An electrosurgical probe can be detachably secured to a handpiece having a motor drive unit and an RF current contact. The electrosurgical probe includes an elongate shaft having a longitudinal axis, a distal dielectric tip, and a proximal hub which is detachably securable to the handpiece. A hook electrode is reciprocatably mounted in the distal dielectric tip, and an RF connector on the hub is couplable to the RF current contact in the handpiece when the hub is secured to the handpiece. A drive mechanism in the hub mechanically couples to the hook electrode, and drive mechanism engages a rotational component in the motor drive unit when the hub is secured to the handpiece. The drive mechanism converts rotational motion from the rotational component into axial reciprocation and transmits the axial reciprocation to the hook electrode to axially displace the hook electrode between a non-extended position and an extended position relative to the dielectric tip.