US Patent 8979859 Depth of Impaction

A method for determining a depth of impaction of a prosthetic cup into an acetabulum using an end effector and a movable impactor shaft is provided, wherein the prosthetic cup may be positioned at a distal end of the impactor shaft. The method may position the distal end of the impactor shaft at a known pose relative to the end effector, track a spatial pose of the end effector relative to a spatial pose of the acetabulum, determine a spatial pose of the prosthetic cup based on the spatial pose of the end effector and the known pose between the distal end of the impactor shaft and the end effector, and determine the depth of impaction based on the spatial pose of the prosthetic cup and the spatial pose of the acetabulum.