Phase I (0-2 weeks postoperative) Objective: to reduce pain and eliminate swelling 1-3 days postoperative 1. ankle pump Action: ankle dorsiflexion (i.e. toe up), hold for 5 seconds, relax, ankle plantarflexion (toe down) Action: to promote lower limb circulation, eliminate swelling and prevent lower limb venous thrombosis. 2, active quadriceps static contraction Action: tighten the quadriceps, lift the patella to the head side to the maximum extent, hold for 5 seconds, relax. Effects: Promote lower limb circulation and prevent muscle atrophy. 3.Place the knee joint in extension position and elevate the whole lower limb Effects: Promote circulation in the lower limb, eliminate swelling, and avoid restriction of passive extension of the knee joint. 4.Straight leg raise Action: Tighten the quadriceps muscle in front of the thigh, while the ankle joint is plantar flexed, tighten the muscles of the posterior group of the calf, lift the knee 10-15 cm from the bed, hold it for 5-10 seconds, put it down, when the knee joint has pain or obvious weakness, it can be done passively or with the help of others. Effects: Promote lower limb circulation and prevent muscle atrophy. 5.Intermittent compression cold therapy for 15-20 minutes each time, once every 1-2 hours at intervals, 4-6 times a day