Hi Mickster. There's another thread on this (if you can't find it look in my post history) - several of us on there have had the op and are asking the same question as you. I've had the arthroscopy for cam impingement and labral tear on my left side (Dec. 2011) but can't really assess the difference it has made as the other hip is now bad as well. I've had the MRA for that and am waiting to hear about the next surgery (hopefully). I'm hopeful about a return to running, though, even if it's not as competitive as before.
How long have you been affected? Can you run at all at the minute? Looking forward to hearing your story. You're welcome to join us on the other thread as well!