A drill system for forming a curved tunnel in a bone includes a drill bit guidance device. The drill bit guidance device includes an elongated stationary outer tube extending along a first axis and an elongated inner tube assembly. The elongated inner tube assembly is configured to slidably move within the elongated stationary outer tube along the first axis and to exit from a distal end of the elongated outer tube. The elongated inner tube assembly includes an actuating tube and an actuator tube. The actuating tube slidably moves within the actuator tube and includes a plurality of semi-cross-sectional slots extending in a slot direction perpendicular to the first axis. Each slot of the actuating tube is configured to collapse inward in the slot direction when exiting the distal end of the elongated outer tube, thereby causing a distal end portion of the elongated inner tube assembly to follow a curved path.
