Abstract: The shape and orientation of rigid or nearly rigid moveable bodies are determined using a shape characterization. Sensors capture a plurality of representations of different perspectives of the body that are analyzed to determine a bounding volume of the body. The shape of the body is determined from the bounding volume. The position of the body is determined using tracking devices that sense the position of the body. The bounding volume and position information are combined to define the shape and orientation in space of the body, and in particular the position of a point of interest on the body.

Abstract: A method of performing an arthroplasty of a ball and socket joint with a surgical navigation system includes the step of digitizing landmarks to provide geometrical parameters of the joint and a limb depending there from, including digitizing aspects of a socket region of the ball and socket joint. A range of motion parameter is determined. A soft tissue tension parameter is determined. A functional goal is computed based on landmark data, the range of motion parameter, the soft tissue tension parameter, and a database of potential implants. An optimal socket position is solved for to minimize impingement of potential implants. An implant is chosen based on the optimal socket position and the functional goal. The joint is prepared to receive the chosen implant. The chosen implant is installed into the joint.

Abstract: An adapter can be easily used to assist a surgical navigation system to determine the effector axis or the effector plane of a surgical device. The adapter has a body with a geometrical feature, the geometrical feature has a known relation with a navigation tracker device that can be attached to the adapter. When the adapter is held against a surgical device in a non-fixed manner, the effector axis or the effector plane of the device can be tracked by the surgical navigation system. The method includes a calibration method to determine the known relation between the effector axis or the effector plane and the location of the navigation tracker.

Abstract: A two dimensional image is registered with mechanical axis data, and possibly other data, using a surgical navigation system. This provides the user with additional graphical information on a display screen as the procedure is performed. The mechanical axis data can be generated using an anatomical assessment.