Abstract: An adjustable prosthesis for a bone joint comprising a joint component, an elongated rod having a distal end and a proximal end, a drive trunnion connected to said rod through an angular gear, an elongated inner sleeve, an outer sleeve and means for preventing rotation of said inner sleeve within said outer sleeve, said elongated rod including a threaded spindle and said inner sleeve including a threaded spindle nut which cooperates with said threaded spindle to provide longitudinal adjustment of the inner sleeve relative to the rod, said inner sleeve being telescopically slidable within said outer sleeve but being prevented by said means from rotating within said outer sleeve, said outer sleeve being secured to said joint component, said elongated rod being supported at its proximal end in said joint component for rotation relative to the joint component by said drive trunnion and angular gear, said drive trunnion being rotatably supported in said joint component, and said elongated rod having means for bein