Looped legs, also known as O-shaped legs. When the baby lies down with the ankles together, if the knee joints are widely spaced and resemble a round or oval shape, then it is considered to be a “roped leg”. Infants with rotator cuffs can be recognized by physical examination, which requires the baby to lie on his/her back with both ankles together, measuring the size of the gap between the knees, and observing whether the lower limbs are in an O-shape, and whether the knees have inwardly turned, etc. In addition, babies with rotator cuffs can also be recognized by physical examination. In addition, the baby rotund leg can also go to the hospital to do some auxiliary examination, such as lower limb X-ray examination to confirm the diagnosis, is mainly to check the lower limb bone development, whether there is inversion or deformity so as to determine whether there is rotund leg. Parents need to pay attention to, if the baby within one year old found rotund legs can not be too nervous, most of them are physiological, can be corrected by themselves. If there is no recovery after the age of two years, it is necessary to go to the hospital in time to intervene and make a reasonable corrective program according to the condition.