Minimally invasive arthroscopy, osteotomy and unicondylar replacement are three methods of knee surgery, as follows: 1. Minimally invasive arthroscopy: for example, removal of joint free bodies, joint thickening synovial membrane, the effect is better; 2. Osteotomy: mainly used for patients with intact joint surface, but lower limb deformation, joint gap is wide and narrow, the surgery is generally divided into two types, one is tibial high osteotomy, after tibial high osteotomy, the lower limb can be flattened, the joint is equally stressed on both sides; the other is fibular osteotomy, the fibula is removed to maintain joint balance; 3. Unicondylar replacement: is to remove the condylar surface and replace half.