted, the tibial tray embedding fixture of the knee prosthesis is driven to rotate around the thrust bearing.

[0010] Furthermore, the testing machine is fixedly mounted with a visual system for the internal rotation angle of the tibial tray and the femoral component.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. The knee prosthesis durability test pretreatment method exemplified in the present invention, this method accurately adjusts the internal rotation, flexion, and posterior tilt angles, and also performs a loading dynamic fatigue test after the internal rotation, flexion, and posterior tilt angle pretreatment. The pretreated angles are prone to change during the installation of the testing machine. The design of integrating the pretreatment device and the loading device not only solves the pain points of complex angle pretreatment, but also solves the difficulties of test installation and loading, thereby ensuring the accuracy of the test method and results.

[0012] 2. The knee prosthesis durability test pretreatment device of the example of the present invention can conveniently control the rotation angle by controlling the pulse number of the corresponding femoral component flexion angle servo motor and the tibial tray posterior tilt angle servo motor when in use; the corresponding rotation angle can be monitored in real time through the femoral component flexion angle sensor and the tibial tray posterior tilt angle sensor, and fed back to the control system to correct the rotation movement accuracy of the femoral component flexion angle servo motor and the tibial tray posterior tilt angle servo motor; the distance from the midline point of the thrust bearing to the slipknot connection point of the tibial tray embedded fixture of the knee prosthesis is the circular motion radius, and the extension or retraction stroke of the linear push rod for the internal rotation angle of the tibial tray and the femoral component is the running The trajectory chord length can be used to conveniently calculate the rotation angle through the circular motion radius and the running trajectory chord length. In addition, since the femoral component and tibial component of the knee prosthesis are irregular products, a fixing device that conforms to the structural type is designed and is suitable for various specifications. At the same time, the tibial component is fixed by embedding. The embedding result design can be demolded after the test to save tooling loss. At the same time, the tibial tray and femoral component internal rotation angle visual system is used as a monitoring and feedback device for the internal rotation angle. The visual system calibrated by a standard ruler compares the running distance of the linear actuator and feeds back to the control system, and then combines the circular motion radius (fixed value) to output the internal rotation angle in real time, which can correct the control accuracy of the linear actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 is a schematic diagram of internal rotation, flexion, posterior tilt angle and loading of the present invention; Figure 2 It is a schematic diagram of the device of the present invention.

[0014] In the figure: 1. Femoral component flexion angle servo motor; 2. Femoral component flexion angle sensor; 3. Tibial tray posterior inclination angle servo motor; 4. Tibial tray posterior inclination angle sensor; 5. Tibial tray and femoral component internal rotation angle linear push rod; 6. Tibial tray and femoral component internal rotation angle visual system; 7. Femoral component embedding fixture of knee prosthesis; 8. Tibial tray embedding fixture of knee prosthesis. DETAILED DESCRIPTION

[0015] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0016] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0017] Embodiment 1: like Figure 1 As shown, this embodiment provides a knee joint prosthesis durability test preprocessing method, comprising: S1. Align and install the femoral component on the testing machine so that it is in the maximum flexion angle in the sagittal plane, and the flexion angle includes the posterior tilt angle; S2. Place the femoral component in contact with the liner and close to the posterior edge of the liner. S3, align all components in the rotational equilibrium position to set the maximum flexion angle, in which the femoral component, liner, and tibial tray are aligned in the coronal plane according to the desired equilibrium alignment; S4, rotation alignment; S5, keep the anterior and posterior center lines of the femoral component and the liner component always in line, and simulate the tibial tray to internally rotate 20° relative to the femoral component; S6. Set the loading force line through the centerline of the femoral component and intersect at the contact point or its posterior side.

[0018] In this embodiment, in step 1, the femoral component is installed according to the test method in ASTM F2083-2012.

[0019] In this embodiment, in step 2, the contact points between the specified components are recorded.

[0020] In this embodiment, in step 2, the anterior-posterior displacement can allow the femur to flex and rotate to a specified angle without generating impact between the femur and the tibia.

