Osteoarthritis is the most commonly diagnosed joint disease and often affects the knee joint. Knee arthritis can cause knee joint pain, stiffness and swelling. Knee arthritis is staged according to severity of joint damage (observed on knee x-ray and other joint imaging studies). When the knee shows no signs of osteoarthritis, it is classified as Stage 0 meaning the knee is normal with no known impairment or signs of joint damage. Stage 1 osteoarthritis patients develop minor wear & tear and early development of bone spur growths (or osteophytes) at the end of the bones of the knee joint. Stage 1 arthritis is unlikely to cause significant knee pain or stiffness. In Stage 2 knee arthritis, diagnostic images including X-rays show more bone spur growth. Even though the knee joint space between the bones appears normal, pateints often begin experiencing symptoms of joint pain and stiffness, especially when sitting for an extended period, immediately after rising in the morning, or after a workout. At this stage, there is breakdown of the cartilage layer from an increased production of enzymes and inflammatory mediators. Stage 3 arthritis is referred to as “moderate” and is characterized by obvious erosion of the cartilage surface between bones with narrowing of the knee joint space. Proteoglycan and collagen fragments secreted into the synovial fluid triggers progressive bone spur development as the joint articular surfaces become rougher. With the progression of osteoarthritis of the knee, there is obvious joint inflammation which causes frequent pain when walking, running, squatting, extending or kneeling. Along with joint stiffness after sitting for long or when waking up in the morning, there may be popping or snapping sounds when walking. Stage 4 arthritis is considered severe. The knee joint space is considerably reduced, causing the cartilage to wear off and leading to increased joint stiffness. Cartilage breakdown triggers a chronic inflammatory response, with decreased synovial fluid, increased friction, and increasing pain and discomfort especially when walking or other joint movement. - @corycalendinemd