Risk factors

• Age. Your likelihood of developing a swollen knee related to arthritis increases as you age.
• Sports. People who participate in sports that involve twisting the knee, such as basketball, are more likely to experience the types of knee injuries that cause swelling.
• Obesity. Excess weight puts added stress on the knee joint, contributing to the tissue and joint overload and knee degeneration that can lead to a swollen knee. Obesity increases your risk of osteoarthritis, one of the more frequent causes of knee swelling.