Abstract: An approach to removing necrotic bone under direct visualization is provided. To remove bone and to watch it being removed at the same time, one example uses an endoscope and bone removal tool assembled together by a sheath. The sheath includes separate passageways for the endoscope and bone removal tool. A surgeon uses the sheath to insert the endoscope and bone removal tool together into the bone tunnel. The passageways are spaced apart such that an axis of rotation of the bone removal tool is offset from the centerline of the bone tunnel. The endoscope remains in the bone tunnel while the surgeon removes bone with the bone removal tool. Advantageously, the surgeon watches the bone removal process as it is happening making the process less tedious and less time consuming.