Genu varum (known as bow-leggedness or bandy-leg) is one of the alignment problems in the knee joint, also called the crooked leg deformity. Apart from cosmetic problems, this problem, which can lead to calcification in the knee joint when left untreated, makes patients candidates for knee joint prosthesis surgery at older ages. This problem can be treated at a young age with surgery to correct the bone alignment (osteotomy surgeries) to the bone area below the knee. For this purpose, you can see the simulation of the surgical application in the video with the OWO-FIX (Open Wedge Osteotomy External Fixator) fixator, which we developed together with TST company (Türk Spinal Travma San. ve Tic. Ltd. Şti) and which has received patent approval from Europe and from the United States besides Turkey.