Removal of bone staples: a potential problem in revision surgery after ligament reconstruction. 
Two cases are presented in which an attempt to remove the staples used to fix an artificial ligament caused the front of the tibia to break.  A mechanical study was performed to measure the force required to extract staples from bone cement, as well as from calf bone with predrilled holes.  Using an extraction tool, it was possible to generate an average maximum force of 500 N by hand.  At that load, all staples remained firmly anchored in cement and bone.  The staples were impossible to remove even when the serrations in the staple legs were reduced by 75%.  Accordingly, special care is necessary to avoid complications with staple removal.