A system for treating a bone includes an insert for a bone screw or a fixation nail. The insert includes a shaft that extends between proximal and distal ends of the insert and a cap. The shaft includes an opening in the proximal end and a cannulation extending from the opening through at least a portion of the shaft. The shaft further includes a fenestration disposed along the cannulation such that the cannulation is configured to provide a pathway for a substance between the opening and the fenestration. The cap is fastened to and seals the opening in the proximal end of the shaft and adjoins the cannulation. The cap is configured to provide a needle access through the cap to the cannulation following implantation of the system within the bone, and is further configured to self-seal after the needle is removed.
