YY/T 1426.3-2017Implants for surgery - Wear of total knee joint prostheses - Part 3: Loading and displacement parameters for displacement controlled wear testing machines and corresponding environmental conditions for test (English PDF)

Foreword

YY/T 1426 "Surgical Implants Total Knee Prosthesis Wear" is divided into the following three parts.

--- Part 1. Load and displacement parameters of load-controlled wear testers and related test environmental conditions;

--- Part 2. Measurement methods;

--- Part 3. Load and displacement parameters of the wear tester for displacement control and related test environmental conditions. This part is the third part of YY/T 1426. This part is drafted in accordance with the rules given in GB/T 1.1-2009. This section uses the translation method equivalent to ISO 14243-3.2014 "Surgical implant total knee prosthesis wear Part 3. The load and displacement parameters of the wear-controlled wear tester and related test environmental conditions. The documents of our country that have a consistent correspondence with the international documents referenced in this part are as follows:

---YY/T 0924.1-2014 Surgical implant parts and total knee prosthesis parts - Part 1. Classification, definitions and dimensions Label (ISO 7207-1.2007, MOD) Please note that some of the contents of this document may involve patents. The issuing organization of this document is not responsible for identifying these patents. This part is proposed by the State Food and Drug Administration. This part is organized by the National Technical Committee for Standardization of Surgical Implants and Orthopedic Devices, orthopedic implants subcommittee (SAC/TC110/ SC1). This section drafted by: Tianjin Medical Device Quality Supervision and Inspection Center, School of Mechanical Engineering, Xi'an Jiaotong University, China University of Mining and Technology material science and Engineering School. The main drafters of this section. Dong Shuangpeng, Zhang Shu, Wang Ling, Hou Yinhui, Zhang Dekun, Chen Kai. Surgical implant wear of the total knee prosthesis Part 3. Displacement controlled wear testing machine Load and displacement parameters and associated test environmental conditions

1 Scope

YY/T 1426.3 is Part 3 of the Chinese series on wear testing of total knee prostheses, and it governs the displacement-controlled variant of the test. It sets the loading and displacement parameters a wear testing machine has to apply and the environmental conditions the test has to run in, so that a knee prosthesis is worn on the bench under motion that represents walking. Wear debris is the main driver of long-term failure in knee replacement, which makes this test central to the durability evidence in a registration dossier. Part 1 covers the load-controlled variant and Part 2 the measurement of the resulting wear, so a laboratory generally needs more than one part of the series. For an orthopaedic manufacturer this is the protocol a Chinese reviewer expects the wear data to have been generated under.

This part of YY/T 1426 specifies the control of axial loading, buckling/extension angle motion control, front and rear displacement control and tibia Buckling/stretching between joint components during wear testing of total knee prosthesis on a partial rotational motion controlled knee wear tester Relative angular motion, loading mode, test speed and duration, specimen assembly and test environment requirements. The kinematics descriptions specified in this section may not apply to highly constrained knee prosthesis designs as they may be tested early It can cause damage to joint components and thus does not represent clinically expected performance.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article. Pieces. For undated references, the latest edition (including all amendments) applies to this document.

YY/T 1426.1-2016 Surgical implants - Total knee prosthesis wear - Part 1 . Load control wear test machine Load and displacement parameters and associated test environmental conditions (

ISO 14243-1.2009, IDT) Surgical implants -- Total knee prosthesis wear -- Part 2 . Methods of measurement ( ISO 14243-2. 2009, IDT) ISO 7207-

1 Surgical implant parts and total knee prosthetic parts - Part 1. Classification, definition and dimensioning (Implantsforsurgery-Componentsforpartialandtotalknee-jointprostheses-Part

3 Terms and definitions

The following terms and definitions apply to this document.

3.1 Before and after (AP) displacement Anterior/Posterior (AP) displacement The amount of offset of the axial force axis relative to the buckling/extension axis measured in a direction perpendicular to the axial force axis and the buckling/extension axis.

Note. This displacement is specified when the total knee prosthesis is at the reference position (3.7), and the axial force axis is relative to the reference position of the total knee prosthesis. Set to a positive value (3.7).

3.2 Front and rear force APforce Perpendicular to the tibial axis and the flexion/extension axis, the shear force exerted by the tibial component on the femoral component, the line of action of the force passing through the axial direction Force axis.

Note. When the direction of action of the force is defined as positive along the tibial component from the back to the front.

3.3 Axial force axisforce The force of the knee prosthesis tibial component applied to the femoral component in a direction parallel to the axis of the tibia.

Note. The regulation is defined as positive when the direction of force is from bottom to top (see Figures 1 and 2). Description. 1

---buckling (femoral component); 2

---Tibial rotation; 3

---The displacement of the tibial component before and after; 4

---axial force. Figure

1 Symbolic rule of force and motion in the left knee of the total knee arthroplasty system Description. 1

---axial force axis; 2

---the humeral axis; 3

4 Principle

The total knee prosthesis is mounted on a test device that applies periodically varying buckling/period to the femoral and tibial component contact surfaces. The angle of extension, the angle of rotation of the tibia, the anteroposterior displacement and the axial force simulate the gait of a normal person. The tibial component is flexed/extended and rotated Movement of the femoral component under rotation, anterior and posterior displacement and axial force loading. The contact force/displacement effect of the load is axial force, buckling/stretching Rotation, front and rear displacement, and tibial rotation. All applied force/displacement actions follow a defined periodic variation law, and each force/motion action There is also a fixed relationship between them. The contact surfaces of the femoral and tibial components are immersed in a test medium that mimics human body lubricating fluid. Soak a control sample Calculate the creep of the test sample and/or by the axial force load in the liquid medium and with the same periodic variation as the test sample The quality change caused by liquid exchange. The test was carried out under controlled conditions simulating physiological conditions. 5 sample, lubricating fluid and sample volume

5.1 Liquid test medium The liquid test medium consists of the following parts.

--- Deionized water diluted protein calf serum solution of 20g/L;

--- Under normal circumstances, the liquid test medium needs to be filtered through 2µm filter membrane/paper;

--- In order to minimize microbial contamination, the liquid test medium should be stored frozen before the test. Can add bacteriostatic agents (such as azide sodium). The reagent may be a hazardous chemical;

--- The pH of the liquid test medium can be monitored regularly. If monitored, the test report should include the test results.

