I was prescribed Levaquin for a sinus infection in March 2009. (750 mg for 21 days). I took the medicine for 14 days and stopped when my knees, legs and feet felt like they were burning from the inside out. I am 38 years old and not overweight. It's 9 months later and I still have severe knee pain. My knees feel like a 90 yr old woman's knees. If I sit more than an hour at the computer for work, they lock and I can barely walk. This drug is a crime.