Abstract: A tripartite set for securing a prosthesis to a bone, namely,a proximal part connected to the prosthesis and adapted to be received in a complementarily processed part of a marrow cavity;a distal part or tip to be fixed in said marrow cavity in an advanced position; anda tie member connecting said two parts, one end of said tie member extending at said tip and forming a wedge bolt or like member which expands upon the exercise of tensile force therewith, and said tie member being an at least axially resilient element with flat spring characteristics at least in the body temperature range.

Abstract: A fixation element for securing a prosthesis in a bone, whereby the effective diameter of the fixation element can be increased by increasing the temperature of at least one element of a material which shrinks or expands when heated, such as shape memory metal, by means of an inductive magnetic field, whereby the change in shape generated with the shrinkage or expansion of the material is converted into an increase in diameter of the fixation element.