System and method for intra-operative leg position measurement

A medical navigational guidance system comprising:

• a sensor for coupling to a bone and orienting toward a site for a medical procedure;
• a target, coupled to an object, for tracking by the sensor;
• and,
• a processing unit in communication with the sensor, the processing unit configured to guide alignment of the sensor with the target, the processing unit using positional signals from the sensor to calculate and display, using a user interface, directional instructions to move into alignment the sensor and target.

A system for making sterile a non-sterile sensor for use in navigational guidance during surgery, the system comprising:

• a sterile drape having an optically transparent window for draping the sensor in a sterile barrier;
• a shroud, which when engaged with a draped optical sensor, secures the sensor through the drape in alignment with the window without breaching the sterile barrier;
• and
• a clamp, which, in its closed and position, is configured to rigidly hold the assembled shroud, drape and sensor, while preserving the optical sensor alignment in the window.