Postoperative functional exercise after posterior cruciate ligament reconstruction (as required, adhere to the exercise to have good function.) 1.Practice calf: from the 1st day to 4 weeks after surgery, hook your foot with maximum force and tense your foot downward with maximum force 800 times a day. (Very important, prevent blood clots!!!) 2.Practice thigh: from the 1st day to 4 weeks after surgery, straighten your leg and lift it off the bed (insist for 5 seconds), then relax (2 seconds), 600 times a day. 3.Straighten the knee joint: 1 day to 4 weeks after surgery, put a pillow under the ankle joint, make sure the knee joint is as straight as the other leg. 4. Flexion of the knee: 1 week after surgery, practice to 70 degrees, 6 weeks after surgery, practice to 120 degrees; 8 weeks after surgery, practice to normal angle. The number of degrees should be gradually increased when practicing the angle, and the maximum number of times per day should be three times. After each practice, use an ice water mixture in a plastic bag and apply cold compresses to the knee joint for 20 minutes. 5. 8 weeks after surgery, start squatting horse stance: do it at a painless angle, with the knee joint not exceeding the toes, for 1 to 2 minutes each time. 6.After 8 weeks postoperatively, gradually start walking, and after 12 months, then slowly sports. 7, To prevent the calf from sinking back, make sure to do the following three things: First, avoid active knee flexion for 6 weeks. Second, every time someone helps flex the knee joint, be sure to hold the back of the knee. Third, avoid kneeling movements for 12 months.