1. Immediately postoperative to 2 weeks postoperative: (1) Control swelling and infection (cold compresses and antibiotics). (2) Passive full extension of the knee immediately after surgery. (3) Gradually restore knee flexion (week 1 to 60°; week 2 to 90°). (4) Isometric contraction of the voluntary quadriceps. (5) Move the patella. (6) Wear a brace (in extension) when walking down to 1/2 weight. 2. 3-6 weeks postoperatively: (1) Control edema (cold compresses, topical fotarine cream). (2) Keep the knee joint straight and gradually restore the knee flexion function (week 3: 120°; week 4: 140°; week 5 160°). (3) Weight-bearing exercises and body posture training (sitting, standing and walking exercises in normal posture), starting from 1/2 weight to 2/3 weight at 4 weeks. (4) Closed chain training of the lower limbs on the operated side or both lower limbs, such as bicycle pedaling exercises. (5) Begin striding exercises at four weeks: the patient stands on the ground with both feet, the affected knee is bent 30 degrees and supported by the affected leg, the healthy leg strides forward, and then the healthy leg is retracted. This is repeated to practice the neuromuscular control ability and stability control of the affected limb. 3. 6-12 weeks after surgery: (1) Start normal weight-bearing. (2) muscle strength exercises (3) step exercises: prepare a small low stool, the patient stands on the low stool with both feet, bend the affected knee, while the healthy limb leaves the low stool from the side of the low stool to touch the ground, the healthy limb touches the ground and then regains standing on the low stool by straightening the healthy knee. This is repeated, mainly to practice the strength of the affected limb and to practice the control of the knee stability. If you want to increase the difficulty of the exercise, you can increase the height of the low stool.