Johannes, it all depends on a lot of things I'm afraid.
Building distance depends how much you are already doing and what pain you have. If you're already running 10km or more, adding 1km once per week might be ok if it isn't painful. If you're only running 2-3km adding 1km might be too much, especially if you're getting pain. I find the best way to return after long term injury is to start by setting a baseline - find how far you can run at a slow comfortable pace without pain. Make note of distance and time. This is your baseline, I often get people to start by running at 10% below this for a week or 2 then gradually build up by around 10% per week. E.g. If your baseline is 1km start at 900m then 990 next week 1090 the next and so on. It will take time to reach your target but it avoids constant setbacks. After a few weeks you can also review your baseline and maybe make bigger gains in distance.
Hope this all makes sense, more info on my site about it here;
http://www.running-physio.com/returnafterinjury/
In terms of risk of stress fracture that depends on you - do you have any history of stress fracture? Have you had an X-ray or MRI of your shin?
The shin is a very complex area - there are around 30 potential diagnoses of shin pain and shin splints is often misdiagnosed. I started writing a piece on shin pain and ended up having to write a 3 parter as it was so complicated! Here is the first part which should be helpful;
http://www.running-physio.com/shinpain/
Hope that's useful
Tom
