Experience with cementless fixation over the last six years indicates that the technique offers greater opportunities for bone conservation. Thus, when cement is used, and especially if it is forced into the skeleton under pressure, the amount of bone incorporated into the implant is considerable. Conversely, if no cement is used, grafting techniques to fill defects are becoming increasingly routine, so that today no bone may be removed from the replaced knee or hip--all fragments that are excised are repositioned as grafts in defects. Thus, cementless fixation meets the fundamental orthopedic maxim of the conservation of bone stock. Given that an implant can be fixed with satisfactory clinical results without cement and without bone ingrowth, it becomes difficult to demonstrate a clinical advantage for the latter. Nevertheless, bone ingrowth is possible both experimentally and (with less confidence) in man. Thus, it is clearly a technique that should be evaluated. However, it is not, in the senior author's view, a technique that should as yet be generally used. Hopefully, investigations of this problem will take place in a restrained scientific way rather than by the current method, which is in response to the dictates of fashion and commerce.