The most common form of knee pain in the elderly is synovitis or osteoarthritis of the knee joint that occurs after a long period of strain. Synovitis is an aseptic inflammatory disease that occurs when the synovial membrane of the knee fails to produce and absorb fluid properly, resulting in fluid accumulation and pain in the knee joint. Osteoarthritis of the knee is a chronic arthritic disease characterized by degeneration and degeneration of the articular cartilage, as well as bone growth at the joint edges and subchondral bone. The origin of the disease is in the articular cartilage. The normal knee joint has a total of six degrees of freedom of motion in all directions, which are normally controlled by the ligaments, joint capsule, bony match, meniscus, and associated neuromuscles. Any injury to one of these tissues and loss of kinetic action will result in abnormal stresses in the knee joint, which can lead to osteoarthritis. Prolonged immobilization of the knee joint is also a joint stress abnormality that can lead to loss of nutrition and degeneration of the cartilage, shortening of the ligaments and osteoarthritis. Elderly people with knee pain should first reduce joint weight-bearing, improve local circulation in the knee joint, increase knee stability, and strengthen functional exercise of the quadriceps muscle. Massage, acupuncture, and physical therapy can also be used. In severe cases, drug injections can also be used.