The incidence is about 2 in 1,000 and there is no difference between men and women. The intoeing gait is easy to mix and fall on its own, but children do not have pain, and it does not cause arthritis. There are three main causes of the inward gait, can be accompanied by other deformities, often family genetic. 1, curved foot (forefoot inward – metatarsal inward): 90% of more than 4-6 months after birth on their own (more obvious from the bottom of the foot), 6-9 months is still deformed serious and stiff, need to carry out plaster or orthopedic shoe treatment, rarely need surgery to correct the metatarsals. 2, tibial distortion (tibial torsion): the most common cause, due to the restriction of the uterine cavity and the occurrence of tibial distortion to the medial side (mostly found at the age of 1 year to start walking), after birth will be more natural rotation to the normal force line before school age, if 8-10 years old still can not be corrected, and obviously affect walking can consider surgery. 3, femoral distortion (femoral anteversion): that is, internal rotation of the femur, generally the most obvious at the age of 5-6 years. It is twice as common in females as in males. The child mostly appears at the age of 2-4 years with an inwardly rotated gait, which is not present at the beginning of walking, and is aggravated with age, with the knee and foot rotating inward while walking. Almost all children can improve with age, but only at the age of 9-10 years old, when the deformity is still severe and affects walking and often stumbles, should we consider osteotomy and de-rotation of the femur. Most children with a pronated gait improve by the age of 8 years, but they need to be seen by a doctor if they have the following symptoms: 1. no improvement after the age of 8 years; 2. limp or pain; 3. one foot is significantly worse; 4. delayed development, such as not talking when it is time to talk; 5. heel failure.