Patent ID: 7497875
Filing Date: 2009-03-03
Classification: A61F

Abstract:
1. A shaft of a hip-joint prosthesis for anchoring in a femur, the shaft comprising anterior, posterior, lateral, and medial sides, wherein the shaft is monolithic and expands on all sides from a distal end in the proximal direction and medially merges with a curved section that is continuous with a prosthesis neck, the shaft having a proximal region with an anterior-posterior dimension that is overdimensioned in the range of about 1 to 3%, with respect to a dimension of a cavity formed by a rasp, in such a way that when the shaft is driven in, it compresses the spongy bone tissue over a large area in the proximal region of the femur, said shaft further comprising middle and distal portions dimensioned to substantially exactly match corresponding dimensions of the cavity, wherein the shaft comprises in the proximal region of the shaft an additional thickness that projects outward from a generally planar surface of at least one of the anterior and posterior sides, the additional thickness defining a generally continuous surface on said at least one of the anterior and posterior sides, the generally continuous surface configured to facilitate the press-fitting of the proximal region of the shaft in the femur and inhibit the risk of a femoral fracture, the generally continuous surface comprising at least one dense layer and at least one porous layer having a maximum thickness of between about 2/10 mm and about 1 mm.