A 65-year-old woman suffered from severe osteoarthritis in her right knee, with recurring flare-ups for many years. Recently, after being exposed to cold, her knee experienced another bout of intense pain. She applied a hot compress for half an hour, which only worsened the pain and swelling. Her family rushed her to the hospital, where a joint aspiration revealed that the fluid was bloody. It turned out that the woman's arthritis was in an acute phase; the synovium inside was congested and fragile, and the hot compress caused small blood vessels to rupture, leading to persistent bleeding.
In daily life, many people's first thought for sudden pain from knee osteoarthritis is to apply heat, believing it will improve blood circulation. However, this is actually not very effective and can sometimes worsen the condition. During the acute inflammatory phase, the main symptoms are redness, swelling, and pain. Local blood vessels dilate, and inflammatory and pain-causing factors leak into the tissues. This situation is like a small fire; it should be extinguished, not heated.
Cold and hot compresses are opposites. Cold causes blood vessels to constrict and slows blood flow to muscles. Prolonged cold compresses can stop bleeding, eliminate synovial inflammation, and promote the recovery and reconstruction of collagen tissue in cartilage and tendons, but sometimes they can also cause muscle spasms. Hot compresses cause blood vessels to dilate and muscle synovial tissue to become congested, which can relieve muscle spasms, but can aggravate inflammation and bleeding, especially in the acute inflammatory phase of arthritis, where excessive heat can worsen the inflammation.
Therefore, it can be seen that the vast majority of acute injuries and at least half of chronic strains can be treated with cold compresses; for some chronic pain, hot compresses on areas with abundant muscle are quite effective, including hot water, heat therapy, wax therapy, and traditional Chinese medicine fumigation. When done at the right time, these methods can significantly improve local blood circulation, facilitate the excretion of inflammatory factors, and achieve good results.
Whether or not to apply heat can be determined by following a principle: if the joint is more swollen than usual, slightly warmer, and more painful, it may indicate an flare-up of osteoarthritis. If it is unclear whether to apply cold or hot compresses, it is best to do nothing, rest, and then seek treatment from a doctor.
