Patent ID: 7842096

Claim:
A hip stem having a medial side, a lateral side, an anterior side, and a posterior side, the hip stem comprising: a neck having an anterior flat surface and a posterior flat surface, said anterior flat surface and said posterior flat surface dimensioned to mate with a corresponding insertion tool to rotationally lock the hip stem to the insertion tool; and a stem portion defining a longitudinal axis and having a stem length, a proximal portion, a distal portion, and a transition portion extending between said proximal portion and said distal portion, said proximal portion extending from between ten percent and thirty percent of said stem length and including an anterior locking surface and a posterior locking surface, said anterior locking surface and said posterior locking surface forming an included angle of between six degrees and twenty degrees, at least a portion of said proximal portion encircled by a porous layer, said transition portion having an anterior face and a posterior face extending substantially parallel to said longitudinal axis of said stem portion, said anterior locking surface of said proximal portion defining an anterior locking surface slope relative to said longitudinal axis, said anterior face of said transition portion defining an anterior face slope relative to said longitudinal axis that differs from said anterior locking surface slope, said posterior locking surface of said proximal portion defining a posterior locking surface slope relative to said longitudinal axis, and said posterior face of said transition portion defining a posterior face slope relative to said longitudinal axis that differs from said posterior locking surface slope, said distal portion having a proximal cross-section defining a circle and a distal cross-section defining a polygon.