Excessive deficiency of calcium or vitamin D causes rotundity affects height, while other causes of rotundity do not affect height. The legs may be formed from a young age, the child’s body lack of calcium or vitamin D during the growth process, causing rickets, resulting in bone deformity and caused by the legs. At this time, the child absorbed to the limited nutrients, the development of bones will have an impact, such as the lack of timely supplementation will have a direct impact on the height of the child. There are many other causes of rotunda, such as sitting cross-legged for a long time, kneeling and other bad posture, so that the knee ligament laxity, caused by rotunda over time; knee injury, treatment is not timely may also cause rotunda, these causes of rotunda will not affect the height. At present, the legs can be corrected by medical means, and should go to the regular hospital in time for consultation.