Patent ID: 7776098

Claim:
A hip prosthesis comprising an elongated stem having a longitudinal stem axis and a metaphyseal flare leading up to a flat upper surface extending perpendicular to the stem axis and having opposite, relatively straight sides; a tapered socket extending a selected distance into the stem from said upper surface, said socket having opposite sides extending substantially parallel to the opposite sides of said surface and being centered on the stem axis; a substantially spherical head having a center of curvature, and a coupling member releasably coupling the head to the stem, said coupling member including a neck having a lower end forming a base with a first axis that substantially coincides with the stem axis and an upper end with a second axis and connected to the head so that said second axis extends through said center of curvature and is angularly offset from the first axis, said base also having a length and taper such that it wedgingly engages in the socket to form a releasable, non-rotatable connection therewith which defines a tapered neck/stem junction centered on and aligned with said stem axis and which has a cross-section with opposite ends, one of which is wider than the other and that is elongated in the direction of the metaphyseal flare, said upper surface and cross-section each having the shape of a trapezoid with rounded corners so that the coupling member can only be coupled to the stem when the head is located above the metaphyseal flare.