An arthroscopic system, comprising: a handpiece with a motor drive ; a probe with a proximal hub and elongate shaft extending about an axis to a working end, the hub configured for detachable coupling to the handpiece , wherein the motor drive is configured to couple to a rotating drive coupling in the hub when the hub is coupled to the handpiece ; and a first magnet component carried by the hub; and a second magnet component coupled to rotate with the rotating drive coupling , wherein the hub is configured for detachable coupling to the handpiece in opposing rotational orientations to provide an upward-facing working end relative to the handpiece and a downward-facing working end relative to the handpiece , wherein said first magnet component comprises first and second independent magnets disposed in opposing sides of the hub spaced outwardly from said axis and said first and second independent magnets of said first magnet component have North poles in opposite orientations relative to said axis , wherein said second magnet component comprises third and fourth independent magnets disposed in opposing sides of the rotating drive coupling and said third and fourth independent magnets of said second magnet component have North poles in opposite orientations relative to said axis , wherein the handpiece further comprises a first sensor configured for sensing a magnetic field of the first or second independent magnets when located adjacent the first sensor and for generating a signal indicating an upward-facing orientation or a downward-facing orientation of the working end, and wherein the handpiece further comprises a second sensor configured for sensing a magnetic field of the third or fourth independent magnet as it is in proximity to the second sensor and for generating a signal indicating a rotational parameter of the rotating drive coupling . a handpiece with a motor drive ; a probe with a proximal hub and elongate shaft extending about an axis to a working end, the hub configured for detachable coupling to the handpiece , wherein the motor drive is configured to couple to a rotating drive coupling in the hub when the hub is coupled to the handpiece ; and a first magnet component carried by the hub; and a second magnet component coupled to rotate with the rotating drive coupling , wherein the hub is configured for detachable coupling to the handpiece in opposing rotational orientations to provide an upward-facing working end relative to the handpiece and a downward-facing working end relative to the handpiece , wherein said first magnet component comprises first and second independent magnets disposed in opposing sides of the hub spaced outwardly from said axis and said first and second independent magnets of said first magnet component have North poles in opposite orientations relative to said axis , wherein said second magnet component comprises third and fourth independent magnets disposed in opposing sides of the rotating drive coupling and said third and fourth independent magnets of said second magnet component have North poles in opposite orientations relative to said axis , wherein the handpiece further comprises a first sensor configured for sensing a magnetic field of the first or second independent magnets when located adjacent the first sensor and for generating a signal indicating an upward-facing orientation or a downward-facing orientation of the working end, and wherein the handpiece further comprises a second sensor configured for sensing a magnetic field of the third or fourth independent magnet as it is in proximity to the second sensor and for generating a signal indicating a rotational parameter of the rotating drive coupling . <EOS>