The tendency of rotundity is hereditary, but heredity does not play a major role, and the aggravation of rotundity in most patients is mainly caused at a later stage. For example, in patients who are growing and developing, early calcium deficiency can cause deformities in bone development, which can lead to rotundity. Most adults have joint degeneration, such as osteoarthritis of the knee joint, when the cartilage is damaged and the cartilage degeneration is very strong, the joint space will be significantly narrowed, which will cause the joint to turn inward and deformed for a long time, thus causing the appearance of rotundity, which is the main reason for the formation of rotundity in older patients. For older patients with osteoarthritis, they need active surgical treatment, such as osteotomy and orthopedic surgery or artificial joint replacement.