Loop leg is the common name of knee inversion, 1 year 4 months baby knee inversion to observe the main, if the symptoms persist, can use the support orthopedic or surgical treatment. Knee inversion refers to the state in which the knee joints cannot be brought together after both lower limbs are straightened, including physiological and pathological. In the early growth and development of the body, there will be a mild physiological knee inversion, often occurring in infants and young children under the age of 2 years, can be corrected with standing and movement, without special treatment. If the inversion persists or the distance between the knees of both legs is too large, then it is considered to be a pathologic inversion of the knee and needs to be treated. Mild knee valgus can be corrected with braces, while severe knee valgus can be treated with surgery. If a 1 year 4 months old baby has a rotund leg, it is recommended to bring the baby to the doctor in time to be examined by a professional doctor to diagnose the condition and give treatment measures.