Procedures for the mechanical testing of knee replacements
This fatigue test is applied to bicondylar knee replacements and specifically targets the metallic tibial plateau (tibial tray). For the test, the plateau is embedded on one side (medial or lateral), while the other side is free to flex. The fatigue strength of the tibial plateau is evaluated under specified cyclic loads and numbers of cycles.
This fatigue test is not applied to cemented tibial components made solely of polyethylene (all-poly) that do not have a metallic plateau.
In March 2022, ASTM published the standard for fatigue testing of the femoral component of knee replacements. This standard complements the fatigue testing of tibial plateaus according to ISO 14879-1 and is the first published standard specifically addressing the fatigue strength of the femoral component.
The test is conducted under “closing conditions,” meaning the femoral component is cyclically compressed along its anterior-posterior axis. Only one posterior condyle is loaded, while the anterior flange is fixed.
A total of 10 million cycles is recommended.
