In any knee disease, atrophy of the quadriceps (the muscle located in the front of the thigh) will occur first. The atrophy of this muscle will cause the knee joint to lose protection and become unstable, which can not only aggravate the symptoms but also be detrimental to the rehabilitation of the knee joint, so for most diseases of the knee joint, patients should be encouraged to do exercises for the quadriceps. The exercises strengthen the stability of the knee joint and improve local blood flow and metabolism, thus relieving pain, improving function and promoting recovery. The functional exercises for the knee shown below can be performed both when the knee is painful and when there is swelling and effusion. These exercises do not aggravate the symptoms, but rather relieve pain, reduce swelling and promote the absorption of effusion. Note: The knee joint should be kept in the straight position during exercise, and there should be no extension or flexion of the knee joint during lifting. There is no specific requirement for the position of the foot. When there is fluid or pain in the knee joint, it does not affect the exercise. Keeping the knee joint in the straight position at all times usually does not aggravate the pain. After fatigue of the affected limb, the same exercise can be done on the healthy side, especially in some patients with bilateral lesions, and walking and weight bearing should be minimized when there is effusion in the knee. (Fig. 1 Knee extension leg lift in sitting or lying position can be done, lifting 10 cm to do repeated exercises, the frequency can be accelerated after muscle strength is increased, and weights can be placed at the ankle to strengthen the exercise. Figure 2 Lateral knee extension in the lateral recumbent position to lift the leg repeatedly. Figure 3 Repeated squeezing of a leather ball held between both knees.) When suffering from osteoarthritis of the knee, daily life precautions include: do not wear high heels or sandals, wear low-heeled shoes and shoes with laces; try to avoid climbing hills and stairs, avoid walking on uneven roads, soft terrain and cobblestone roads; use bicycles for walking, and should raise the bicycle seat to reduce the stress on the patella when riding a bicycle; try to avoid climbing stairs, use the handrail of the stairs slowly when there is no elevator. When climbing stairs, the knee on the healthy side should start first, and then the leg on the affected side should go up; avoid walking with weight; avoid standing; when sitting, the knee joint should be slightly extended, and the position should be constantly changed, and the knee joint should not be flexed under the chair.