It has been over six weeks since the injury happened so I decided to slowly start running again.
I ran 2.5 miles last night on pavement, very slow run (10min/mile) and it felt good.
I still feel the spot on fibula when striking forefoot but midfoot strike is fine.
My next run (planning in two days) is going to be on a trail.
It feels so great to be able to run again !
I am still puzzled by what actually caused the injury. In my last month of running I was not increasing my mileage and my speed was the same. I was just comfortably doing 15-20 trail miles a week running every other day and felt great and relaxed.
It probably was not the transition back to pavement. The only thing I can think of is not taking my usual one day off between runs.
A side note about my partial tarsal coalition
As long as I can remember (from my twenties) my right ankle has been always clicking when walking. Step-click, step-click. It was not causing me any problems and I got used to it.
Some 3 years ago (still in shoes) I started jogging, doing 1-2 miles in the morning. My right ankle always got a little swollen but I did not mind because there was never any pain or discomfort and it always went away in a day. I only lasted 2 months anyway and than quit running for a while.
In June 2010 I started BFR. Taking it really slowly. Right ankle - the swelling is back. Again, no pain, no discomfort, just clicking. And it's gone in a day.
My wife convinces me to see a podiatrist just to "make sure". I get x-rays done and the doctor tells me I have a Partial Tarsal Coalition (condition in which 2 bones in the hind-foot are partially joined) in my both ankles. He is a BFR advocate so he encourages me to keep running barefoot with the idea the natural way of running will make things stronger and eventually fix the fused bones.
And as far as I can tell it has worked. In the following 5 months of running strictly barefoot after the diagnosis my ankles got stronger and there was no swelling anymore. Just the occasional clicking.
I strongly believe that will disappear too given more time.