Orthopaedic injuries and degenerative conditions are the most common cause of severe long-term pain and disability. The majority of injuries do not heal well with conservative management, and frequently require surgery. Treatment of degenerative arthritis is primarily symptomatic and may eventually require joint replacement.
We don’t really know why arthritis causes knee pain. Some factors are inflammation due to wear and tear on knee cartilage, abnormal joint stress that puts pressure on the knee joint, ligaments and other soft tissue, and mechanical stress that causes bone pain. Reducing and repositioning the bone reduces stress, inflammation, and joint pain.
Traumatic sports injuries, repetitive use injuries, and traumatic auto and fall injuries, often cause cartilage damage, and lead to chronic pain and disability. With age, the cartilage on the ends of the bones, called articular cartilage, degenerates and is subject to Osteoarthritis.