Children with O-legs (also known as inversion of the knee) can be divided into physiologic and pathologic conditions, the former generally does not require correction, while the latter correction methods mainly include non-surgical and surgical treatment. 1. Physiological inversion of the knee: it is a normal stage of children’s growth and development, there is no pathological abnormality, generally no need to be corrected, with the development of standing and sports inversion of the knee can be improved by itself. 2. Pathological knee inversion: caused by rickets, osteochondral dystrophy and other diseases, generally cannot be self-cured, need to be based on the treatment of the primary disease, the lower limb deformity for correction. (1) Non-surgical methods: mainly use the brace to correct the deformity, which is suitable for patients with mild disease, with less side effects but uncertain effect. (2) Surgical method: it is suitable for patients with serious deformity or ineffective conservative treatment, commonly used techniques include osteotomy and orthopedic fixation, semi-epiphyseal block, knee replacement, etc. However, it should be noted that the above correction methods are not suitable for patients with severe deformity or ineffective conservative treatment. However, it should be noted that the specific efficacy of the above correction methods may vary depending on the individual’s physical condition and treatment compliance. Children with O-legs should seek prompt medical attention to identify the cause of the problem and then formulate a treatment plan under the guidance of the doctor according to the actual situation of the individual. It is important not to make blind judgments and dispose of the problem on one’s own in order to avoid inappropriate interventions and adverse consequences.