ASTM F1820: Standard Test Method for Determining the Forces for Disassembly of Modular Acetabular Devices
Three different tests according to the above listed procedure are developed to determine the mechanical quality of the fitting between insert and cup of a hip endoprosthesis. The push-in/push-out procedures determines the axial locking strength against dislocation of the liner.
To gain more information about implant safety in-vivo, the resistance against torque is determined using a second test setup.
A third test assesses the resistance of the locking mechanism to edge forces. They could occur when the neck of the femoral stem impinges on the edge of the acetabular liner. Two different test methods can be applied: the offset pull-out or the lever-out disassembly test.