System, method and apparatus for automatic registration in computer assisted bone milling surgery

A system to determine the location of an inner cortical surface of a bone during a surgical procedure comprising:

• a surgical tool;
• a localization system comprising a first tracking element coupled to the surgical tool and a second tracking element coupled to a bone, the bone having a cortical segment having an outer surface and an inner surface, the inner surface defining a cancellous segment contiguous with the inner surface, the localization system providing localization data associated with a location of the first tracking element and a location of the second tracking element to determine a relative position;
• one or more sensors coupled with the surgical tool and configured to output sensor data;
• and,
• a non-transient storage element storing computer instructions, which instructions when executed by a processor configure the processor to:
• receive a 3D bone model comprising the cortical segment and the cancellous segment;
• receive 3D implant plan information with respect to the 3D bone model;
• receive the localization data and the sensor data in response to the surgical tool travelling along an initial commanded trajectory, the initial commanded trajectory including a plurality of contacts of an end effector of the surgical tool with the inner cortical surface and the sensor data indicating contact with the inner cortical surface;
• synchronously measure relative positions of the first tracking element and the second tracking element using the localization data and associating the relative positions with the sensor data;
• determine 3D inner cortical shape information based at least in part on the sensor data and the relative positions;
• register the 3D bone model with the 3D inner cortical shape information;
• register the 3D bone model to the second tracking element;
• and
• command an updated trajectory for a desired implant position based on the 3D implant plan information with respect to the 3D bone model.