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 constant amplitude. However, there is not sufficient information available to crate 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.