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The AMTI Ortho-POD is a multidirectional pin-on-disc machine capable of replicating the complex motions essential for accurately simulating the in vivo wear of polyethylene joint implants.

Multidirectional motions

The Ortho-POD is capable of simulating both unidirectional and bidirectional sliding. Research has demonstrated that the wear rate of certain polymers, such as ultra-high molecular weight polyethylene, is highly dependent on the "cross-shear" motions that occur between the mating components of prostheses. Unidirectional motion strain-hardens polyethylene, gradually increasing its integrity along the established path. However, this same effect also makes the material increasingly susceptible to wear from motions that cross the established path in another direction.

The Ortho-POD is capable of simulating both unidirectional and bidirectional sliding, allowing it to easily replicate the cross-shear motions experienced by a prosthesis in vivo.

Three controlled degrees of freedom

Pin rotation, disc rotation, and dynamic pin loading are all independently controllable.

Advanced control and acquisition software

The machine's motions and loads are fully programmable through the included control and acquisition software. Custom waveforms serve as motion and loading templates. Waveforms may be defined mathematically or through the Ortho-POD's intuitive learning mode, which allows users to teach the pin-on-disc machine a path by "sketching" it using the Ortho-POD's manual jog controls.

Three integrated multi-axis load cells

Three AMTI multi-axis load cells are integrated into the pin-on-disc machine, enabling the three orthogonal forces to be measured at the pin/disc interface. Additionally, the coefficient of friction may be independently sampled at each pin periodically during the course of a test.

» Download a PDF of the full specifications.