Starsnuffer's point cannot be overstated. See a specialist. Not a chiropractor, not a general practice doc, not an ER doc. My DH was "lucky" enough to tear his ACL while in college - he was treated by one of the absolute best surgeons (associated with the University) in the business, followed up with physical therapy at a college known for its sports medicine program - his knee is still holding up to sports of all kinds 20 years later.