Standard Test Method for Determination of Frictional Torque and Friction Factor for Hip Implants Using an Anatomical Motion Hip Simulator

Importancia y uso:

5.1 This test procedure provides a method of evaluating the frictional torque and friction factor of artificial hip joint bearings under the stated in-vitro test conditions.

5.2 Friction is not simply a materials property. The specimen system and the effects on its friction are multi-factorial, including the materials and processing of the components, the design and assembly of the components, the test parameters, and environmental factors (lubricant, temperature, etc.).

5.3 The procedure may be used as a standardized method of measuring friction for a particular system, or as a method of investigating the effects of specific test parameters such as hip sizes, designs, radial clearance, different lubricants, clamping (nonuniform sphericity), misalignments during installation, etc.

5.4 The procedure may be used to study the variation of friction with time as the specimens wear, which is particularly useful for samples that undergo a transition from “run-in” to “steady-state” wear behavior. Since the motion and load waveforms are identical to those specified in ISO 14242-1:2014, standardized friction and wear measurements may be combined and viewed in the correct perspective where they affect each other.

5.5 Frictional torque, and in particular the maximum value, are useful to assess the torques that may compromise fixation, or cause disassociation of modular components in acetabular cup or liner/shell assemblies through a lever-out or torsion-out mechanism.

5.6 Friction factor is a useful parameter for comparison of materials and designs, and provides insights into the lubrication regime operating in the implant system. Friction factor measurement may also be able to detect acetabular liner deformation (clamping referred to earlier).

Subcomité:

F04.22

Volúmen:

13.02

Número ICS:

11.040.40 (Implants for surgery, prosthetics and orthotics)

Palabras clave:

friction testing; frictional torque; hip friction; hip joint prosthesis;