Abstract: A set of surgical instruments which comprises a saw guide and a drill guide respectively for guiding a saw blade cutting a bone and for guiding a drill bit for thereafter forming a passage in the bone. The saw guide has a seat formation for seating against the bone, and a guide formation for guiding the saw. The drill guide comprises a bit guide and an anchor to align the bit guide relative to the cut. Also provided are a saw guide and a drill guide; and a method of carrying out an osteotomy procedure by making an oblique cut through a long bone at a position where bone portions which are misaligned intersect each other to provide two bone fragments, whereafter they are loosely bolted together and then rotated about the axis provided by the bolting until the misalignment is reduced, after which they are bolted tightly together.