Medial knee osteoarthritis is not uncommon, and high tibial osteotomy (HTO) for some surgeons is a unique treatment option for young and active patients. However, the deformity is not always located at the level of proximal part of the tibia and the overcorrection needed to achieve a lasting functional result can lead to an oblique joint line. To avoid this undesirable effect to the joint line, a double-level osteotomy (DLO), one at the distal part of the femur and another one at the proximal part of the tibia, is a viable option. The aim of this article is to present the preoperative radiological assessment, the operative procedure, the indications of HTO, distal femoral osteotomy (DFO), and DLO presenting the rationale behind the treatment options. Long-leg radiographs are mandatory to measure the hip-knee-ankle angle, and the femoral and tibial mechanical axes to plan the location of the osteotomy. The best indication for DLO is a severe varus knee deformity with femoral and tibial mechanical axes in varus. This argument can be applied to a genu valgum deformity, especially when the femur is in valgus as well as the tibia, which is not rare. Although the operative technique is demanding, the biggest challenge is not the procedure itself but rather how to reach the exact degree of overcorrection. Computer-assisted surgery is a good alternative and can improve the accuracy of the surgery.