A 26 year old woman visits her physician with a complaint of discomfort in her left knee for 2 weeks. It is exaggerated when she is sitting for a long time and relieved with analgesics. She admits that she had this discomfort on and off since she was at high school. On examination, the left knee doesn’t show any signs of inflammation. It shows induration and tenderness on the back of the knee. X-ray shows local opacity on the back of the left knee joint. What is the most likely diagnosis? A- Acute arthritis B- Hydrarthrosis C- Baker cyst D- Tear of posterior collateral ligament E- Osteoarthritis Answer: http://medical-usmle.com/?p=7708
