Abstract: The shaft surface of a cementlessly implantable prosthesis is provided with a large number of holes which are formed as blind or pocket holes. Each hole is surrounded by a bulb in the form of a crater edge. The bony tissue that grows into the holes and around the bulbs ensures a firm seating of the prosthesis over a long time. The holes are preferably oriented in such a way that the bone pegs that extend into them can take up a desired load which may be either a compressive or a tensile force. A tensile force exerted on the bone will stimulate its growth.