[0021] In this embodiment, in step 5, on the pad-fixed system, after simulating internal rotation, only one condyle will be at the maximum posterior contact point, and the other condyle should be close to the center of the pad. In order to make both femoral condyles contact with the pad before loading, it is necessary to change the valgus and valgus positioning of the tibial component. In order to ensure appropriate flexion and correct force line, it is also necessary to rotate the femoral component to achieve the 20° requirement.

[0022] On the other hand, the present embodiment also provides a preprocessing device for implementing the above-mentioned preprocessing method, including a knee prosthesis femoral component embedding fixture 7 and a knee prosthesis tibial tray embedding fixture 8, the knee prosthesis femoral component embedding fixture 7 is driven by a femoral component flexion angle servo motor 1, the femoral component flexion angle servo motor 1 is fixedly installed on a testing machine, a femoral component flexion angle sensor 2 is fixedly installed on the testing machine, and the femoral component flexion angle sensor 2 is coaxially fixedly connected to the knee prosthesis femoral component embedding fixture 7; the knee prosthesis tibial tray embedding fixture 8 is driven by a tibial tray posterior tilt angle servo motor 3, the tibial tray posterior tilt angle servo motor 3 is fixedly installed on the testing machine, A tibial tray tilt angle sensor 4 is correspondingly installed on the machine, and the tibial tray tilt angle sensor is coaxially fixedly connected with the tibial tray embedding fixture 8 of the knee prosthesis. A tibial tray and femoral component internal rotation angle linear push rod 5 is provided below the tibial tray embedding fixture 8 of the knee prosthesis. One end of the tibial tray and femoral component internal rotation angle linear push rod 5 is fixed to the bottom plate of the testing machine through a slipknot, and the other end is connected to the tibial tray embedding fixture 8 of the knee prosthesis through a slipknot. The tibial tray embedding fixture 8 of the knee prosthesis is fixed to the bottom plate of the testing machine through a set of thrust bearings. When the tibial tray and femoral component internal rotation angle linear push rod 5 is pushed out or retracted, the tibial tray embedding fixture 8 of the knee prosthesis is driven to rotate around the thrust bearing.

[0023] In this embodiment, the tibial tray and the femoral component internal rotation angle visual system 6 are fixedly installed on the testing machine.

[0024] This method accurately adjusts the internal rotation, flexion and posterior tilt angles, and after pre-processing the internal rotation, flexion and posterior tilt angles, a loading dynamic fatigue test is performed. The pre-processed angles are prone to change during the installation of the testing machine. The design of integrating the pre-processing device and the loading device not only solves the pain points of complex angle pre-processing, but also solves the difficulties of installation and loading of the test, thereby ensuring the accuracy of the test method and results. At the same time, when the device is in use, the rotation angle can be conveniently controlled by controlling the number of pulses of the corresponding femoral component flexion angle servo motor 1 and the tibial tray posterior tilt angle servo motor 3. The corresponding rotation angle can be monitored in real time through the femoral component flexion angle sensor 2 and the tibial tray posterior tilt angle sensor 4, and the feedback is given to the control system to correct the rotation action of the femoral component flexion angle servo motor 1 and the tibial tray posterior tilt angle servo motor 3. Accuracy: The distance from the midline point of the thrust bearing to the slipknot connection point of the tibial tray embedding fixture 8 of the knee prosthesis is the circular motion radius, and the extension or retraction stroke of the linear push rod 5 for the internal rotation angle of the tibial tray and the femoral component is the chord length of the running trajectory. The rotation angle can be easily calculated through the circular motion radius and the chord length of the running trajectory. In addition, since the femoral component and tibial component of the knee prosthesis are irregular products, a fixing device that conforms to the structural type is designed and is suitable for various specifications. At the same time, the tibial component is embedded and fixed, and the embedding result design can be demolded after the test, saving tooling loss. In addition, the tibial tray and femoral component internal rotation angle visual system 6 is used as a monitoring and feedback device for the internal rotation angle. The visual system calibrated by a standard ruler compares the running distance of the linear push rod and feeds back to the control system, and then outputs the internal rotation angle in real time in combination with the circular motion radius (fixed value), which can correct the control accuracy of the linear push rod.

