Straight stem for the implantation into a proximal femur

摘要

The present invention relates to a straight stem (10) for the implantation into a proximal femur, the stem (10) comprising a proximal stem section (12) and a distal stem section (14), the distal stem section (14) having a distal end (24) and a distal tip (26) arranged directly adjacent to the distal end (24) and defining a distalmost point of the distal end (24), the stem (10) having, in an anterior-posterior view, a medial contour and a lateral contour, and the stem (10) having a straight stem center axis (20) between the medial contour and the lateral contour, wherein the distal end (24), in an anterior-posterior view, has a convexly curved contour, and wherein the convexly curved contour of the distal end (24) merges with straight sections (46, 48) of the medial contour and of the lateral contour at a medial merging point (22) and a lateral merging point (28), respectively, wherein the medial merging point (22) and the lateral merging point (28) are offset with respect to each other in a direction parallel to the stem center axis (20), wherein the lateral merging point (28) is arranged proximally with regard to the medial merging point (22), wherein the convexly curved contour of the distal end (24) is such that the distal tip (26) is medially offset with respect to the stem center axis (20), wherein the convexly curved contour of the distal end (24) has a curved medial section extending between the distal tip (26) and the medial merging point (22) and a curved lateral section extending between the distal tip (26) and the lateral merging point (28), and wherein the contour of the distal end (24) is asymmetrically convexly curved such that the degree of curvature of the curved lateral section is smaller than the degree of curvature of the curved medial section.

主权项

1. A stem for implantation into a proximal portion of a femur, the stem comprising:
a body extending from a proximal stem section to a distal stem section, the body having a medial side and a lateral side and defining a straight stem center axis positioned between the medial side and the lateral side, the body having a cross-sectional contour, when implanted and viewed in a coronal plane, extending along the lateral side, around a distal end of the body, to the medial side, the contour including a lateral straight section that extends distally to a lateral merging point, the contour including a convexly curved lateral distal section that is devoid of straight sections and extends distally from the lateral merging point to a distal tip, the distal tip representing the distal most point of the distal end and being medially offset with respect to the stem center axis, the convexly curved lateral distal including a first region directly adjacent to the lateral merging point, the first region having a first radius of curvature, the convexly curved lateral distal section further including a second region directly adjacent to the first region, the second region having a second radius of curvature different from the first radius of curvature, the contour including a convexly curved medial distal section that extends proximally from the distal tip to a medial merging point, the medial merging point located more distal than the lateral merging point, and the contour including a medial straight section that extends proximally from the medial merging point.