Adults with O-legs can be corrected surgically. Of course, it is not possible to use special orthotics as in infancy and childhood to correct O-legs gradually, but adults can have O-legs corrected by doing appropriate orthopedic surgical treatment. The specific method is to determine the angle of the knee deformity in the full-length X-ray of both lower limbs, decide the angle of wedge osteotomy at the proximal end of the tibial plateau, and need to break the fibular head position, and then do the orthopedic treatment, and need to do the appropriate and secure internal fixation. Once the orthopedic surgery is done the bone is completely healed and the O-leg can be corrected.