[0025] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

[0026] Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims

1. A pretreatment method for a knee joint prosthesis durability test, characterized in that: include: S1. Align and install the femoral component on the testing machine so that it is in the maximum flexion angle in the sagittal plane, and the flexion angle includes the posterior tilt angle; S2. Place the femoral component in contact with the liner and close to the posterior edge of the liner. S3, align all components in the rotational equilibrium position to set the maximum flexion angle, in which the femoral component, liner, and tibial tray are aligned in the coronal plane according to the desired equilibrium alignment; S4, rotation alignment; S5, keep the anterior and posterior center lines of the femoral component and the liner component always in line, and simulate the tibial tray to internally rotate 20° relative to the femoral component; S6. Set the loading force line through the centerline of the femoral component and intersect at the contact point or its posterior side.

2. The knee joint prosthesis durability test pretreatment method according to claim 1, characterized in that: In the above-mentioned S1, the femoral component is installed according to the test method in ASTM F2083-2012.

3. The knee joint prosthesis durability test pretreatment method according to claim 1, characterized in that: In the above-mentioned S2, the contact points between the specified components are recorded.

4. The knee joint prosthesis durability test pretreatment method according to claim 3, characterized in that: In S2, the anterior-posterior displacement allows the femur to flex and rotate to a specified angle without generating impact between the femur and tibia.

5. The knee joint prosthesis durability test pretreatment method according to claim 1, characterized in that: In the S5 described above, on the liner-fixed system, only one condyle will be at the maximum posterior contact point after simulated internal rotation, and the other condyle should be close to the center of the liner. In order to make both femoral condyles contact the liner before loading, it is necessary to change the valgus and valgus positioning of the tibial component. In order to ensure appropriate flexion and correct force line, it is also necessary to rotate the femoral component to achieve the 20° requirement.

6. A pretreatment device for implementing the pretreatment method according to any one of claims 1 to 5, characterized in that: The invention comprises a knee joint prosthesis femoral component embedding fixture (7) and a knee joint prosthesis tibial support embedding fixture (8), wherein the knee joint prosthesis femoral component embedding fixture (7) is driven by a femoral component flexion angle servo motor (1), the femoral component flexion angle servo motor (1) is fixedly mounted on a testing machine, a femoral component flexion angle sensor (2) is fixedly mounted on the testing machine, and the femoral component flexion angle sensor (2) is coaxially fixedly connected to the knee joint prosthesis femoral component embedding fixture (7); the knee joint prosthesis tibial support embedding fixture (8) is driven by a tibial support posterior tilt angle servo motor (3), the tibial support posterior tilt angle servo motor (3) is fixedly mounted on the testing machine, and a tibial support posterior tilt angle sensor (2) is correspondingly mounted on the testing machine. The sensor (4) is coaxially fixedly connected to the tibial tray embedding fixture (8) of the knee joint prosthesis. A tibial tray and femoral component internal rotation angle linear push rod (5) is provided below the tibial tray embedding fixture (8) of the knee joint prosthesis. One end of the tibial tray and femoral component internal rotation angle linear push rod (5) is fixed to the bottom plate of the testing machine through a slipknot, and the other end is connected to the tibial tray embedding fixture (8) of the knee joint prosthesis through a slipknot. The tibial tray embedding fixture (8) of the knee joint prosthesis is fixed to the bottom plate of the testing machine through a set of thrust bearings. When the tibial tray and femoral component internal rotation angle linear push rod (5) is pushed out or retracted, the tibial tray embedding fixture (8) of the knee joint prosthesis is driven to rotate around the thrust bearing.

7. The knee joint prosthesis durability test pretreatment device according to claim 6, characterized in that: The testing machine is fixedly mounted with a tibial tray and a femoral component internal rotation angle visual system (6).

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