I have undergone many MRI and xray to no avail.
All docs say no to surgery to clean out the crunchies and have prescribed drug after drug.
I too have no pain during the day but ache like hell at night and when seated for long durations. I am currently trying synvisc injections prior to scoping the knee to suck out the crunchies. You have Crepitus or Chondra Malasia or both.