The possible reasons for the cool feeling in the knee include osteoarthritis, lumbar spine lesions, and localized cold joints. 1. Osteoarthritis: the cause of osteoarthritis is not yet completely clear, may be related to heredity, inflammation, obesity, age and other factors, when there is a cold, weather changes, the knee joints may appear to be sore, cold and other abnormal sensations, but also may be accompanied by joint stiffness, swelling and so on. 2. Lumbar spine lesions: If the patient has lumbar disc herniation, spinal stenosis and other diseases, it may stimulate the nerves of the intervertebral discs, leading to sensory abnormalities in the lower limbs, and thus the symptoms of cold knee joints may appear. 3. Cold knees: If you do not pay attention to the warmth of the knee joints, the surrounding temperature is too low, which can cause the knee joints to be cold, and may also be accompanied by the symptoms of limited joint movement. If you have a cold feeling in your knees, it is recommended that you go to a regular hospital in time to find out the cause of the coldness and treat it actively.