In the past, children with internal and external knee deformities had to wait until the physiological epiphysis closure period before and after the osteotomy orthopedic surgery, which is not only painful, but also significantly affects the learning and life. In addition, long-term immobilization has a significant impact on knee function. In 1949, Blount reported the application of Staple nail to correct the limb deformity by half epiphyseal block, which was not widely accepted due to the many complications, and in 2007, American doctor Peter Steven reported the first 8-word steel plate to treat the knee deformity, which was successful and is now generally accepted. It has very small incision, no osteotomy, no external fixation, automatic orthopedic growth by itself, few complications, and is very popular among patients. In late 2009, we started to apply it in the clinic, and the orthopedic effect is satisfactory. Indications: knee joint internal and external deformity, at least one year from the physiological closure of epiphysis. If the epiphysis is close to or has already closed, this method cannot be used. Therefore, it is necessary for orthopaedic surgeons to change their mindset and not to wait for osteotomy until epiphyseal closure and miss the opportunity to apply minimally invasive orthopaedic treatment with a figure-of-eight plate in these patients.