The hazards of calf valgus mainly include damage to knee cartilage, joint wear and tear, and lumbar scoliosis. 1. Knee cartilage damage: when the calf is turned out, the outer ligament of the knee joint becomes tight, and the inner ligament is loose, which leads to symptoms such as knee joint loosening and instability, and then leads to knee cartilage damage. 2. Wear and tear of joints: calf ectropion will lead to shortening of the calf and limp easily when walking, and the limp will lead to a greater burden on the ankle and hip joints, which will easily lead to the wear and tear of the ligaments and tendons in the joints. 3. Lumbar scoliosis: Knee valgus will affect the lumbar spine, pelvis and lower limbs of the normal line of force, the patient is prone to lead to pelvic tilt, lumbar spine compensatory scoliosis. Patients with calf ectropion should go to the hospital in time and under the guidance of the doctor for regular treatment.