The assessment of the risk of flank fracture became more important over the last years, especially for wind gearboxes. Usually, a flank fracture leads to additional damages on other gears or bearings, often with fatal results for the gearbox. Due to the lack of methods to detect a flank fracture in early stages and the unsystematic occurrence of this damage mechanism, where some gears fail after short time of operation, while others reach the high cycle fatigue regime, flank fractures currently are one of the main concerns during the design phase of a gearbox. To accurately assess the risk of a flank fracture, the effect of local hardness, residual stresses and material defects like non-metallic inclusions or coarse grains need to be considered. Additionally, a stress hypothesis for the multiaxial stress state has to be applied, which usually creates a big computational effort. In [11], a general model for the fatigue behavior of surface strengthened steels was developed and verified. The principles of this new concept will be presented with emphasis on the retrieval of the necessary input data like distribution functions for material defect size or hardness and residual stress profiles. The verification based on simulations of flank fracture fatigue tests will be shown in detail, focusing not only on the fatigue strength itself, but also on the orientations of the fatigue cracks and the positions of the fatigue crack initiations.