Knee pain after routine tests (such as knee X-ray, magnetic resonance, rheumatoid, etc.), can not be detected, usually may be caused by a cold knee. Symptoms can be relieved through rest, physical therapy and medication. 1. Rest: You should pay attention to rest and limit the activities of the knee joint to avoid aggravating the condition. At the same time, pay attention to the warmth of the knee joint to avoid getting cold. 2. Physiotherapy: Infrared therapy, low-frequency electrotherapy, medium-frequency electrotherapy and other physiotherapeutic methods can be adopted, which is conducive to the promotion of blood circulation and improvement of pain symptoms. 3. Medication: If the pain symptoms are serious, non-steroidal anti-inflammatory drugs such as ibuprofen, diclofenac sodium and celecoxib can be taken orally to relieve the pain symptoms. It is recommended to use medication under the guidance of a doctor, not blindly self-medication to avoid adverse effects.