Robotic Acetabulum Preparation For Acceptance of Acetabular Cup With Engagement Features

An acetabular cup comprising:

• an inner surface;
• an outer surface;
• an end face separating the inner surface and the outer surface, the end face defining an opening;
• and
• a protrusion on the outer surface, the protrusion having an elongate dimension and a width dimension, a surface of the protrusion from a first side of the width to a second side of the width opposite the first side being convex, a first location on the protrusion being a first distance from the pole and a second location on the protrusion being a second distance from the pole, the first distance being different from the second distance.

An acetabular cup comprising:

• an inner surface;
• an outer surface;
• an end surface separating the inner surface from the outer surface, the end surface defining an opening such that an axis extends through a pole of the outer surface and a center of the opening;
• and
• a protrusion that includes first, second and third apices each at a first distance from the pole of the outer surface, the first distance being the shortest distance between the protrusion and the pole,
• wherein a first plane is coincident with the first apex and the axis, and
• wherein the protrusion continuously extends from the first apex in a first direction away from the first plane on a first side of the first plane and in a second direction away from the first plane on a second side of the first plane, the second side being opposite the first side.