ASTM F3574-22

4.1?The function of the SIJ fusion device assembly is to stabilize the SIJ to facilitate arthrodesis of the motion segment. This test method outlines materials and methods for the characterization and evaluation of the mechanical performance of different SIJ fusion device assemblies so that comparisons can be made between different designs.

4.2?These test methods are designed to quantify the static and dynamic characteristics of different designs of SIJ fusion device assemblies. These tests are conducted in vitro to allow for analysis and comparison of the mechanical performance of SIJ fusion device assemblies to specific force modalities.

4.3?The forces applied to the SIJ fusion device assemblies during the tests described herein may differ from the complex loading seen in vivo and, therefore, the results from these tests may not directly predict in vivo performance. The results, however, can be used to compare mechanical performance of different SIJ fusion device assemblies.

4.4?Since the environment may affect the dynamic performance of SIJ fusion device assemblies, dynamic testing in a saline environment may be considered for implants with wearing surfaces or with movable components or for implants with components that are temperature dependent. Fatigue tests should first be conducted in air (at ambient temperature) for comparison purposes since the environmental effects could be significant. If a simulated in vivo environment is necessary, the investigator should consider testing in a saline environmental bath at 37 ?C (for example, 0.9 g NaCl per 100 mL water). A simulated body fluid, a saline drip or mist, distilled water, or other type of lubrication at 37 ?C could also be used with adequate justification.

4.5?If the devices are known to be temperature and environment dependent, testing should be conducted in physiologic solution as described in 4.4. Devices that require physiologic solution for testing should be tested in the same type of solution for comparison purposes.

4.6?The location within the simulated joint space and position of the SIJ fusion device assembly with respect to the loading axis will be dependent upon the design, the manufacturers recommendation, or the surgeons preferred method for implant placement.

4.7?It is well known that failure of materials is dependent upon stress, test frequency, surface treatments, and environmental factors. Therefore, when determining the effect of changing one of these parameters (for example, frequency, material, or environment), all others must be kept constant to facilitate interpretation of results.

1.1?These test methods cover the materials and methods for the static and dynamic testing of sacroiliac joint (SIJ) fusion device assemblies, SIJ implants designed to promote arthrodesis at the sacroiliac joint.

1.2?These test methods are intended to provide a basis for the mechanical comparison among past, present, and future nonbiologic SIJ fusion device assemblies. These test methods allow for comparison of SIJ fusion device assemblies intended to be implanted with a trajectory in line with the joint space (in-line implant) or for comparison of SIJ fusion devices intended for implantation across the joint space (transverse implant). These test methods are intended enable the user to compare SIJ fusion device assemblies mechanically and do not purport to provide performance standards for SIJ fusion device assemblies.

1.3?These tests describe static and dynamic tests by specifying force types and specific methods of applying these forces. These tests are designed to allow for the comparative evaluation of SIJ device assemblies.

1.4?Guidelines are established for measuring displacements, determining the yield force or moment, and evaluating the stiffness and strength of the SIJ fusion device assemblies.

1.5?Some SIJ fusion device assemblies may not be testable in all test configurations.

1.6?The values stated in SI units are to be regarded as standard. No other units of measurements are included in this standard, with the exception of angular measurements, which may be reported in terms of either degrees or radians.

1.7?This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8?This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.