Distal femoral osteotomy is a surgical procedure used to correct patellar luxation, secondary to a femoral deformity. A distal femoral osteotomy using the tibial plateau levelling osteotomy-jig to temporarily provide stability of the distal femoral osteotomy, maintaining limb alignment in the frontal and axial planes prior to internal plate fixation of the osteotomy, has been described. This report describes a novel jig named Deformity Reduction Device (DRD). This device was developed with the specific aim of increasing precision and predictability during corrective osteotomy execution in order to be consistent with the preoperative planning. The distal femoral osteotomy DRD-assisted procedure is described in detail, discussing the theoretical and practical principles of the application.