Patent ID: 7559950

Claim:
A hip prosthesis, comprising: a shaft which is configured to be anchored in a medullary canal of a femur and includes a distal portion which is configured to be anchored in a diaphysis, the shaft having a core cross-section which tapers toward a distal end, the shaft core cross-section being substantially rectangular with an axis ratio of at least 1.5:1 at a distance of approximately 1 cm from the distal end, the distal portion of the shaft extending from a proximal start of the shaft to the distal end; wherein the distal portion of the shaft comprises a plurality of longitudinal ribs protruding from the shaft and arranged on a lateral side and a medial side of the distal portion of the shaft, the plurality of longitudinal ribs including at least two edge ribs arranged on lateral corners of the rectangular cross-section of the shaft near the distal end, wherein a height of the plurality of ribs continuously increases relative to the shaft core surface from the proximal start of the distal portion to the distal end of the shaft, whereas a height of the plurality of ribs does not increase relative to a longitudinal axis of the shaft from the proximal start of the distal portion to the distal end of the shaft.