The major factors that affect the length of time venison will hold frozen is:
            1) The condition of the meat when it was frozen.
            2) If it is muscle meat or ground meat.
            3) How it is wrapped.
            4) Freezer temperatures and quality of the freezer.
    Getting the deer to a processor right away is great if the processor also took care of it in a timely fashion. The problem is that many processors take all the deer that they can get, and end up holding them longer  that they should in order to make the extra money. This can result in bacterial growth on the venison which reduces the quality and causes spoilage to accelerate when it is thawed out.
    Grinding meat creates more surface area which increases the dehydration process while it is frozen.
    If the venison is double wrapped and the outside wrap is freezer paper it will hold up significantly longer than single wrapped, freezer bagged, and even vacuum packed.
    I believe most home economists would tell you that ground venison should only be frozen for 6-12 months, to maintain maximum quality. Ruth and I have actually used some of our own properly handled double wrapped ground venison that was three years old with no ill affect. While this is pushing the limit in our opinion, it was still usable.
    On the other side, we have reprocessed ground venison that customers have brought in the was only 6-9 months old and it was already starting to freezer burn because it was single wrapped.
    In our business we still encourage our customers to use the one year rule and they will have absolutely no problems.

    I personally have never heard of anyone getting sick from eating old venison, but I'm sure that there have been a lot of people that didn't enjoy the experience do to the quality issues. I would recommend making a plain hamburger out of it and see how it tastes, if it's ok that way it would be good in all burger dishes.

    Good Luck,
Dave