There is no fastest way to straighten O-shaped legs, which is also known as “inversion of the knee” or “O-shaped legs”, and the methods include orthopedic treatment such as braces and insoles, exercise and surgical treatment. If the symptoms of O-shaped leg are mild, it can be corrected by braces, splints, and shoe inserts. It can also be corrected with exercise such as straight leg press and side leg press. If you are over 18 years old and have severe deformity, you need to undergo surgery to restore the normal shape and appearance of the limb through osteotomy. It is recommended to go to the hospital in time after the appearance of O-shaped legs, early and regular treatment.