System and method for tracking bones

A method of determining a position and an orientation of a subcutaneous bone of an anatomical feature, the method comprising:

• anchoring a portion of a trackable reference device to the bone using a surgical pin to fasten a single end of the trackable reference device to the bone, the single end defining a first portion on the trackable reference device;
• removably mounting a remainder of the trackable reference device to skin around the bone using a wearable attachment located at a second position of the trackable reference device spaced axially apart from the first position along a longitudinal axis of the trackable reference;
• determining a distance between the trackable reference device and the bone at a third position along the longitudinal axis of the trackable reference, the second position disposed axially between the first position and the third position along the longitudinal axis;
• registering position and orientation readings of reference markers fixedly attached to the trackable reference device in a reference coordinate system;
• determining the position and the orientation of the bone in the reference coordinate system using the position and orientation readings and the distance of the position of the trackable reference device from the bone.

A wearable trackable reference device for determining a position and an orientation of a bone of an anatomical feature, the bone underlying an outer-skin surface of the anatomical feature, the wearable trackable reference device comprising:

• a surgical pin at a first position on a body of the trackable reference device, the first position defined along a longitudinal axis of the trackable reference device, the surgical pin being attachable to the bone to anchor the body to the bone;
• a wearable attachment configured to be mounted about the outer-skin surface of the anatomical feature to mount the body to the outer-skin surface, the wearable attachment being axially spaced apart from the surgical pin and located at a second position along the longitudinal axis;
• at least one distance sensor located at a third position on the body, the at least one distance sensor being axially spaced apart from the first position and the second position along the longitudinal axis, the at least one distance sensor operable to determine a distance measurement between the body of the wearable trackable reference the bone, at the third position, in a transverse direction relative to the longitudinal axis;
• and
• at least one reference marker array having a plurality of reference markers fixedly mounted at fixed positions along the body, between the surgical pin and the at least one distance sensor.