Patent ID: 7175668

Claim:
A shaft of a hip-joint prosthesis for anchoring in a femur, comprising: a prosthesis neck; and a femur-anchoring section that is connected to the prosthesis neck and that tapers along a longitudinal axis toward a distal end, wherein the femur anchoring section has an anterior surface, a posterior surface, a lateral surface and a medial surface, wherein the femur-anchoring section has an external contour in a plane perpendicular to the longitudinal axis having concave facets at corner junctions of adjacent surfaces, each of the concave facets extending along a circular arc from one of the surfaces to one of the adjacent surfaces, wherein at least one of a first dimension between the anterior and posterior surfaces and a second dimension between the medial and lateral surfaces is over-dimensioned relative to corresponding pre-determined rasping dimensions of a femur cavity, and in the regions of the corner junctions between pairs of adjacent surfaces, the shaft is sized to be substantially equal to corresponding pre-determined rasping dimensions, wherein the femur-anchoring section comprises longitudinal grooves in the posterior and anterior surfaces of the anchoring section configured to promote revascularization of spongy bone tissue in the grooves.