ASTM F1717 | Medical Devices and Equipment | Mechanical Properties
Spinal Implants are tested according to several ASTM standards. ASTM F1717 is intended to provide a basis for the mechanical comparison among past, present and future spinal implant assemblies. Three static and one fatigue mechanical test of a spinal construct are governed by ASTM F1717. The three static tests are compression bending, tension bending and torsion.
The fatigue test is a compression bending test. The mechanical tests are conducted using simplified loading schemes and do not attempt to mimic the complex loads of the spine.
Prior to conducting ASTM F1717, it is important to read the entire specification in the relevant ASTM publication.
Load at a rate not to exceed 60 deg/min and record the torque vs angle curve.
Calculate angle at 2% offset yield, elastic angle, yield torque and torsional stiffness.
Compressive Bending Fatigue Test
Apply a constant load amplitude sinusoidal control profile at no faster than 5Hz. A constant load ratio, R, for all tests should be established and should be greater than or equal to 10.
Evaluate two specimens at the initial fatigue loads. Determine the maximum run out load based on no samples failing prior to 5 million cycles.
Continue fatigue testing pairs of specimens until the difference between the load at which a specimen fails and the run out load is no greater than 10% of the compression bending ultimate load.
ADMET biaxial universal testing systems are available for static only or for both the static and fatigue tests outlined above. These tests require specific fixturing described in the F1717 specification and can be provide by ADMET.