In our usual work, we always advocate early functional exercises after arthroscopy, because the muscle strength level is low, the tissue has a more obvious inflammatory response, and the reconstructed ligaments are still relatively fragile. Therefore, endurance exercises with small loads are the main focus. In the early stage, we should not walk too much and should not use walking as an exercise method. Otherwise, it will easily cause joint swelling and fluid accumulation, which will affect the functional recovery and tissue healing. 1.After the anesthesia subsides, start to actively move the toes and ankle joints; if the pain is not obvious, try to contract the quadriceps. That is, tense and relax the muscles on the front side of the thigh. 2.Intravenous antithrombotic pump – forceful, slow, full range of flexion and extension of the ankle joint. 1 group/hour. (Important to promote circulation, reduce swelling and prevent deep vein thrombosis). 3. Quadriceps (anterior thigh muscle group) isometric exercises-i.e. thigh muscle tensing and relaxation. Do as many as possible without increasing pain. (More than 500 times/day). 4, N rope muscle (posterior thigh muscle group) isometric exercise – the affected leg force down the padded pillow, so that the posterior thigh muscle tense and relax. Requirements as above, more than 500 times / day. 5, straight leg lift exercise – straight leg lift after knee extension to heel 15M from the bed, hold until exhaustion. 10 times/group, 2-3 groups/day (pain at the knee skin incision is normal and should be tolerated during the exercise. 6.Lateral leg raise exercise, 30 times/group, 2-4 groups/day, 30 seconds rest between groups. 7.Weight-bearing and balancing – separate both feet under protection, alternately move the center of gravity left and right within the range of slight pain, and strive to achieve full weight-bearing standing on one leg, 5 minutes/time, 2 times/day. Separate both feet back and forth, move the center of gravity, and strive to achieve full weight-bearing standing on one leg. 8. Immediately after the flexion exercise, apply ice for about 20 minutes. If you usually have obvious heat and swelling feeling in the joint, you can ice again 2-3 times / day. 9.Strengthen the weight-bearing and balancing exercises, gradually until you can stand on one foot with the affected leg. If it can be done easily, then start to use a single crutch (holding on the healthy side) to walk. 10.Extension exercise (sitting suspension)-Pillow at the heel, make the affected leg leave the bed completely, relax the muscles to make the knee joint extend naturally. 30 minutes/time, 1-2 times/day. 11, prone position “leg hook” exercise – 30 times / group, 2-4 groups / day. 12.Knee flexion exercises in sitting or lying position. Hold the knee until you start to feel pain, hold it for 10 seconds, relax slightly (do not rest completely straight throughout the exercise), rest for 5 seconds, then hold the knee again, repeat the exercise for 20 minutes, once a day. 13.Standing position “hook leg” exercise. Should be static exercises, flexion to pain-free angle to maintain 10-15 seconds. 30 times / group, 4 groups / day. 14.Backward and forward, lateral straddle exercises. 15.Static squatting or sliding exercises against the wall.