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 .