An insertion instrument comprising an elongate shaft, a suction head provided at the front end thereof for connection to a joint socket, a suction device with a piston guided in the shaft, a suction line opening out at the suction head, and an actuating element which is guided along a guiding track on the shaft. The guiding track can be helically shaped and have a locking arrangement, preferably in the form of a recess, for the actuating element in a suction position. Due to the helical shape of the guiding track, the actuating element executes a rotational and longitudinal movement during its displacement. The longitudinal movement produces a negative pressure in the suction line ensuring maintenance of the pressure, while the rotating movement causes rotation of the actuating element such that it reaches its locking position at the end of the guiding track, providing simplified handling of the instrument.
