ASTM F1440-92(2008)

This practice can be used to describe the effects of materials, manufacturing, and design variables on the fatigue resistance of metallic stemmed femoral components subjected to cyclic loading for relatively large numbers of cycles. The recommended test assumes a “worst case” situation where proximal support for the stem has been lost. It is also recognized that for some materials the environment may have an effect on the response to cyclic loading. The test environment used and the rationale for the choice of that environment should be described in the report.

It is recognized that actual in vivo loading conditions are not ofconstant amplitude. However, there is not sufficient information available to create standard load spectrums for metallic stemmed femoral components. Accordingly, a simple periodic constant amplitude force is recommended.

In order for fatigue data on femoral stems to be useful for comparison, it must be reproducible among different laboratories. Consequently, it is essential that uniform procedures be established.

1.1 This practice describes a method for the fatigue testing of metallic stemmed femoral components used in hip arthroplasty. The described method is intended to be used to evaluate the comparison of various designs and materials used for stemmed femoral components used in the arthroplasty. This practice covers procedures for the performance of fatigue tests using (as a forcing function) a periodic constant amplitude force.

1.2 This practice applies primarily to one-piece prostheses and modular components, with head in place such that prostheses should not have an anterior/posterior bow, and should have a nearly straight section on the distal 50 mm of the stem. This practice may require modifications to accommodate other femoral stem designs.

1.3 The values stated in SI units are to be regarded as the standard.

1.4 For additional information see Refs. (1-5) .