Dill.
It does indeed sound familiar, I twinged my MCL on the Brecons 40 but thought it was ok after a few weeks rest, then I started to get a dull pain in what I can only describe as the hinge part of the outside of my knee just below the actual bone, it started about six miles into a fairly hilly run when I first got it, starts off just above the hinge then settles into a 5-6 scale pain with occasional bursts up to 7-8. It doesn't come on at any other time, there's no pain on cycling, swimming or even cross training, no pain on lunges or stair climbing and there's no pain or discomfort on lateral or medial movement of the actual knee joint.
As you've described the pain stops when I do but comes on again almost immeadiately upon running. I've been absolutely beasted by my sports masseuse, who I have a great deal of faith in, as well as my physio but it hasn't shown any improvement whatsoever, I went for a short run last night and again this morning which had to be curtailed as it was starting to affect my gait and I didn't want to bring any other complications into it.
My physio seems to think it's a tightness in the distal part of the ITB where it runs below the joint and joins up to the bone under the knee but despite all the treatment so far I haven't seen any improvement which I would expect if it was just tightness?
Dave.
I'm also seeing an osteo who's said pretty much what you've said in your post above, I've done some mobilisation exercises for my ankle but we're concentrating mostly on my hip capsule, adductors and piriformis, again thus far without success.
At the moment it's snafu, though I am considering amputation if things don't improve 