Osteoarthritis of the knee: Osteoarthritis of the knee is a common disease that causes degeneration, thinning, peeling and detachment of the articular cartilage, resulting in degenerative changes in the entire joint, resulting in pain, swelling, squatting and difficulty walking. The disease is common in middle-aged and elderly people, and is triggered by obesity, knee deformity and overexertion of the knee joint.