The human body is symmetrical and perfect, especially for the right and left hands and both lower limbs. However, overlapping healing of fractures, or obstructed development of epiphyseal injuries, can result in unbalanced deformity of both limbs, with one long and one short, disrupting the harmony of movement and physical beauty. Other disorders, such as congenital hip dislocation, poliomyelitis sequelae, bone and joint tuberculosis or septic inflammation, can also cause limb, especially lower limb, unequal length. The upper limbs are mainly used for holding movements, and the slight difference in length between the two sides is not easily seen in appearance and has little effect on function. However, the main function of the lower limbs is to support walking, the difference of 3 cm or less can still be compensated by scoliosis, pelvic tilt, more than this length, can appear limp. Not only does it affect the image of appearance, but more importantly, it brings many difficulties to work and life. In the past, the lower limbs are not equal in length, to wear high shoes, crutches to compensate, but the effect is not very satisfactory. People can’t help but think, if you can extend the short leg that would be great. Muscles, skin, nerves and blood vessels and other soft tissues have a certain elasticity, as long as the slow pull, can be smoothly extended. Hard bones can also be extended, but with more difficulty. There are various methods of lengthening bones, such as pelvic osteotomy lengthening, which is to truncate the pelvic iliac bone, embed a piece of its own bone between the broken bones, and then fix it with steel pins or plates. This method is very suitable for patients with pelvic tilt, but the lengthening length is limited, and nothing can be done for more than 3 cm. The long bones of children’s limbs, such as the femur of the thigh and the tibia of the lower leg, have a structure like a sugar cane “node” called epiphyseal cartilage, which has a special growth capacity. Epiphyseal osteotomy limb lengthening cleverly takes advantage of this special structure and physiological characteristics of the human body. The bone is cut at the epiphysis of the shortened limb (artificially caused fracture), a number of steel pins are threaded across the top and bottom of the limb, and the bone lengthener is fixed at the extracutaneous steel pins on both sides. The osteotomy gap can be pulled by turning the nut on the extender and is usually lengthened by 1 mm per day. Since the bone growth capacity here is particularly vigorous, the bone heals as it is pulled open. The bone can be lengthened by a small amount. It has been reported that the bone can be lengthened by 5 to 6 cm in general and up to 22 cm in length. The best time to have lengthening surgery is between the ages of 8 and 15, preferably when the epiphysis is about to close. If the epiphysis is lengthened too early, the epiphysis may not grow longer due to osteotomy injury, while the side grows as usual, causing a new imbalance. After the epiphysis is completely closed, the growth force is not as vigorous as in the past, and it is difficult to heal and grow, plus the patient’s muscle strength is not enough and the activity is unstable after lengthening, so it is not advisable to lengthen at this time. The lengthening speed should not be too fast, too fast, exceeding the vascular and nerve tolerance, causing blood supply disorder or nerve paralysis, and the bone marrow growth speed of electricity can not keep up. The lengthening must be closely observed to prevent complications. If necessary, stop or slow down the lengthening speed, apply antibiotic tired to prevent and control infection. Bone iliac lengthening effect is indeed, people naturally think of using it to increase the height for short stature people, which is not desirable. Because the bone lengthening surgery is very traumatic, there are certain risks, and to make the body taller, both sides must be lengthened at the same time, planing injury, risk is greater. In this regard, both the doctor and the patient must be cautious.