Osteoarthritis often presents with swelling, most commonly seen in knee osteoarthritis. The swelling occurs because of inflammation. For example, if knee arthritis is accompanied by synovitis, it will become swollen and the local temperature will be relatively high. To reduce swelling, the first measure is immobilization, meaning you should avoid bearing weight or moving, and lie in bed without bending the joint, which can help decrease the swelling. Second, you can apply heat, using a hot water bottle or heated salt for heat therapy. Third, if there is fluid accumulation in the joint cavity, draining this fluid can also reduce swelling. Fourth, physical therapy, acupuncture, and massage can all help reduce swelling.