An implant fixation stem has a distal portion with a controlled stiffness. In one embodiment the deflection in response to a given force is equal to other similarly designed stems to give a surgeon consistent implantation feedback regardless of implant size. The deflection is preferably provided via a slot in the stem, the slot length being determined as a function of the stem's moment of inertia. Alternate embodiments provide for flutes of unequal length.