Guidelines for rehabilitation after arthroscopic knee surgery: Arthroscopic surgery is a minimally invasive procedure with minimal trauma and rapid recovery of knee function after surgery. It is essential to restore knee mobility and strength through proper functional exercises. There are many types of arthroscopic knee surgery, ranging from simple meniscoplasty to complex ligament reconstruction procedures. The amount of trauma to the knee joint varies from procedure to procedure, as do post-operative rehabilitation procedures. Each patient should have a rehabilitation program that is appropriate for his or her specific situation, which needs to be done under the guidance of a physician. Functional exercise in general consists of three major areas: muscle strength, joint mobility, and weight bearing and walking exercises. Not all functional rehabilitation will go well, especially for those who have had major surgery such as ligament reconstruction. If you experience swelling or pain in your knee after specific exercise activities, you should reduce or stop exercising until you feel better, or until you have been treated medically accordingly. If symptoms persist, you should promptly practice with your doctor. There is no timeline for the rehabilitation process, patients should adjust according to their tolerance and response after exercise, and master the principle of gradual progress. 1) Muscle strength exercises: 1) Straight leg raise: straight leg raise exercise: supine position, knee flexion on the healthy side, knee extension on the affected side. Slowly lift the affected limb with the heel about 12 cm from the bed and hold for 5 seconds. Continue raising 12 cm to 24 cm and hold for another 5 seconds. Then reverse the previous procedure and lower 12 cm, hold for 5 seconds, lower another 12 cm and return to the starting position. Repeat 10 times. In the seated position, the knee is gradually straightened from flexion and the exercise is repeated to strengthen the quadriceps. 2) Strengthening exercises: Place a heavy object such as a sandbag on the ankle joint before starting the exercise, gradually increasing from 1 kg to a maximum of 5 kg after 4 weeks. Or the assistant exerts a counter force and the patient exercises against it. Patients can also apply counterforce with the healthy limb on their own to help with the exercises. 3) Those with weak quadriceps strength often cannot complete the straight leg raise exercise by themselves. This time, the patient can raise the thigh about 90° with the assistance of the assistant, which is the patient only needs very little force to stabilize the thigh. Patients can slowly lower their thighs about 10° at a time for 1 minute. Straight leg raising can be completed after repeated exercises. 2. Joint mobility exercises: Active exercises: 1) Seated knee flexion exercises: Sit on the edge of the bed, contract the N cord muscle and flex the knee joint. Try to flex backwards. 2) Reclining knee flexion exercises: first raise the straight leg to 90°, hold the N fossa with both hands crossed, flex the knee joint downward using the gravity of the lower leg, and then apply the N cord muscle contraction to flex as far as possible. (3) Sitting knee extension exercise and leg-holding knee flexion exercise: In the sitting position, the knee joint is gradually straightened from flexion and repeatedly practiced. Sit on the bed and flex the knee. Cross your hands over the mid-calf and apply tension backwards to flex the knee. 4) Terminal knee extension exercise: Lie on your back with a towel roll or pillow under the knee joint. Straighten the knee joint and hold for 5 seconds, then slowly return to the starting position. Repeat 10 times. Strengthening exercise: Before starting the exercise, tie a weight such as a sandbag to the ankle joint, gradually increasing from 1 kg to a maximum of 5 kg after 4 weeks. 5) Prone knee extension exercise: prone position, knee joint on the edge of the bed, lower leg extended beyond the trauma, lower leg gravity down, straighten the knee joint.