The treatment of O-legs, which is also known as inversion of the knee in clinical practice, mainly depends on the age of the patient. For infants and children under one and a half years of age with O-legs, it is usually recommended to observe for the time being, increase the time of sunbathing, and take vitamin D and calcium supplements to strengthen the nutritional support. For infants within one and a half years of age, physiologic knee valgus is usually the main cause, and the degree of valgus will gradually decrease with age, and can be corrected by one and a half years of age. For infants and children over one and a half years of age who are still uncorrected, the treatment of O-leg entropion is recommended to be corrected by orthopedic appliances. Orthopedic braces are worn at night for about six months to a year. For infants and young children with O-legs, it is not recommended that they undergo leg binding or other informal treatments too early, and it is recommended that they go to the hospital in time for examination and consultation.