Stages of Knee Osteoarthritis

Cartilage is a slippery tissue that provides a smooth surface for joint motion and acts as a cushion between the bones. Synovium is soft, and it lines the joints. It produces fluid, called synovial fluid, for lubrication, and it supplies nutrients and oxygen to the cartilage. As these functions break down, they no longer protect the bones of the knee joint, and bone damage occurs. OA of the knee can cause pain and stiffness. The symptoms worsen over time