Knee pain refers to discomfort or aching in or around the knee joint — one of the largest and most complex joints in the body. It can affect anyone at any age, but becomes more common as we get older or after injury. Knee pain can significantly limit everyday activities like walking, climbing stairs, or standing.
Shoulder pain refers to discomfort in or around the shoulder joint — an intricately structured area that supports a wide range of movement including lifting, reaching, and rotation. Because the shoulder has the greatest range of motion of any joint in the body, it is also prone to injury and overuse.
Arthritis is a form of joint disorder that involves inflammation of one or more joints. The most common form of arthritis is osteoarthritis (OA), also known as degenerative joint disease. Over time, this inflammation causes wear and tear of the cartilage in your joints, causing pain and decreased mobility. Some other forms of arthritis include rheumatoid arthritis, psoriatic arthritis, and related autoimmune diseases.