I. Early 0 to 2 weeks 1. Quadriceps isometric stretching exercises: repeated contraction and relaxation between maximum intensity contraction and complete relaxation, and continuous practice for as long as possible without other exercises. 2.Stand with your feet shoulder-width apart; or stand apart front to back. Move the center of gravity so that the feet alternate weight-bearing, gradually transitioning to single-leg standing of the affected leg, 5 minutes each time, 2 to 3 times a day. 3, the second week began to flexion exercises, depending on the situation, the exercise angle gradually increased. Second, the middle 3 to 6 weeks 1, quadriceps isometric contraction to maximum strength contraction, and hold for 5 seconds, relax for 1 second for 1 time, 50 to 100 times each group, 2 to 3 groups per day. 2, each lateral and backward leg lift to resistance, that is, the rubber band as a resistance to complete the original action, load control in the completion of about 22 times that fatigue, 22 times per group, 2 to 4 groups per day, 45 seconds rest between groups. 3, to 3 weeks, flexion up to 90 degrees. 4.Full 4 weeks, wear external brace to lift leg straight to 30 degrees (individual can maintain without external brace), hold for 30 seconds for 1 time, 10 to 15 times per set, 2 to 4 sets per day. 5.Start active knee flexion exercises, sitting or lying down, the posterior thigh muscle force, so that the knee flexion to the maximum angle, hold 2 to 5 seconds for 1 time, 30 times per set, 2 sets of daily, straight by the healthy leg help or with the help of rubber band, the affected leg absolutely no force. 6. By 6 weeks, the flexion reaches 100 degrees. Third, the latter 6 to 12 weeks 1, eight weeks 120 degrees. 2.Strengthen the muscle strength exercises on the affected side. 3.Twelve weeks, flexion angle of the knee is the same as the healthy.