Osteotomy assistance jig, digital template, and long bone corrective osteotomy

An osteotomy assistance jig used to set a fixing position of a distal screw bolt and a fixing position of a proximal screw bolt, the distal screw bolt and the proximal screw bolt being for fixing a fixing plate to a long bone after bone cutting, the osteotomy assistance jig comprising:

• a first registration member that includes a positioning plate serving as a disposition reference, and sets the fixing position of the distal screw bolt;
• and
• a second registration member that is connected to the first registration member so as to be pivotable with respect to the first registration member at a pivot axis set on a bone cutting line, and sets the fixing position of the proximal screw bolt, the bone cutting line serving as a reference for cutting, wherein
• the fixing position of the distal screw bolt and the fixing position the proximal screw bolt are set based on a position of the first registration member, and a connection position and a connection angle of the second registration member with respect to the first registration member wherein the pivot axis is variable along the bone cutting line;
• a hinge axis member that pivotably supports the second registration member with respect to the first registration member, wherein:
• the first registration member includes:
• a first hinge setting plate that includes a plurality of first hinge candidate holes arranged on the bone cutting line in a plan view viewed from an anterior-posterior direction;
• and a distal screw bolt guide section for setting the fixing position of the distal screw bolt, the second registration member includes:
• a second hinge setting plate that includes a plurality of second hinge candidate holes corresponding to the plurality of first hinge candidate holes;
• and a proximal screw bolt guide section for setting the fixing position of the proximal screw bolt, and the hinge axis member is inserted through one of a plurality of pairs of the plurality of first hinge candidate holes and the plurality of second hinge candidate holes and the first hinge setting plate is connected to the positioning plate such that the bone cutting line is changeable in a plurality of stages, and the second hinge setting plate includes the plurality of second hinge candidate holes corresponding to all positions that the plurality of first hinge candidate holes is allowed to take.