Abstract: The present invention provides, in certain embodiments, a device for determining the tibial mechanical axis and the femoral mechanical axis. The present invention also provides a surgical orientation device, a reference device, and/or a module configured to track the mechanical axes during movement to facilitate limb alignment. The present invention further provides the surgical orientation device, the reference device, and/or the module configured to determine a gap measurement.

Abstract: A system can include a module to measure mobility, such as pre-operative pelvic mobility, for surgical planning. The module can include one or more inertial sensors that can be positioned relative to the anatomy of a patient. Hip navigation systems can guide an acetabular cup to patient-specific target angles, based in part, on the pre-operative pelvic mobility of the patient.