Pes anserine bursitis is a painful knee condition that occurs most commonly in young people involved in sports, middle-aged women who are obese, and people aged 50-80 who have osteoarthritis of the knee.The pes anserine bursa is a small, fluid-filled sac located 2–3 inches below the inner side of the knee. It lies beneath 3 tendons of the hamstring muscle, and it prevents the tendons from rubbing on the shinbone of the lower leg. Bursitis occurs when the bursa has become irritated and inflamed, and this condition is usually painful. Pain and swelling are usually felt on the inner lower side of the knee. Pain may also be experienced when bending or straightening the knee. This pain usually leads to difficulty walking, sitting down, rising from a chair, or climbing stairs. Certain positions, motions, or disease processes can cause constant friction or stress on the bursa, leading to the development of bursitis. Physical therapy will help you return to your normal lifestyle and activities. The time it takes to heal the condition varies, but results can be achieved in 6 to 8 weeks or less when a proper stretching and strengthening program is implemented.