Rehabilitation principles: painless, gradual 0-4 weeks 1, foot back up and down, contract the calf muscles (ankle pump) 2, tense thigh muscles when the knee is straightened, for 5~10 seconds? 3.Straight leg elevation (with knee brace), 30~50 degrees, for 5~10 seconds 4.In 1 week: can fully straighten 0° 5.Heel sliding, knee flexion less than 45° 6.Ice packs immediately after each functional exercise, 10-15 minutes each time 7.Can’t walk with weight, crutches without stepping on the ground, with knee brace 4-8 weeks 1.Swing the back of the foot up and down, contract the calf muscles (ankle pump) 2.Tighten the thigh muscles when the knee is straight, for 5-10 seconds 3.Straight leg elevation (with knee brace), 30-50 degrees, for 5-10 seconds 4.Full knee extension 0° 5.Heel sliding, practice knee flexion 90°-120° 6.After each functional exercise, according to the swelling, appropriate ice 7.Double crutch partial weight-bearing, over to single crutch partial weight-bearing