There is no such thing as the fastest cure for weak and achy knees. It may be caused by physiological factors such as overactivity, or pathologic factors such as chondromalacia patellae and meniscus injury, etc. Depending on the cause of the disease, the condition can be improved through general treatment, medication, surgery, and so on. 1. Physiological factors: due to excessive activity can cause fatigue of the soft tissues around the knee joint, leading to the phenomenon of knee weakness, patients should pay more attention to rest, reduce activities, can also be hot compresses, no special treatment, can gradually ease the symptoms. 2. Chondromalacia patella: patients should avoid strenuous exercise such as excessive knee bending, going up and down stairs, squatting, etc., can follow the doctor’s instructions to take non-steroidal anti-inflammatory drugs such as ibuprofen, aspirin, etc., as well as dextrose and other medications for treatment, the effect of conservative treatment is not good, but also the choice of surgical treatment. 3. Meniscus injury: when the meniscus is acutely injured, plaster or brace can be used for fixation and braking, and those with serious injuries should choose surgical treatment, such as total meniscectomy, meniscus repair, allograft meniscus transplantation and so on. Knee weakness may also be caused by other reasons, it is recommended that the patient actively seek medical attention to clarify the cause of the targeted treatment, daily should also avoid excessive exertion, pay attention to cold and warmth, so as not to aggravate the symptoms of knee discomfort.