I'd get a second opinion. Most ER docs don't do that kind of stuff on a regular basis i would say, better to see someone who sees it almost every day.
I'd find a CCSP certified chiropractor, a DPT or orthopedist if you can.
Surgery probably isnt needed but rehab is needed for sure.
I dont know your mechanism of injury but i'd definitely get a second opinion cause you dont want it to be ACL etc.......