O-shaped leg does not only mean that the bone is bent, mainly with the lower limb knee joint force line of the structural changes, is their own joint parts of the bone deformation, the leg appears leg shape abnormal symptoms. 1.O-shaped leg is the patient’s legs together, bilateral ankle joints touch together, there is a gap in the middle of the knee joints, can not touch, resulting in the lower limbs show the shape of the letter O, commonly known as O-shaped leg, O-shaped leg of the patient’s distal end of the knee joints to the medial side of the bend in the name of the knee is also called the knee inversion. 2. O-shaped leg is associated with excessive obesity and overweight, localized fibrocartilage dysplasia, rickets, post-traumatic deformity, bone developmental anomalies, osteoarthritis of the knee joint and so on. 3. After the diagnosis of O-shaped leg, if it is not particularly serious, it can be corrected through the support or orthosis under the guidance of the doctor, if the situation is more serious, it is necessary to correct the treatment through surgical methods.