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. The elongated inner tube 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 has a partially slotted distal end portion including a plurality of semi-cross-sectional slots extending perpendicular to the first axis. Each slot is configured to collapse inward in the slot direction when exiting the distal end of the elongated outer tube, thereby curving the distal end portion of the elongated inner tube.