A measurement system for use with a powered surgical instrument for sensing a position of a leading edge of a tool relative to anatomic structures of a patient, the measurement system comprising: a first sensor disposed with respect to the powered surgical instrument to measure a tool drive parameter that is characteristic of the tool portion acting on the patient and output a tool drive signal representative the tool drive parameter as the tool portion is advanced relative to anatomy of the patient; a displacement sensor disposed with respect to the powered surgical instrument to measure an axial displacement of the leading edge of the tool portion relative to a reference point and output a displacement signal representative of the axial displacement; and a controller in operative communication with the first sensor to receive the tool drive signal and in operative communication with the displacement sensor to receive the displacement signal, wherein the controller is operative to identify a change in the tool drive parameter over a given amount of axial displacement of the leading edge of the tool portion that is indicative of the leading edge of the tool portion moving through an interface between anatomic structures of the patient, wherein the controller is operative to determine a moving average for the tool drive parameter with respect to the axial displacement of the leading edge of the tool portion relative to the anatomy of the patient, and wherein the controller is operative to identify the change in the tool drive parameter relative to a given amount of axial displacement of the leading edge of the tool portion based on an inflection of the moving average. a first sensor disposed with respect to the powered surgical instrument to measure a tool drive parameter that is characteristic of the tool portion acting on the patient and output a tool drive signal representative the tool drive parameter as the tool portion is advanced relative to anatomy of the patient; a displacement sensor disposed with respect to the powered surgical instrument to measure an axial displacement of the leading edge of the tool portion relative to a reference point and output a displacement signal representative of the axial displacement; and a controller in operative communication with the first sensor to receive the tool drive signal and in operative communication with the displacement sensor to receive the displacement signal, wherein the controller is operative to identify a change in the tool drive parameter over a given amount of axial displacement of the leading edge of the tool portion that is indicative of the leading edge of the tool portion moving through an interface between anatomic structures of the patient, wherein the controller is operative to determine a moving average for the tool drive parameter with respect to the axial displacement of the leading edge of the tool portion relative to the anatomy of the patient, and wherein the controller is operative to identify the change in the tool drive parameter relative to a given amount of axial displacement of the leading edge of the tool portion based on an inflection of the moving average. <EOS>