Abstract: A computer-assisted surgery (CAS) system for navigating a surface of an anatomical feature in a coordinate system comprises an apparatus for obtaining points of a surface of an anatomical feature including a base adapted to be secured to the anatomical feature, a spherical joint supported by the base, the spherical joint having a ball member rotatable in at least two rotational degrees of freedom relative to the base and having a center of rotation fixed relative to the base, a distance-measurement device connected to the ball member such that a distance-measurement axis of the distance-measurement device passes through said center of rotation of the ball member. An inertial sensor unit produces signals representative of the orientation of the distance-measurement device.

Abstract: A computer-assisted surgery (CAS) system for tracking an orientation of a pelvis comprises at least one instrument, the instrument having an acetabulum abutment end adapted to be received in an acetabulum, a rim abutment adapted to be abutted against a rim of the acetabulum, and an indicator representative of a physical orientation of the instrument. An inertial sensor unit is connected to the at least one instrument, the inertial sensor unit producing readings representative of its orientation.

Abstract: A surface digitizing tool has a film of micro-sensor elements, with each micro-sensor element related in a network affected by a shape of the film. The film is flexible to conform to a shape of a selected surface of an object. A processing unit receives signals from the micro-sensor elements of the network. The processing unit has a model generator producing a model of the selected surface of the object from the signals of the network of resistive elements. A positioning frame aligns a position and orientation of a drilling tool with respect to a bone element.