This invention relates to a device and method therefor used in osteotomy for removing a right-angled bone wedge from a leg bone. The device consists of a trapezoidal block having one column of transverse bores and other columns of oblique bores. The columns of oblique bores are positioned at predetermined angles from the column of transverse bores. A first tower member is mounted atop the block. The first tower also has a plurality of transverse bores that align with the transverse bores in the block. A surgical pin can be inserted through the tower until the tip of this pin lies above the apex of the bone wedge to be cut. Surgical pins are then inserted through the corresponding transverse bores in the block and drilled into the bone until the ends of these pins align with the end of the first pin inserted in the first tower. This procedure establishes the height of the bone wedge. A second tower is coupled to an oblique bore at the desired predetermined angle. The second tower also has a plurality of transverse bores. A surgical pin is inserted through one of the bores in the second tower until the tip of this pin abuts the tip of the pin inserted in the first tower. Surgical pins are then inserted through the corresponding oblique bores in the block and drilled in the bone until the ends of these pins are aligned with the end of the first pin inserted in the second tower.