Is 7206 ISO standard enough to prove the endurance of femoral components of hip prostheses?

The design of a cementless femoral stem that fractured at the neck–shoulder junction was analysed with reference to parts 4 and 8 of ISO standard 7206. The stresses in the section where fracturing occurred were calculated assuming the 2300 N loading specified in ISO 7206-8. The results show that the prosthesis met ISO standard requirements regarding fatigue behaviour. However, this feature does not occur when a load of 4000 N, corresponding to a patient with a body weight of 1000 N, is applied. It is therefore suggested that patient body weight should be taken into account when designing and choosing the appropriate stem size.