An apparatus for orthopedic surgery includes a fixture with a supporting plate and a guide bar. The supporting plate and the guide bar are held to each other by a holding element. A jig assembly with cutting block having first surface and second surface is provided in the apparatus. The second surface is configured to engage at least two clamps. The cutting block has slot extending from first surface to second surface. Further, jig assembly is engageable with guide bar of the fixture in a moveable manner. A method of measuring a resection distance on a tumor bone and cutting the tumor bone at the resection distance includes providing, on the tumor bone, the apparatus as briefly described above. The bone is clamped at resection point. The jig assembly is disengaged from guide bar and a saw blade is introduced through the slot to cut bone at the resection point.