There are several ASTM and ISO specifications that require Torque Testing;ISO 594-1, ASTM F543, ASTM 2502, F1541, and A938. There are also many medical device companies that could use a torsion testing system for R&D and prototyping. Many times, the axial forces are low, and the torque capacity is less than 50Nm. ADMET's 81T Torsion Tester comes in 1-100Nm capacity with dead weight pulley system to offset or to apply load to the sample. A Biaxial configuration, for both linear and torsional control, is available in single or dual column configurations at an additional cost.

Constitutive models are necessary to predict the mechanical behavior of biological tissues. However, biological materials present challenges in constitutive modeling due to their complex mechanical behavior. Their oriented fibrous structures often exhibit pronounced mechanical anisotropy. Due to anisotropy, stress strain data generated from uniaxial tests cannot be used to extrapolate to generalized three-dimensional constitutive equations. Since biological tissues are generally considered incompressible, planar biaxial testing allows for a two-dimensional stress-state that can be used to characterize their mechanical properties and validate the constitutive models.

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.  An outline of the four test procedures is as follows: