Knee arthritis is a common condition that occurs when the cartilage in the knee joint wears down over time. This can lead to pain, stiffness, and swelling, making it difficult to move the knee. There are different types of knee arthritis, with osteoarthritis and rheumatoid arthritis being the most prevalent. Symptoms of knee arthritis can vary from mild to severe and may include difficulty walking, bending, or climbing stairs. Treatment options often include physical therapy, medications, and in some cases, surgery. Maintaining a healthy weight and staying active can help manage symptoms and improve joint function.