Systems and methods for determining placement of prosthetic components in joint including defining patient-specific frame of reference for joint, determining patient-specific postoperative range of motion of joint, evaluating patient-specific range of motion of joint, automatically planning placement of components balancing need for range of motion with prosthesis stability through bony coverage, and applying manual adjustments to the automatically planned placement of component by giving greater or lesser weight to need for range of motion or prosthesis stability through bony coverage. Apparatuses for defining center of prosthetic femoral head and axis of prosthetic femoral neck including primary cylinder, first alignment receptacle and second alignment receptacle, and a divot on exterior of primary cylinder, divot having normal parallel to longitudinal axis of second alignment receptacle and position of the divot being translated toward an opening of the first alignment receptacle on the primary cylinder. Methods for using apparatuses. Apparatus for mounting spatially tracked device to impactor for impacting prosthetic cup into reamed socket.