An apparatus for impacting bone material comprises an impaction element and a guide element having a bore. The bore has a longitudinal axis. The impaction tool is connected to the guide element, and is provided at a predetermined distance to the bore in a direction substantially perpendicular to the longitudinal axis of the bore. A guide rod may be connected to a medical device and can be inserted into the bore. Thus, the apparatus may be guided into a cavity adjacent the medical device for impacting bone material inserted into the cavity.