5.2 Test sample The size combination and design details of the selected test sample should be representative of the expected most unfavourable wear of the total knee system being tested. condition. Unless the physical characteristics of the implant system prove that it is not achievable, the tibial component should be supported on the dorsal articular surface (eg bone cement) Or machined humeral support for imitation of the inner surface). If the articular surface of the patella component is fixed to the tibial tray by a snap ring/fastening device, the workpiece Should be able to provide the same fixed conditions. If the normal backing or bone cement cannot be used due to the physical characteristics of the implant system, the support system of the tibial component can simulate positive Often design features and conditions of use, and allow for non-destructive disassembly of parts for wear measurements (if needed). Parts may be sterilized in the same manner as clinically, as they may affect the wear properties of the material. If feasible, should All test and control components of the specified test group were sterilized simultaneously (in the same container) to reduce the difference between the samples.

5.3 Control sample The size combination and design of the parts should be the same as the test samples.

5.4 Number of test samples The wear test for each type of prosthesis should use at least three test samples and two control samples. Both control samples can be used as A soak control, or one as a passive soak control and one as a loading control.

5 Control parameters. AP movement changes with time period

6.8 humerus rotation control system Can provide the tibial rotation motion specified in Figure 6 and Table 4, and maintain the error of the motion amplitude within a period of the specified maximum ±5% and maximum phase error are ±3% of the full period. The tibial rotation limit signal is ignored when determining tolerances. The humerus rotates about an axis parallel to the axis of the tibia. The positive direction follows

6 Control parameters. changes in tibial rotation over time

6.9 front and rear force measurement system The front and rear forces (6.7) can be measured in the direction of the back and forth motion. This system is only required for component installation and is optional during testing.

6.10 Tibial Torque Measurement System The tibial rotational moment (6.8) can be measured on the same axis of rotation of the humerus. The recommended accuracy of the tibial torque measurement system is at least ±

0.3 N·m and each sample can be measured separately. This system is only required for component installation and is optional during testing.

6.11 Lubrication system The prosthetic contact surface can be kept immersed in the liquid test medium.

Note. Use a seal to prevent evaporation of the liquid.

6.12 Temperature Control System The temperature of the liquid test medium can be maintained at 37 ° C ± 2 ° C.

6.13 Control workstation The periodic load as shown in Fig. 3 can be applied without generating the motion as shown in Figs. 4, 5 and 6. Control workstations should follow the provisions of 6.2, 6.3, 6.4,

6.12 above. The loading effect causes only a small fraction of the increase in liquid absorption relative to the amount of sample liquid absorbed by the lubricating fluid and temperature. If you can It is sufficient to prove that the liquid absorption generated by loading the control sample is less than 5% of the total liquid absorption, and it is not necessary to load the control sample.

7 Test procedure

7.1 Initial measurement. Calibrate each test bench with a load cell. Calibration should be applied to all other workstations (if any) get on. In order to determine the amount of subsequent wear, an initial measurement of the unworn sample is required.

Note. YY/T 1426.2 gives a method for measuring wear.

7.2 After the initial state of the sample is measured, clean the test sample according to the provisions of 4.5.2~

4.5.5 of YY/T 1426.2-2016.

7.3 Mounting the femoral component of the test sample on the testing machine and making measurements of the AP force measurement system and the tibial torque measurement system Zero. Adjust the centering of the femoral component according to the design of the testing machine so that the buckling/extension axis and the actual flexion/extension motion applied to the testing machine The axes of rotation are identical.

7.4 Install the tibia part of the test sample on the testing machine and make the axial force direction of the test machine parallel in the error range of ±1°. On the humeral axis. The tibial component is tilted relative to the tibial axis at the angle recommended by the manufacturer, according to clinical requirements. If the tibia portion contains a pad with a metallic or other tibial tray, the tibial tray should be included in the test.

Note. When the tibial component is fixed by bone cement, the tibial component can be centered after filling the bone cement with a temporary adjustable support.

7.5 Place the passive soak control sample in a container and place the container in a similar temperature environment as the test sample. For active soaking control For samples, repeat steps

7.1 to 7.4. For specific samples of the same material, shape and size, a comparison of previous tests can be used data.

7.6 Completely immerse the contact surfaces of the test and control samples in the test liquid medium (5.1). Keep the temperature of the test liquid medium at Temperature measurement at a position representative of the overall temperature of the liquid at 37 ° C ± 2 ° C.

7.7 Start the test machine, adjust the test machine, and within ±5% of the maximum force and ±5% of the maximum angle and line displacement value The load and displacement specified in Figures 3 to 6 were applied to the sample, and the load specified in Figure 3 was applied to the control sample. See Appendix A for details on the parameter settings equivalent to the tests in Figures 3 to 6. For highly constrained knee joint prostheses, The AP force and rotational torque peaks given in Tables 3 and 4 of YY/T 1426.1-2016 to determine the appropriate AP motion and tibial rotation position Move value.