Correction of asevere tibial varus deformity near the knee joint with only aslight influence on leg length and patella height. Medial osteoarthritis and/or cartilage damage with asevere varus deformity > 10° with amedial proximal tibial angle (MPTA) < 80°. Femoral varus deformity with lateral distal femoral angle > 91°, severe lateral cartilage damage, lateral osteoarthritis, lateral meniscus loss. Skin incision of approx. 8-10 cm between the tibial tuberosity and the head of the fibula. Exploration of the peroneal nerve. Detachment of the extensors. Insertion of an obliquely ascending guidewire ending approximately 10 mm below the medial articular surface. Insertion of asecond guidewire. This aims at the middle of the first wire (hemi wedge). Check the wire position under fluoroscopy. Osteotomy with an oscillating saw under cooling. Removal of the wedge and closure of the osteotomy. Percutaneous needling of the medial collateral ligament with acannula to carefully lengthen the ligament. Check the correction result with ametal rod. Osteosynthesis with lateral angle-stable plate. Partial weight-bearing with 10 kg for 6weeks postoperatively, free range of motion. Reports from the literature show that good clinical results can be achieved with this procedure for severe tibial varus deformities. Postoperative leg length discrepancies are less common with this procedure than with laterally closing osteotomy.